AP Psychology Brain Structures

Cerebral Cortex

  • Definition: The cerebral cortex is everything you can see when you remove the skull from the brain; it is the outer layer of the brain.

  • Lobe overview: There are different lobes of the cortex with specialized functions.

    • Frontal Lobe

    • Functions: motor movements, behavior, expressive language, and decision making.

    • Contains the motor cortex: all voluntary movement is through that cortex.

    • Parietal Lobe

    • Functions: somatosensory processing; sensation and touch.

    • Mnemonic cue: Think of the parietal lobe when you’re hugged by your parents—the chin rests on the parietal area; parietal and parent are similar words.

    • Occipital Lobe

    • Functions: sight; visual information processing.

    • Contains the visual cortex.

    • Location: at the back of the brain, not near the eyes.

    • Temporal Lobe

    • Functions: auditory processing/hearing; memory.

    • Contains the auditory cortex; located near the ears.

  • Mnemonic for cortex: FPOT (Frontal, Parietal, Occipital, Temporal) to remember the order of lobes.

Brainstem

  • Overview: The brainstem contains multiple essential structures that regulate basic life functions and arousal.

    • Medulla

    • Functions: controls heart rate and breathing; where many sensory and motor pathways cross.

    • Note: Referenced in pop culture (e.g., Kanye West lyric) to illustrate heart rate and breathing.

    • Reticular Formation

    • Structure: a pencil-shaped core running along the brainstem; foundational to arousal.

    • Functions: arouses the cerebral cortex; maintains wakefulness.

    • Clinical note: Damage to the reticular formation can lead to coma or irreversible death in many cases.

    • Pons

    • Functions: associated with sleep and relaxation (remembered via the "ponds relax you" cue).

    • Also involved in fine motor movement, though this is less emphasized in AP content.

    • Thalamus

    • Location: at the top of the brainstem.

    • Function: acts as a relay "motherboard"—sends all sensory information to the cortex and routes it as needed.

    • Cerebellum

    • Location: on top of the brainstem; sometimes described as a "mini brain."

    • Functions related to AP focus: balance and coordinated movements.

  • Connection: The brainstem connects upward to the cerebellum and higher brain regions;
    these structures together regulate baseline arousal, motor control, and sensory routing.

Limbic System

  • Overview: The limbic system is heavily involved in emotion and behavior, with multiple interconnected parts.

    • Hippocampus

    • Function: long-term memory formation.

    • Mnemonic: " Hippocampus" -> see a hippo on campus, you’d remember that moment well.

    • Amygdala

    • Function: emotion, especially fear and aggression.

    • Mnemonic: Amy as a cue for Amygdala and emotion.

    • Hypothalamus

    • Function: homeostasis regulation; regulates body temperature and hunger; involved in stress responses and autonomic regulation.

    • Note: Do not confuse with the thalamus (they are distinct structures).

    • Corpus Callosum

    • Function: connects the two cerebral hemispheres, enabling interhemispheric communication.

    • Wordplay cue: "corpus callosum" contains the word "call"—the two hemispheres communicate through it.

    • Clinical relevance: in split-brain procedures, the corpus callosum is severed to reduce seizures by limiting cross-hemispheric communication.

Split-Brain Procedure ( Corpus Callosotomy )

  • Purpose: A surgical procedure used for people with severe epilepsy where there is excessive, disruptive interhemispheric communication.

  • Procedure: The corpus callosum is cut to prevent information from crossing between the two hemispheres.

  • Consequences:

    • Reduced seizures due to decreased cross-hemispheric communication.

    • Side effects and practical trade-offs: there are significant side effects because two hemispheres can no longer communicate as effectively.

    • Example of effect: information from the right visual field cannot be relayed to the left hemisphere after surgery, leading to difficulties naming or reporting what is seen in the right visual field (demonstrates lateralization of function and language centers).

  • Practical takeaway: Split-brain procedures are reserved for severe cases of epilepsy and come with substantial trade-offs in perception and communication.