Chapter 8 Sensorimotor Flashcards
Sensory feedback
Sensor signals that are produced by a response and are often used to guide the continuation of the response.
Posterior parietal association cortex
An area of association cortex that receives input from the visual, auditory, and somatosensory systems and is involved in the perception of spatial location and guidance of voluntary behavior.
Frontal eye field
A small area of prefrontal cortex that controls eye movements.
Apraxia
A disorder in which patients have great difficulty performing movements when asked to do so out of context but can readily perform them spontaneously in natural situations.
Contralateral neglect
A disturbance of the patient’s ability to respond to visual, auditory, and somatosensory stimuli on the side of the body opposite to a site of brain damage, usually the left side of the body following damage to the right parietal lobe.
Dorsolateral prefrontal association cortex
The area of the prefrontal association cortex that plays a role in the evaluation of external stimuli and the initiation of complex voluntary motor responses.
Secondary motor cortex
Areas of the cerebral cortex that receive much of their input from association cortex and send much of their output to primary motor cortex.
Supplementary motor area
The area of secondary motor cortex that is within and adjacent to the longitudinal fissure.
Premotor cortex
The area of secondary motor cortex that lies between the supplementary motor area and the lateral fissure.
Cingulate motor areas
Two small areas of secondary motor cortex located in the cingulate gurus of each hemisphere.
Mirror neurons
Neurons that fire both when a person makes a particular movement and when he person observes somebody else making the same movement.
Primary motor cortex
The cortex of the precentral gyrus, which is the major point of departure for motor signals descending from the cerebral cortex into lower levels of the sensorimotor system.
Somatotopic
Organized, like the primary somatosensory cortex, according to a map of the surface of the body.
Motor homunculus
The somatotopic map of the human primary motor cortex. (Homunculus means “little man.”)
Stereognosis
The process of identifying objects by touch.
Astereognosia
An inability to recognize objects by touch that is not attributable to a simple sensory deficit or to general intellectual impairment.
Dorsolateral corticorubrospinal tract
The descending motor tract that synapses in the red nucleus of the midbrain, decussates, and descends in the dorsolateral spinal white matter.
Betz cells
Large pyramidal neurons of the primary motor cortex that synapse directly on motor neurons in the lower regions of the spinal cord.
Posterior parietal association cortex involved in
Plays a role in integrating information about original positions of the parts of the body that are to be moved, positions of any external objects with which the body will interact, in directing behavior by providing spatial information, and in directing attention.
Dorsolateral corticospinal tract
The motor tract that leaves the primary motor cortex, descends to the medullary pyramids, decussates, and then descends in the contralateral dorsolateral spinal white matter.
Ventromedial corticospinal tract
The direct ventromedial motor pathway, which descends ipsilaterally from the primary motor cortex directly into the ventromedial areas of the spinal white matter.
Ventromedial cortico-brainstem-spinal tract
The indirect ventromedial motor pathway, which descends bilaterally from the primary motor cortex to several interconnected brain stem motor structures and then descends in the ventromedial portions of the spinal cord.
Tectum
The “roof,” or dorsal surface, of the Mesencephalon; it includes the superior and inferior colliculi.
Vestibular nucleus
The brain stem nucleus that receives information about balance from receptors in the semicircular canals.
Reticular formation
A complex network of nuclei in the core of the brain stem that contains, among other things, motor programs that regulate complex species-common movements such as walking and swimming.
Motor units
A single motor neuron and all of the skeletal muscle fibers that are innervated by it.
Motor end-plate
The receptive area on a muscle fiber at a neuromuscular junction.
Motor pool
All of the motor neurons that innervate the fibers of a given muscle.
Flexors
Muscles that act to bend or flex a joint.
Extensors
Muscles that act to straighten or extend a joint.
Synergistic muscles
Pairs of muscles whose contraction produces a movement in the same direction.
Antagonistic muscles
Pairs of muscles that act in opposition.
Isometric contraction
Contraction of a muscle that increases the force of its pull but does not shorten the muscle.
Dynamic contraction
Contraction of a muscle that causes the muscle to shorten.
Golgi tendon organs
Receptors that are embedded in tendons and are sensitive to the amount of tension in the skeletal muscles to which their tendons are attached.
Muscle spindles
Receptors that are embedded in skeletal muscle tissue and are sensitive to changes in muscle length.
Intrafusal muscle
A threadlike muscle that adjusts the tension on a muscle spindle.
Intrafusal motor neuron
A motor neuron that innervated an interfusal muscle.
Skeletal muscle (extrafusal muscle)
Striated muscle that is attached to the skeleton and is usually under voluntary control.
Patellar tendon reflex
The stretch reflex that is elicited when the patellar tendon is struck.
Stretch reflex
A reflexive counteracting reaction to an unanticipated external stretching force on a muscle.
Spindle afferent neurons
Neurons that carry signals from muscle spindles into the spinal cord via the dorsal root.
Withdrawal reflex
The reflexive withdrawal of a limb when it comes in contact with a painful stimulus.
Reciprocal innervation
The principal of spinal cord circuitry that causes a muscle to automatically relax when a muscle that is antagonistic to it contracts.
Cocontraction
The simultaneous contraction of antagonistic muscles.
Recurrent collateral inhibition
The inhibition of a neuron that is produced by its own activity via a collateral branch of its axon and an inhibitory interneuron.
Central sensorimotor programs
Patterns of activity that are programmed into the sensorimotor system.
Motor equivalence
The ability of the sensorimotor system to carry out the same basic movements in different ways that involve different muscles.
Response-chunking hypothesis
The idea that practice combines the central sensorimotor programs that control individual responses into programs that control sequences of responses (chunks of behavior).
