sensorimotor integration Flashcards
Why do sea squirt larvae have a brain but adults don’t?
Larvae use their brain to swim; after attaching, they become immobile and digest their brain.
What is a primary evolutionary purpose of the brain?
To generate meaningful movement (behaviour).
What is the minimal unit of sensorimotor integration?
The monosynaptic stretch reflex.
How does the monosynaptic stretch reflex work?
Muscle stretch → mechanoreceptor activation → afferent neuron fires → motor neuron activated → muscle contracts.
What does the knee jerk reflex illustrate?
Local integration of sensory and motor signals without full central processing.
What factors influence behaviour selection in a changing world?
Context, internal state, life stage, prior experience (memory), and current sensory info.
What type of reflex involves the CNS?
Postsynaptic reflexes.
What do cones in the fovea do?
Detect light and transduce it into neural signals.
What do ganglion cells do?
Convey visual information to the brain.
What brain region is involved in visual attention and saccades?
Posterior parietal cortex.
What happens if the posterior parietal cortex is damaged?
Attentional deficits, such as spatial neglect.
What role does the superior colliculus play?
Visuomotor integration and eye movement mapping.
What are the two main neuron types in the superior colliculus?
Movement-related neurons (fire before saccade) and visual-fixation neurons (fire after saccade).
How is tonic inhibition lifted to allow a saccade?
Caudate nucleus disinhibits the superior colliculus by inhibiting the substantia nigra pars reticulata.
What are the major visual pathways?
Geniculostriate: motion, depth (dorsal), colour, contours (ventral)
Tectopulvinar: spatial awareness (“where”)
How does the brain predict where a ball will bounce?
By combining prior knowledge (memory) with sensory input to estimate trajectory.
What are the basal ganglia’s roles in movement?
- Action selection
- Initiating/terminating actions
- Associating actions with outcomes
What are the two main loops in motor control?
Oculomotor loop (eye movement)
Skeletomotor loop (voluntary movement)
What is the motor homunculus?
A map of motor cortex areas controlling different body parts.
What activates different parts of the motor cortex?
Different movement stages (approach, swing, hit).
What triggers muscle fiber contraction at the neuromuscular junction?
Acetylcholine released by motor neuron terminals.
What does the brain do after an action?
It predicts the outcome and compares it with actual results.
What happens if there’s a prediction error?
The reward system reinforces or modifies the action.
What systems are involved in tracking and hitting a ball?
- Visual system
- Memory (prior knowledge)
- Motor control
- Reward system
