ABSTRACT
Movement-related MEG activity initiated by voluntary unilateral index finger movement was studied in 16 normal volunteers. Evoked motor field response was obtained by averaging with respect to movement onset detected by the actogram. Group averaging of single dipole solutions for the peak of the readiness field (Bereitschaftspotential) revealed activation of the cortical area corresponding to typical motor representation of the hand. Individual data showed strong individual differences in dipole localization, which may be associated with simultaneous activation of sensorimotor cortical areas. Readiness field obtained from each individual was localized either in the pre- or post-central gyrus. Individual differences in the localization may be related to simultaneous activation of the cortical areas incorporated in the sensorimotor complex. The study demonstrates that single dipole modeling may be used for the localization of the sensorimotor complex, but it is insufficient to separate the activity components of this complex.
Subject(s)
Brain Mapping/methods , Magnetoencephalography/methods , Motor Cortex/physiology , Adolescent , Adult , Female , Fingers/physiology , Humans , Male , Motor Activity , Young AdultABSTRACT
The functional characteristics of the frequency components ofalpharhythm was studied in schizophrenic patients. The frequency components of the alpha-range EEG were elicited by spectral analysis with FFT-transform. In 80% cases of the patients, the power spectra EEG have multimodal distribution in alpha-range. Spectral analysis from the left and right occipital leads have revealed multimodality in spectral EEG in 20 out of 25 patients. The hyperventilation test in the patients revealed a decreased multimodality and increased unimodality.
Subject(s)
Alpha Rhythm , Cerebral Cortex/physiopathology , Schizophrenia/physiopathology , Adolescent , Electroencephalography , Fourier Analysis , HumansABSTRACT
Increased central-parietal EEG theta-2 activity (about 6.5 per sec) was found in children with cognitive disorders (in Rett's syndrome, fragile X-syndrome, infantile autism) and in elderly patients with Alzheimer-type dementia (with prevalence of neuropsychological "frontal" disorders) in the presence of suppressed alpha rhythm. This theta-activity was closely associated with cognitive deficits and possessed a specific functional topography, namely it focused in the parietal region and suppressed by both visual stimulation and motor tests. The similar EEG pattern was observed in some patients treated with neuroleptics and/or during hyperventilation. By taking into account the data available in the literature on motor, oculomotor, regional cerebral blood flow and the probability prediction in frontal lobar dysfunction, it is suggested that the theta-activity described appears in the visuomanual coordination system and is a physiological correlate of decreased functional status of frontal lobes.
Subject(s)
Electroencephalography , Frontal Lobe/physiopathology , Aged , Aged, 80 and over , Alzheimer Disease/physiopathology , Antipsychotic Agents/pharmacology , Autistic Disorder/physiopathology , Child , Child, Preschool , Female , Fragile X Syndrome/physiopathology , Frontal Lobe/drug effects , Humans , Hyperventilation/physiopathology , Male , Middle Aged , Rett Syndrome/physiopathology , Theta RhythmSubject(s)
Dementia, Vascular/physiopathology , Dementia/physiopathology , Electroencephalography , Aged , Alzheimer Disease/physiopathology , Alzheimer Disease/psychology , Cognition , Dementia/psychology , Dementia, Vascular/psychology , Factor Analysis, Statistical , Female , Humans , Middle Aged , Neuropsychological TestsABSTRACT
Quantitative EEG was used to reveal the specific features of its amplitude-frequency parameters and topography in patients with mild dementia of different genesis versus healthy elderly individuals. All four study groups of patients differ in EEC relative spectral density, they also differ from the healthy persons while alpharhythm was suppressed in Alzheimer's disease (AD) and vascular dementia (VD) and there was slower alpha-rhythm and higher theta-activity in senile AD (SAD). Patients with VD were characterized by desynchronized EEG. Factorial and stepwise discriminant analyses of EEG parameters showed that the control group greatly differed from patients with mild dementias. Patient groups mainly with atrophic atrophic AD and SAD or vascular (VD and mixed) dementia were also different whereas the mixed vascular-atrophic group is intermediate in EEC parameters between the VD group and the partially overlapped AD and SDA patient groups. Quantitative EEC data may be thus used for differential diagnosis to optimize therapy and prognosis even in mild dementia.
Subject(s)
Brain/pathology , Dementia/diagnosis , Dementia/etiology , Electroencephalography , Aged , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Prognosis , Severity of Illness IndexABSTRACT
There has been studied application of a complex approach to development of automated ways to gain contactless psychophysiological correction of functional status and improvement of performance of working up operators. The psychophysiological support of operator consisted in combined presentation of functional music, surf noise and pulsed dynamic green lighting under a special program built-up on the principle of biological feedback of heart and respiration rates. The individually adaptable audio and visual pulses on the programme showed a rather high efficiency as was confirmed by the change in the set of psychophysiological indices (heart rate, arterial pressure, cutaneogalvanic reaction, accommodation volume, critical rate of flicker fusion, electroencephalogram), and subjective SAM (self-feeling, activity, mood) estimates in the course of extended operator's activity.
