Synaptic plasticity: Understanding the neurobiological mechanisms of learning and memory. Part II

Plasticity of the nervous system has been related to learning and memory pr ocessing as early as the beginning of the century; although, remotely, brai n plasticity in relation to behavior has been connoted over the past two ce nturies. However, four decades ago, several evidences have shown that exper ience and training induce neural changes, showing that major neuroanatomica l, neurochemical as well as molecular changes are required for the establis hment of a long-term memory process. Early experimental procedures showed t hat differential experience, training and/or informal experience could prod uce altered quantified changes in the brain of mammals. Moreover, neuropsyc hologists have emphasized that different memories could be localized in sep arate cortical areas of the brain, but updated evidences assert that memory systems are specifically distributed in exclusive neural net-works in the cortex. For instance, the same cortical systems that lead us to perceive an d move in our environment, are used as neural substrates Cot memory retriev al. Such memories are the result of the repeated activity of millions of ne urons assembled into distinct neural networks, where plastic changes in syn aptic function leads to the strengthening of the same synaptic connections with the result of reconstructed permanent traces that lead to remembrance (Hebb Postulate). Elementary forms of learning and memory have been studied in simple neural systems of invertebrates, and as such have led the way fo r understanding much of the electrophysiological and neurochemical events o ccurring during LTP. Long-term potentiation (LTP) is the result of the incr ease in the strength of synaptic transmission, lasting as long as can be me asured from hours to days. LTP ha, been detected in several areas of the br ain, particularly, in the hippocampus, amygdala, and cortex, including Seve ral related limbic Structures in the mammalian brain. LTP represents up to date the best Model available fur understanding the cellular basis of learn ing and memory in the central nervous system of mammals including humans.