Biomedical subjects

J Schoenfield-McNeill

Publications and source records attributed to J Schoenfield-McNeill.

3 recordsLinked to original sources

PubMed2002

Anatomic subdivisions in human temporal cortical neuronal activity related to recent verbal memory.

We identified functional anatomical subdivisions of human lateral and basal temporal cortex related to recent verbal memory for object names, text and auditory words. Extracellular neuronal activity was recorded during memory encoding compared to identification, during encoding, storage or recall retrieval stages of the memory task, during recognition memory, and during implicit memory as measured by repetition priming. Changes in frequency of activity during encoding were recorded from most neurons. In lateral temporal cortex, these encoding changes in the dominant hemisphere were more likely to be polymodal, whereas those in nondominant hemisphere were unimodal. There was substantial separation of neurons with changes in other aspects of memory, defining additional subdivisions. Inferior lateral and basal cortex were related to memory stages, and superior-posterior lateral cortex was related to implicit and recognition memory.

Adolescent↗

PubMed1999

Activity of neurons in human temporal cortex during identification and memory for names and words.

Extracellular recordings of human temporal cortical neuronal activity during identification and memory for object names or words were obtained from 31 neurons at 18 sites in 12 left language dominant patients undergoing left (10) or right (2) awake craniotomy for epilepsy under local anesthesia. Frequency of activity during identification was compared with perceptual controls, that during the encoding phase of recent memory to identification of the same material. Statistically significant changes in one or more temporal epoch (p < 0.005) of one or more comparisons were present for 27 of the 31 neurons in either hemisphere. Few neurons changed activity in the same direction for both words and names. The instruction to retain an item in recent memory changed activity in most neurons from that during identification of the same material, although the items presented were identical and overtly identified in each task. Any individual neuron usually changed activity in one direction for only one task. There are separate, widely distributed neural networks for identification or recent memory for each type of material. The majority of nearby neurons recorded through the same extracellular microelectrode were related to the networks for different tasks. The temporal characteristics of these changes were also investigated; 31% of the changes were "phasic": temporally related to presentation or response to the item. Most of the remaining neuron changes were sustained throughout a task, often for several minutes. These task-specific sustained changes may reflect effects of thalamo-cortical attentional systems. Individual neurons had both sustained and phasic changes to different tasks.

Action Potentials↗

PubMed1998

Neurons in human temporal cortex active with verbal associative learning.

In neuronal activity recorded from human middle temporal gyrus during learning of associations between word pairs, a population was identified that had greater activity for associations that were learned rapidly during initial encoding compared to those learned slowly or not at all by an individual subject. This population can be separated from other neurons by the combination of inhibition during word reading when no learning is required and excitation during recent memory for words. These neurons are present in both hemispheres, predominately in deeper layers of cortex. During initial encoding, the increased activity appears at presentation of all word pairs but persists for several seconds only for the rapidly learned pairs, likely reflecting rehersal of items being learned. Human associative learning is related to activity of this specific population of "association" neurons, identified here for the first time.

Adult↗