Midbrain Flashcards
Superior cerebral peduncle
Directly anterior to superior aqueduct. Composed of efferent or motor nerve fibers that travel from the motor areas of the cerebral cortex down to the brain stem and eventually the spinal cord. Major pyramidal tract.
Pyramidal Tract
Fibers that run from motor cortex to the spinal cord, responsible for initiating movement
Corpora Quadrigemina
Composed of superior and inferior colliculi. Dorsally positioned and plays a role in the mediation of auditory and visual reflex. The functional union
Superior Colliculi
Responsible for the mediation and regulation of visual reflex.
Inferior Colliculi
Involved in relay in auditory information. Responsible for the mediation and regulation of auditory reflex
Tectum
Anatomic union for superior and inferior colliculi
Substantia Nigra
Strip of gray matter that sits just posterior to the nuclei of the cerebral peduncle. Important for motor control. Has fibers that extend to frontal lobe, so it also plays a role in attention, and in our executive functions. Also produces neurotransmitters called dopamine.
Executive Functions
How we exercise control over our cognitive processes, like inhibition, self-monitoring, planning, regulation of emotion, and motivation
Parkinson’s disease
Disease when substantia nigra cells die and depletes dopamine, which is important for movement.
Pons
It’s a connector. It connects midbrain to medulla oblongata and connects cerebellum to rest of the brain.
Red Nucleus
Sits just posterior to substantia nigra and it’s involved with movement. The relay center for extrapyramidal system.
Reticular Formation Three Functions
- An efferent and afferent communication network that extends from the level of the thalamus all the way down to the spinal cord.
- Early warning system that warns the thalamus and structures above that sensory information is going to be forthcoming.
- Works with thalamus to help regulate circulation, respiration, and gastrointestinal activities.
Vermis
Connects the two hemispheres of the cerebellum
Anterior Lobe
Receives proprioceptive impulses from spinal cord
Posterior Lobe
Connected to cerebrum, regulates coordination of muscle activity
Flocculonodular Lobe
Primarily responsible for mediating equilibrium
Ipsilateral
Each side of the hemisphere is responsible for the side of the body its on.
Inferior Cerebrellar Peduncle/ Restiform Body
Receives information coming through medulla, from the cortex above, which is motor, and it receives information from the spinal cord via the medulla that is sensory in nature.
Middle Cerebellar Peduncle/ Brachium Pontis
Carries fibers from frontal and temporal lobe, carry motor information to cerebellum via the pons
Superior Cerebellar peduncle/ Brachium Conjuntivum
Carry sensory information from cerebellum via midbrain to the thalamus.
Cerebellar Function 3 Step Process
- The cerebellum recieves incoming motor information to warn it about an impending motor movement
- Receives incoming sensory information with feedback about how the movement actually went
- Sends out sensory information that allows us to adjust and execute the motor action
4 Functions of the Cerebellum
- Center for inhibition and excitation of connecting neurons
- Responsible for muscle synergy
- It provides the fine coordination for rapid alternating movement
- It helps us maintain posture and balance for things like walking, eating, dressing, and writing
3 Primary Systems for Speech and Their Functions
- Pyramidal System- Responsible for initiating voluntary speech movements
- Extrapyramidal System- Provides non voluntary support that lets you perform the purposeful movement
- Cerebellar System- Provides the precise and specialized motor control that enables us to produce the rapid alternating and repetitive movements needed for smooth coordinated conversational speech
