The neurological system operates via electric and electromagnetic signals. Does it not make sense to address neurological disease states from an electrophysiological rather than pharmaceutical-chemical based point of view?
Research points to conclusion that Alzheimer's disease and other neurological / physiological disease states are related by electrophysiological abnormality.
Electrophysiological abnormality exists in;
epilepsy, Parkinson's, migraine, cluster and other headache syndromes, severe PMS, attention deficit disorder ADD, attention deficit hyperactivity disorder ADHD, depression, schizophrenia, anxiety, insomnia and sleeping disorders in general, muscle twitch, tremor disorders, muscle weakness and (local) electrophysiologic abnormality at site of chronic wounds, bone non-unions and endometriosis.Several hundred pulsed electromagnetic field therapy citations contained in our research bibliographies are linked directly to PubMed a service of the U.S. National Library of Medicine and the U.S. National Institutes of Health.
1: Ann Neural. 2003 Jun;53(6):824; author reply 824-5. Related Articles, Links
Comment on:
* Ann Neurol. 2003 Jan;53(1):102-8.
Motor cortex hyperexcitability to transcranial magnetic
stimulation in Alzheimer's disease: evidence of impaired glutamatergic
neurotransmission?
Di Lazzaro V, Oliviero A, Pilato F, Saturno E, Dileone M, Tonali PA.
Publication Types:
* Comment
* Letter
PMID: 12783435 [PubMed - indexed for MEDLINE]
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2: Neuropsychologia. 2003;41(8):952-67. Related Articles, Links
Spelling via semantics and phonology: exploring the effects
of age, Alzheimer's disease, and primary semantic impairment.
Cortese MJ, Balota DA, Sergent-Marshall SD, Buckner RL.
Department of Psychology, Morehead State University, 601 Ginger Hall,
Morehead, KY 40351, USA.
Spelling performance across a common set of stimuli was examined in
young adults, healthy older adults, individuals with early stage
dementia of the Alzheimer's type (DAT), and four individuals with a
primary semantic impairment (PSI). The stimuli included homophones and
low-frequency sound-to-spelling consistent (i.e. words with more
predictable spellings) and inconsistent words (i.e. words with less
predictable spellings). The results indicate that when spelling
homophonic words (spelling/pleIn/ as plane versus plain), younger
adults and to a greater extent individuals with PSI placed relatively
more emphasis on phonological information (i.e. spell the word based on
sound-to-spelling principles) whereas healthy older adults and
individuals with DAT placed relatively more emphasis on semantic
information (i.e. spell the word based on the dominant usage). For
non-homophonic words, large consistency effects (spelling plaid as
plad) were observed for both individuals with DAT and individuals with
PSI. It is proposed that the decrease in accuracy for inconsistent
words has different bases in DAT and PSI. We propose that deficits in
attentional control (i.e. selection) underlie performance in DAT
whereas disruption of semantic representations underlies performance in
PSI.
PMID: 12667531 [PubMed - indexed for MEDLINE]
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3: Hippocampus. 2003;13(1):67-80. Related Articles, Links
Encoding of novel picture pairs activates the perirhinal
cortex: an fMRI study.
Pihlajamaki M, Tanila H, Hanninen T, Kononen M, Mikkonen M, Jalkanen V,
Partanen K, Aronen HJ, Soininen H.
Department of Neuroscience and Neurology, University of Kuopio, Kuopio,
Finland.
It is well established in nonhuman primates that the medial temporal
lobe (MTL) structures, the hippocampus and the entorhinal and
perirhinal cortices, are necessary for declarative memory encoding. In
humans, the neuropathological and neuropsychological changes in early
Alzheimer's disease (AD) further support a role for the rhinal cortex
in the consolidation of new events into long-term memory. Little is
known, however, regarding the function of the rhinal cortex in humans
in vivo. To examine the participation of the interconnected MTL
structures as well as the whole-brain network of activated brain areas
in visual associative long-term memory, functional magnetic resonance
imaging (fMRI) was used to determine the brain regions that are
activated during encoding and retrieval of paired pictures in 12 young
control subjects. The most striking finding in the MTL activation
pattern was the consistent activation of the perirhinal cortex in the
encoding-baseline and encoding-retrieval comparisons with a strict
statistical threshold (P < 0.00001). In contrast, no perirhinal
cortex activation was detected in the retrieval-baseline or
retrieval-encoding comparisons even with a low statistical threshold (P
< 0.05). The location of the perirhinal activation area was in the
transentorhinal part of the perirhinal cortex, in the medial bank of
the collateral sulcus. The hippocampus and the more posterior
parahippocampal gyrus were activated in both encoding and retrieval
conditions. During the encoding processing, MTL activations were more
consistent and the hippocampal activation area located more anteriorly
than during retrieval. The frontal, parietal, temporal, and occipital
association cortices were also activated in the encoding-baseline and
retrieval-baseline comparisons. The data suggest that encoding, but not
retrieval, of novel picture pairs activates the perirhinal cortex. To
our knowledge, this is the first fMRI study reporting encoding
activation in this transentorhinal part of the perirhinal cortex, the
site of the very earliest neuropathological changes in AD.
PMID: 12625459 [PubMed - indexed for MEDLINE]
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4: Methods Find Exp Clin Pharmacol. 2002;24 Suppl D:17-20. Related Articles, Links
Simultaneous ERP and event-related fMRI: focus on the time
course of brain activity in target detection.
Mulert C, Jager L, Pogarell O, Bussfeld P, Schmitt R, Juckel G, Hegerl
U.
Laboratory for Clinical Neurophysiology, Department of Psychiatry, LMU,
Munich, Germany.
The event-related P300 potential has been widely used in
neurophysiological research. It is usually evoked with an oddball
paradigm. One main reason for its broad application in
neurophysiological research is the fact that in several brain/mental
diseases, such as Alzheimer's disease or schizophrenia, attenuations of
the P300 amplitude and latency have been described. However, a precise
correlation of the scalp data to the underlying brain regions was not
possible, as the correct localization of the generators of
scalp-measured electroencephalogram (EEG) data was limited, due to the
low spatial resolution of EEG-data. With the availability of modern
imaging technologies, functional Magnetic Resonance Imaging (fMRI) in
particular, the underlying brain activations could be detected using an
oddball task. Although the spatial resolution of fMRI is excellent, the
time resolution is restricted. For a comprehensive understanding of the
brain activity underlying the P300 paradigm, we have used a combination
of EEG and fMRI to get a precise localization and a high-time
resolution of the underlying brain activity.
PMID: 12575464 [PubMed - indexed for MEDLINE]
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5: Ann Neurol. 2003 Jan;53(1):102-8. Related Articles, Links
Motor cortex excitability in Alzheimer's disease: A
transcranial magnetic stimulation study.
Ferreri F, Pauri F, Pasqualetti P, Fini R, Dal Forno G, Rossini PM.
Department of Neurology, University Campus Biomedico.
