Motor Skills Exam 2

Rostral on a quadruped

toward the head

Caudal on a quadruped

toward the tail

Ventral on a quadruped

toward the belly

Dorsal on a quadruped

toward the back

Rostral on a biped

superior towards head

Caudal on a biped

inferior towards feet

Ventral on a biped

anterior towards front of body

Dorsal on a biped

posterior towards glute

Rostral at curve near temporal lobe

anterior towards forehead

Dorsal at curve near temporal lobe

posterior/top of head; crown of the head

Ventral at curve near temporal lobe

inferior part of head towards temporal lobe or chin

Caudal at curve near temporal lobe

towards neck/brainstem; inferior to the head

Sagittal plane

vertical plane dividing left and right halves of the body

Parasagittal plane

vertical plane dividing body into uneven left and right halves

Horizontal plane

parallel to the ground/horizon when upright; divides body into a top and bottom

Transverse plane

perpendicular to the long axis that runs from head to lower body; divides body into top and bottom

What directions do ascending axons run?

Rostral

What directions do descending axons run?

Caudal

Afferent vs efferent

• Input to CNS = afferent

• Output from CNS = efferent

Ipsilateral

on the same side

Contralateral

on opposite sides

Decussate

crosses the midline

What two structures make up the CNS?

Brain + spinal cord

5 sections of the spinal cord

• Cervical

• Thoracic

• Lumbar

• Sacral

• Coccygeal

3 parts of the brain stem

• Midbrain

• Pons

• Medulla

Diencephalon consists of what?

thalamus + hypothalamus

What makes up the PNS?

• Nerves not in the CNS, including:

  • Ganglia

  • Autonomic nervous system response

Nucleus vs ganglion

Nucleus = cell body within CNS

Ganglion = cell body within the PNS

Tract vs nerve

Tract = bundle of axons within the CNS

Never = bundle of axons within the PNS

Gray matter consists of…

mainly nerve cell bodies and dendrites

White matter consists of….

mostly axons

Why is white matter white?

From the myelin of the axons

How does layout of grey and white matter differ between the spinal cord and cerebral cortex?

• In spinal cord, white matter surrounds butterfly shaped white gray matter

• In cerebral cortex, gray matter surrounds the white

Function of the spinal cord

Recieves sensory input from all of the body and begins the processing of this input before conveying messages to higher centers. It also contains the efferents of the ANS (autonomic) and sends motor ouput information.

Dorsal horn contains what

interneurons and sensory neuron axons

Intermediate zone of gray matter contains what

interneurons

Ventral horn of gray matter contains what

motor neurons

What are the three types of motor output?

1. Involuntary: these are reflexes that only reach the spinal cord

2. Central pattern generators: neural circuitry that mediates rhythmic activitities

3. Voluntary movement: choosing to move

What are central pattern generators (CPGs) are where are they located

These are neuron groups that mediate rhythmic activities autonomously. They are located in the brain stem and spinal cord.

Walking and chewing are what kinds of motor output

central pattern generators

Sulcus vs gyrus

• Gyrus = a ridge or raised bump on the surface of the cerebral cortex

• Sulcus = a groove or depression separating those ridges (gyri)

Fissure vs sulcus

• Sulus = shallow groove in the cerebral cortex

• Fissure = deep greeve in the cortex

What are the 3 cerebral cortex fissures?

Interhemispheric, lateral, parieto-occiptial

What are the 2 sucli of the cerebral cortex

central and cingulate

Central sulcus separates what?

The frontal lobe from the parietal lobe

Cingulate sulcus separates what?

separates the cingulate gyrus from the medial frontal gyrus and paracentral lobule 

What does the interhemispheric fissure separate?

Divided the brain into right and left halved

What does the lateral fissure separate?

Separates the frontal and parietal lobes

What does the parieto-occipital fissure separate?

Divided parietal lobe and occipital lobe

What is the homunculus?

• “little man”

• It is a distorted visual map of the human body drawn across the surface of the brain

• M1 and S1 have their own versions of their little man

What are the three parts of the motor cortex?

• Primary motor cortex (M1)

• Premotor cortex (PM)

• Supplementary motor area (SMA)

Primary motor cortex is stimulated by what?

• Individual joint movements and muscle contractions

• Simple movements

Projections of the primary motor cortex

• Descending tracts

• Mostly contralateral

  • Right side of the brain controls the left side

• Some are bilateral

Pre-motor cortex is stimulated by what?

Complex movements; it plans and prepares movements based on external sensory cues (ex: visual or tactile cues)

Supplementary motor area is stimulated by what?

Complex movements; it plans and selects complex movements or multi-step motor sequences based on internal cues (ex: memory, thoughts)

Projections of the premotor cortex

• Descending

  • They go to axial and proximal muscles

• Corticocortical

  • Sends feedforwards signals about external cues to M1 to trigger planned movement sequences

Projections of the supplementary motor area

• Corticocortical

  • Projects to M1 to provide signals about internal cues, allowing for complex motor movement

Parietal lobe main function

Processes sensory input and projects to premotor cortex and primary motor cortex so that they can use this input to plan movement

Thalamus

• Processes movement signals (projections) coming from the cerebellum and basal ganglia and helps relay them to the motor cortex to help coordinate smooth voluntary movements

• Also recieves sensory information and sends sensory information to S1

Basal ganglia function

movement modulation; controls voluntary movement and plays roles in learning/habit formation

Cerebellum function

Coordination, balance, motor learning, cognitive; “little brain”

What are the three parts of the sensory cortex?

Primary somatosensory area (S1), secondary somatosensory area (S2), or posterior parietal cortex (PP)