Neuronal recordings in human lateral temporal lobe during verbal paired associate learning.

The temporal lobe has a role in memory and learning. The objective of this study was to assess the activity of neurons in the temporal cortex of humans during learning. Single neuron activity was recorded with extracellular microelectrodes in adults undergoing awake craniotomies for resections for medically intractable epilepsy. Participants were administered control tasks of overt reading, silent reading, nonword visual controls and a recent verbal memory task with distracters followed by a verbal paired associates (PA) paradigm. Forty-nine neurons were identified and characterized by their relationship to language and memory. Neurons related to overt speech (Type A neurons) showed increased activity during learning in patients who were good learners compared to patients who were poor learners. Neurons not related to language or to memory (Type D neurons) showed increased activity with exposure to unlearned word pairs in poor learners compared with those who were good learners. Activity in all groups diminished with practice. Levels of activity in specific types of neurons in human temporal lobe differ in patients who learn word pairs rapidly or poorly.