Motoneurons innervating axial and proximal muscles are located (laterally/medially) in the ventral horn of the spinal cord.
Motoneurons innervating distal muscles are located (laterally/medially) in the ventral horn of the spinal cord.
Motoneurons innervating extensor muscles are located (ventral/dorsal) to those innervating flexor muscles.
(T/F) Interneuron pools in the intermediate gray that innervate motoneurons are segregated in the same way as motoneurons in the ventral horn.
(T/F) Descending tracts are located in the white matter adjacent to the relevant motoneuron pools they control.
Proprioceptive input to a cortical column arises in the joint (proximal/distal) to the muscle that the column controls.
Cutaneous input to a cortical column arises where?
From a skin region in the path of limb movement that the column controls.
Inputs to the cortical columns travel through the ______________ and _____________ thalamic nuclei.
Ventroanterior and ventrolateral thalamic nuclei
The standard visuo-motor reflex takes about ___ms.
The standard cortical reflex takes about ___ms.
90% of the corticospinal tract arises in the ____________ and ___________ cortices.
Precentral and postcentral
Pathways controlling axial and proximal muscles for use in posture typically undergo (phasic/tonic) innervation.
(TPP) = Tonic, Proximal, Posture
Pathways controlling distal muscles for use in discrete movements typically undergo (phasic/tonic) innervation.
(PDD) = Phasic, Distal, Discrete
Muscle tracts that make use of tonic innervation include:
- Pontine reticulospinal
Tonic = Control Postuer (Axial and proximal muscle groups)
Muscle tracts that makes use of phasic innervation include:
- Medullary reticulospinal
Phasic = Control Discrete Muscle Movement (Distal muscle groups)
The lateral corticospinal tract primarily terminates upon (flexor/extensor) interneurons.
The rubrospinal tract usually (activates/inhibits) flexors and (activates/inhibits) extensors of the upper body.
- Activates flexors
- Inhibits extensors
Massive effect on force (flexor part of emergency control; i.e. grabbing onto tree when you fall)
Acts on alpha motor neurons
The medullary reticulospinal tract usually (activates/inhibits) flexors and extensors.
(T/F) Upon entering sleep, the medullary reticulospinal tract hyperpolarizes the body's flexor and extensor interneurons. This is a defense mechanism to cause paralysis during sleep and prevent movement during vivid or imaginative dreams.
The vestibulospinal tract primarily activates (flexor/extensor) alpha motor neurons and interneurons. It is important in maintaining balance and prevention of injury while falling.
The pontine reticulospinal tract typically (activates/inhibits) extensor interneurons.
Helps you stand up
The tectospinal tract activates (extensor/flexor) interneurons of the upper cervical areas to track objects on the edges of the field of vision by moving the neck.
What path do fibers in the corticospinal tract travel after leaving the motor cortices?
- Corona radiata
- Internal capsule (posterior limb)
- Cerebral peduncle (middle third)
- Decussation into lateral and anterior corticospinal tracts
Glutamate is (excitatory/inhibitory).
Inputs to the striatum (caudate nucleus and putamen) from the cerebral cortices use the neurotransmitter _____________.
Inputs to the striatum (caudate nucleus and putamen) from the thalamus use the neurotransmitter ______________.
Inputs to the striatum (caudate nucleus and putamen) from the substantia nigra use the neurotransmitter ______________.
Inputs to the striatum (caudate nucleus and putamen) from the raphe nucleus use the neurotransmitter _______________.
Outputs from the striatum travel to the _________ and _________.
Globus pallidus and substantia nigra
The ___________ and __________ function to regulate output from the striatum.
Subthalamic nucleus and external pallidum (of globus pallidus)