Nervous system HIGHER BRAIN, FUNCTIONS & EMOTION

Question 1

State the location of the reticular activating system (RAS)

Answer 1

It extends through the central core of the medulla oblangata, pons and midbrain. It is composed of clusters of neurons in white matter.

The neuron for 3 columns along the brainstem

1. Midline raphe nuclei flanked by..
2. Medial group of nuclei (large cell)
3. Lateral group of nuclei (small cell)

Question 2

What are the functions of the RAS?

Answer 2

1. Processes info from cerebral motor cortex, proprioceptors and visual & equilibrium pathways
2. Responsible for proper balance and posture
3. Instructs cerebral motor cortex and subcortical motor centers, resulting in smooth coordinated movements

Question 3

Describe the mechanism of action of the RAS

Answer 3

Arouses specific cortical areas by increasing blood flow, allowing us to move from relaxed state to focused attention.
Filters external stimuli, thus suppressing repeated/familiar/weak stimuli to prevent sensory overload

Question 4

What are the targets for the RAS?

Answer 4

Ascending tracts to cerebral cortex, thalamus and hypothalamus as well as descending tracts to cerebellum

Question 5

List the principal physiological functions of the RAS

Answer 5

RAS and thalamus influence arousal, sleep-wake transition, motor responses, autonomic functions, eating, dreaming

During sleep, RAS inhibits frequency of afferent neurons firing

During wakefulness, afferent neurons fire at greater frequency

Question 6

Compare declarative and non-declarative memory

Answer 6

Declarative (fact) - learning explicit info like names and faces. Is related to our conscious thoughts and ability to manipulate symbols & language. When stored in LTM, it’s filed in the context in which it was learned.

Non-declarative - unconscious learning through experience and repetition and best remembered by performing the action. Once learned, they’re hard to unlearn.

1. Procedural memory = piano
2. Motor memory = tying shoes
3. Emotional memory = pounding of heart when you see rattlesnake

Question 7

Compare short-term and long-term memory

Answer 7

STM - small chunks of info such as cellphone number over seconds

LTM - permanently storing, managing and retrieving the info for later use. Memories may be available for lifetime and limitless capacity