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Biomedical subjects

P May

Publications and source records attributed to P May.

191 records · Page 11Linked to original sources
PubMedDate not supplied

Frequency change detection in human auditory cortex.

We offer a model of how human cortex detects changes in the auditory environment. Auditory change detection has recently been the object of intense investigation via the mismatch negativity (MMN). MMN is a preattentive response to sudden changes in stimulation, measured noninvasively in the electroencephalogram (EEG) and the magnetoencephalogram (MEG). It is elicited in the oddball paradigm, where infrequent deviant tones intersperse a series of repetitive standard tones. However, little apart from the participation of tonotopically organized auditory cortex is known about the neural mechanisms underlying change detection and the MMN. In the present study, we investigate how poststimulus inhibition might account for MMN and compare the effects of adaptation with those of lateral inhibition in a model describing tonotopically organized cortex. To test the predictions of our model, we performed MEG and EEG measurements on human subjects and used both small- (<1/3 octave) and large- (>5 octaves) frequency differences between the standard and deviant tones. The experimental results bear out the prediction that MMN is due to both adaptation and lateral inhibition. Finally, we suggest that MMN might serve as a probe of what stimulus features are mapped by human auditory cortex.

Adaptation, Physiological↗
PubMedDate not supplied

Idiopathic intracranial haemorrhage in the fetus.

Intracranial haemorrhage in the fetus has been reported with associated mortality and morbidity. This case report describes idiopathic subdural haematomas diagnosed at 32 weeks of gestation, with delivery by caesarean section of a live male infant in good condition at 34 weeks.

Adult↗