Human Hippocampal Neurons Predict How Well Word Pairs Will Be Remembered

• Published in: Neuron (Cambridge, Mass.) Vol. 30; no. 1; pp. 289 - 298
• Main Authors: Cameron, Katherine A, Yashar, Sharona, Wilson, Charles L, Fried, Itzhak
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-04-2001
• Subjects: Adolescent; Adult; Entorhinal Cortex - cytology; Entorhinal Cortex - physiology; Epilepsy - complications; Epilepsy - pathology; Epilepsy - physiopathology; Female; Hippocampus - cytology; Hippocampus - physiology; Humans; Learning - physiology; Male; Memory - physiology; Memory Disorders - etiology; Memory Disorders - pathology; Memory Disorders - physiopathology; Middle Aged; Neurons - cytology; Neurons - physiology; Predictive Value of Tests; Psychomotor Performance - physiology; Verbal Behavior - physiology; Word Association Tests; words
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/S0896-6273(01)00280-X

What is the neuronal basis for whether an experience is recalled or forgotten? In contrast to recognition, recall is difficult to study in nonhuman primates and rarely is accessible at the single neuron level in humans. We recorded 128 medial temporal lobe (MTL) neurons in patients implanted with intracranial microelectrodes while they encoded and recalled word paired associates. Neurons in the amygdala, entorhinal cortex, and hippocampus showed altered activity during encoding (9%), recall (22%), and both task phases (23%). The responses of hippocampal neurons during
encoding predicted whether or not subjects later remembered the pairs successfully. Entorhinal cortex neuronal activity during
retrieval was correlated with recall success. These data provide support at the single neuron level for MTL contributions to encoding and retrieval, while also suggesting there may be differences in the level of contribution of MTL regions to these memory processes.