Neural Basis

The associative nature of long-term memory is based in the brain's neural networks. These networks are composed of neural cells, called neurons. It is estimated that there are over 100 billion neurons in the brain which can form many trillions of potential interconnections. These neurons form complex webs that enable the brain to perform as an extremely powerful, parallel processor. Neurons communicate across junctions, called synapses, by electrochemical means. There are approximately one million trillion synapses.

As we learn, our neural circuitry changes. Synapses increase in efficiency to facilitate the transmission of nerve impulses as learning occurs. Our brain alters the strength of existing neural connections, alters the information contained in neural webs, and/or produces new neural connections between neurons. This means that our brains are constantly changing throughout our lifetime. The more that specific neural pathways are used the stronger they become and the more likely they will be used again. As multiple pathways are simultaneous excited, new neural pathways are created which increases the brain's ability to learn.

The more we recall and use specific memories or information the easier recall of the information becomes. However, this does not mean that memories, particularly of our life experiences, will remain 100% as they were first encoded in our neural pathways. Overtime with repeated recall some memories undergo change. It may be that our emotional state at recall influences how we experience the memory which in turn effects its neural coding.

Neuron (NIDA)	Neural Web (Dr. Robert Malenka Stanford University)