CHANGES IN SYNAPSES

Changes in Synapses



Changes in Synapses

Introduction

The synapse is a contact zone function that occurs between two neurons or between a neuron and another cell (muscle cell or sensory receptors). Changes in synapse induce learning. It ensures the conversion of an action potential in the pre-synaptic neuron into a signal in the postsynaptic cell. It is estimated that for some cell types (e.g. pyramidal cell and Purkinje cell); about 40% of the membrane surface is covered with synapses.

There are usually two types of synapses:

The chemical synapses are a vast majority synapses, which uses neurotransmitters to transmit information;

The electrical synapse is a synapse that is transmitted electrically through a gap junction.

Discussion

Not everyone can tune a piano; you must first learn to perceive even small differences in the pitches. The visual system is capable of learning. We learn line lengths, angles, or shades to keep them apart. It is what the scientist calls discrimination learning. Any learning process changes the synapses, which is the junctions of neuronal cells in the brain. 

Synapses are modifiable, both short and long term. It is believed that such changes underlie the memory (Datta et al, 2004, pp.3). There is not a single synapse or cell that stores the memory contents, but a whole network of synaptic connections. Nerve cells have up to several thousand synapses, i.e., they received information from a very large number of other nerve cells. The memory content is then stored at many synapses of nerve cells that together form a network. 

Simultaneous Activation

The simultaneous activation of a large number of certain nerve cells of some of their contact points leads to activation of the memory contents. The single nerve cell with its many thousands of synapses is the hub of numerous networks. The failure of a single cell or a synapse will not lead to a loss of memory contents. Only an extensive death of nerve cells or a massive disruption of connections between the nodes of the network leads to loss of memory contents. The original concept of the 'grandmother cell', i.e. a cell is like memory content is no longer represented for many years.

Training and Retention

Training and retention of memories in the brain is based on extraordinary plasticity of the nervous system. It lasts changes in the strength of synapses, and connections between neurons, as well as functional and structural remodeling of neuronal networks activated during the learning. Research conducted over the past twenty years shows that a particularly durable and sensible form of synaptic changes plays a pivotal role in the mechanisms of learning and memory. This is the long-term potentiating (LTP) which is a significant, and it increases the synaptic efficacy when it stores memory (Benjamin, 2007, pp.98). 

In addition to the growth of different synapses, and changes in their shape and size, we now know that unlike the long accepted dogma, the brain continues to produce persistent neurons in adulthood. This is the case in the hippocampus, a structure strongly implicated in learning and memory. In the dentate gyrus, a structure of the hippocampus involved in learning phenomena, this nagging neurogenesis led to the birth of thousands of new neurons a day. A minority of these new cells, produced from a population of progenitor cells survive ...