Understanding:
• The cerebral cortex forms a larger proportion of the brain and is more highly developed in humans than
other animals
The cerebral cortex is the outer layer of neural tissue found in the cerebrum of humans and other mammals
- It is composed of grey matter and is involved in complex actions, such as memory, perception, consciousness and thought
The cerebral cortex is much more highly developed in humans than other animals and forms a larger proportion of the brain
- The cerebral cortex can be externally classified according to four topographical lobes – frontal, parietal, temporal, occipital
Comparison of Cerebral Cortex Density in Humans and Other Mammals
Link: The Human Brain in Numbers (Frontiers in Human Neuroscience)
Understanding:
• The human cerebral cortex has become enlarged principally by an increase in total area with extensive
folding to accommodate it within the cranium
Through evolution, the human cerebral cortex has been greatly enlarged in comparison to other brain structures
- The disproportional enlargement of the cerebral cortex in humans is responsible for our capacity for cognitive thought
The increase in total area is mediated by extensive folding (gyrification) to form wrinkled peaks (gyrus) and troughs (sulcus)
- This greatly increases surface area without increasing volume – allowing the brain to fit within the cranium
The extent of gyrification of the cerebral cortex is a reliable indicator of potential cognitive capacity
- Primates and humans have a greater degree of folding compared to lower mammals (e.g. rats have a smooth cortex)
Brain Comparison – Human versus Rat (Not to Scale)
