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Free keywords:
Action Potentials/physiology
Adult
Amygdala/physiopathology
Brain Mapping
Electroencephalography
Epilepsy, Temporal Lobe/*pathology/*physiopathology
Female
Hippocampus/*pathology/physiopathology
Humans
Learning/*physiology
Male
Neurons/classification/*physiology
Photic Stimulation/methods
Psychomotor Performance/physiology
Recognition, Psychology/physiology
Time Factors
Abstract:
The ability to distinguish novel from familiar stimuli allows nervous systems to rapidly encode significant events following even a single exposure to a stimulus. This detection of novelty is necessary for many types of learning. Neurons in the medial temporal lobe (MTL) are critically involved in the acquisition of long-term declarative memories. During a learning task, we recorded from individual MTL neurons in vivo using microwire electrodes implanted in human epilepsy surgery patients. We report here the discovery of two classes of neurons in the hippocampus and amygdala that exhibit single-trial learning: novelty and familiarity detectors, which show a selective increase in firing for new and old stimuli, respectively. The neurons retain memory for the stimulus for 24 hr. Thus, neurons in the MTL contain information sufficient for reliable novelty-familiarity discrimination and also show rapid plasticity as a result of single-trial learning.
