Midbrain ( brainstem)

Question 1

what is the midbrain composed of?

Answer 1

the Mesencephalon: upper brain stem

Question 2

what are the important areas in the mesencephalon(part of midbrain)?

Answer 2

-the tectum:superior and inferior
-Tegmentum – motor nuclei

Question 3

what are the functions of the tectum(part of midbrain)?

Answer 3

it is divided in:
- superior colliculus -receives sensory information form the eyes
- inferior colliculus - receives sensory information from the ears

Question 4

what are the functions of the tegmentum(part of midbrain)?

Answer 4

-Red nucleus: limb movement
-Substantia nigra:
Dopamine projection neurons (parkinsons disease)
Connection to basal ganglia & limbic system
-Periaqueductal grey: pain responses

Question 5

what are the main functions of the midbrain?

Answer 5

-sensory-motor connections
-Orienting behaviors to visual, auditory and noxious information
-Response in relation to value of objects

Question 6

What symptoms do you expect when the midbrain is disconnected from the rest of the brain? (High decerebrate)

Answer 6

behaviors in response to stimuli would still be intact;
Orientation to sounds and movement, intact appetitive, operant and automatic behaviors
E.g. Approach and rejection of food depending on satiety state

-Problems with self-initiated behaviors and habituation to stimuli (e.g. in response to loud noises),
overall drowsy state.
Behaviors are not energetic

Question 7

what is a spontaneous movement?

Answer 7

-it responds to simple visual and auditory stimulation.
-it performs automatic behaviours (grooming)
-when stimulated: a subset of voluntary movements(standing)