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Wes Wallace

Publications and source records attributed to Wes Wallace.

5 recordsLinked to original sources
PubMed2004

A morphological correlate of synaptic scaling in visual cortex.

We studied the response of dendritic spines in the thalamic-recipient zone of rat visual cortex to simple manipulations of the visual environment. We measured the morphologies of a total of 3824 spines located on the basal dendrites of 60 layer 3 pyramidal cells. As expected from previous studies, we found a significantly lower spine density in dark-reared animals at postnatal day 30 (P30) compared with light-reared controls. Additional analysis revealed that the spines in dark-reared animals were significantly shorter and more bulbous than in light-reared animals. When these two results were combined, we found that the total synaptic area per unit length of dendrite was conserved, compatible with the phenomenon of "synaptic scaling." We also found that the increase in average spine head diameter is reversed by 10 d of light exposure (starting at P20), but surprisingly, the decrease in spine density is not. Thus, not all effects of dark rearing can be reversed by subsequent visual experience, even when the experience occurs during the third postnatal week.

Animals↗
PubMed2003

The vibrating nerve impulse in Newton, Willis and Gassendi: first steps in a mechanical theory of communication.

In later editions of his two major works, Isaac Newton proposed an electrical hypothesis of nervous transmission. According to this hypothesis, an electrical aether permeates the nerve and transmits vibrations along it. This implies that the nerve is a communication line, and potentially, an extension of the mind. The opposite view was held by Cartesian mechanists, who taught that the nerve is a power line, transmitting either pressure or tension, and that the mind is separate from the nervous system. The Newtonian model eventually supplanted the Cartesian model in the mid 18th century, and became a crucial part of the conceptual environment in which neuroscience originated. In this paper I examine the scientific origins of the Newtonian model of nervous transmission. I argue that Newton's model relies on prior work by Thomas Willis and Pierre Gassendi. Willis supplied the anatomical and physiological "hard data" upon which the model was built. But Gassendi, a generation before, laid out the conceptual foundations of the problem, including the principle of impulse-transmission, and the corrolary principle of the muscle as an autonomous generator of force. I conclude that Gassendi's work has been undeservedly neglected as a turning-point in the history of neuroscience.

Biomechanical Phenomena↗