Unit 7: Biological Bases of Behavior

Agonist → mimics or stimulates neurotransmitters

Antagonist → blocks the production of a neurotransmitter

• Corpus Callosum → connects the right and left hemisphere of the brain and allows them to communicate

  • Hemispheric Specialization → specilization occurs between the two hemispheres but a person is never left or right brained

    • Can be seen in split-brained patients

Hindbrain

• Medulia Oblongata → Located on top of the spinal cord; the very bottom of the brain

  • involved in the control of our blood pressure, heart rate, and breathing

• Pons → Located on top of the medulla; larger swelling

  • connects the hindbrain with the midbrain and forebrain

  • involves the control of facial expressions

• Reticular Formation → Located through the middle of the medulla & the pons; in between the ears

  • involved in various physiological functions, including pain sensitization, alertness, fatigue, sleep, and motivation

• Cerebellum → Located in the rear of the brain; large & deeply folded structure; “little brain”

  • Coordinates some habitual muscle movements such as tracking a target with our eyes or playing the saxaphone

• Brain Stem → Located in the lower part of the brain that connects to the spinal cord

  • helps regulate vital body functions that you don’t have to think about, like breathing and your heart rate

Forebrain

• Limbic System → Located as a loosley connected netwrok of structures

  • responsible for mood & emotions, as well as the experience of pain and fear

• Thalamus → Located on top of the brainstem

  • responsible for recieving the sensory signals coming up the spinal cord and sending them to the appropriate areas in the rest of the forebrain

    • smell is the only thing that does not go through the thalamus but is directly wired to the Limbic system

• Hypothalamus → Located directly underneath the thalamus & directly above the pituitary gland

  • controls several metabolic functions including body temperature, sexual arousal, hunger,thirst, and the endocrine system

• Hippocampus → Curved structure located within each temporal lobe; wraps around the back of the thalamus

  • vital to our memory system

  • memories are processed through this area and then sent to other locations in the cerebral cortex for permanent storage

• Amygdala → Two almond shaped structures located near the hippocampus

  • vital to our experiences of emotion

Cerebrum

• Frontal Lobe → Located in front of the brain; underneath the forehead, largest lobe

  • important for voluntary movement, expressive language and for managing higher level executive functions

• Prefrontal Cortex→

  • thought to play a critical role in directing thought process

  • acts as the brains central executive and is beleived to be important in forseeing consequences, pursuing goals, and maintaing emotional control

  • also beleived to be responsible for abstract thought

• Primary Motor Cortex →

  • provides the most important signal for the production of skilled movements

• Broca’s Area →

  • responsible for controlling the muscles involved in producing speech

  • if damaged, you may be unable to make the muscle movements needed for speech

• Temporal Lobe → Located just behind the temples; below the parietal lobe

  • process’s sound sensed by our ears

  • sound waves are processed by the ears, turned into neutral impulses, and interpreted in our auditory cortices

• Auditory Cortex →

  • processes auditory information

• Wernicke’s Area →

  • interprets both written and spoken speech

  • if damaged, the ability to understand language would be affected and our speech might sound fluent but lack the proper syntax and grammatical structure needed for meaningful communication

• Parietal Lobe → Located on top of the head; between the frontal & occipital lobes

  • Sensory cortex → which recives incoming touch sensations from the rest of the body

    • integrating sensory information, including touch, temperature, pressure and pain

• Somatosensory Strip →

  • recieves sensory input like heat or pain

• Occipital Lobe → Located towards the back of the brain; at the base of the cortex

  • processes visual signals and works cooperatively with many other brain areas

• Visual Cortex →

  • region of the brain that recieves, integrates, and processes visual information relayed from the retinas

Ways to See the Brain

• EEG → used majorily in sleep studies

  • gives us brain function but not structures

• CAT/CT → uses x-rays to see how the brain is operating in a region

  • used mostly on heads

  • will show a structure but not function

• MRI → show structure but not function

  • most commonly used

• PET→ injected with an isotope to see how your brain is reacting

  • shows function but not structure

• fMRI → only imagining technique that shows both function and structure

  • combined an MRI with a PET scan

• Brain Mapping → occurs when a doctor identifies what part of your brain controlls vision, speech, and movement to determine the precise location to perform brain surgery without reducing yout brain function

Case Study → Phineas Gage

• railroad worker who packed the explosives into the rock

• explosives ignited while he was packing it in

  • rod blew through his left eye and through his head

• survived the incident

• the rod went through his face and destroyed a portion of his brain

• after this incident, his personaity changed

  • went from friendley and a family man to bitter

Blindsight

• large amoun of places in the brain where eyesight can be effected

• sight passes through the thalamus

• even if you are blind, the thalamus continues to function and send signals

Sensory Homunculus

picture

Case Study → Joe

• suffered from epilepsy that would travel between the left and right parts of the brain via the corpus callosum

• as. a last ditch effort, they removed the corpus callosum to stop the transfer between the two parts