Leona Zamora: A comparison of neuronal firing rates for distracted versus non-distracted working memory

Abstract

Awake temporal lobe epilepsy patients undergoing neurosurgery present a unique opportunity for the study of neuronal activity during cognitive tasks. During anesthesia, extracellular microelectrodes recorded 113 neurons in 31 patients while the patient engaged in identification tasks for modality blocked and randomly represented auditory words, text words, and naming of visual objects. Using a Brown-Peterson paradigm, we assessed recent distracted and non-distracted working memory after nine seconds. Each trial included an acquisition item, a period of time where the memory must be stored (with or without an intervening task) and a cue for retrieval by overt recall. For the distracted trials, three unrelated items were presented between an acquisition item and the cue for overt recall. For the non-distracted trials, black slides or silence were presented between the acquisition item and the cue for overt recall. We then compared the activity between the two conditions, testing whether specific neurons were sensitive to distracted versus non-distracted stimuli. We observed significant sensitivity (p < .00625) in approximately 29% (29/110) of the neurons. Most activity differences occurred during the storage component of the experiment, however, this activity was not modality specific.