Motor deficits affect patients with Alzheimer's disease only at later
stages. Recent studies demonstrate that the primary motor cortex is
affected by neuronal degeneration accompanied by the formation of
amyloid plaques and neurofibrillary tangles. It is conceivable that
neuronal loss is compensated by reorganization of the neural
circuitries occurring along the natural course of the disease, thereby
maintaining motor performances in daily living. Cortical motor output
to upper limbs was tested via motor-evoked potentials from forearm and
hand muscles elicited by transcranial magnetic stimulation of motor
cortex in 16 patients with mild Alzheimer's disease without motor
deficits. Motor cortex excitability was increased, and the center of
gravity of motor cortical output, as represented by excitable scalp
sites, showed a frontal and medial shift, without correlated changes in
the site of maximal excitability (hot-spot). This may indicate
functional reorganization, possibly after the neuronal loss in motor
areas. Hyperexcitability might be caused by a dysregulation of the
intracortical GABAergic inhibitory circuitries and selective alteration
of glutamatergic neurotransmission. Such findings suggest that motor
cortex hyperexcitability and reorganization allows prolonged
preservation of motor function during the clinical course of
Alzheimer's disease.
PMID: 12509853 [PubMed - in process]
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6: Brain Res Cogn Brain Res. 2002 Nov;14(3):347-56. Related Articles, Links
Functional magnetic resonance imaging of brain activity in
the visual oddball task.
Ardekani BA, Choi SJ, Hossein-Zadeh GA, Porjesz B, Tanabe JL, Lim KO,
Bilder R, Helpern JA, Begleiter H.
Center for Advanced Brain Imaging, Nathan Kline Institute for
Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962,
USA.
Abnormalities in the P300 ERP, elicited by the oddball task and
measured using EEG, have been found in a number of central nervous
system disorders including schizophrenia, Alzheimer's disease, and
alcohol dependence. While electrophysiological studies provide high
temporal resolution, localizing the P300 deficit has been particularly
difficult because the measurements are collected from the scalp.
Knowing which brain regions are involved in this process would
elucidate the behavioral correlates of P300. The aim of this study was
to determine the brain regions involved in a visual oddball task using
fMRI. In this study, functional and high-resolution anatomical MR
images were collected from seven normal volunteers. The data were
analyzed using a randomization-based statistical method that accounts
for multiple comparisons, requires no assumptions about the noise
structure of the data, and does not require spatial or temporal
smoothing. Activations were detected (P<0.01) bilaterally in the
supramarginal gyrus (SMG; BA 40), superior parietal lobule (BA 7), the
posterior cingulate gyrus, thalamus, inferior occipitotemporal cortex
(BA 19/37), insula, dorsolateral prefrontal cortex (BA 9), anterior
cingulate cortex (ACC), medial frontal gyrus (BA 6), premotor area, and
cuneus (BA 17). Our results are consistent with previous studies that
have observed activation in ACC and SMG. Activation of thalamus,
insula, and the occipitotemporal cortex has been reported less
consistently. The present study lends further support to the
involvement of these structures in visual target detection.
PMID: 12421658 [PubMed - indexed for MEDLINE]
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7: Neuroimage. 2002 Nov;17(3):1403-14. Related Articles, Links
Functional imaging of visuospatial processing in Alzheimer's
disease.
Prvulovic D, Hubl D, Sack AT, Melillo L, Maurer K, Frolich L,
Lanfermann H, Zanella FE, Goebel R, Linden DE, Dierks T.
Department of Psychiatry, University of Frankfurt, Frankfurt, Germany.
Alzheimer's disease (AD) is known to cause a variety of disturbances of
higher visual functions that are closely related to the
neuropathological changes. Visual association areas are more affected
than primary visual cortex. Additionally, there is evidence from
neuropsychological and imaging studies during rest or passive visual
stimulation that the occipitotemporal pathway is less affected than the
parietal pathway. Our goal was to investigate functional activation
patterns during active visuospatial processing in AD patients and the
impact of local cerebral atrophy on the strength of functional
activation. Fourteen AD patients and fourteen age-matched controls were
measured with functional magnetic resonance imaging (fMRI) while they
performed an angle discrimination task. Both groups revealed
overlapping networks engaged in angle discrimination including the
superior parietal lobule (SPL), frontal and occipitotemporal (OTC)
cortical regions, primary visual cortex, basal ganglia, and thalamus.
The most pronounced differences between the two groups were found in
the SPL (more activity in controls) and OTC (more activity in
patients). The differences in functional activation between the AD
patients and controls were partly explained by the differences in
individual SPL atrophy. These results indicate that parietal
dysfunction in mild to moderate AD is compensated by recruitment of the
ventral visual pathway. We furthermore suggest that local cerebral
atrophy should be considered as a covariate in functional imaging
studies of neurodegenerative disorders.
PMID: 12414280 [PubMed - indexed for MEDLINE]
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8: Hum Brain Mapp. 2002 Dec;17(4):230-6. Related Articles, Links
Novelty detection and repetition suppression in a passive
picture viewing task: a possible approach for the evaluation of
neuropsychiatric disorders.
Jessen F, Manka C, Scheef L, Granath DO, Schild HH, Heun R.
Department of Psychiatry, University of Bonn, Bonn, Germany.
The applicability of functional magnetic resonance imaging (fMRI) in
patients with Alzheimer's disease (AD) or schizophrenia is frequently
limited by cognitive impairment, which prevents the adequate execution
of complex tasks. An experimental design that puts only minor demands
on the patients' cognitive ability but engages disease-relevant brain
structures would be of benefit. Novelty detection and repetition
suppression are two basic components of memory that might be used to
investigate specific brain areas under these conditions. Novelty
detection has been related to hippocampal activation increases.
Stimulus repetition related activation decreases (suppression) have
been observed in the extrastriate cortex and have been related to
perceptual priming. Both processes have been examined primarily in
neuroimaging studies with complex cognitive tasks. We used
event-related fMRI to investigate novelty- and repetition-related
effects in an attended but passive picture-viewing task in healthy
subjects. The differential activation, detected in the novel vs.
repeated contrast, was located in the bilateral anterior hippocampus
and in bilateral occipital and inferior-temporal areas. The hippocampal
activation is of interest because medial temporal lobe lesions are key
features in AD and schizophrenia. The repetition-related activation
decreases in the extrastriate areas are of potential value in
investigating the conflicting results regarding perceptual priming
impairment in both disorders. Our results indicate that activation of
disease-relevant brain regions under passive task conditions is
possible. This might increase the utility of functional imaging in
cognitively impaired patients. Copyright 2002 Wiley-Liss, Inc.
PMID: 12395390 [PubMed - indexed for MEDLINE]
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9: Neurosci Lett. 2002 Sep 6;329(3):293-6. Related Articles, Links
Motor cortex excitability in Alzheimer disease: one year
follow-up study.
Pennisi G, Alagona G, Ferri R, Greco S, Santonocito D, Pappalardo A,
Bella R.
Department of Neurological Sciences, University of Catania, Azienda
Policlinico dell' Universita, Via S. Sofia, 78, 95123 Catania, Italy.