Subject(s)
Multiphasic Screening/methods , Work Simplification , Work , Electroencephalography , Hemodynamics , Humans , Work/physiology , Work/psychology , Work Capacity EvaluationABSTRACT
A total of 160 patients with Alzheimer-type dementias (ATD), including 84 with Alzheimer's diseases (AD) and 76 with senile dementia (SD), were examined. The initial signs of the disease were analyzed by making a retrospective assessment of informative history data. The prospective follow-up involved clinical, neuropsychological and electrophysiological (EEC mapping, evoked potentials) studies by applying the standardized assessment of results. There was shown to be a set of clinical and paraclinical parameters for the status of ATD patients, indicating a distinct-quantitative and qualitative difference between patients with AD and those with SD and supporting the heterogeneity of ATD.
Subject(s)
Alzheimer Disease/diagnosis , Aged , Alzheimer Disease/classification , Brain Mapping , Dementia/diagnosis , Diagnosis, Differential , Electroencephalography , Evoked Potentials , Follow-Up Studies , Humans , Retrospective StudiesABSTRACT
EEG topographic correlates of the severity and type of Alzheimer-type dementias have been studied in 21 patients with senile dementia (SD) and 18 with Alzheimer's disease (AD) who were subdivided into smaller groups by MMSE grades for the severity of dementia, as well as in 15 mentally normal elderly persons. EEC maps in SD and AD patients differed from those in normal subjects in increased theta-delta EEG spectral power and suppressed alpha-band power that was more pronounced in the left hemisphere in AD than in SD patients. AD and SD patients had also different EEG topographical changes with intensified cognitive dysfunctions. The results suggest that there is a great cholinergic deficiency and cortical rather than subcortical impairments in patients with AD than in those with SD.
Subject(s)
Alzheimer Disease/physiopathology , Brain Mapping , Electroencephalography , Alzheimer Disease/classification , Alzheimer Disease/diagnosis , Dementia/diagnosis , Dementia/physiopathology , Diagnosis, Differential , Humans , Mental Status ScheduleABSTRACT
In 20 patients with neurosis-like schizophrenia and in 10 healthy subjects the authors, using the spectral analysis, assessed the composition of the alpha-range of the baseline EEG and studied the peculiarities of the frequency components of alpha-rhythm in various states. The patients were characterized by multimodality of the baseline EEG. The patients (versus the normal subjects) presented significantly different types of response of the main frequency components of EEG alpha-rhythm to the hyperventilation test.
Subject(s)
Alpha Rhythm , Neurotic Disorders/diagnosis , Schizophrenia/diagnosis , Adolescent , Adult , Chronic Disease , Electroencephalography/methods , Humans , Hyperventilation/physiopathology , Male , Neurotic Disorders/physiopathology , Schizophrenia/physiopathology , Wakefulness/physiologyABSTRACT
The functional interrelationships of the brain structures of freely moving cats in generation of rhythmic EEG activity during the states of drowsiness and light sleep were evaluated using the claster analysis of mean values indexes of rhythms in different structures as well as correlation coefficients between them in time. It was shown that according these parameters visual cortical areas and lateral geniculate body appeared in different clusters. Lateral geniculate body suggested not to be the only pacemaker of EEG rhythms in visual cortex. The wide convergence of subcortical inputs to the visual cortex and possibility of autonomic generation of EEG rhythms at the cortical level are discussed as putative mechanisms of dissociation of EEG activities in visual cortex and thalamus.
Subject(s)
Brain/physiology , Periodicity , Animals , Cats , Electroencephalography , Electrophysiology , Software , Statistics as Topic , Time FactorsABSTRACT
The similarity of frequency parameters of electroencephalograms (EEG) recorded from visual, associative and sensorimotor cortical area, caudate nucleus and several thalamic nuclei have been analysed using the period analysis of EEG and cluster analysis of data obtained to clarify the functional interrelationships between these parts of the brain during generation of rhythmic activity of different types. Functional interrelationships between brain structures in freely moving cats during the states of drowsiness and slow-wave sleep have been shown to differ from "classical" thalamo-cortical pacemaker relations.
Subject(s)
Brain/physiology , Electroencephalography , Animals , Cats , Caudate Nucleus/physiology , Cerebral Cortex/physiology , Electrodes, Implanted , Electroencephalography/methods , Sleep/physiology , Thalamic Nuclei/physiologyABSTRACT
Synchronized EEG activity of visual cortex and some other parts of the brain was recorded in cats during milk licking. The frequency range, cortico-subcortical topography and some conditions of its appearance and blockade were analyzed. It was found, that this activity consisted of two rhythms with frequencies of 6--9 and 9--15 c/s and was strongly influenced by visual conditions. By come parameters it also differed from EEG of drowsiness and light sleep. Possible mechanisms and localization of pacemakers of this activity was discussed as well as its similarity to human alpha rhythm.
