Chapter 7.3, Problem 1TY

Summary Introduction

Introduction

Memories are dynamic; with time, humans forget many details of what they have learned or experienced. Donald Hebb proposed that the physiological changes that happen at the synapses and the gaps between one neuron's end and the other's dendrite or cell body represent memory and learning in the brain.

Explanation of Solution

Answer and explanation

In their experiment on immediate and delayed recall, Muller and Pilzecker (1900) found that participants in the delayed group were able to recall more information than those in the immediate recall group. On the basis of this research, they proposed the concept of consolidation, which they defined as the process that converts fragile, new memories into a more permanent state. When these changes occur at synapses, it is known as synaptic consolidation.

Hebb proposed that, in the brain, memories are represented as the physiological changes that occur at the synapses. He further proposed that repeated activity at these synapses can strengthen them, along with strengthening the memory, by changing the structure of the synapse and increasing the release of neurotransmitters. Studies by Chokovski and colleagues (2004) and Kida and coworkers (2002) support the idea that activity at the synapse causes the release of certain chemicals which further lead to structural changes at the synapse, which strengthens synaptic transmission. This strengthening leads to enhanced firing of neurons because of repeated activity and is known as long-term potentiation. Thus, these results indicate that memories are represented at the synapses, and experience and learning lead to changes at the synapse.