Somatosensation PDF
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Uploaded by BallerGiraffe0118
Concordia University
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Summary
This document provides a detailed overview of somatosensation, focusing on tactile receptors, their locations in the skin, and responses to different stimuli. It covers mechanoreceptors like Merkel cells and Pacinian corpuscles, as well as spatial and temporal resolution involved in tactile perception.
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Somatosensation: body sensation Touch Touch: transduces mechanical energy into the skin Exteroception: Sense of the external world Tactile receptors Located in the skin ◦ Epidermis ◦ Dermis: under the epidermis, where mechanoreceptors are Classified based on ◦ Type of stimulation to wh...
Somatosensation: body sensation Touch Touch: transduces mechanical energy into the skin Exteroception: Sense of the external world Tactile receptors Located in the skin ◦ Epidermis ◦ Dermis: under the epidermis, where mechanoreceptors are Classified based on ◦ Type of stimulation to which they respond ◦ Size of their receptive field ◦ How quickly they adapt Slowly (SA): fire as long as the stimulus is applied Fast/Rapid (FA): fire only at the start and end of a stimulus Good to detect changes in tactile stimuli Mechanoreceptors: respond to mechanical stimulation Pressure, vibration, movement 1. Merkel cells (SA 1) - respond best to indentation Small RF High spatial/low sensitivity to temporal variations Perceiving pattern, texture, and shape Closer to skin to surface 2. SA 2 - respond best to stretch Large RF Low spatial/low sensitivity to temporal variations Perceiving skin stretch and hand conformation Deeper in dermis 3. Meissner corpuscles (FA 1) - respond best to iskin Small RF High spatial/medium sensitivity to temporal variations Perceiving slip; maintaining grip control Closer to skin to surface 4. Pacinian corpuscles (FA 2) - respond best to vibration Large RF Low spatial/high sensitivity to temporal variations Perceiving fine textures through transmitted vibration Deeper in dermis Spatial thresholds 2-point discrimination dependent on the density of the receptions and where the receptors are in the skin ◦ Spatial resolution: Fingers: low threshold = high resolution Thigh: high threshold = low resolution ◦ Temporal resolution: touch: 5 ms vision: 25 ms hearing:
