Unravelling the mechanism of sensory neurons

Aqsa, Jamia Millia Islamia

Mechanism of sensory neurons-

The touch receptors present on our skin generate the signals received by an external stimulus. These generated signals travel along the sensory nerves, which remain connected to the sensory neurons in the spinal cord. These signals then move to the thalamus and finally to the rest of the brain. This information is then directed towards the somatosensory cortex, a region of the brain, which is responsible for interpreting sensation. It is responsible for processing sensory information such as pain, pressure, temperature, etc. This area has numerous connections with the other brain areas to process sensory information. It receives sensations such as touch, pressure, temperature, and pain and translates them into touch perception. The somatosensory cortex uses sensory information to perform specific functions that now instructs the body to perform a particular function.

Somatosensory information from all over the body reaches the somatosensory cortex. The somatosensory cortex then interprets this information. The sensitive areas in the body can stimulate the somatosensory cortex much faster than less sensitive regions. These areas include lips, fingertips, etc. The reason is that the number of receptors per unit area is more in a sensitive area when compared to a less sensitive area.

A recent discovery-

Recent research has revealed that touch-sensitive neurons work more chaotically rather precisely. To study how exactly neurons respond to touch, scientists studied neural movement in rat’s whiskers. Whiskers in mice are richly supplied with nerve endings and act as sensory equipment. They are present in all rodents and help to gather information about their surroundings. These are driven by facial muscles. And these facial muscles remain supplied by motor neurons, which regulate the whisker movement. All these properties make whiskers ideal for studying how sensory neurons work.

The researchers stimulated it through a range of motions, directions, speeds, and forces. It was kept in mind to imitate what a real rat would experience in its natural environment. The researchers implanted electrodes in the whiskers. It successfully measures the activity of neurons that received the touch signals. At last, the researchers quantified how neurons responded to a broad range of sensations. It was found that all neurons responded differently to different types of stimuli. This study suggests that touch signals do not get filtered at the first stage. These signals travel in a jumbled or messier manner. When this jumbled information gets to a higher level (brain), it is sorted or interpreted.

Conclusion-

Earlier studies showed that each neuron is assigned for some aspect of the touch stimulus. But this study concluded that some neurons respond more than others to some features of the stimulus. The neurons were found to respond to many combinations of forces applied to the whisker in the mouse. And when all different forces were compared, it was found that the stimuli they responded to overlap with each other. It was expected to be found that neurons could be one of a few different types. But this study concluded that each neuron was a little different from all the others.

Also read: Do angry bees produce protein-dense bee venom?

References:

1. Am, Morris, a, & University, N. (n.d.). Neurons that respond to touch are less picky than expected. Retrieved August 15, 2021, from https://medicalxpress.com/news/2021-08-neurons-picky.html 
2. Blumenrath, S. (n.d.). The neuroscience of touch and pain. Retrieved August 15, 2021, from https://www.brainfacts.org:443/thinking-sensing-and-behaving/touch/2020/the-neuroscience-of-touch-and-pain-013020

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