Functional Brain Systems

Question 1

Describe the Functional Brain Systems

Answer 1

Networks of neurons working together and spanning wide areas of the brain

Limbic System

&

Reticular Rormation

Question 2

Describe the Limbic System

Answer 2

• Evolutionarily primitive parts of the forebrain, responsibilit for basic physiological drives, instincts, and emotions
• Electrical stimulation of certain areas of the limbic system can caues intense sensations of pleasure, pain, or rage
• Attaches emotinoal responses to odors (e.g., skunks smell bad)
• Located on medial aspects (deep) of cerebral hemispheres & diecephalon

Question 3

What are the Limbic System structures?

Answer 3

Amygdala

Hippocampus

Cingulate gyrus

Hypothalamus

Anterior nucleus of the thalamus (plus other structures)

Question 4

Where does right/left communication occur?

Answer 4

via the fornix and anterior commissure

Question 5

Which structures of the limic system are especially important in emotions?

Answer 5

Amygdala

&

Cingulate gyrus

Question 6

What does the amygdala do?

Answer 6

Deals with anger, danger, and fear responses and fear memory

e.g., if damaged, an animal cannot learn to be afraid of a stimulus

Question 7

What does the Cingulate gyrus do?

Answer 7

plays a role in expressing emotions via gestures and resolves mental conflict

Question 8

Which structure of the Limbic System is especially important in forming memory?

Answer 8

Hippocampus

Question 9

What does the Hippocampus do?

Answer 9

Converts new information into long-term memories

Question 10

Within the Limbic system, what is the relationship between emotion and cognition?

Answer 10

• The limbic system interacts with the prefrontal lobes, therefore:
  
  • one can react emotionally to conscious understandings
  • one is consciously aware of emotion in one’s life
  • negative emotions impact the ability to form long-term memory

Question 11

Describe Reticular Formation

Answer 11

Composed of three broad columns along the length of the brain stem:

Raphe nuclei, Medial group, Lateral group

Has extensive axonal connections with spinal cord, hypothalamus, thalamus, cerebellum

RAS = Reticular Activating System - sends impulses to the thalamus and cerebral cortex to keep it active and alert

Question 12

How does the RAS or Reticular Activiting System work?

Answer 12

• Sends impulses to the thalamust and cerebral cortex to keep it conscious and alert
  
  • • keeps the resting potentials near threshold – thus, maintains wakefulness
• Filters out repetitive and weak stimuli, keeps the brain in a “ready” state (demo)
• Controls Motor function
• Controls Sleep and waking

Question 13

Explain the Motor Function of the RAS?

Answer 13

• Autonomic centers regulate visceral motor functions
  
  • BP, HR & breathing rate all increase or decrease in response to RAS input

Question 14

How does RAS help control sleep and waking?

Answer 14

Sleep: need to minimuze inputs (lights down, noise down, etc.)

Awaken: need to increase inputs (lights on, sound volumen up, etc.)

Question 15

What is Reticular Formation Damage?

Answer 15

• If the brain stem is damaged at midbrain or higher, reticular activity is not conveyed to the forebrain and the person is rendered comatose (unable to wake up)
• If the brain stem is damaged below the Reticular Formation, there will be normal sleep/wake patters (visual & auditory input unaffected) but will likely cause paralysis