The Dorsal and Ventral Surfaces of the Brain

Overview

• The primary subdivisions of the cerebral hemispheres can be viewed from both dorsal and ventral surfaces.
• Dorsal view reveals bilateral symmetry and landmarks such as the central sulci and parieto-occipital sulci.
• Ventral view highlights features like the olfactory tracts and various cortical structures.

Dorsal Surface

• Bilateral Symmetry: Appears in the cerebral hemisphere.
• Major Landmarks:
  • Central sulci
  • Parieto-occipital sulci
• Corpus Callosum:
  • Connects the two hemispheres.
  • Contains axons from neurons in both hemispheres.

Ventral Surface

• Olfactory Tracts:
  • Extend along the inferior surface of the frontal lobe.
  • Arise from olfactory bulbs receiving input from nasal cavity neurons.
  • Associated with Cranial Nerve I (Olfactory Nerve).
• Parahippocampal Gyrus: Conceals the hippocampus, important for memory.
• Uncus:
  • Conical protrusion.
  • Includes pyriform cortex for processing olfactory information.
• Optic Chiasm: Centrally located on the ventral forebrain.
• Hypothalamus:
  • Ventral surface includes infundibular stalk and mammillary bodies.
• Cerebral Peduncles:
  • Large tracts projecting to motor neurons in the brainstem and spinal cord.
• Other Structures:
  • Ventral surfaces of the pons, medulla, and cerebellar hemispheres visible.

Important Structures and Their Functions

• Corpus Callosum: Facilitates communication between hemispheres.
• Olfactory Bulbs: Receive sensory input from nasal epithelium.
• Hippocampus: Plays a critical role in memory formation.
• Optic Chiasm: Site for visual information processing.
• Hypothalamus: Involved in various autonomic processes.

References

• Neuroscience, 2nd edition, edited by Purves et al.
• Figures and detailed descriptions can be accessed on the NCBI Bookshelf.