LTP promotes formation of multiple spine synapses between a single axon terminal and a dendrite

TLDR: In this paper, the morphology of synapses activated by high-frequency stimulation and identified by accumulated calcium in dendritic spines was analyzed using electron microscopy to identify the formation of new synapses contacting the same presynaptic terminal.

Abstract: Structural remodelling of synapses and formation of new synaptic contacts has been postulated as a possible mechanism underlying the late phase of long-term potentiation (LTP), a form of plasticity which is involved in learning and memory Here we use electron microscopy to analyse the morphology of synapses activated by high-frequency stimulation and identified by accumulated calcium in dendritic spines LTP induction resulted in a sequence of morphological changes consisting of a transient remodelling of the postsynaptic membrane followed by a marked increase in the proportion of axon terminals contacting two or more dendritic spines Three-dimensional reconstruction revealed that these spines arose from the same dendrite As pharmacological blockade of LTP prevented these morphological changes, we conclude that LTP is associated with the formation of new, mature and probably functional synapses contacting the same presynaptic terminal and thereby duplicating activated synapses