Different in degree or kind: human memory (Introduction)

by David Turell , Monday, December 09, 2013, 15:39 (4002 days ago) @ David Turell

Very complex changes in synapses mediate memory:-"More than a century ago, scientists generally recognized that the number of neurons in the adult brain did not increase significantly with age. That gave neurobiologists good reason to believe that memories were not formed by new neuron production, but rather by a strengthening of the connections between existing neurons to improve the effectiveness of their communication.
 
The strength of two connected neural pathways is thought to result in the storage of information. This process of synaptic strengthening is known as long-term potentiation (LTP).
 
"LTP is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. Memories are thought to be created, or encoded, by modifications in synaptic strength. It is known that LTP and memory formation requires gene transcription at cell nucleus.
 
Yasuda's team has been looking at the behaviours of proteins involved in synaptic plasticity within dendritic spines ... small bristles on the surface of neurons that receive synaptic signals. There are roughly 10,000 spines on the dendritic branches of each neuron (and roughly 100 billion neurons in the adult brain).
 
His team's most surprising and unexpected finding, he said, was that induction of LTP in as few as three of these spines was sufficient to exert profound effects on activity of proteins that control gene transcription in the cell nucleus. The team also discovered that these spines needed to be distributed over at least two dendritic branches for this process to be triggered. Interestingly, efficiency of gene transcription was higher with a more geographically distributed pattern of spines."-http://medicalxpress.com/news/2013-12-biochemical-mechanisms-memory.html