LTP and spatial learning?Where to next?

Abstract

Hebb suggested, in 1949, that memories could be stored by forming associative connections between neurons if the criterion for increasing the connection strength between them be that they were active simultaneously. Much attention has been devoted towards trying to determine a) if there is a physiological substrate of such a rule, and b) if so, whether the phenomenon participates in real‐life memory formation. The discovery of the electrically induced increase in synaptic strength known as long‐term potentiation (LTP), in the early 1970s, demonstrated that a neural version of the Hebb rule could be observed under laboratory conditions in the hippocampus, a structure important for some types of learning. However, a quarter of a century later, the evidence linking LTP to learning and memory is still contradictory. The purpose of the present article is to review and assess the types of approach that have been taken in trying to determine whether hippocampal synaptic plasticity participates in memory formation. Hippocampus 7:95–110, 1997. © 1997 Wiley‐Liss, Inc.

Small Conductance Ca2+-Activated K+Channels Modulate Synaptic Plasticity and Memory Encoding

“…It is generally accepted that some form of an increase in synaptic efficacy in the hippocampus is necessary for encoding spatial memory in the water maze task (Moser et al, 1998). Whether such memory formation in the hippocampus is dependent on LTP or LTD has been difficult to establish (Holscher, 1997;Jeffery, 1997;Shors and Matzel, 1997). In the present study, blockade of SK channels increases excitability, reduces the threshold for hippocampal synaptic plasticity, and facilitates hippocampal memory encoding.…”

Scrapie-Induced Defects in Learning and Memory of Transgenic Mice Expressing Anchorless Prion Protein Are Associated with Alterations in the Gamma Aminobutyric Acid-Ergic Pathway

“…LTP that strengthens synaptic efficacy in the hippocampus has been considered a correlate of memory formation (19,23). Owing to our finding of defective cognitive learning in scrapie-infected GPI Ϫ/Ϫ PrP tg mice ( Fig.…”

A Review of Glutamate Receptors I: Current Understanding of Their Biology

“…Although hippocampal LTP and spatial learning are impaired by NMDA receptor blockade 270 , learning deficits can be almost completely prevented if rats are previously trained in a different water maze 301,302 . Therefore, NMDA receptors may not be required for encoding the spatial representation of a specific environment but rather in other forms of memory important for learning this task 303 .…”