Seventeen patients affected by Alzheimer disease (AD) underwent two
transcranial magnetic stimulation (TMS) studies separated by an
interval of 12 months, in order to monitor possible changes in motor
cortex excitability. After the first examination, all patients were
treated with cholinesterase inhibitor drugs. Motor threshold (MT),
amplitude of motor evoked potentials and central motor conduction time
were considered. After one year, the mean MT values showed a decrease
significantly correlated with the severity of cognitive involvement,
evaluated by means of the Mini Mental State Examination (MMSE). The
difference in MT between the two recording sessions showed no
significant correlation with the difference in MMSE score. One year of
treatment with cholinesterase inhibitor drugs did not stop the
progressive increase in motor cortex excitability. Serial analysis of
TMS might represent a method to monitor the rate of change in motor
cortex excitability in patients with AD.
PMID: 12183034 [PubMed - indexed for MEDLINE]
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10: Neurology. 2002 Aug 13;59(3):392-7. Related Articles, Links
Noninvasive in vivo assessment of cholinergic cortical
circuits in AD using transcranial magnetic stimulation.
Di Lazzaro V, Oliviero A, Tonali PA, Marra C, Daniele A, Profice P,
Saturno E, Pilato F, Masullo C, Rothwell JC.
Institute of Neurology, Catholic University, Largo A. Gemelli 8, 00168
Rome, Italy.
BACKGROUND: A recently devised test of motor cortex excitability (short
latency afferent inhibition) was shown to be sensitive to the blockade
of muscarinic acetylcholine receptors in healthy subjects. The authors
used this test to assess cholinergic transmission in the motor cortex
of patients with AD. METHODS: The authors evaluated short latency
afferent inhibition in 15 patients with AD and compared the data with
those of 12 age-matched healthy controls. RESULTS: Afferent inhibition
was reduced in the patients (mean responses +/- SD reduced to 85.7% +/-
15.8% of the test size) compared with controls (mean responses +/- SD
reduced to 45.3% +/- 16.2% of the test size; p < 0.001, unpaired
t-test). Administration of a single oral dose of rivastigmine improved
afferent inhibition in a subgroup of six patients. CONCLUSIONS: The
findings suggest that this method can be used as a noninvasive test of
cholinergic pathways in AD. Future studies are required to evaluate
whether short latency afferent inhibition measurements have any
consistent clinical correlates.
PMID: 12177373 [PubMed - indexed for MEDLINE]
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11: J Neurosci. 2002 Aug 15;22(16):7218-24. Related Articles, Links
Compromised hemodynamic response in amyloid precursor protein
transgenic mice.
Mueggler T, Sturchler-Pierrat C, Baumann D, Rausch M, Staufenbiel M,
Rudin M.
Central Technologies, Novartis Pharma, AG, CH-4002 Basel, Switzerland.
APP23 transgenic mice overexpressing amyloid precursor protein (APP751)
reproduce neuropathological changes associated with Alzheimer's disease
such as high levels of amyloid plaques, cerebral amyloid angiopathy,
and associated vascular pathologies. Functional magnetic resonance
imaging (fMRI) was applied to characterize brain functionality in these
mice through global pharmacological stimulation. The cerebral
hemodynamic response to infusion of the GABA(A) antagonist bicuculline
was significantly reduced in aged APP23 mice compared with age-matched
wild-type littermates. This is in part attributable to a compromised
cerebrovascular reactivity, as revealed by the reduced responsiveness
to vasodilatory stimulation by acetazolamide. The study shows that fMRI
is a sensitive tool to phenotype genetically engineered animals
modeling neuropathologies.
PMID: 12177216 [PubMed - indexed for MEDLINE]
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12: Ann Neurol. 2002 Apr;51(4):491-8. Related Articles, Links
Subjective memory complaints: objective neural markers in
patients with Alzheimer's disease and major depressive disorder.
Gron G, Bittner D, Schmitz B, Wunderlich AP, Riepe MW.
Memory Clinic, University of Ulm, Germany.
Patients with probable Alzheimer's disease and depressive patients
frequently present with subjective memory complaints. Objective
distinction of underlying neuronal substrate malfunction and early
cross-sectional differential diagnosis have been elusive thus far. We
used repetitive learning and free recall of abstract geometric patterns
during functional magnetic resonance imaging to assess episodic memory
in older subjects (ages 56-64 years) who sought first-time medical
attention with subjective memory complaints and were diagnosed with
probable Alzheimer's disease (NINCDS-ADRDA criteria; ages 51-67 years)
or major depressive disorder (DSM-IV; ages 50-65 years). Contrasting
healthy seniors or depressive patients with Alzheimer's disease
patients revealed superiority of hippocampal activation. Contrasting
Alzheimer's disease patients with seniors showed bilateral prefrontal
activity as a correlate of futile compensation of episodic memory
failure. Contrasting patients who had major depressive disorder with
seniors or patients who had Alzheimer's disease showed bilateral
activation of the orbitofrontal cortex and the anterior cingulate.
Subjective memory complaints may be classified objectively and very
early with functional magnetic resonance imaging of episodic memory in
groups of patients with Alzheimer's disease and depressive syndrome.
This may facilitate drug trials with evaluation of specific treatments,
but further studies will be needed to establish the differential
diagnosis for the individual patient.
PMID: 11921055 [PubMed - indexed for MEDLINE]
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13: Neurosci Lett. 2001 Nov 13;314(1-2):57-60. Related Articles, Links
Transcranial magnetic stimulation in Alzheimer disease: motor
cortex excitability and cognitive severity.
Alagona G, Bella R, Ferri R, Carnemolla A, Pappalardo A, Costanzo E,
Pennisi G.
Department of Neurological Sciences, University of, Catania, Italy
To study the possible changes of cortical excitability in the Alzheimer
disease (AD) by transcranial magnetic stimulation (TMS) and to evaluate
their eventual correlation with its stage twenty-one AD patients and 18
normal controls underwent TMS. Motor threshold, amplitudes of motor
evoked potentials (MEPs), central motor conduction time (CMCT) and
silent period (SP) were considered. The motor threshold in AD patients
was lower than in normal subjects with a significant correlation
between the stage of cognitive severity. The amplitude of MEPs was
increased and the SP duration was reduced in AD patients. No
significant differences were obtained for CMCT. These findings could
suggest a correlation between increased motor cortical excitability and
cognitive severity. Moreover, the increased cortical excitability could
represent a key to understand the mechanism of AD and may have
implication for novel treatment strategies.
PMID: 11698146 [PubMed - indexed for MEDLINE]
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14: Neurology. 2001 Sep 11;57(5):812-6. Related Articles, Links
Dissociation of regional activation in mild AD during visual
encoding: a functional MRI study.
Kato T, Knopman D, Liu H.
Center for Magnetic Resonance Research, Department of Radiology,
University of Minnesota, Minneapolis, USA.
OBJECTIVE: The authors studied mild patients with AD with a visual
learning paradigm to determine whether activations of medial temporal
regions on fMRI differ in AD compared to nondemented individuals.
