Term
| Medial Descending System of Brainstem |
|
Definition
-control posture by integrating visual, vestibular, and somatosensory inputs
-vestibulospinal, recticulspinal, tectospinal tracts |
|
|
Term
| Lateral Descending System of Brainstem |
|
Definition
-control distal limb muscles (goal oriented mvts, arm and hand)
-rubrospinal |
|
|
Term
|
Definition
-contains circuity activating axial muscle and proximal limb muscle for maintenance of balance, regulation of posture, orienting of visual gaze
-important to support limb mvt
-recticular formation-diffuse functions |
|
|
Term
|
Definition
-maintain balance and posture
-vestibular nuclei-->med, lat vestibulospinal tract
-recieves sensory information from the semicircular canal and otolith organs
-position and angulation of the head
-eye mvts (VOR) |
|
|
Term
|
Definition
-circuits from Rostral midbrain to caudal medulla
-nuclei embedded (NE, DA, 5HT)
-arousal, cardiovascular, respiratory control, eye mvts, sleep/wake regulation, motor control of locomotion (ex:mesencephalic locomotor region)
-maintains posture when body position and stability is disturbed
-initiates adjustments |
|
|
Term
| reticular formation-anticipatory maintenance of body posture |
|
Definition
-gastroc was activated before biceps
-postural control involve anticipatory/feed forward mechanism
-predicts postural disturbance and generate stabilizing postural response |
|
|
Term
|
Definition
| Descending projections from the brainstem to the spinal cord |
|
|
Term
|
Definition
| Recticular Formation Location |
|
|
Term
|
Definition
Feedforward and feedback mechanisms of postural control
-importance of recticukar formation for feedforward mechanism |
|
|
Term
| Indirect Pathways from the motor cortex to the spinal cord |
|
Definition
-direct(corticospinal) vs indirect(corticoreticulospinal) pathways
-lesioned direct pathways(mokeny)-able to activate proximal, axial muscles(stand, walk, run) loss of control of distal muscle, ex:hand, loss independent, fractionated mvt of the fingers
-lesioned indirect pathway-lost feedforward postural mechanism for postural adjustments |
|
|
Term
|
Definition
-terminates on the brainstem nuclei (cranial nerve nuclei)
-control muscles of the face and neck
-Bilateral (mostly) |
|
|
Term
|
Definition
-terminates on the spinal cord motor neurons
-control muscles of the lims and trunk
-crossed (mostly) |
|
|
Term
| the motor cortex is responsible for: |
|
Definition
| planning mvt, executing mvt, and adjusting the force of a mvt |
|
|
Term
|
Definition
-skilled voluntary mvt
-concerted activation of motor cortical areas
-motor cortical neurons firing related to direction and amount of force
-similar to somatosensory cortex, capable of reorganization after injury |
|
|
Term
|
Definition
Motor Cortex Damage and Rehab
|
|
|
Term
|
Definition
-skilled voluntary mvt
-concerted activation of motor cortical areas
-motor cortical neurons firing related to direction and amount of force
-similar to somatosensory cortex, capable of reorganization after injury |
|
|
Term
| divisions of the motor cortex in the macaque monkey brain |
|
Definition
-premotor cortex-direct and indirect influence on motor behavior
-lateral-important in (visually cued) conditional motor task; fire max when visual cue is presented before signal to perform mvt
-selection of mvts based on external cues
-mirror motor neurons-encoding the actions of others |
|
|
Term
| mirror MN activity in a ventral anterior sector of the lateral premotor cortex |
|
Definition
-mirror motor neurons fires during passive observation of the same action performed by others
-no firing when a pliers was used
-neurons still fire when the action is out of view
-encoding the intentions and behaviorally relevant actions of others, imitation learning |
|
|
Term
| medial part of the premotor cortex |
|
Definition
-also mediates the selection of mvts
-initiating mvts specified by internal cues rather than external cues
-lesion-reduced number of self-initiated, or spontaneous mvts |
|
|
Term
|
Definition
-contains neuronal circuits that mediate reflexes and rhythmic mvts
-stretch reflex
-contains MN for execution of mvts-final common pathway |
|
|
Term
| sensory input to the spinal cord |
|
Definition
-sensory information influences motor output in many ways at all levels of the motor system
-sensory input to the spinal cord directly triggers reflex response
-sensory input, especially proprioceptive information, is integral in motor control |
|
|
Term
| muscle spindles vs golgi tendon organ |
|
Definition
MS-Ia muscle length
GTO-Ib muscle tension |
|
|
Term
|
Definition
-stretch, tendon, myotatic
-muscle are always under some degree of stretch
-this circuits normally responsible for steady level of tension in muscles called muscle tone |
|
|
Term
|
Definition
-electrical equivalent of the tendon jerk
-elicited by electrical stimulation of afferent Ia axons
stimulus is low amplitude
Ia axons have lower electrical threshold than MN
no role of muscle spindle or fusimotor drive in stimulation of h reflex
-modulated by central excitation and inhibition |
|
|
Term
| why do we use hoffman reflex |
|
Definition
-changes in spinal cord excitability
maintain upright when trip on carpet
weightlessness flight
-measure the role of descending control |
|
|
Term
|
Definition
-innervates contractile component of spindles
activation of GMN causes a contraction which shortens the spindles, increasing the gain of the stretch reflex
-level of GMN activity=gamma bias or gain, can be adjusted by MN pathway or local circuitry
-larger the gain of the stretch reflex, greater the change in muscle force with stretch-->small stretch of the intrafusal fibers will recruit a large amount of MN and a large increase in their firing rate--> more force
-during voluntary and involuntary mvt, alpha and gamma MN coactivate by higher centers to prevent muscle spindles from being unloaded (alpha-gamma coactivation)
-baseline of GMN activity is high when a mvt is difficult |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| -MN of the spinal cord and brainstem that directly innervates the skeletal muscles |
|
|
Term
|
Definition
-PARALYSIS or paresis
-atrophy
-fibrillations and fasiculations
-decreased muscle tone
-loss of tendon reflex |
|
|
Term
|
Definition
-originate in higher regions of the brain(motor cortex) and synapse on the LMN to convey descending commands for mvt
-pre motor neurons |
|
|
Term
|
Definition
-paralysis or PARESIS
-spasticity
-increased muscle tone
-overactive tendon reflex
-abnormal plantar extension reflex |
|
|
Term
|
Definition
| patterns of facial weakness and their importance for localizing neurological injury |
|
|
Term
|
Definition
| umn and lmn lesions summary table |
|
|
