PerLecture 11/12(AIver)- The Cutaneous Senses

This set covers the somatosensory system, mechanoreceptors, tactile sensitivity, object perception, and the physiological and psychological aspects of pain as presented in the lecture.

Cutaneous senses

The perception of touch and pain resulting from the stimulation of the skin.

Proprioception

The ability of the body to sense the position of the limbs and the body itself.

Kinesthesis

The ability to sense the movement of the body and the limbs.

Ian Waterman

A patient who lost his sense of touch, proprioception, and kinesthesis due to an autoimmune reaction that led to nerve damage, though he retained his sense of pain and temperature.

Epidermis

The outer layer of the skin, which is comprised of dead skin cells and serves as a protective layer.

Dermis

The inner layer of the skin which contains mechanoreceptors that respond to stimuli like pressure, stretching, and vibration.

Mechanoreceptors

Receptors in the skin that respond to mechanical stimulation such as pressure, stretching, and vibration.

Merkel receptors (SA1)

Mechanoreceptors located near the surface of the skin that are slowly adapting (SA), fire to continuous pressure, and help sense shape and texture.

Meissner corpuscle (RA1)

Mechanoreceptors located near the surface of the skin that are rapidly adapting (RA), fire to the onset and offset of stimulation, and assist with grasping control.

Ruffini cylinder (SA2)

Deeper mechanoreceptors with large receptive fields that are slowly adapting and respond to skin stretch.

Pacinian corpuscle (RA2)

Deeper mechanoreceptors with large receptive fields that are rapidly adapting and respond to vibration and textures moving across the skin.

Medial lemniscus

The pathway in the spinal cord that carries signals related to proprioception and touch.

Spinothalamic tract

The pathway in the spinal cord that carries signals related to temperature and pain.

Ventrolateral nucleus

A nucleus in the thalamus where somatosensory nerve fibers from the spinal cord travel before reaching the cortex.

Homunculus

A visual representation of the body map on the primary somatosensory cortex ($S1$), showing how different body parts are represented spatially.

Dr. Wilder Penfield

A brain surgeon known for mapping the somatosensory cortex and his work on cortical representations of the body.

Two-point threshold

A measure of tactile sensitivity representing the minimum distance between two points on the skin that can be perceived as separate.

Grating acuity

A measure of tactile sensitivity determined by the ability to detect the orientation (vertical or horizontal) of a stimulus.

Cortical plasticity

The brain's ability to reorganize itself by changing the size of cortical areas representing specific body parts, as seen in Braille readers and violin players.

Duplex theory of texture

Katz's ($1925$) proposal that texture perception depends on both spatial cues (for large elements) and temporal cues or vibration (for fine elements).

Haptic perception

The active exploration of 3-D objects with the hand, relying on interactions between the sensory, motor, and cognitive systems.

Exploratory procedures (EPs)

A set of movements, such as lateral motion or contour following, typically used to identify objects haptically; described by Lederman and Klatzky ($1987$).

Inflammatory pain

Pain caused by damage to tissue or inflammation of the joints.

Neuropathic pain

Pain caused by damage to the nervous system itself.

Nociceptive pain

Pain caused by the activation of nociceptors in the skin.

Phantom limb pain

The experience of pain in a limb that is no longer present; demonstrates that pain can occur without nociceptor activity.

Gate control model

A model suggesting that pain perception is a balance between nociceptive activity and non-nociceptive activity from the skin and central signals from the brain.

Placebo effect

A decrease in pain resulting from the expectation that a substance (like saline) is an actual drug.

Anterior cingulate cortex (ACC)

A brain area involved in the affective or emotional components of pain, such as how annoying or sickening the sensation is.

Endorphins

Naturally occurring chemicals in the body that stimulate opiate receptors and can reduce pain or influence the placebo effect.

Naloxone

A chemical that blocks opiate receptor sites, used to stop drug overdoses and capable of eliminating the effects of endorphins and placebos.

Cyberball

A game used by Naomi Eisenberger to measure social exclusion, which was found to activate the Anterior cingulate cortex similarly to physical pain.