Overview of Brain Regions

• The brain is divided into three major regions: hindbrain, midbrain, and forebrain.

• Developmental differentiation: Clear differentiation at three weeks in the human embryo; by birth, the forebrain overshadows the others in size.

Brain Anatomy

• Key structures within the regions play vital roles in regulating functions.

• Hindbrain:

  • Structures: Cerebellum, Medulla, Pons.

  • Cerebellum: Critical for coordination and equilibrium; damage affects fine motor skills.

  • Medulla: Regulates unconscious functions (breathing, circulation, muscle tone).

  • Pons: Connects brain structures; regulates sleep and arousal.

Understanding the Hindbrain

• The hindbrain is positioned relative to the brain stem, which resembles a stem growing from the brain.

• The reticular formation runs through the hindbrain and midbrain, regulating muscle reflexes, breathing, and pain perception, essential for survival.

• Activity in the reticular formation is crucial for sleep and wakefulness.

Midbrain Functions

• Located between hindbrain and forebrain.

• Involved in sensory processes and voluntary movement control via dopamine neurons.

• Importance of dopamine: Degeneration in the midbrain correlates to Parkinson's disease symptoms (tremors, impaired movement).

Overview of Forebrain

• The largest and most complex brain region.

• Key structures include thalamus, hypothalamus, limbic system, and cerebrum.

Structures of the Forebrain

• Thalamus:

  • Sensory relay for all senses except smell.

  • Controls the routing of sensory information to the cerebral cortex.

• Hypothalamus: Regulates basic biological drives including:

  • Fighting, fleeing, feeding, and mating (the four f's).

• Limbic System: Includes structures like the amygdala and hippocampus; linked to emotions and memory processing.

• Cerebrum: Responsible for complex mental activities, divided into two hemispheres connected by the corpus callosum.

Cerebral Lobes

• The cerebrum contains four lobes:

  • Frontal Lobe:

    • Primary motor cortex governs muscle movement (mapped in the motor homunculus).

    • Prefrontal cortex involved in working memory and reasoning.

  • Parietal Lobe: Registers touch and integrates visual spatial information; contains the primary somatosensory cortex.

  • Temporal Lobe: Processes auditory information; contains the primary auditory cortex, with initial sound processing via the thalamus.

  • Occipital Lobe: Handles visual signals; primary visual cortex begins visual processing.

Quiz Time

• Reinforce understanding of brain anatomical features and associated functions.