AP Psychology: The Brain Structure, Functions, and Plasticity

Key Brain Structures and Functions

  • Brain: Central organ of the nervous system responsible for processing sensory information, regulating bodily functions, and enabling cognition, emotions, and behaviors.

  • Brainstem: Connects the brain to the spinal cord and controls vital functions like heartbeat, breathing, and sleep cycles.

  • Reticular Activating System (RAS): A network of neurons in the brainstem that regulates wakefulness, sleep-wake transitions, and filters incoming sensory information.

  • Cerebellum: Located at the back of the brain; coordinates voluntary movements, balance, and motor skills, while contributing to cognitive functions like attention and language.

The Cerebral Cortex and Lobes

Lobes of the cerebral cortex

  • Cerebral Cortex: Outer layer of the brain responsible for complex functions including perception, thought, language, and conscious awareness.

  • Occipital Lobes: Located at the back of the brain; process visual information and visual perception.

  • Temporal Lobes: Located on the sides of the brain; handle auditory information processing, language comprehension, memory, and emotional responses.

  • Parietal Lobes: Situated at the top and back of the brain; process sensory information for touch, temperature, and pain, aiding spatial orientation and body awareness.

  • Frontal Lobes: Located at the front of the brain; responsible for decision-making, problem-solving, planning, voluntary movement, and behavioral/emotional control.

Brain Lateralization and Primary Speech Regions

Location of Broca's area and Wernicke's area in the brain

  • Brain Lateralization: Specialization of neural functions in specific hemispheres. Motor and sensory neurons connect laterally (each hemisphere controls the opposite side of the body).

  • Corpus Callosum: Axon bundle connecting left and right hemispheres for seamless communication. Without it, hemispheres function independently.

  • Split-Brain Research: Conducted by Roger Sperry and Michael Gazzaniga by severing the corpus callosum of epilepsy patients.

  • Broca's Area: Left frontal lobe region directing muscle movements for speech expression, discovered by Paul Broca.

    • Aphasia: Inability to produce or formulate language, caused by damage/lesions to Broca's Area.

  • Wernicke's Area: Left temporal lobe region responsible for language comprehension, discovered by Carl Wernicke.

Brain Plasticity Across a Lifetime

  • Plasticity: The brain's capability to adapt by redirecting or creating alternative neural pathways from existing neurons in response to damage.

    • Plasticity is limited to neurons with similar functions (e.g., vision and audition).

  • Neurogenesis: The brain's ability to slowly generate small amounts of new neurons.

  • Age Dependence: Plasticity is highest during youth. Adapting adult brains requires intentional effort.

  • Acetylcholine Mechanism: The neurotransmitter acetylcholine primes the brain for structural realignment.

    • Repeated genuine mistakes during physical skill practice (~30 minutes of failure) trigger large acetylcholine releases, opening a ~60-minute window of heightened plasticity to adapt skills or habits.

Contemporary Brain Research Methods

  • EEG (Electroencephalography): Measures brain electrical activity through scalp electrodes; used for studying brain waves and diagnosing conditions like epilepsy.

  • fMRI (Functional Magnetic Resonance Imaging): Detects changes in blood flow to observe active brain regions during tasks.

  • Case Studies: In-depth examinations of individuals with specific brain injuries or conditions to map structural functions.

  • Surgical Procedures (Lesioning): Intentionally damaging targeted brain regions to study resulting cognitive and behavioral changes.