Copy of Brain Structures

Studying the Brain

Tools for Brain Study

  • Lesioning

    • Involves tissue destruction to understand brain functions.

    • Can be surgically induced; for example, in a rat’s hypothalamus.

Structural Imaging Techniques

  • Structural Imaging: Shows the composition of the brain.

    • Computer Tomography (CT or CAT) Scan:

      • Utilizes a series of X-rays taken from various angles.

      • A computer program combines these images to form a 3D representation of the brain.

    • Magnetic Resonance Imaging (MRI):

      • Employs magnetic fields and radio waves.

      • Magnetic field aligns hydrogen (H) atoms in the body, while radio waves disrupt this alignment.

      • Realignment releases energy recorded by an RF receiver to generate images.

Functional Imaging Techniques

  • Functional Imaging: Shows changes in the brain as they occur (e.g., blood flow and electrical activity).

    • Functional MRI (fMRI):

      • Conducts several MRIs rapidly in succession.

      • Measures blood flow changes in response to brain activity.

    • Electroencephalogram (EEG):

      • Detects electrical signals from the brain using an electrode cap.

    • Positron Emission Tomography (PET) Scan:

      • Identifies areas of brain activity by detecting radioactive glucose used by active neurons.

Brain Structures

History of Brain Study

  • Phrenology:

    • A pseudoscience claiming personality could be discerned by skull shape and size.

    • Accurately identified that different brain areas control various emotions, but incorrectly suggested head measurements could reflect personality traits.

Key Case Study

  • Phineas Gage (1848):

    • Index case illustrating how brain damage affects personality.

    • Accidentally damaged his left frontal lobe, resulting in short-term delirium and cognitive shifts.

    • Long-term effects included irritability and mood swings, fundamentally altering his personality.

Evolution of Brain Structures

  • Old Brain:

    • Responsible for sustaining basic life functions.

  • Limbic System:

    • Mainly involved with emotions and memory processing.

  • New Brain:

    • Associated with higher functions like perception, cognition, and speech.

Moral Dilemmas and Decision Making

Scenario Discussion

  • Considers a runaway train dilemma:

    1. Diverting the train to save five people at the cost of one.

    2. Pushing a large man into the track to save others.

  • Most respondents lean towards utilitarianism when it involves a switch, driven by a logical mindset.

  • Much stronger emotional ties inhibit the decision to physically harm another individual.

Brain Areas Involved in Decision Making

  • Dorsolateral Prefrontal Cortex:

    • Involved in logical cognition and decision-making.

  • Ventromedial Prefrontal Cortex (VMPFC):

    • Essential for regulating emotional responses; damage here significantly affects moral decision-making ability.

  • Study Findings:

    • Respondents with VMPFC damage often respond positively to both scenarios, lacking emotional guilt associated with such actions.

Ventromedial Prefrontal Cortex (vmPFC)

  • Located in the frontal lobe, involved in risk and fear processing, and in regulating emotional responses.

  • Plays a crucial role in decision-making and self-control.

  • Engages in the cognitive evaluation of moral dilemmas.

Old Brain Structures

  • Brainstem:

    • Controls basic automatic functions for survival.

    • Includes:

      • Medulla: regulates heartbeat and breathing.

      • Pons: coordinates movement.

      • Reticular Formation: maintains consciousness and sleep cycles.

      • Cerebellum: responsible for non-verbal learning and memory, as well as voluntary movement.

Limbic System Components

  • Hypothalamus: Regulates endocrine and autonomic nervous systems.

  • Amygdala: Key in emotion regulation and decision-making; its stimulation can evoke anger or anxiety.

  • Thalamus: Acts as a relay for sensory information (except smell).

  • Hippocampus: Critical for memory storage, connecting emotions to memories.

New Brain Structures

  • Cerebrum:

    • Largest brain division composed of two hemispheres with four lobes each.

  • Cerebral Cortex:

    • Acts as the outer layer of the cerebrum, housing areas for higher mental functions.

  • Brain Lobes:

    • Four main lobes defined by their locations with distinct functions:

      • Frontal Lobes: Personality, consciousness, and voluntary muscle movements.

      • Parietal Lobes: Processes touch and spatial awareness.

      • Occipital Lobes: Handles visual information.

      • Temporal Lobes: Involved in auditory processing and speech comprehension.

Brain Plasticity

  • Plasticity:

    • The ability of the brain to rewire itself after injury or during growth.

    • Encourages new neural pathways and adapts based on experiences.

  • Neurogenesis: Formation of new neurons.

  • Neural Pruning: Elimination of unused neural pathways to improve efficiency.

  • Glial Cells: Support and nourish neurons.

Phantom Sensation

  • Phantom Limb: Condition where individuals feel sensations from missing limbs.

  • Treatment Method: Utilizes mirror therapy, reflecting the existing limb to alleviate phantom pain.

Brain Lateralization

  • Right and Left Hemispheres:

    • Each hemisphere controls the opposite side of the body and is involved in different cognitive functions.

  • Brain Lateralization Principle:

    • The left and right hemispheres have specialized functions (e.g., language and processing areas).

    • "Left-brained" or "right-brained" personality traits are considered pop psychology.

Split Brain Conditions

  • Corpus Callosum: Connects the two brain hemispheres; severing it allows independent function.

Dual Processing Theories

  • Dual Process Theory:

    • Proposes the simultaneous operation of the conscious and unconscious mind.

    • Explains behaviors where individuals can multitask without full awareness.

  • Application: This theory can elucidate various psychological phenomena, including moral decision-making.

The structures and functions of the brain play a crucial role in shaping our behavior, personality, and interactions with the world. For example, the frontal lobes are involved in personality and decision-making; damage can lead to changes in personality traits such as irritability or mood swings as illustrated by the case study of Phineas Gage. The limbic system, which processes emotions and memory, greatly influences how we respond emotionally to situations. Additionally, areas like the ventromedial prefrontal cortex (VMPFC) regulate emotional responses and moral decision-making, affecting how we make choices based on our values and emotions. Understanding these brain functions can help clarify how we interpret experiences and engage in social interactions.