April 25, 2022–What part of the brain allows the experience of pain in the body? It is nearly axiomatic that pain – among other examples of conscious experience – is an outcome of still-unclear forms of neural processing that occur in the cerebral cortex – the outermost layer of the brain that is linked with our highest mental capabilities.
The cerebral cortex is primarily made out of gray matter (tissue made up of neurons), with between 14 and 16 billion nerve cells located there. It has been thought that the center of pain transmission in the brain is specifically within the thalamocortical network, which is a relay station that organizes electrical signals that are information routes within the cortex. Previous studies have shown that this network is active when people feel pain and that people with mental disorders have disrupted functional activity in this and related networks.
The belief that pain and all other forms of conscious experience are felt via the cortex is based mostly on the fact that this outermost layer expanded dramatically in the course of primate evolution, especially in humans.
But now, Prof. Marshall Devor and doctoral student Mark Baron of the Department of Cell and Developmental Biology in the Silberman Institute of Life Sciences at the Hebrew University of Jerusalem have collected evidence from a number of sources that feeling pain is unlike the other senses and may not, in fact, be an expression of cortical processing.
These include the virtual inability to evoke pain by stimulating the cortex by implanting electrodes on the surface of the brain, and the fact that it is rare for epilepsy patients to suffer painful auras (sensations) before they have a seizure.
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