BACKGROUND: Changes in activation patterns of medial temporal lobe
regions may serve as a biologic marker of altered brain function early
in the course of AD. METHODS: The authors studied eight healthy young
subjects, eight late middle-age nondemented volunteers, and seven
patients with mild AD. All subjects underwent fMRI scanning in which
they viewed a set of geometric designs for 45 seconds. Changes in blood
flow were analyzed by comparing the prestimulus fMRI signal with that
present during the stimulus presentation. RESULTS: Patients with AD,
who had very poor recall of the geometric designs subsequently, showed
increased blood flow (activation) during stimulus presentation only in
a visual association area. Both the young and older nondemented
subjects, all of whom had good recall of the designs, showed
activations during stimulus presentation of the right entorhinal
cortex, right supramarginal gyrus, right prefrontal regions, and left
anterior-inferior temporal lobe. The younger and older nondemented
subjects did not differ in fMRI activation patterns. CONCLUSIONS:
Failure of activation in AD of either temporal lobe or prefrontal
regions is consistent with established clinical-pathologic correlations
in AD. fMRI may be useful in confirming a memory disorder diagnosis and
also may be useful in detecting individuals with incipient dysfunction
in learning as a result of disorders such as AD.
PMID: 11552009 [PubMed - indexed for MEDLINE]
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15: J Cogn Neurosci. 2000;12 Suppl 2:24-34. Related Articles, Links
Functional brain imaging of young, nondemented, and demented
older adults.
Buckner RL, Snyder AZ, Sanders AL, Raichle ME, Morris JC.
Howard Hughes Medical Institute and Department of Psychology,
Washington University, St. Louis, MO 63130, USA.
Brain imaging based on functional MRI (fMRI) provides a powerful tool
for characterizing age-related changes in functional anatomy. However,
between-population comparisons confront potential differences in
measurement properties. The present experiment explores the feasibility
of conducting fMRI studies in nondemented and demented older adults by
measuring hemodynamic response properties in an event-related design. A
paradigm involving repeated presentation of sensory-motor response
trials was administered to 41 participants (14 young adults, 14
nondemented older adults, and 13 demented older adults). For half of
the trials a single sensory-motor event was presented in isolation and
in the other half in pairs. Hemodynamic response characteristics to the
isolated events allowed basic response properties (e.g., amplitude and
variance) between subject groups to be contrasted. The paired events
further allowed the summation properties of the hemodynamic response to
be characterized. Robust and qualitatively similar activation maps were
produced for all subject groups. Quantitative results showed that for
certain regions, such as in the visual cortex, there were marked
reductions in the amplitude of the hemodynamic response in older
adults. In other regions, such as in the motor cortex, relatively
intact response characteristics were observed. These results suggest
caution should be exhibited in interpreting simple main effects in
response amplitude between subject groups. However, across all regions
examined, the summation of the hemodynamic response over trials was
highly similar between groups. This latter finding suggests that, even
if absolute measurement differences do exist between subject groups,
relative activation change should be preserved. Designs that rely on
group interactions between task conditions, parametric manipulations,
or group interactions between regions should provide valuable data for
making inferences about functional-anatomic changes between different
populations.
PMID: 11506645 [PubMed - indexed for MEDLINE]
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16: Clin Neurophysiol. 2001 Aug;112(8):1436-41. Related Articles, Links
Motor cortex disinhibition in Alzheimer's disease.
Liepert J, Bar KJ, Meske U, Weiller C.
Department of Neurology, Friedrich Schiller University, Jena, Germany.
OBJECTIVES: To explore subclinical disturbances in the motor cortex of
patients with Alzheimer's disease (AD). METHODS: We used transcranial
magnetic stimulation in a paired pulse technique to test intracortical
inhibition (ICI) and intracortical facilitation in mildly to moderately
demented AD patients with a normal neurological examination. Patients
were studied before and during treatment with the cholinesterase
inhibitor donepezil. RESULTS: AD patients had a reduced ICI compared to
an age-matched control group. The amount of disinhibition correlated
with the severity of dementia. Treatment with 10 mg donepezil daily was
associated with an increase of ICI. CONCLUSIONS: The subclinical motor
cortex disinhibition in AD patients indicates a functional disturbance,
and is probably associated with a cholinergic deficit.
PMID: 11459683 [PubMed - indexed for MEDLINE]
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17: Neuroscience. 2001;104(3):667-76. Related Articles, Links
Remembering familiar people: the posterior cingulate cortex
and autobiographical memory retrieval.
Maddock RJ, Garrett AS, Buonocore MH.
Depaartment of Psychiatry, University of California Davis, Sacramento
65817, USA.
Most functional imaging studies of memory retrieval investigate memory
for standardized laboratory stimuli. However, naturally acquired
autobiographical memories differ from memories of standardized stimuli
in important ways. Neuroimaging studies of natural memories may reveal
distinctive patterns of brain activation and may have particular value
in assessing clinical disorders of memory. This study used functional
magnetic resonance imaging to investigate brain activation during
successful retrieval of autobiographical memories elicited by name-cued
recall of family members and friends. The caudal part of the left
posterior cingulate cortex was the most strongly activated region and
was significantly activated in all eight subjects studied. Most
subjects also showed significant activation of the left anterior
orbitomedial, anterior middle frontal, precuneus, cuneus, and posterior
inferior parietal cortices, and the right posterior cingulate and motor
cortices.Our findings are consistent with prior studies showing
posterior cingulate cortex activation during autobiographical memory
retrieval. This region is also consistently activated during retrieval
of standardized memory stimuli when experimental designs emphasizing
successful retrieval are employed. Our results support the hypothesis
that the posterior cingulate cortex plays an important role in
successful memory retrieval. The posterior cingulate cortex has strong
reciprocal connections with entorhinal and parahippocampal cortices.
Studies of early Alzheimer's disease, temporal lobectomy, and hypoxic
amnesia show that hypometabolism of the posterior cingulate cortex is
an early and prominent indicator of pathology in these patients. Our
findings suggest that autobiographical memory retrieval tasks could be
used to probe the functional status of the posterior cingulate cortex
in patients with early Alzheimer's disease or at risk for that
condition.
PMID: 11440800 [PubMed - indexed for MEDLINE]
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18: Neuroreport. 2001 Jun 13;12(8):1649-52. Related Articles, Links
Preserved stimulus deviance detection in Alzheimer's disease.
Pekkonen E, Jaaskelainen LP, Erkinjuntti T, Hietanen M, Huotilainen M,
Ilmoniemi RJ, Naatanen R.
Department of Neurology, University of Helsinki, and Medical
Engineering Centre, Helsinki University Central Hospital, Finland.
Aging attenuates automatic auditory discrimination to duration change,
whereas frequency change detection is relatively unimpaired in aging
and in Alzheimer's disease (AD). Here we studied with a whole-head
magnetometer whether cortical auditory discrimination to duration
change as shown by magnetic mismatch negativity (MMNm) response is
impaired in AD. Twenty AD patients with mild to moderate cognitive
impairment and 18 age-matched healthy subjects were monaurally
presented a sequence of frequent standard tones embedded with
occasional deviants with shorter duration. MMNm was significantly
delayed in the left hemisphere ipsilaterally to the ear stimulated in
the patient group, whereas the MMNm amplitudes over both hemispheres
were quite similar in both groups. This suggests that although MMNm is
delayed in the left hemisphere, the automatic discrimination to
duration change in the auditory cortex is not attenuated in the early
stages of AD.
PMID: 11409733 [PubMed - indexed for MEDLINE]
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19: Brain. 2001 Jun;124(Pt 6):1131-7. Related Articles, Links
Examination of motor output pathways in patients with
corticobasal ganglionic degeneration using transcranial magnetic
stimulation.
