Neuroscience proprioception

Proprioception

The ability to sense one’s body position in space.

Visual System and Proprioception

Vision influences proprioception by providing environmental cues, making it easier to know body position.

Vestibular System Role

The vestibular system helps maintain balance and equilibrium which are crucial for proprioception.

Muscle Spindle

Sensory receptors that detect muscle length and rate of change; involved in maintenance of muscle tone.

Equatorial Part of Muscle Spindle

Central non-contractile region of a muscle spindle that detects muscle length.

Gamma Motor Neurons

Neurons that adjust tension in intrafusal fibers, regulating the sensitivity of the stretch reflex.

Golgi Tendon Organ (GTO)

Proprioceptors embedded in tendons that detect tension and cause muscle relaxation to prevent tearing.

Joint Receptors

Respond to mechanical deformation at joints, providing proprioceptive information to the cerebellum.

Muscle Tone

The continuous state of muscle contraction at rest that helps maintain balance around joints.

Hypotonicity

Abnormal decrease in muscle tone, often linked to lower motor neuron lesions.

Hypertonicity

Excessive muscle tone often associated with upper motor neuron lesions and spasticity.

Clasp Knife Phenomenon

A condition where severe spasticity at a joint releases with a sustained stretch.

Cogwheel Rigidity

A form of muscle rigidity characterized by jerky, alternating movements.

Clonus

Uncontrolled oscillations or vibrations of a muscle, often a sign of neurological dysfunction.

Neurological Mechanisms of Muscle Tone

Involve upper motor neurons, basal ganglia, extrapyramidal structures, and feedback/ feedforward loops.

Therapeutic Technique to Increase Muscle Tone

Methods include quick stretch on agonist or tapping muscle belly.

Therapeutic Technique to Decrease Muscle Tone

Methods include sustained stretch on agonist or deep pressure on tendon to activate GTO.

Polar part of muscle spindle

 the contractile ends of the intrafusal muscle fibers controls the tension and sensitivity of the spindle.

Slow responding

Tonic/static

Fast responding

Phasic/dynamic

Type 1a fibers

 Large; Heavily myelinated; fast conducting

Type 2 fibers

Medium-sized; slow adapting; respond to changes in length

Gamma 1 (Dynamic)

• Have plate endings and terminate on the polar region of the nuclear bag

• Fast, rapid response

Gamma 2 (static)

Have multi-branch endings and terminate on the nuclear chain

Muscle Strength

muscle’s ability to contract and create force in response to resistance. (Conscious) 

Rigidity

Difficulty moving on both sides of joint

Spasticity

difficulty actively and passively moving muscles on one side of joint