The Neuroscience of Pain Practice Flashcards

Flashcards covering the fundamental concepts of the neuroscience of pain, the Mature Organism Model, receptor types, and peripheral nervous system mechanisms.

Adriaan Louw

The individual who stated that a fundamental understanding of the neuroscience of pain is needed to understand, examine, and treat individuals experiencing pain.

Nociception

A process modulated at multiple levels including nociceptors, sensory axons, the DRG, the dorsal horn of the spinal cord, $2nd$ order neurons in the thalamus, and the brain.

Mature Organism Model (M.O.M)

A model created by Louis Gifford that categorizes the pain experience into input mechanisms, processing mechanisms, and output mechanisms.

Input Mechanisms (M.O.M)

Information sent to the brain from the body's tissues (nociception) and environmental influences.

Processing Mechanisms (M.O.M)

The brain's interpretation of input, involving sensory, cognitive, and emotional areas, and sampling of past experiences, knowledge, and beliefs.

Output Mechanisms (M.O.M)

The biologic response to input and the brain's interpretation, which includes pain, altered behavior, altered physiology, and systems driven by survival instincts.

Mechanoreceptors

Sensory receptors that respond to the mechanical deformation of the receptor.

Chemoreceptors

Sensory receptors that respond to substances released from cells.

Thermoreceptors

Sensory receptors that respond to changes in temperature.

Nociceptors

Sensory receptors stimulated mechanically, thermally, or chemically by noxious stimuli; they are located almost everywhere in the body except the brain.

Inflammatory “soup”

A collective term for chemical agents such as Bradykinin, Prostaglandin, Serotonin, Histamine, and Cytokines that can irritate nociceptors and lead to peripheral sensitization.

Ion Channels

Proteins found in non-myelinated areas of neurons (Nodes of Ranvier, DRG somas, or injured nerves) that open or close based on specific ion types to affect membrane voltage.

Ion Channel Half-life

The period for ion channels is about $48$ hours, resulting in responsive neuroplasticity to changing conditions.

Ectopic Foci

Locations outside of the receptor (such as a nerve stump or areas of myelin damage) that generate action potentials, creating pain signals without receptor input.

Tinel Sign

A clinical sign in the peripheral nervous system where an injured nerve or sites of ectopic foci are extremely sensitive to mechanical stimulation.

Ephaptic Transmission

Also known as cross-talk; it occurs in demyelinated regions where a lack of insulation allows an action potential in one neuron to induce an action potential in another.

Nerve Compression

A condition that initially results in numbness, weakness, or pins and needles; if unresolved, it can lead to neurogenic inflammation and demyelination.

Dorsal Root Ganglia (DRG)

The location for cell bodies of most peripheral sensory neurons (primary afferents) which connects the PNS to the CNS via two axons.

Pseudounipolar

The structural type of DRG neurons having two axons: a distal axon conducting from receptor to cell body, and a proximal axon projecting to the spinal cord or brainstem.

Cross-excitation

A process where the DRG depolarizes due to activity in an adjacent neuron; in neuropathic states, this can contribute to the DRG becoming a generator of pain signals.