Valls-Sole J, Tolosa E, Marti MJ, Valldeoriola F, Revilla M, Pastor P,
Blesa R.
Unitat d'EMG, Neurology Service, Hospital Clinic, Universitat de
Barcelona, Villarroel, 170 Barcelona 08036, Spain.
The alien hand sign (AHS) is often encountered in patients with
corticobasal ganglionic degeneration (CBGD), revealing a unilateral
dysfunction of the motor system of unknown pathophysiology. We examined
the possibility of an abnormal cortical representation of hand muscles
in 10 patients with probable CBGD and a prominent AHS. Cortical maps
were obtained from the responses to magnetic stimuli applied with a
figure of eight coil at an intensity of 110% above motor threshold. For
comparison, the same study was carried out in 10 normal volunteers,
eight patients with Parkinson's disease and eight patients with
Alzheimer's disease. AHS patients had a larger extension of the
cortical map to stimulation of the hemisphere contralateral to the AHS
in comparison with the ipsilateral hemisphere. Furthermore, in six
patients, focal stimulation of the hemisphere ipsilateral to the AHS
gave rise to ipsilateral responses, delayed by a mean of 7.7 +/- 2.2 ms
with respect to those recorded in the same muscle to contralateral
stimulation. None of the other patients or control subjects had
ipsilateral responses. Our results indicate an enhanced excitability,
or reduced inhibition, of the motor area of the hemisphere
contralateral to the AHS. The delay of the ipsilateral responses is
compatible with a disinhibited transcallosal input.
PMID: 11353729 [PubMed - indexed for MEDLINE]
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20: Hum Brain Mapp. 2000 Aug;10(4):195-6. Related Articles, Links
Comment on:
* Hum Brain Mapp. 2000 Aug;10(4):197-203.
Perceptual priming and extrastriate cortex: consensus and
controversy.
Nyberg L.
Department of Psychology, Umea University, Sweden.
Publication Types:
* Comment
PMID: 10949056 [PubMed - indexed for MEDLINE]
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21: AJNR Am J Neuroradiol. 2000 Mar;21(3):524-31. Related Articles, Links
Functional MR imaging using a visually guided saccade
paradigm for comparing activation patterns in patients with probable
Alzheimer's disease and in cognitively able elderly volunteers.
Thulborn KR, Martin C, Voyvodic JT.
Department of Radiology, MR Research Center, University of Pittsburgh
Medical Center, PA, USA.
BACKGROUND AND PURPOSE: Alzheimer's disease is associated with
progressive visuospatial dysfunction. This study used functional MR
(fMR) imaging with an eye movement paradigm to investigate differences
in visuospatial cognition between patients with probable Alzheimer's
disease (pAD) and cognitively able elderly volunteers. METHODS: Using
established, although imperfect, clinical criteria, patients with pAD
(n = 18) and cognitively able elderly volunteers (n = 10) were selected
for study. All patients underwent echo-planar fMR imaging at 1.5 T. The
visually guided saccade paradigm consisted of alternating periods (30
s) of central fixation and visually guided saccades to a target
appearing randomly along the horizontal meridian. Activation maps were
derived using a voxelwise t test, comparing the signal intensities
between the two steady-state conditions. The activation patterns were
characterized by Talairach coordinates, activation volumes, and
laterality ratios (LRs). RESULTS: Statistically significant differences
existed between the activation patterns of the patients with pAD and
those of the volunteers. In contrast to the control group, a
left-dominant parietal activation pattern and enhanced prefrontal
cortical activation were observed in most patients with pAD.
CONCLUSION: Within the limitations of the imperfect clinical standard
of reference, the reduction in right parietal activation producing the
left-dominant LR for the intraparietal sulcus may reflect the
progressive dysfunction in spatial attention associated with
Alzheimer's disease, considering the known parietal lobe involvement in
this function and the disease. The high specificity of a positive
intraparietal sulcal LR measured by fMR imaging may have a role in
detecting and monitoring Alzheimer's disease.
PMID: 10730646 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
22: Dtsch Med Wochenschr. 1999 Dec 23;124(51-52):1577-81. Related Articles, Links
[Neurology. Therapeutic advances through systems research and
molecular biology]
[Article in German]
Hohlfeld R, Brandt T.
Institut fur Klinische Neuroimmunologie, Klinikum Grosshadern, Ludwig
Maximilians Universitat, Munchen.
PMID: 10664661 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
23: Brain Res. 1999 Dec 11;850(1-2):179-88. Related Articles, Links
Regulation of GTPase and adenylate cyclase activity by
amyloid beta-peptide and its fragments in rat brain tissue.
Soomets U, Mahlapuu R, Tehranian R, Jarvet J, Karelson E, Zilmer M,
Iverfeldt K, Zorko M, Graslund A, Langel U.
Department of Neurochemistry and Neurotoxicology, Arrhenius
Laboratories, Stockholm University, Sweden.
Modulation of GTPase and adenylate cyclase (ATP pyrophosphate-lyase, EC
4.6.1.1) activity by Alzheimer's disease related amyloid beta-peptide,
A beta (1-42), and its shorter fragments, A beta (12-28), A beta
(25-35), were studied in isolated membranes from rat ventral
hippocampus and frontal cortex. In both tissues, the activity of GTPase
and adenylate cyclase was upregulated by A beta (25-35), whereas A beta
(12-28) did not have any significant effect on the GTPase activity and
only weakly influenced adenylate cyclase. A beta (1-42), similar to A
beta (25-35), stimulated the GTPase activity in both tissues and
adenylate cyclase activity in ventral hippocampal membranes.
Surprisingly, A beta (1-42) did not have a significant effect on
adenylate cyclase activity in the cortical membranes. At high
concentrations of A beta (25-35) and A beta (1-42), decreased or no
activation of adenylate cyclase was observed. The activation of GTPase
at high concentrations of A beta (25-35) was pertussis toxin sensitive,
suggesting that this effect is mediated by Gi/G(o) proteins. Addition
of glutathione and N-acetyl-L-cysteine, two well-known antioxidants, at
1.5 and 0.5 mM, respectively, decreased A beta (25-35) stimulated
adenylate cyclase activity in both tissues. Lys-A beta (16-20), a
hexapeptide shown previously to bind to the same sequence in A
beta-peptide, and prevent fibril formation, decreased stimulation of
adenylate cyclase activity by A beta (25-35), however, NMR diffusion
measurements with the two peptides showed that this effect was not due
to interactions between the two and that A beta (25-35) was active in a
monomeric form. Our data strongly suggest that A beta and its fragments
may affect G-protein coupled signal transduction systems, although the
mechanism of this interaction is not fully understood.
PMID: 10629763 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
24: J Neurol Sci. 1999 Nov 30;170(2):119-23. Related Articles, Links
Motor cortex inhibition is not impaired in patients with
Alzheimer's disease: evidence from paired transcranial magnetic
stimulation.
Pepin JL, Bogacz D, de Pasqua V, Delwaide PJ.
University Department of Neurology, CHR Citadelle, Bd du XIIeme de
Ligne, 1, 4000, Liege, Belgium.
