Molecular, neurochemical and neurophysiological mechanisms of memory

Abstract

Introduction. Learning and memory have proven to be fascinating mental processes because they address one of the fundamental features of human activity: our ability to acquire new informations and to retain it over time in memory. (Kandel ER, 2001). The brain has to process a continuous input from our sensory organs and at the same time it must be able to store memories, sometimes even for a lifetime. One of the fundamental questions in memory research is how our experiences of life can persist over time. What is the cellular foundation of this long-term information storage of neurons in neuronal networks, which is so important for humans? It is generally acknowledged that the memory processes are the result of the interplay between synaptic plasticity and orchestrated network activity that finally culminates in the long-term storage of information. Overall, information storage starts with the encoding of new information and progresses to the short-term memory. At this stage the engram might be either consolidated for a lifetime, destabilized, or restabilized in the course of memory retrieval. These neuronal dynamics start and end with synaptic and cellular plasticity and can be observed at the behavioral level (Korte M, Schmitz D, 2016). The formation of long-term memory involves gene transcription, protein synthesis and synaptic plasticity dynamics. This plasticity is dependent on a well-regulated program of neurotransmitter release, postsynaptic receptor activation, intracellular signaling cascades, gene transcription, and subsequent protein synthesis. In the last decade, epigenetic markers like DNA methylation and posttranslational modifications of histone tails have emerged as important regulators of the memory process. (Zovkic IB et al, 2013).