Brain Regions and Structures — Key Concepts

Hindbrain: medulla, pons, cerebellum; essential survival functions; breathing, sleep/wake, coordination and balance
Midbrain: atop brainstem; connects hindbrain to forebrain; some motor movement; transmits auditory and visual information
Forebrain: cerebral cortex, thalamus, hypothalamus; manages complex cognition, sensory/associative processing, and voluntary motor activities

Thalamus: central control center at top of brainstem; directs sensory messages to cortex; transmits replies to cerebellum and medulla
Reticular formation: nerve network through brainstem into the thalamus; controls arousal
Cerebellum: little brain at the brainstem rear; processes sensory input; coordinates voluntary movement output and balance; enables nonverbal learning and memory

Amygdala: two bean-sized neural clusters; emotions
Hypothalamus: below the thalamus; maintains homeostasis; directs endocrine system via pituitary; emotion and reward
Hippocampus: seahorse-shaped; explicit, conscious memory

Cerebral cortex: ultimate control and information-processing center of the body; approx. $20\text{-}23\ \text{billion brain nerve cells}$ and $300\ \text{trillion synaptic connections}$
Cerebral hemispheres: paired; cortex of each hemisphere divided into four lobes; interconnected neural cells

Motor cortex: rear of frontal lobes; controls voluntary movements
Mapping the motor cortex: body areas requiring precise control occupy the most cortical space (Foerster and Penfield)
Brain-machine interfaces: device implants studied to detect and facilitate motor cortex activities; implant recipients have learned to direct robotic arms with their thoughts

Somatosensory cortex: receives input from skin senses and movement of body parts; located in front of parietal lobes; behind motor cortex; body region sensitivity is larger here
Visual cortex: receives input from eyes; sends information to task-specific areas (face identification, emotion detection, face recognition); located in occipital lobes at the brain’s back
Auditory cortex: receives information from ears; circuitous route from one ear to the auditory receiving area above the other ear; located in temporal lobes

Association areas: cerebral cortex areas not involved in primary motor or sensory functions; involved in higher mental functions (learning, remembering, thinking, speaking); found in all four lobes
Prefrontal cortex: enables judgment, planning, social interactions, and new memory processing; damage can alter personality and inhibit, disconnecting moral behavior from action