Motor cortex excitability was studied by transcranial magnetic
stimulation (TMS) in 17 patients with Alzheimer's disease (AD). Resting
and active thresholds for TMS were significantly reduced in AD patients
compared to young and aged healthy subjects. The maximum amplitude of
the motor response evoked by TMS was also significantly increased in AD
patients. We have tested if these changes are related to a modification
of the short-lasting intracortical inhibition of the motor cortex by
paired conditioning-test TMS. We found no significant differences
between AD patients and aged healthy subjects even if there is a slight
but significant difference between aged and young normal subjects. We
conclude that the modification of excitability of the motor cortex does
not result from an impaired intracortical inhibition.
PMID: 10561527 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
25: J Int Neuropsychol Soc. 1999 Jul;5(5):377-92. Related Articles, Links
Neuroanatomic substrates of semantic memory impairment in
Alzheimer's disease: patterns of functional MRI activation.
Saykin AJ, Flashman LA, Frutiger SA, Johnson SC, Mamourian AC, Moritz
CH, O'Jile JR, Riordan HJ, Santulli RB, Smith CA, Weaver JB.
Department of Psychiatry, Dartmouth Medical School, Lebanon, NH 03756,
USA.
Impairment in semantic processing occurs early in Alzheimer's disease
(AD) and differential impact on subtypes of semantic relations have
been reported, yet there is little data on the neuroanatomic basis of
these deficits. Patients with mild AD and healthy controls underwent 3
functional MRI auditory stimulation tasks requiring semantic or
phonological decisions (match-mismatch) about word pairs
(category-exemplar, category-function, pseudoword). Patients showed a
significant performance deficit only on the exemplar task. On
voxel-based fMRI activation analyses, controls showed a clear
activation focus in the left superior temporal gyrus for the
phonological task; patients showed additional foci in the left
dorsolateral prefrontal and bilateral cingulate areas. On the semantic
tasks, predominant activation foci were seen in the inferior and middle
frontal gyrus (left greater than right) in both groups but patients
showed additional activation suggesting compensatory recruitment of
locally expanded foci and remote regions, for example, right frontal
activation during the exemplar task. Covariance analyses indicated that
exemplar task performance was strongly related to signal increase in
bilateral medial prefrontal cortex. The authors conclude that fMRI can
reveal similarities and differences in functional neuroanatomical
processing of semantic and phonological information in mild AD compared
to healthy elderly, and can help to bridge cognitive and neural
investigations of the integrity of semantic networks in AD.
PMID: 10439584 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
26: J Neurol. 1997 May;244(5):304-7. Related Articles, Links
Magnetic stimulation in Alzheimer's disease.
de Carvalho M, de Mendonca A, Miranda PC, Garcia C, Luis ML.
Department of Neurology, Hospital de Santa Maria, Lisbon, Portugal.
Alzheimer's disease (AD) is a common cause of dementia in which some
clinical motor abnormalities have been described. We used transcranial
magnetic stimulation in order to test the hypothesis that the change in
the motor cortex might cause modifications in motor excitability.
Fourteen mildly to moderately affected AD patients were compared with
11 controls matched for age, height and sex. The motor evoked potential
threshold value for the relaxed abductor digiti minimi was lower in the
AD patients than in the control group for both left and right
hemispheres (P < 0.05). No statistically significant difference was
found comparing the left and the right hemispheres thresholds in each
population. The mean interside threshold differences were small and not
significantly different between patients and controls. The spinal motor
neuron excitability, as evaluated by F/M and H/M waves amplitude
ratios, showed no difference between the groups, reinforcing the motor
cortex increased excitability hypothesis to explain this difference.
Degeneration of inhibitory gabaergic terminals might be the basis for
the increased cortical excitability in the motor cortex of the
Alzheimer patients; postsynaptic changes in the GABAA receptors might
also affect inhibitory gabaergic transmission. The increased
excitability found by transcranial magnetic stimulation in the motor
cortex is important for understanding the emergence of seizures and
myoclonus in this disease.
PMID: 9178155 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
27: Neuroreport. 1996 May 31;7(8):1365-8. Related Articles, Links
Alzheimer's disease affects parallel processing between the
auditory cortices.
Pekkonen E, Huotilainen M, Virtanen J, Naatanen R, Ilmoniemi RJ,
Erkinjuntti T.
Department of Psychology, University of Helsinki, Finland.
Auditory evoked magnetic fields (AEFs) were recorded from 11 patients
with Alzheimer's disease (AD) and 11 age-matched controls using the
122-channel whole-head magnetometer. Auditory stimuli were monaurally
presented with interstimulus intervals (ISI) of 0.5 and 2.5 s in
different blocks. The peak latencies of P50m and N100m responses were
significantly longer in AD patients than in controls over the
ipsilateral but not over the contralateral auditory cortex with respect
to the ear stimulated. This finding suggests that parallel auditory
processing is impaired between the auditory cortices in AD patients.
The present MEG measurement might provide an objective index to
evaluate auditory dysfunction in AD.
PMID: 8856676 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
28: J Neurol Sci. 1996 Jan;135(1):31-7. Related Articles, Links
Evaluation of the motor cortex by magnetic stimulation in
patients with Alzheimer disease.
Perretti A, Grossi D, Fragassi N, Lanzillo B, Nolano M, Pisacreta AI,
Caruso G, Santoro L.
Department of Clinical Neurophysiology, University of Naples, Italy.
Motor evoked potentials (MEPs) from abductor pollicis brevis (APB) and
tibialis anterior (TA) muscles elicited by transcranial magnetic
stimulation of the motor cortex were studied in 15 patients with
Alzheimer disease (AD). An abnormally higher MEP threshold in APB,
frequently associated with absence of the MEP in relaxed TA muscles,
was found in 40% of patients, almost all of them in the more severe
stage of the disease. The MEP amplitude and averaged MEP/MAP ratio were
reduced respectively by 20% and 26% in the APB muscle, and by 46.7% and
53.3% in the TA muscle. The less frequent prolongation of the central
conduction time (CCT) (20%) might reflect preservation of the impulse
propagation along the surviving pyramidal fibers. In 63.6% of the
patients the central silent period (cSP) duration in the APB muscle was
shortened; the mean value was significantly different between patients
and controls. The results of this study suggest that loss and/or
dysfunction of motor cortex neurones, including pyramidal cells and
inhibitory interneurones may occur in AD patients before clinical signs
become apparent.
PMID: 8926493 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
29: J Med Chem. 1995 Apr 28;38(9):1558-70. Related Articles, Links
In vitro muscarinic activity of spiromuscarones and related
analogs.
Wu ES, Griffith RC, Loch JT 3rd, Kover A, Murray RJ, Mullen GB, Blosser
JC, Machulskis AC, McCreedy SA.
Department of Chemistry and Biology, Fisons Pharmaceuticals, Rochester,
New York 14623, USA.
The cholinergic hypothesis of Alzheimer's disease suggests that
cholinergic agonists may have therapeutic potential for treating the
attendant memory deficits of the disease. As part of a program aimed at
preparing metabolically stable, nonquaternary analogs of muscarone,
1-oxa-2,8-dimethyl-8-azaspiro[4.5]decan-3-one, 2a, and related analogs
have been synthesized and their in vitro muscarinic activity evaluated.
