The Dorsal and Ventral Surfaces of the Brain

Overview

• Primary subdivisions of the cerebral hemispheres can be seen from a lateral view.
• Key landmarks are better viewed from the dorsal and ventral surfaces of the brain.

Dorsal Surface

• Approximate Bilateral Symmetry:
  • Symmetry of the cerebral hemisphere is visible from the dorsal view.
  • Major landmarks include the central sulci and parieto-occipital sulci, typically similar on both sides.
• Corpus Callosum:
  • Visible when cortical hemispheres are slightly separated.
  • Contains axons from neurons in both cerebral hemispheres that contact target nerve cells in the opposite hemisphere.

Ventral Surface

• Olfactory Tracts:
  • Located along the inferior surface of the frontal lobe near the midline.
  • Arise from the olfactory bulbs, which receive input from neurons in the nasal cavity.
  • Forms the first cranial nerve (olfactory nerve).
• Parahippocampal Gyrus:
  • Conceals the hippocampus, critical for memory.
• Uncus:
  • A conical protrusion medial to the parahippocampal gyrus, includes the pyriform cortex.
  • Processes olfactory information.
• Optic Chiasm:
  • Located at the central aspect of the ventral forebrain surface.
• Hypothalamus and Related Structures:
  • Includes the infundibular stalk (base of the pituitary gland) and mammillary bodies.
• Cerebral Peduncles:
  • Large tracts oriented rostral/caudally, contain axons projecting to motor neurons in the brainstem and the spinal cord.
• Additional Structures:
  • Ventral surfaces of the pons, medulla, and cerebellar hemispheres are visible.

Images and Figures

• Figure 1.13:
  • Shows dorsal and ventral views of the human brain, indicating major features visible from these perspectives.