psychology lec 2- 2025-02-01T17:35:09

Evolution and Structure of the Brain

Advances in technology provide clearer insights into brain structure and function.
The brain stem contains older structures common to many animals, including humans.
Basic physiological functions such as breathing and heart rate are controlled by the brain stem.
Modern structures, such as the cerebrum, are built upon the brain stem and are involved in higher-order processes, including thinking and reasoning.

The brain consists of three primary parts:
- Hindbrain: Involved in essential survival functions.
- Midbrain: Controls movement patterns, sleep, and arousal.
- Forebrain: Comprises the limbic system, thalamus, and cerebral cortex.

Brain Stem: The most primitive part, vital for life support systems; loss of function can be fatal.
- Components:
  - Medulla: Controls heartbeat and breathing; well-developed at birth.
    - Mediates contralateral control (e.g., right side of the body controlled by the left side of the brain).
  - Pons: Connects various parts of the nervous system; facilitates autonomic functions, sleep, and arousal.
  - Cerebellum: Coordinates muscle movement and balance; affected significantly by alcohol consumption.

Houses centers for vision, eye movement, hearing, and body movement.
Reticular Formation: Filtering information, regulating arousal, important for multitasking.
Damage can lead to coma, while stimuli such as smelling salts can arouse patients.

Involved in emotion, motivation, and memory, often called the visceral brain.
Components:
- Hypothalamus: Regulates autonomic functions, body temperature, hunger, and thirst; includes reward centers.
- Amygdala: Regulates fear responses and aggression; damage can impair emotional reactions.
- Hippocampus: Critical for memory formation and spatial orientation; involved in processing new information.

The outer layer of the cerebrum, about 2.5mm thick; responsible for higher cognitive functions like thinking and learning.
Comprises about 80% of the human brain's volume.
Contains sensory and motor areas as well as association areas that integrate information.

Houses the motor cortex, responsible for motor functions and speech production (e.g., Broca's area).
Involved in planning, judgment, and higher-order cognitive functions.

Highly integrative, supporting complex mental activities.
Not easily mapped; activation observed in neuroimaging studies.
Prefrontal cortex: Responsible for executive functions like decision-making and impulse control.

Each hemisphere specializes in different functions:
- Left Hemisphere: Language, logic, mathematics, and positive emotions.
- Right Hemisphere: Spatial awareness, pattern recognition, melodies, and negative emotions.
Contralateral Control: Sensory and motor functions are cross-related between the hemispheres.

Severing the corpus callosum treats extreme epilepsy but disrupts inter-hemispheric communication.
Findings from Split-Brain Patients:
- Tasks involving stimuli presented to one hemisphere highlight independence.
- Example: Patients may not name an object in the left visual field but can draw it with the left hand, controlled by the right hemisphere.

The brain operates through complex interactions between its parts, illustrating how specific areas relate to cognitive functions and emotional responses.