Lecture 8 - Voluntary Control of Locomotion Flashcards
What is brain mapping
Applying electrical current to an area of the brain and seeing what happens
What is the motor humunculous
A mapping of what areas of the brain/motor cortex control what areas
What is a motor sequence
A complex movement can be broken down into a chain of small components - catching a ball- first lift arm, etc
Repetitive performance of complex motor sequences allows you to develop
Automation (motor memory)
Motor sequence
A sequence of movements programmed by the brain and produced as a unit
To create a motor sequence, what happens
The cortex sends general programs to the brainstem and spinal cord. Spinal cord coordinates specific movements
Examples of convolutions in brain
Gyri and sulci
Cerebral cortex - convolutions allow for
3 times the information to be packed in compared to a perfectly smooth structure
Cerebral cortex appearance
Thin outer shell of grey matter with neurons including UMN
Left & right cortex are connected by
Corpus callosum, which transfers information between the two halves of the brain
Regions of the cortex are grouped into 4 lobes named after the skull bones under which they lie. Name them:
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Cerebral cortex is organized into
6 layers
Layer 4 of cerebral cortex receives input from
Main input from thalamus
Layer 5 of the cerebral cortex’s main output is to
Spinal cord, thalamus, and brain stem
Cortex is organized into columns. Cells in layers in columns predominately participate in
A function - ie movement of index finger
Where is sensory input relayed from
Afferent neuronal receptors
Primary sensory areas (somatosensory, 1° visual, 1° auditory cortices) does the initial cortical processing of
Specific sensory input
Higher sensory areas do
Further elaboration and processing of specific sensory input
Association areas do
Integration, storage, and use of diverse sensory input for planning of purposeful action
Higher motor areas do programming of
Sequences of movement in context of diverse information provided
Primary motor cortex does commanding of
Efferent motor neurons to initiate voluntary movement
Motor output is relayed through
Efferent motor neurons to appropriate skeletal muscles, which carry out desired action
Somatosensory cortex is located posterior to
Central fissure
Somatosensory cortex is for simple awareness of
Touch
Temperature is handled by the
Thalamus
Somatosensory cortex
More complex processing of sensation such as localization of touch and intensity is handled by the
Somatosensory cortex
Somatosensory cortex projects to
Higher centres (eg posterior parietal lobe) for integration with input from other cortical areas
The thalamus participates in sensory detection but can’t tell you
Where you’re feeling it - happens when there’s damage to somatosensory cortex
Receptive fields vary depending on
The region innverated
Receptive fields of fingers vs upper arm
Fingers have many and upper arm has few
Way to test receptive fields
Two-point discrimination task - put calipers on back and spread apart until person can feel there’s two then do same thing on hand with eyes closed - then measure the distance
Somatotopic
Body representation
Sensory somatotopic map: sensory humunculous
Maps are plastic and can change following training, amputation of a limb, etc
Somatosensory input from the limbs is sent from the ________ to the ___________
From the Somatosensory cortex to the association cortices (parietal lobe)
Visual input regarding limb position is sent from _______ to _______
Occipital lobe to the parietal lobe
A body map is generated which relies on
Both visual and somatosensory input
Areas movement is planned in
Supplemental motor, pre-motor, and prefrontal cortex
Primary motor cortex is responsible for
Simple movements (like moving ur finger)
The pre motor and supplementary motor area generate complex movements by
Chaining together movements produced by the primary motor cortex
Are the motor somatotopic and sensory somatotopic map the same?
No, similar, but not identical
Where inputs to the motor cortex?
Premotor Cortex, corpus callosum, prefrontal cortex
Major output of primary motor cortex
Axons from primary motor cortex
Spinal cord (motor neurons & muscles)
Brain: cerebellum, brainstem, basal ganglia
What Corticospinal tract is involved in coordinating fine movement tasks
Lateral Corticospinal tract
Precision vs power grip
Precision grip is precise, power grip is just for strength
Is the motor cortex active during power grip
No, different neurons active in power grip.
Is motor cortex active during precision grip
Yes
Is the motor cortex active during movement
Only active in planning & executing movement
If a cat is walking up to an obstacle, will it hit the obstacle with hind limbs when walking by?
No, as the brain has noted it and will send signals to avoid it
Basal ganglia consist of
4 large subcortical nuclei that participate in control of movement
Do basal ganglia have direct input or output with the spinal cord?
NO
Where is basal ganglia’s input/output?
Input - from cortex
Output - to thalamus and then on to cortex
3 theories on basal ganglia function
- facilitate and inhibit various movements
-compares motor commands with what body is doing - initiation of automatically generated movement sequences
Is Parkinson’s disease documented in animals other than humans?
No
Lesion studies involving the basal ganglia show that
Basal ganglia plays a key role in movement selection
