Boron Chapter 16 Circuits of the Central Nervous System

Stretch Reflex (myotactic reflex)

Passive stretching of a skeletal muscle causes a reflexive contraction of that same muscle and relaxation of the antagonist muscles

Golgi Tendon Reflex

Interneuron circuitry may inhibit the muscle in which tension has increased and excite the antagonistic muscle (opposite of the stretch reflex) or during rapid movements (ex. Locomotion) sensory input from Golgi tendon organs may excite the motor neurons activating the same muscle

Flexion-withdrawal reflex

Coordinates the movement of entire limbs and even pairs of limbs (spinal interneurons) to avoid noxious stimuli

Paresis

Muscle weakness

Paralysis

Loss of motor function

Areflexia

No reflexes

Atonia

Muscles become flaccid

Atrophy

Loss of muscle mass

Paraplegia

Paralysis in both legs

Hemiplegia

Paralysis on one side of the body

Quadriplegia

Paralysis arms, trunk and legs

Spinal shock

Areflexia and hypotonia

Hypotonia

Reduced muscle tone

Hypertonia

Exaggerated muscle tone

Hyperreflexia

Heightened stretch reflex

Rhythmic Activity

Sequence of muscle movements that occurs without any need for sensory feedback

Central pattern generators

Cyclic, coordinated timing signals generated by a cluster of interconnected neurons that may command up to several hundred muscle

Interaural intensity localization

The ear facing the high frequency sound hears it as louder than the ear facing away because the head casts a "sound shadow"

Interaural delay localization

The ear facing the low frequency sound receives it first and the brain processes the signal slightly faster than the ear on the oppoiste side of the sound.