Lecture Notes: Brain Anatomy and Functions

Ventral View of the Frontal Lobe

• Landmarks:
  • Olfactory Tracks and Bulbs on the ventral surface.
  • Orbital Frontal Cortex: deals with emotions, rich connections with the amygdaloid nucleus (amygdala).
  • Amygdala: Handles emotions, predominantly fear.
• Prefrontal Cortex:
  • Role in inhibition, decides what to say/not to say.
  • Reduction of inhibitory fibers with aging can lead to less social inhibition.

Parietal Lobes

• Central Sulcus:
  • Post Central Gyrus: Primary sensory area, areas 3, 1, 2.
  • Sensory modalities: Taste, touch, pressure, pain, temperature, kinesthetic sense.
• Inferior Parietal Cortex:
  • Area 40 (Supramarginal Gyrus):
    • Lesions here can cause asterognosis (inability to recognize objects by touch).
  • Area 39 (Angular Gyrus):
    • Integrates information from visual, auditory, and general sensory.
    • Associated with logic and math.
• Superior Parietal Lobe:
  • Areas 5 and 7.
  • Lesions can lead to neglect syndrome on the opposite side of the body (e.g., right lesion causes left neglect).

Occipital Lobe

• Visual Cortex: Defined by preoccipital notch and parietal-occipital fissure.
  • Area 17 (Primary Visual Cortex):
  • Areas 18 and 19 (Visual Association Cortex): Integrates visual information and memory.
  • Large representation on the medial surface.

Temporal Lobe

• Auditory Cortex:
  • Area 41 (Primary Auditory Cortex):
  • Area 42 and 22 (Auditory Association Cortex):
  • Wernicke's Area: Understanding of words, traditionally in the posterior superior temporal gyrus but can vary.

Other Key Concepts

• Hippocampus and Hypothalamus: Involved in emotion and memory.
• Broca's Area (44 and 45): Involved in speech production.
• Insula: Potentially involved in speech and visceral functions.
• Corpus Callosum: Connects the two hemispheres. Some individuals may lack it (agenesis).
• Cell Types in Cortex:
  • Pyramidal cells and stellate cells contribute to cortical function.

Functional Pathways and Syndromes

• Corticospinal Tract: Carries voluntary motor signals from area 4 and adjacent areas (3, 1, 2, 5).
• Neglect Syndrome: Results from right superior parietal lesions, affects awareness of the left body side.
• Stereognosis: The ability to recognize objects by touch, linked to specific cortical areas.

Experimental Insights

• Lesions and Cognitive Functions:
  • Studies on Einstein's brain focused on prefrontal and angular gyrus areas.
  • Distribution of Wernicke's area may vary among individuals with different intelligence levels.
• Neuroplasticity:
  • Dendritic branching increases with higher education levels.

Miscellaneous

• Blood Supply:
  • Posterior cerebral artery supplies visual cortex and part of the inferior temporal lobe.
• Paramal and Stellate Cells: Major cell types in the cortex.
• Functional Anatomy and Educational Implications:
  • Knowing specific brain areas is crucial for neurological and educational studies.
• Visual Cortex Representation:
  • Extensive representation on the medial surface of the brain.