Interfacing Brain & Body Flashcards
Define interface
a point where two systems meet and interact.
How do brain processes fold outside of consciousness and why is this useful?
- the brain plans actions ahead of time to ensure smooth and timely movements.
- This is crucial because there’s a slight delay (about 200 milliseconds) between the brain sending motor commands and the body reacting.
Describe the cerebellum
Important function in making decisions outside of conscious awareness
It knows what your doing 8 seconds before you are consciously aware of it
What is the cerebellum also involved in?
learning, cognitive functions and multiple motor control
What is motor invariance?
typically movements are carried out in a similar manner
When we execute movements, there are a number of other decisions we need to make. What are these 6 planning choices?
Duration
Path
Velocity
Joint angles
Muscle activity
Neural firing pattern
Give an example of motor invariance?
Humans show highly stereotyped trajectories for eye and arm movements e.g;
Path = sequence of positions of the hand in space
Velocity = time sequence of along a path
What is neuromuscular junction?
The interface between our brain and limbs/ muscles
What are the main 4 components of neuromuscular junction?
Pre synaptic axon & terminal
Postsynaptic membrane
Synaptic vesicles
Acetylcholine receptors
Define the main function of the retina
Contains light sensitive cells which detect sensory information in from the visual world
To not use too much energy, the visual system needs to reduce how much info goes from the eye to the brain. Define compression
Compression = the brain interacts with the world in a very efficient and comfortable manner
What is the problem with compression?
it doesn’t always work correctly or is sometimes too efficient and tricks us into seeing things that aren’t really there
The world contains too much information, there’s two problems the brain needs to solve for us to perceive the world. What are these?
The resolution problem:
The amount of information the brain records from the eyes is vast
The energy problem:
If all of the cells in the retina were active all of the time the amount of energy required would be huge
What is the solution to the problems?
Compression:
Only transmit important info
- Changes are more important than the stuff that stays the same
Changes across space = only detect edges
Changes over time = only detect things that move (new objects)
What is Compression mechanism I ?
= spatial inhibition > simultaneous contrast-type illusions
Encoding changes over space:
How does encoding change over space?
G cells detect green at different (nearby) locations
Spatial inhibitors turn off cells if their like minded neighbours are active (i.e lateral inhibition)
Every “G” cell has a spatial inhibitor cell linked to it
Adaption is fast thus, the brain compresses signals that stay the same over time
What is lateral inhibition?
Disables the spreading of action potentials from excited cells to neighbouring cells
It enhances the contrast between stronger and weaker signals (improves localisation of objects)
What is Compression mechanism II ?
= temporal inhibition > after-effect type illusions
Encoding changes over time
How does encoding change over time?
Temporal inhibitors turn off cells if they are active for a long time
Adaption is slow, thus the brain compresses signals that stay the same over time
