Our research reveals the critical role of the suprachiasmatic nucleus (SCN) vasoactive intestinal peptide (VIP) neurons in mediating light-induced transient forgetting. Acute exposure to bright light selectively impairs trace fear memory by activating VIP neurons in the SCN, as demonstrated by increased c-Fos expression and Ca²⁺ recording. This effect can be replicated and reversed through optogenetic and chemogenetic manipulations of SCN VIP neurons. Furthermore, we identify the SCN → PVT (paraventricular nucleus of the thalamus) VIP neuronal circuitry as essential in this process. These findings establish a novel role for SCN VIP neurons in modulating memory accessibility in response to environmental light cues, extending their known function beyond circadian regulation and revealing a mechanism for transient forgetting.
Animals ; Vasoactive Intestinal Peptide/metabolism* ; Male ; Mice ; Neurons/metabolism* ; Suprachiasmatic Nucleus/physiology* ; Light ; Mice, Inbred C57BL ; Memory/physiology* ; Fear/physiology* ; Suprachiasmatic Nucleus Neurons/metabolism* ; Optogenetics ; Proto-Oncogene Proteins c-fos/metabolism*