Muscarinic cholinergic influences in memory consolidation.

The central cholinergic system and muscarinic cholinergic receptor (mR) activation have long been associated with cognitive function. Although mR activation is no doubt involved in many aspects of cognitive functioning, the extensive evidence that memory is influenced by cholinergic treatments given after training either systemically or intra-cranially clearly indicates that cholinergic activation via mRs is a critical component in modulation of memory consolidation. Furthermore, the evidence indicates that activation of mRs in the basolateral amygdala (BLA) plays an essential role in enabling other neuromodulatory influences on memory consolidation. Memory can also be affected by posttraining activation of mRs in the hippocampus, striatum and cortex. Evidence of increases in hippocampal and cortical acetylcholine (ACh) levels following learning experiences support the view that endogenous ACh release is involved in long-term memory consolidation. Furthermore, the findings indicating that mR drug treatments influence plasticity in the hippocampus and in sensory cortices strongly suggest that mR activation is involved in the storage of information in these brain regions.