Brain Anatomy and Function Lecture Notes

Overview of the Forebrain

• Forebrain: Highest integration center of the nervous system and the seat of consciousness.
• Cerebrum: Composed of two hemispheres (left and right).
  • Separated by the longitudinal fissure.
  • Connected by the corpus callosum.

Brain Hemispheres and Functions

• Hemispheres:
  • Are generally mirror images but have lateralized functions.
  • Lateralization: Different cognitive functions predominate in each hemisphere.
• Caution: Avoid broad stereotypes like "left is logical, right is creative".

Brain Structure and Surface

• Convolutions (Gyri and Sulci): Increase brain surface area.
• Central Sulcus: Divides the brain into lobes.
• Lobes:
  • Frontal Lobe: Motor commands, conscious thought, problem-solving.
  • Parietal Lobes: Sensory processing like touch, temperature, pain.
  • Occipital Lobe: Visual processing.
  • Temporal Lobe: Auditory processing.
  • Insular Lobe: Conscious awareness of balance.

Frontal Lobe

• Precentral Gyrus: Contains the primary motor cortex.
  • Responsible for voluntary movements.
• Broca's Area: Speech production.

Parietal Lobe

• Postcentral Gyrus: Contains the primary somatosensory cortex.
  • Processes sensory input like touch, temperature, and pain.

Sensory and Motor Pathways

• Primary Areas:
  • Beginning or termination of projection pathways for sensory and motor signals.
• Association Areas:
  • Surround primary areas, involved in processing and planning responses.

Insular Lobe

• Vestibular Cortex: Awareness of balance.
• Integrates input from the eyes and proprioceptors in the neck.

Basal Ganglia

• Regulates voluntary movement (start, stop, intensity).
• Stores learned movement patterns (e.g., playing instruments, driving).

Limbic System

• Involved in emotional processing.
• Amygdala:
  • Recognizes emotions like anger and fear.
  • Connects to olfactory inputs and pheromones.
  • Responsible for "amygdala hijack"—strong emotional responses.
• Hypothalamus: Connects emotions to physiological responses via the autonomic and endocrine systems.

Olfactory and Emotional Connections

• Olfactory Cortex: Processes smells, linked to emotions.
• Uncus: Primary olfactory processing, part of the limbic system.

This lecture provided an in-depth overview of the brain's structure and function, focusing on different lobes, their associated functions, and how emotions are processed through the limbic system. Understanding these concepts is crucial for comprehending how different parts of the brain work together to control behavior and bodily functions.