The synthetic strategy in the formation of the 1-spiro[4.5]decan-3-one
ring system of 2a involved cyclization of the diol 4 in the presence of
Nafion-Hg. The spiromuscarone 2a was found to displace [3H]Oxo-M
binding with a Ki value of 7 nM. Affinities of the oxime and hydrazone
analogs of 2a were lower than 2a. The compounds in these series were
partial muscarinic agonists as demonstrated by stimulation of
phosphatidyl inositol hydrolysis assay, with 2a showing the highest
intrinsic intrinsic activity (60% as compared with carbachol). The
results from this study indicate that an exo double bond at the C-3
position is essential for the receptor binding.
PMID: 7739014 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
30: West J Med. 1994 Sep;161(3):273-8. Related Articles, Links
Mapping human brain activity in vivo.
Mazziotta JC.
Department of Neurology, Reed Neurological Research Center, Los
Angeles, CA.
A wide range of structural and functional techniques now exists to map
the human brain in health and disease. These approaches span the gamut
from external tomographic imaging devices (positron-emission
tomography, single photon-emission computed tomography, magnetic
resonance imaging, computed tomography), to surface detectors
(electroencephalography, magnetoencephalography, transcranial magnetic
stimulation), to measurements made directly on the brain's surface or
beneath it (intrinsic signal imaging, electrocorticography). The
noninvasive methods have been combined to provide unique and previously
unavailable insights into the macroscopic organization of the
functional neuroanatomy of human vision, sensation, hearing, movement,
language, learning, and memory. All methods have been applied to
patients with neurologic, neurosurgical, and psychiatric disease and
have provided a rapidly expanding knowledge of the pathophysiology of
diseases such as epilepsy, cerebrovascular disease, neoplasms,
neurodegenerative diseases, mental illness, and addiction states. In
addition, these new methods have become a mainstay of preoperative
surgical planning and the monitoring of pharmacologic or surgical
(transplantation) interventions. Most recently, the ability to observe
the reorganization of the human nervous system after acute injury, such
as occurs with cerebral infarction or head trauma, or in the course of
a progressive degenerative process such as Alzheimer's or Parkinson's
disease, may provide new insights and methods in the rapidly expanding
field of neurorehabilitation. Our newfound ability to generate maps and
databases of human brain development, maturation, skill acquisition,
aging, and disease states is both an exciting and formidable task.
Publication Types:
* Review
* Review, Tutorial
PMID: 7975566 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
31: J Med Chem. 1994 Aug 19;37(17):2774-82. Related Articles, Links
Design, synthesis, and neurochemical evaluation of
2-amino-5-(alkoxycarbonyl)-3,4,5,6-tetrahydropyridines and
2-amino-5-(alkoxycarbonyl)-1,4,5,6-tetrahydropyrimidines as M1
muscarinic receptor agonists.
Dunbar PG, Durant GJ, Rho T, Ojo B, Huzl JJ 3rd, Smith DA, el-Assadi
AA, Sbeih S, Ngur DO, Periyasamy S, et al.
Department of Medicinal and Biological Chemistry, College of Pharmacy,
University of Toledo, Ohio 43606.
Four regioisomers of
2-amino-(methoxycarbonyl)-3,4,5,6-tetrahydropyridine (2a-5a) were
synthesized as the racemates to evaluate the utility of exocyclic
amidines in the development of novel agonists for M1 muscarinic
receptors. Of the four regioisomers, only racemic
2-amino-5-(methoxycarbonyl)-3,4,5,6-tetrahydropyridine (4a; CDD-0075-A)
displayed high affinity (IC50 = 10 +/- 3.0 microM) and activity at
muscarinic receptors coupled to PI metabolism in the rat cortex (260
+/- 4.5% stimulation above basal levels at 100 microM). A series of
2-amino-5-(alkoxycarbonyl)-3,4,5,6-tetrahydropyridines then was
synthesized for further evaluation as M1 agonists. Only the propargyl
derivative (4d) retained substantial agonist activity (120 +/- 14% at
100 microM) in this series. On the basis of the activity of the
5-(alkoxycarbonyl)-1,4,5,6- tetrahydropyrimidines (1a and 1d) and the
2-amino-5-(alkoxycarbonyl)-3,4,5,6-tetrahydropyridines, the
corresponding cyclic guanidine derivatives were synthesized and tested.
2-Amino-5-(methoxycarbonyl)-1,4,5,6-tetrahydropyrimidine (7a) displayed
a modest affinity for muscarinic receptors in the CNS (22 +/- 5.3
microM) and an ability to stimulate PI turnover in rat cerebral cortex
(81 +/- 16% at 100 microM). The propargyl derivative (7d) also had
modest binding affinity (31 +/- 15 microM) and high activity (150 +/-
8.5% at 100 microM), as expected based on the activity of propargyl
esters of 1,4,5,6-tetrahydropyrimidine and
2-amino-3,4,5,6-tetrahydropyridine. Computational chemical studies
revealed five distinct minimum-energy conformations for 1a, (R)-4a, and
7a, and three for 1d, (R)-4d, and 7d, each with a unique orientation of
the ester moiety. Each of the five conformations for 1a could be
superimposed upon a unique conformer of (R)-4a and 7a, suggesting that
the compounds interact with muscarinic receptors in a similar fashion.
Taken together, the data indicate the general utility of amidine
systems as suitable replacements for the ammonium group of
acetylcholine in developing ligands with activity at M1 muscarinic
receptors in the central nervous system. Such compounds might be useful
in the treatment of patients with Alzheimer's disease.
PMID: 8064804 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
32: Cerebrovasc Brain Metab Rev. 1992 Spring;4(1):1-27. Related Articles, Links
PET correlates of normal and impaired memory functions.
Heiss WD, Pawlik G, Holthoff V, Kessler J, Szelies B.
Max-Planck-Institut fur neurologische Forschung, Koln, Germany.
To date, positron emission tomography (PET) has been the only
technology for the quantitative imaging of the changes of regional
cerebral glucose (rCMRGl) or oxygen metabolism and blood flow (rCBF)
associated with psychophysical stimulation and with the performance of
mental tasks. So far, the majority of studies performed in healthy
subjects demonstrated activation patterns involving not only certain
limbic structures, most of all hippocampus, amygdala, parahippocampus,
and cingulate, but also temporal, parietal, and occipital association
cortex, depending on the applied paradigm. Indeed, the closest
correlation between regional metabolism and memory test scores was
found in mesiotemporal structures during the performance of memory
tasks. Metabolic or CBF studies also seem to indicate that memorizing
strategies may differ among individuals. PET was repeatedly used to
investigate metabolic and/or blood flow abnormalities in patients with
various amnestic syndromes. In cases with uni- or bilateral lesions of
mesiotemporal structures, caused by surgery, herpes simplex
encephalitis, or permanent ischemic, anoxic, or toxic damage,
disturbances of metabolism and blood flow typically extended far beyond
the morphological defects detected by computed tomography or magnetic
resonance. In acute transient global amnesia, CBF and metabolism were
decreased bilaterally in the mesiotemporal lobes, where hypometabolism
persisted for some time, while higher values were observed in thalamus
and some cortical areas. Diencephalic lesions causing Korsakoff's
syndrome were associated with decreased rCMRGl in the hippocampal
formation, upper brainstem, cingulate, and thalamus. Discrete thalamic
infarcts caused amnesia and metabolic depression in the morphologically
intact ipsilateral thalamus and in various projection areas of the
infarcted nuclei. In ischemic forebrain lesions, amnestic deficits
could be related to involvement of the anterior cingulate and of basal
cholinergic nuclei. A large number of pathologies are diffusely spread
out in the brain and affect partially or predominantly structures in
memory processing. This holds true especially in the various dementias
where memory disturbances are a consistent and often leading feature.
