Neuronal population representation of human emotional memory

Understanding how emotional processing modulates learning and memory is crucial for the treatment of neuropsychiatric disorders characterized by emotional memory dysfunction. We investigate how human medial temporal lobe (MTL) neurons support emotional memory by recording spiking activity from the hippocampus, amygdala, and entorhinal cortex during encoding and recognition sessions of an emotional memory task in patients with pharmaco-resistant epilepsy. Our findings reveal distinct representations for both remembered compared to forgotten and emotional compared to neutral scenes in single units and MTL population spiking activity. Additionally, we demonstrate that a distributed network of human MTL neurons exhibiting mixed selectivity on a single-unit level collectively processes emotion and memory as a network, with a small percentage of neurons responding conjointly to emotion and memory. Analyzing spiking activity enables a detailed understanding of the neurophysiological mechanisms underlying emotional memory and could provide insights into how emotion alters memory during healthy and maladaptive learning. [Display omitted] •Neuronal responses to emotional and neutral stimuli were studied during a memory task•Amygdala, hippocampal, and entorhinal cortex neurons encoded emotion and memory•Demixed principal-component analysis separated emotional and memory representations•Emotional selectivity was detected before memory responsiveness during retrieval Fetterhoff et al. conducted electrophysiological microwire recordings in the amygdala, hippocampus, and entorhinal cortex of patients with pharmaco-resistant epilepsy during an emotional memory task. They found that neural populations processed both emotional and memory information and used demixed principal-component analysis to segregate emotional and memory representations in the recorded neurons.