Week 5 Flashcards
(31 cards)
What forms the outer surface of the forebrain and how many layers are there?
Cerebral cortex
6 layers
Describe a Betz cell
very large pyramidal cells which are in layer 5 of the primary motor cortex
Where do Betz cells go?
They project from the motor cortex to the spinal tract, also to the brain stem (only 5% to motor neurons, rest reach the spinal interneurons)
How does the corticospinal tract interact with Betz cells?
Betz cells innervate alpha and gamma motor neurons which then switches sides in the medulla, so limbs are controlled by the contralateral motor cortex
What is the relationship between sensory and motor maps?
Close mirror relationship
How do effector specific regions work?
They interlock with regions showing different connectivity, structure and function
They show high connectivity to each other and to networks
They become active during planning and lack effector specificity (2 parallel regions in the primary motor cortex)
What is the effect of electrical stimulation in our motor cortex?
Brief stimulation (50ms) = contraction of muscles
Prolonged stimulation (500ms+) = complex goal directed actions e.g. climbing/reaching
What is represented in our motor cortex?
Motor lesions result in loss of individual use of fingers (affects more fine skills)
Where is the primary motor cortex located?
Frontal lobe
Describe the frontal eye fields
(equivalent to primary motor cortex but for eye movements)
Heavily connected to occipital lobe and prefrontal cortex
Has a somatotopic map of the representation of space
Describe secondary areas
Very dense connections between secondary motor areas
Heavily connected to primary cortex
SMA and PMC more involved in planning movements
Describe the Posterior Parietal Cortex
Links the frontal cortex with premotor area
Receives info from sensory regions
Important for determining potential actions/goals
What are the two areas of the supplementary motor area?
SMA proper (learning) and pre SMA (execution)
What are the purposes of the SMA?
Postural stability
Planning and executing sequential movements
Initiation of internally generated movements
What is the purpose of the Dorsal premotor?
Important in preparation of movement; learning conditional actions
What is the purpose of the ventral premotor?
Important for sensory guidance of movement: responsive to tactile, visual and auditory stimuli
What are the purpose of mirror neurons?
Important for learning through observation and for understanding other people’s intentions
How do mirror neurons work?
They are sensitive to experience and learning about environmental contingencies
Define neuroplasticity
The ability of the brain to form and reorganise synaptic connections, especially in response to learning/ experience/following injury
How can somatotopic maps change?
Rapid changes in somatosensory evident after changes in input e.g. training (learning) or denervation (injury)
How do the changing of maps reflect neuroplasticity?
LT changes in functional connectivity
Branching of dendritic connections
Neurons “compete” for space in the cortex
What are the learning based neural changes in the pre-synapse?
Increase vesicle volume
Increase availability of vesicles
Increase release probability
What are the learning based neural changes in the synaptic cleft?
Reduced re-uptake mechanisms
Reduce gap dimensions
What are the learning based neural changes in the post-synapse?
Increase receptor density/area
