THE HIPPOCAMPUS, LONG-TERM POTENTIATION AND MEMORY

1. The induction of long-term potentiation (LTP) at excitatory synapse s on CA1 pyramidal neurons occurs partly through an increase in the qu antal AMPA current, It is also accompanied by an increase in the numbe r of active sites. Any presynaptic modification, requiring the presenc e of a retrograde messenger, remains uncertain. 2. There are no defini tive data that establish a causal link between LTP and the formation o f memories. Pharmacological blockage of NMDA and mGLU receptors and ge netic mutants with proteins deleted that are thought to be involved in LTP induction or maintenance or in the formation of memories have all linked deficits in LTP with impairments to behavioural learning, but these links are not necessarily causal, The development of tissue- and time-specific lesions of gene expression for multiple gene products m ay overcome the present limitations of gene deletion experiments and p rovide more revealing insights into the relationship between LTP and m emory.