Brain Structure and Function - Vocabulary Flashcards

Central Nervous System and Brain Activity

• The brain is a part of the nervous system, specifically the central nervous system (CNS).
• The CNS is comprised of the brain and the spinal cord and makes the big decisions for the body.
• Our understanding of those big decisions is complicated because the brain does not show external signs of what it’s doing inside.
• We rely on technology to link brain activity to behavior, including:
  • EEG
  • CT scans
  • PET scans
  • MRI
  • fMRI
• These tools provide many details about brain structure, but only some (EEG, PET, and fMRI) show us exactly how the brain functions.
• Before modern technologies, and even today, an important way to study the brain is through accidents (natural experiments). A famous example is Phineas Gage in $1848$, who survived a gunpowder accident in which a rod passed through the front part of his skull.
• After the accident, Gage’s personality changed dramatically: he became mean, emotional, and impulsive, indicating that damage to the frontal region affected behavior.
• This case supported the idea of brain localization: different areas of the brain control different parts of behavior.
• Brain localization allows scientists to divide brain functions into distinct regions for study of structure and function.
• There are three major parts of the brain: hindbrain, midbrain, and forebrain.
• The brain’s organization supports both specialized functions and integration across regions via networks and connections.

Major Parts of the Brain

• The hindbrain rests at the top of the spinal cord and is the oldest, most ancient part of the brain.
• It evolved first and has helped keep us alive by controlling basic biological functions.
• Hindbrain components (as described in the transcript):
  • Medulla: controls involuntary but essential actions such as breathing, blood pressure, and heart rate.
  • Pons: passes neural information between the three brain regions and helps coordinate movements like facial expression.
  • Reticular Activating System (RAS): controls arousal or alertness.
  • Thalamus: receives and relays sensory information.
  • Cerebellum: means "little brain"; controls muscle movement, balance, and emotions; attached to the underside of the hindbrain.
• The midbrain sits just above the spinal cord and just below the forebrain and mainly coordinates simple movements using sensory information.
• Midbrain major components: tectum (the brain’s roof) and tegmentum (the brain’s floor).
• The forebrain contains the limbic system, the emotional center of the brain, and is associated with higher brain functions.
• Forebrain structures highlighted in the transcript include:
  • Hippocampus: involved in processing new learning and new memories.
  • Amygdala: more involved in the expression of emotions such as anger and frustration.
  • Hypothalamus: regulates many bodily functions (temperature, water balance, hunger), the sympathetic nervous system, the endocrine system, sex drive, and sleeping patterns.
• The forebrain also houses the cerebral cortex, the gray matter full of densely packed neurons that covers the brain.
• The cerebral cortex grows and wrinkles with development, increasing neural connections.

The Cerebral Cortex and Hemispheric Specialization

• The cerebral cortex covers the two hemispheres, left and right, and each hemisphere specializes in different functions (a concept called brain lateralization or hemisphere specialization).
• Left hemisphere: more involved in language processing and logical tasks.
• Right hemisphere: more involved in creative and spatial reasoning.
• The hemispheres are connected by the corpus callosum, a band of nerve fibers that allows them to work together.
• Roger Sperry showed that each hemisphere can operate independently in split-brain patients (patients whose corpus callosum was severed to treat severe seizures).
• The cerebral cortex can be broken down into four distinct lobes in each hemisphere:
  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe

Sensory and Motor Cortices

• The cortex contains:
  • Sensory cortex: processes incoming sensory information.
  • Motor cortex: controls outgoing motor commands.
• The frontal lobe houses high-level thinking; behind the eyes, the prefrontal cortex acts as the brain’s boss and is associated with executive thought processing and emotional control.
• The left hemisphere contains one of the brain’s two language processing centers, Broca’s area, which controls speech production.
• Broca’s area was identified by Paul Broca; damage to this area causes expressive aphasia (the inability to speak).
• The parietal lobe includes the somatosensory cortex, which receives touch sensations and information about body temperature and position.
• The occipital lobes are involved in vision and house the visual cortex. Visual information from the right eye is interpreted by the right occipital lobe, while information from the left eye is interpreted by the left occipital lobe.
• The temporal lobes, located near the ears, process sound and contain Wernicke’s area, which interprets speech; damage to Wernicke’s area can cause receptive aphasia (difficulty understanding speech).
• The rest of the cortex consists of association areas, responsible for more complex thinking, learning, memory, humor, and other higher-order processes.

The Special Case: Split-Brain and Lateralization

• In split-brain patients, severing the corpus callosum can prevent seizures from spreading between hemispheres.
• This procedure demonstrates that each hemisphere can function independently to some extent and highlights the modularity and integration of brain functions.

Brain Plasticity and Why It Matters

• The brain is not fixed in its wiring; plasticity allows it to adapt, grow, and heal itself.
• Plasticity underlies learning, recovery from brain injury, and adaptation to new experiences.
• Because psychology studies behavior, emotion, thought, and learning, understanding brain structure and function helps explain many psychological phenomena.

Connecting to Psychology: Significance and Implications

• Brain localization supports the idea that different brain regions contribute to distinct aspects of behavior and cognition.
• Technologies that map structure and function have transformed our understanding of mental processes and clinical approaches.
• The concept of lateralization explains why certain abilities (like language) are more strongly associated with one hemisphere.
• The existence of association areas emphasizes that complex behaviors rely on coordinated activity across multiple regions.
• Ethical and practical implications include considerations about brain injury, neurosurgical interventions (e.g., treatment for seizures), and the interpretations of brain–behavior relationships.

Quick Reference: Key Terms and Concepts

• Central nervous system (CNS)
• Brain localization
• Hindbrain, Midbrain, Forebrain
• Medulla, Pons, Reticular Activating System (RAS)
• Thalamus, Cerebellum
• Limbic system: Hippocampus, Amygdala, Hypothalamus
• Cerebral cortex; gray matter; neuronal density
• Cerebral hemispheres; Left vs Right; Lateralization
• Corpus Callosum; Split-brain; Roger Sperry
• Lobes: Frontal, Parietal, Temporal, Occipital
• Sensory cortex; Motor cortex
• Broca’s area; Expressive aphasia
• Wernicke’s area; Receptive aphasia
• Association areas; Brain plasticity

Closing Note

• Psychology, while grounded in behavioral study, is deeply informed by brain structure and function; understanding the brain enhances our grasp of human behavior, cognition, emotion, and learning.