3.3 The Brain and Behavior

Research Methods

• *Lesioning (animals)
• *Electrical stimulation of the brain (ESB) (animals and sometimes humans through required brain surgery)
• *CT Scan (humans)
• *MRI Scan (humans)
• *PET Scan (humans)
• *fMRI (humans)

Structures of Brain

• Cerebrum: Responsible for sensing, thinking, learning, emotion, consciousness, and voluntary movement
• Corpus Callosum: Bridge of fibers passing information b/w the 2 cerebral hemispheres
• Thalamus: Relay center for cortex; handles incoming & outgoing signals
• Cerebellum: Structure that coordinates fine muscle movement; balance; critical to sense of equilibrium; role if sensing position of limbs
• Reticular formation: Group of fibers that carry stimulation related to sleep and arousal through brainstem
• Spinal cord: Responsible for transmitting information b/w brain & rest of body; handles simple reflexes
• Medulla: Responsible for regulating largely unconscious functions such as breathing and circulation
• Pons: involved in sleep & arousal
• Hippocampus: Part of limbic system involved in learning and memory
• Pituitary Gland: Master gland that regulates other endocrine glands
• Hypothalamus: Responsible for regulating basic biological needs: hunger, thirst, temperature control
• Amygdala: Part of limbic system involved in emotion and aggression

The Hindbrain

• Includes:
• Cerebellum (function depressed by alcohol; damage disrupts fine motor skills (such as those involved in writing, typing, playing instrument)
• Medulla
• Pons
• *Brain circuits running from the cerebellum to the profrontal cortex appear to be involved in high-order functions, incl., attention, planning, & visual perception

Midbrain

• Midbrain: concerned with integrating sensory processes; dopamine-releasing neurons originates here, which is involved in voluntary movements among other things
• decline in dopamine synthesis that causes Parkinson's is caused by degeneration of a structure located in midbrain
• Reticular formation runs through hindbrain & midbrain

forebrain

• Core: thalamus, hypothalamus (lies beneath the thalamus), limbic system (includes parts of the thalamus & hypothalamus, the hippocampus, amygdala)- located near the top of the brainstem
• Above the core is the cerebrum (divided into 4 lobes), with the cerebrum cortex being the wrinkled surface of the cerebrum
• Limbic system is also the "pleasure area" of the brain; heaviest concentration of pleasure site is in the medial forebrain bundle

Brain Plasticity

• 1. Aspects of experience can sculpt features of brain structure.
• 2. Damage to incoming sensory pathways or destruction of brain tissue can lead to neural reorganization.
• 3. Adult brain can generate new neurons (which plays role in learning & memory).
• Neural wiring is flexible and evolving but there is a limit. Plasticity declines with age.