Synaptic potentiation

Fear learning induces synaptic potentiation between engram neurons in the rat lateral amygdala. This study by Marios Abatis et al. demonstrates how fear conditioning strengthens synaptic connections between engram cells in the lateral amygdala, revealed through optogenetic identification of neuronal ensembles and electrophysiological measurements. The work provides crucial insights into memory formation mechanisms at the synaptic level, with implications for understanding anxiety disorders and developing targeted interventions. Presented by Dr. Kenneth Hayworth, this journal club will explore

Unlike traditional monoamine-based antidepressants that require weeks to exert effects, ketamine alleviates depression within hours, though its clinical use is limited by side effects. While ketamine was initially thought to work primarily through NMDA receptor (NMDAR) inhibition, our research reveals a more complex mechanism. We demonstrate that NMDAR inhibition alone cannot explain ketamine's sustained antidepressant effects, as other NMDAR antagonists like MK-801 lack similar efficacy. Instead, the (2R,6R)-hydroxynorketamine (HNK) metabolite appears critical, exhibiting antidepressant effec

The recruitment of synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors underlies the strengthening of neuronal connectivity during learning and memory. This process is triggered by N-methyl-D-aspartate (NMDA) receptor-dependent postsynaptic Ca2+ influx. Synaptotagmin (Syt)-1 and -7 have been proposed as Ca2+ sensors for AMPA receptor exocytosis, but are functionally redundant. Here we identify a cytosolic C2 domain-containing Ca2+-binding protein Copine-6 that forms a complex with AMPA receptors. Loss of Copine-6 expression impairs activity-induced exocytosis of AMP

…examined the frequency-dependency of synaptic plasticity in MPP-DG and LPP-DG synapses of the dorsal hippocampus of freely behaving adult male rats using patterned afferent stimulati

Memories are thought to be encoded in the brain via synaptic strengthening among memory engram cells. Still, it has not been possible to observe if learning potentiates synaptic connections and simultaneously show that these changes are causally related to memory expression (i.e., they occur in engram neurons). We used a novel engram allocation-based approach to observe synaptic changes in engram neurons upon learning in-vivo. Using optogenetics, we assigned selected Medial Entorhinal Cortex (MEC) neurons to a context fear memory. This takes advantage of the fact that neurons with more excitab

How can short-lived molecules selectively maintain potentiation of synapses to sustain long-term potentiation (late-LTP) and long-term memory? One possibility, suggested by Francis Crick (Nature, 1984), is that continual interaction between synaptic molecules maintains the strengthening of activated synapses in the face of molecular turnover. Here, we tested the hypothesis that continual interaction between KIBRA, a postsynaptic scaffolding protein genetically linked to human memory performance, with the autonomously active, atypical PKC isoform PKMζ, maintains late-LTP and long-term memory. U

Astrocytes are glial cells that participate in crucial processes in brain homeostasis and play a key role in modulating neuronal activity. Numerous astrocytic receptors transduce signals via cAMP although how changes in astrocytic cAMP levels modulate brain activity or animal behaviour is not fully understood. Our goal is to control cAMP in cortical astrocytes using DdPAC, a recently developed phytochrome photoreceptor that increases cAMP upon red light, and evaluate its responses at three levels: a) cellular, by analysing neuronal activity using multi-electrode arrays b) systemic, by measurin

Many animals live in complex social groups. To survive, it is essential to know who to avoid and who to interact. Although naïve mice are naturally attracted to any adult conspecifics, a single defeat experience could elicit social avoidance towards the aggressor for days. The neural mechanisms underlying the behavior switch from social approach to social avoidance remains incompletely understood. Here, we identify oxytocin neurons in the retrochiasmatic supraoptic nucleus (SOROXT) and oxytocin receptor (OXTR) expressing cells in the anterior subdivision of ventromedial hypothalamus, ventrolat