Week 5 (Chapter 43-45) Flashcards
What are 3 potential triggers for brain reorganization?
- changed input (due to training)
- input loss (due to amputation)
- substrate loss (due to stroke)
What are alternate reasons for cortical map changes, rather than cortical reorganization?
- unmasking of pre-existing cortical map connections
- subcortical reorganization
What is reorganization?
When a specific neuron or brain region changes so that it becomes responsive to a new input, or produces entirely new output
S1 is typically an _____ structure, and M1 an ____ structure
- input
- output
What is the difference between S1 and M1 in terms of spatial resolution?
S1 shows more detailed representations of hand digits, while M1 represents body parts more crudely
What is a topographic map in terms of brain representations?
An orderly relationship of activity patterns on the cortical sheet that reflects the relationships of stimuli/movements along a specific physical dimension
What is gain modulation?
A brain area that used to weakly respond to a stimulus, becomes more responsive to it
What happens to neurons in the hand area of S1 when a hand is amputated?
They become activated by the chin
What happens to neurons in the hand area of M1 when a hand is amputated?
The neurons still control hand function
By utilizing reported phantom sensations, multiple studies have found that ______
Representations relating to the phantom hand persist in the peripheral and central nervous systems
What is functional reorganization?
A neural change that is causally related to changes in behaviour
What is the likely cause of changes in cortical maps?
Subcortical reorganization
What behaviour impairments are caused by dysfunction of the basal ganglia?
Reduction in speed and extent of movement
What is a proposed key computational function of the basal ganglia?
Controlling low-level parameters of movement
There is a dramatic ____ in cell number as one progresses through the _____ of the basal ganglia
- decrease
- internal circuitry
The basal ganglia have a _____ pathway through the ______
- reentrant
- thalamus
In mammals, afferent inputs to the basal ganglia come from the ______
Thalamus
Hippocampus
Amygdala
Neocortex
In mammals, the _____ and _____ receive all types of cortical input to the basal ganglia
- caudate
- putamen
What is considered the primary input nucleus of the basal ganglia?
The striatum
The striatum is composed of ~95% _____
inhibitory projection neurons
Direct-projecting principal neurons of striatum express _____, while indirect-projecting neurons express _____
- D1-type dopamine receptors
- D2-type dopamine receptors
Studies show that the basal ganglia are not necessary for the execution of movements, but for ______
Their invigoration
The basal ganglia have also been proposed to contribute to higher- level cognitive functions such as _____
Decision-making
The act of preparation is distinct from the act of ______ a movement - it happens ___ we need to move
- generating
- before
What is preparation?
A rapid process where specified high-level goals are translated into a policy suitable for movement and ready to be evoked when movement initiation is triggered
The delay between timing of movement preparation and initiation suggests _______
They are distinct processes
What is a fast error?
When a movement is initiated before the correct movement can be selected and prepared
Premovement population activity in PM/M1 reliably _______
Converges to a specific state
How long does movement preparation take?
No more than 50-100ms
Research suggests an overlap between mechanisms by which a decision was formed and ______
The mechanisms for representing a movement
