Showing papers in "Electroencephalography and Clinical Neurophysiology in 1989"

TL;DR: Description of mapping methods using spherical splines, both to interpolate scalp potentials (SPs) and to approximate scalp current densities (SCDs) with greater accuracy in areas with few electrodes.

TL;DR: Magnetic coil stimulation percutaneously of human occipital cortex was tested on perception of 3 briefly presented, randomly generated alphabetical characters, finding effects consistent with the topographical representation in visual cortex, but incompatible with an effect on attention or suppression from an eyeblink.

TL;DR: The influence of planning of self-paced voluntary finger movements on alpha band components was studied and it is concluded that the side of movement is predetermined more than 1 sec before movement onset.

TL;DR: The evolving topographical patterns of the P100 and N140 electrogeneses, revealed by bit-mapped data, suggest complex interactions between posterior parietal and prefrontal cortex whereby the sensory information is placed into spatial coordinate systems and matched with representations of relevant objects or relationships in space for target processing in the sequential tasks.

TL;DR: It was concluded that the spatial location of a sound source is coded in the hypothesized neuronal stimulus traces reflected by the mismatch negativity (MMN) and that a change in this location is automatically detected by the brain by means of the MMN generator process.

TL;DR: The investigation deals with the topography of principal sulci and of the temporal lobe within the international 10-20 system for electrode placement using magnetic resonance imaging in 16 healthy volunteers to study variability zones.

TL;DR: The discriminating EEG power spectral analyses indicated 3 classes of neurophysiological variables which are attributable to mechanical head injury: (1) increased coherence and decreased phase in frontal and frontal-temporal regions; (2) decreased power differences between anterior and posterior cortical regions; and (3) reduced alpha power in posterior cortex regions.

TL;DR: During voluntary contraction, minimal latency compound motor action potentials (CMAPs) in contralateral arm were elicited both by focal anodic and appropriately orientated MC stimulation, indicating the importance of appropriately orientating a standard round MC and using a specially designed MC to obtain the various types of motor response to stimulation of cerebral cortex.

TL;DR: Axonal conduction in the motor and somatosensory tracts of the cord was significantly correlated with the reduction in posttraumatic SCBF and, therefore, these data provide quantitative evidence linking posttraumatic ischemia to axonal dysfunction following acute cord injury.

TL;DR: Event-related potentials were recorded while subjects performed 2 recognition memory tasks and it is suggested that 'old/new' ERP differences may not reflect processes necessary for discrimination between old and new items in recognitionMemory tasks.

TL;DR: Average maps pooling data of parkinsonians and controls confirmed the presence of reduced evoked activity for the whole duration of wave N30 on those mid- and parasagittal frontal districts where this peak is maximally represented in normals.

TL;DR: The TCR provides unique information concerning the functional integrity of callosal projection neurons, their axons and transsynaptic processes in recipient cortex, which may prove useful in the evaluation of intrinsic cerebral mechanisms and in establishing cortical viability.

TL;DR: It is concluded that N1 of the foot pain SEPs is generated mainly from the foot area of SI, and the variable scalp distribution of the N1 component of the FootpainSEPs is likely due to an anatomical variability among subjects and even between sides.

TL;DR: A new method that measures between-channel, event-related covariances (ERCs) from scalp-recorded brain signals has been developed and may be an advancement toward characterizing, both spatially and temporally, functional cortical networks in the human brain responsible for perception and action.

TL;DR: Pre- and post-central cortical SEPs were of reduced amplitude and altered wave form when the median nerve stimulus was delivered during active movement of the thumb, suggesting that sensory input associated with the movement exerts a 'gating' effect which is at least as significant as that due to centrifugal influences.

TL;DR: The results of the neuromagnetic measurements presented here prove that the ECD location also shifts with changing stimulus intensity, and imply that, while topical mechanism of frequency coding are similar at cortex and at the cochlear level, topical mechanisms of intensity coding are different at these levels.

TL;DR: EEG topography was compared in patients with senile dementia of the Alzheimer's type, aged normal controls, and young normal controls to assess regional differences and marked delta asymmetry in temporal regions was characterized by SDAT patients.

TL;DR: The results suggest that the passive sequence paradigm may be a useful and reliable means of eliciting the P3 ERP in subject populations or experimental situations in which an active discrimination task cannot be performed.

TL;DR: C is regarded as one aspect of cooperativity in a cellular dynamic system with fine structure in the fractional millimeter and second range; so far it is observing it with severely distorting smoothing procedures.

TL;DR: Cortical auditory evoked potentials to the synthesized syllables [da] and [ta] and to the isolated 3 formants of [da[ were obtained from 32 normal infants studied at monthly intervals from birth through 3 months and at 6 months of age, suggesting a relative maturational equivalence in those regions of auditory cortex responding to stimuli across the frequency range present in human speech.

TL;DR: The studies suggest that the effects of aging should be incorporated into models aiming at explaining the physiology of sleep, and that the results may reflect a progressive tendency toward 'lightening' of sleep with increasing age.

TL;DR: The results indicate that, following seizures, there is activation of interictal spiking which is not paralleled by changes in background activity, and is most often widespread and not necessarily most prominent at the site of seizure onset.

TL;DR: Early components of somatosensory evoked magnetic fields with a sensitive 7-channel first-order gradiometer using a wide recording passband and high sampling frequency imply that these two deflections are generated by different neural networks.

TL;DR: It is concluded that even if the mean values of quantitative EEG variables analysed from the T6-O2 derivation showed distinct slowing at the time of the AD diagnosis and further deterioration 1 year later, in 50% of these early AD cases there was no EEG alteration or worsening in 1 year follow-up, suggesting heterogeneity of the disease.

TL;DR: Quantitative EEG data were analyzed statistically with respect to cortical cerebral blood flow (CBF) and oxygen metabolism (CMRO2) measured by positron emission tomography in 47 patients with unilateral cerebral infarction to find no significant difference in the EEG data between the 2 groups.

TL;DR: An easily applicable procedure for obtaining high-quality scalp DC recordings is described, using a sophisticated amplifier technique, skin potential reduction and stabilisation of electrode potential.

TL;DR: Men with high amounts of fast alpha activity at baseline, in lead P4-O2, reported feeling less 'high' and less overall feelings of intoxication after ethanol than the men with lower amounts of pre-drug fast alpha waves.

TL;DR: The observed changes in EEG power density support the hypothesis that this EEG parameter reflects the homeostatic process S and helps to test predictions of the 2-process model of sleep regulation.

TL;DR: Central motor conduction to abductor digiti minimi was evaluated in 22 patients with motor neurone disease using magnetic stimulation of the motor cortex and electrical stimulation at the C7/T1 interspace, revealing subclinical upper motor neur one involvement and document central motor pathway dysfunction in MND.

TL;DR: The assumption of symmetry is not valid for individual subjects, there is some evidence to suggest that the plantar-flexor EMG is related to dominance, and pooled subject data conceal bilateral differences in individual subjects.