Notably, Alzheimer's disease can be distinguished from other dementias
by its characteristic pattern of metabolic dysfunction, with the most
prominent changes occurring in parietotemporal and frontal association
cortex whose residual metabolism is related to the severity of the
disease. Therefore, activation studies using paradigms involving memory
functions enhance that typical pattern. Only in the activated state is
metabolism of mesiotemporal structures significantly correlated with
the performance in memory tests. Other dementias also affect some of
the distributed memory networks, with Huntington's disease suggesting a
role of the striatum in memory processing.(ABSTRACT TRUNCATED AT 400
WORDS)
Publication Types:
* Review
* Review, Academic
PMID: 1562450 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
33: Acupunct Electrother Res. 1992;17(2):107-48. Related Articles, Links
Common factors contributing to intractable pain and medical
problems with insufficient drug uptake in areas to be treated, and
their pathogenesis and treatment: Part I. Combined use of medication
with acupuncture, (+) Qi gong energy-stored material, soft laser or
electrical stimulation.
Omura Y, Losco BM, Omura AK, Takeshige C, Hisamitsu T, Shimotsuura Y,
Yamamoto S, Ishikawa H, Muteki T, Nakajima H, et al.
Heart Disease Research Foundation, New York.
Most frequently encountered causes of intractable pain and intractable
medical problems, including headache, post-herpetic neuralgia, tinnitus
with hearing difficulty, brachial essential hypertension, cephalic
hypertension and hypotension, arrhythmia, stroke, osteo-arthritis,
Minamata disease, Alzheimer's disease and neuromuscular problems, such
as Amyotrophic Lateral Sclerosis, and cancer are often found to be due
to co-existence of 1) viral or bacterial infection, 2) localized
microcirculatory disturbances, 3) localized deposits of heavy metals,
such as lead or mercury, in affected areas of the body, 4) with or
without additional harmful environmental electro-magnetic or electric
fields from household electrical devices in close vicinity, which
create microcirculatory disturbances and reduced acetylcholine. The
main reason why medications known to be effective prove ineffective
with intractable medical problems, the authors found, is that even
effective medications often cannot reach these affected areas in
sufficient therapeutic doses, even though the medications can reach the
normal parts of the body and result in side effects when doses are
excessive. These conditions are often difficult to treat or may be
considered incurable in both Western and Oriental medicine. As
solutions to these problems, the authors found some of the following
methods can improve circulation and selectively enhance drug uptake: 1)
Acupuncture, 2) Low pulse repetition rate electrical stimulation (1-2
pulses/second), 3) (+) Qi Gong energy, 4) Soft lasers using Ga-As diode
laser or He-Ne gas laser, 5) Certain electro-magnetic fields or rapidly
changing or moving electric or magnetic fields, 6) Heat or moxibustion,
7) Individually selected Calcium Channel Blockers, 8) Individually
selected Oriental herb medicines known to reduce or eliminate
circulatory disturbances. Each method has advantages and limitations
and therefore the individually optimal method has to be selected.
Applications of (+) Qi Gong energy stored paper or cloth every 4 hours,
along with effective medications, were often found to be effective, as
Qigongnized materials can often be used repeatedly, as long as they are
not exposed to rapidly changing electric, magnetic or electro-magnetic
fields. Application of (+) Qi Gong energy-stored paper or cloth, soft
laser or changing electric field for 30-60 seconds on the area above
the medulla oblongata, vertebral arteries or endocrine representation
area at the tail of pancreas reduced or eliminated microcirculatory
disturbances and enhanced drug uptake.(ABSTRACT TRUNCATED AT 400 WORDS)
Publication Types:
* Clinical Trial
PMID: 1353650 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
34: J Neurol Neurosurg Psychiatry. 1991 May;54(5):443-8. Related Articles, Links
Posterior cortical dementia with alexia: neurobehavioural,
MRI, and PET findings.
Freedman L, Selchen DH, Black SE, Kaplan R, Garnett ES, Nahmias C.
Department of Psychology, Mississauga Hospital, Ontario, Canada.
A progressive disorder of relatively focal but asymmetric biposterior
dysfunction is described in a 54 year old right handed male. Initial
clinical features included letter-by-letter alexia, visual anomia,
acalculia, mild agraphia, constructional apraxia, and visuospatial
compromise. Serial testing demonstrated relentless deterioration with
additional development of transcortical sensory aphasia, Gerstmann's
tetrad, and severe visuoperceptual impairment. Amnesia was not an early
clinical feature. Judgment, personality, insight, and awareness
remained preserved throughout most of the clinical course. Extinction
in the right visual field to bilateral stimulation was the sole
neurological abnormality. Early CT was normal and late MRI showed
asymmetrical bioccipitoparietal atrophy with greater involvement of the
left hemisphere. Results from positron emission tomography (PET) showed
bilaterally asymmetric (left greater than right)
occipitotemporoparietal hypometabolism. The metabolic decrement was
strikingly asymmetric with a 50% reduction in glucose consumption
confined to the left occipital cortex. The picture of
occipitotemporoparietal compromise verified by MRI, PET, and
neurobehavioural testing would be unusual for such degenerative
dementias as Alzheimer's (AD) and Pick's disease, although atypical AD
with predominant occipital lobe involvement cannot be excluded. This
case supports the concepts of posterior cortical dementia (PCD) as a
clinically distinct entity and for the first time documents its
corresponding metabolic deficit using PET.
PMID: 1865209 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
35: Eur Neurol. 1991;31(4):259-69. Related Articles, Links
Mapping of event-related potentials to auditory and visual
odd-ball paradigms in patients affected by different forms of dementia.
Onofrj M, Gambi D, Del Re ML, Fulgente T, Bazzano S, Colamartino P,
Malatesta G.
Istituto di Clinica Neurologica, Universita G. D'Annunzio, Chieti,
Italia.
The paper reports the results of recordings and maps of event-related
potentials (ERPs) in patients with Alzheimer's disease (AD),
progressive supranuclear palsy (PSP) and in subjects affected by
dementia in multiple sclerosis (MS). ERPs were recorded from 19 scalp
electrode derivations using both visual and acoustic paradigms. In 43%
of AD patients, ERPs were normal; in 20%, although present, ERP
components were delayed, while in the other 37% none of the N2 and P3
peaks could be recorded, because of abnormal topography of potentials
on the scalp. In patients with PSP, the normal ERP sequence was not
identified. In patients with MS delayed ERPs (50%), abnormal topography
of ERPs (30%) and absence of ERPs (20%) were observed. The follow-up of
AD patients showed a progressive alteration of ERPs. ERP topography
alterations were observed in AD, PSP and MS patients with poorest
cognitive performances.
PMID: 1868869 [PubMed - indexed for MEDLINE]