Structure and Function of Major Brain Regions in Psychology

Brain Structure and Function

Overview

The human brain is composed of several major regions, each responsible for specific functions essential to survival, behavior, and cognition. Understanding these regions is fundamental in psychology, as they underlie processes such as movement, emotion, memory, and sensory perception.

Major Brain Regions

Brainstem

The brainstem is the oldest part of the brain, responsible for basic life functions such as breathing and sleep. It acts as a relay center, receiving information and sending it to other brain areas.

• Hindbrain: Includes the cerebellum, reticular formation, pons, and medulla.

• Midbrain: Contains dorsal (sensory) and ventral (motor) areas.

• Diencephalon: Composed of the hypothalamus and thalamus, located below the hypothalamus.

• Basal Ganglia: Involved in motor coordination and learning.

Hindbrain

• Oldest part of the brain

• Functions: Motor functions (e.g., breathing, sleep), balance

Midbrain

• Relay center for information between higher and lower brain regions

Diencephalon

• Relay center

• Sends information up and down the brain

Cerebellum

• Motor movement: Coordinates voluntary movements (e.g., playing sports)

• Emotional control: Influences cognitive effects and attention span

• Located at the base, on the brainstem and cortex

• Ventral = closer to the back of the neck

Medulla

• Controls breathing

• Essential for life

Reticular Formation

• Stimulates neurons in higher areas

• Regulates sleep, alertness, and wakefulness

Pons

• Largest, smooth white structure

• Controls automatic body movements (e.g., sneezing, vomiting)

Dorsal (Superior) vs. Ventral (Inferior)

• Dorsal (Superior): Top, sensory information, like the fin of a fish

• Ventral (Inferior): Bottom, motor function

Basal Ganglia

• Motor coordination

• Smooth motion

• Associated learning

Limbic System

The limbic system is a group of structures located deep within the brain, involved in motivation, emotion, and memory.

• Medial location (towards the center)

• Motivational behavior

• Memories:

  • Amygdala: Responsible for fear responses, anxiety, and PTSD

  • Hippocampus: Shaped like a seahorse, involved in long-term memory (e.g., studying), located internally

Thalamus and Hypothalamus

• Thalamus:

  • Sensory relay center (except smell)

  • Auditory center

  • Located in the middle of the brain

  • Olfactory (smell) information bypasses the thalamus

• Hypothalamus:

  • Regulates the "four F's": Flight, Flee, Feed, Fornication

  • Controls temperature

  • Involved in forms of emotional behavior

The Brain (Cortex)

The cortex is the outermost layer of the brain, responsible for higher-order functions such as perception, thought, and voluntary movement. It is divided into several lobes, each with specialized functions.

Summary Table: Major Brain Structures and Functions

Structure	Main Function(s)	Location
Hindbrain	Basic life functions (breathing, sleep, balance)	Base of brain
Midbrain	Relay center for sensory/motor info	Above hindbrain
Diencephalon	Relay center, includes thalamus/hypothalamus	Central brain
Cerebellum	Motor coordination, balance, emotional control	Base, behind brainstem
Basal Ganglia	Motor coordination, learning	Deep within cerebral hemispheres
Limbic System	Emotion, motivation, memory	Medial, deep brain
Thalamus	Sensory relay (except smell)	Center of brain
Hypothalamus	Homeostasis, emotion, drives	Below thalamus
Medulla	Breathing, heart rate	Base of brainstem
Pons	Automatic movements	Above medulla
Reticular Formation	Sleep, alertness	Runs through brainstem
Amygdala	Fear, anxiety, PTSD	Limbic system
Hippocampus	Long-term memory	Limbic system

Key Terms

• Motor function: Movement and coordination of muscles

• Sensory function: Processing of sensory information (touch, sight, sound, etc.)

• Relay center: Area that transmits information between different brain regions

• Homeostasis: Regulation of internal body conditions (temperature, hunger, etc.)

Example Applications

• Damage to the hippocampus can result in difficulty forming new long-term memories (anterograde amnesia).

• Overactivity of the amygdala is associated with anxiety disorders and PTSD.

• Lesions in the basal ganglia can cause movement disorders such as Parkinson's disease.