Chapter 25, End of Chapter, Review Questions, Exercise 1

The cerebral cortex is the outer grey matter layer over the cerebral hemispheres. The neurons in this cerebral cortex are known as cortical neurons. The cell bodies of these neurons lie parallel to each other. The axons of the cortical neurons enter through the white matter into the brain stem. 

A selective stimulus that triggers the neuron is called selectivity of the neuron. 

The sensory stimulation occurring from the experience is subjected to long-term potentiation which is later converted to short-term memory. Long-term potentiation is also known as memory acquisition. The subjection of short-term memory  towards consolidation, allows its conversion to long-term memory. 

One of the cortical neurons is the inferotemporal neuron. The receptive field of this neuron is in the visual cortex. Its main function is facial recognition. The inferotemporal neuron forms a projection into the medial temporal lobe. These inferotemporal neurons have a unique feature called stimulus selectivity. The stimulus selectivity is the kind of selectivity that changes with the repeated stimulation brought about by the same image such as a human face. Consider the example of a student entering his first lecture of the academic year in a new college. When a novel face is seen for the first time only a medium stimulus is developed. The repeated visual exposure to the same faces, as the student starts attending college regularly, allows the occurrence of the shift in the selectivity. As a result, the person is able to recognize the common faces faster than others. 

Before the face is recognized each neuron detects a normal stimulus. A unique manner or activity ratio of neurons occurs with the recognition and learning process of the brain. The learning of a face is not restricted to a single neuron. Rather a pattern formed by neurons stores the facial memory. This manner of memory storage is called distributed memory. But once the pattern design is formed, then even if one neuron dies away the other neurons and the associated network or pattern can still recognize the same earlier faces.