What is the Difference Between Chimpanzee Brain and Human Brain

The main difference between chimpanzee brain and human brain is that the human brain is three times bigger than the chimpanzee brain. Furthermore, the chimpanzee brain is more symmetrical while the human brain has a more asymmetric shape.

Chimpanzee brain and human brain are two major parts of their central nervous system. The differences between the two brains may contribute to the remarkable cognitive abilities of humans.

Key Areas Covered

1. What is Chimpanzee Brain
     – Definition, Anatomy, Significance
2. What is Human Brain
     – Definition, Anatomy, Significance
3. What are the Similarities Between Chimpanzee Brain and Human Brain
     – Outline of Common Features
4. What is the Difference Between Chimpanzee Brain and Human Brain
     – Comparison of Key Differences

Key Terms

Chimpanzee Brain, Cognitive Abilities, Human Brain, Size, Symmetry

What is Chimpanzee Brain

Figure 1: Human and Chimpanzee Skull and Brain

Chimpanzee brain is one of the two components of their central nervous system while the second component is the spinal cord. Significantly, it displays numerous signs of intelligence, from the ability to remember symbols to cooperation, tool use, and perhaps language. Also, chimpanzees are one of the species that have passed the mirror test, indicating self-awareness. The main reason behind the considerably high level of cognitive abilities of the chimpanzee brain is mainly due to the increased size of the neocortex when compared to the brains of other lower animals. However, the neocortex of the human brain is larger than the neocortex of the chimpanzee brain.

However, the average size of the adult chimpanzee brain is comparatively small. It is 384 g in weight in adults while their brain has developed up to 36% in size at birth. Additionally, the chimpanzee brain does not show lopsidedness as the human brain does. In humans, some areas of the left hemisphere are bigger than those in the right hemisphere.

What is Human Brain

The human brain is a part of the central nervous system located in the skull. It is comparatively large in size and the average size of the adult human brain is around 1352 g. The brain has developed up to 27% in humans at birth. As in other mammals, the three main parts of the human brain are the cerebrum, the brainstem, and the cerebellum. Among them, cerebrum is the largest part of the human brain, containing two cerebral hemispheres. Also, the core of the cerebrum is made up of white matter while the outer layer or the cerebral cortex is made up of gray matter. Furthermore, the two parts of the cerebral cortex are the neocortex, which is the largest, and the allocortex. Neocortex covers the two brain hemispheres while the allocortex covers the hippocampus and olfactory bulb.

Figure 2: Human Brain

Moreover, each brain hemisphere is made up of four lobes: frontal, temporal, parietal, and occipital lobes. These lobes are responsible for the characteristic cognitive abilities of the human brain. Here, the front lobe is responsible for some executive functions including self-control, planning, reasoning, and abstract thought. Whereas, the temporal lobe is responsible for visual memory, language comprehension, and emotion association. On the other hand, the parietal lobe is responsible for spatial sense and navigation while occipital lobe serves as the visual processing complex. The left hemisphere is responsible for functions including language while the right hemisphere is responsible for visual-spatial abilities.

Similarities Between Chimpanzee Brain and Human Brain

• Chimpanzee brain and human brain are two structures of the central nervous system.
• Both occur in the head region protected by the skull.
• Both their brains involve in high-level cognitive, communicative, and emotional functions due to the structure of their brains.
• Also, the main components of both brains are cerebrum, cerebellum, and brain stem.
• Furthermore, the size of both brains is generally larger in proportion to body size.
• This enlargement of the brain is due to the massive expansion of the cerebral cortex.
• Besides, both have a similar molecular structure in their cerebellum.
• Their prefrontal cortex and parts of the cortex involved in vision are large.
• Additionally, both brains are more gyrified than the brains of other primate species.
• Moreover, Broca’s and Wernicke’s area of both brains produce similar landmarks.
• And, both brains have a dense distribution of von Economo neurons in the anterior cingulate and frontoinsular cortex.
• Both brains also show a more complex level of connectivity and function within the arcuate fascicularis and mirror neuron systems.

Difference Between Chimpanzee Brain and Human Brain

Definition

Chimpanzee brain refers to the upper part of the central nervous system of chimpanzee, displaying numerous signs of intelligence, from the ability to remember symbols to cooperation, tool use, and perhaps language while human brain refers to the command center for the human nervous system with the same basic structure as other mammal brains but is larger in relation to body size than any other brains.

Average Weight of Adult Brain

The average adult brain size of the chimpanzee is 384 g while the average adult human brain size is 1,352 g. Thus, this is one main difference between the chimpanzee brain.

Symmetry

Another important difference between the chimpanzee brain is that the chimpanzee brain is more symmetrical while the human brain is asymmetrical; some areas of the left hemisphere are bigger than those in the right hemisphere.

Size of the Neocortex

Size of the neocortex is another difference between the chimpanzee brain. Chimpanzee brain has a comparatively small neocortex while the human brain has a large neocortex.

Number of Neurons

Moreover, Chimpanzee brain contains around 28 billion neurons while human brain contains around 86 billion neurons.

Patterns of Gene Expression

The patterns of gene expression in the chimpanzee brain result in less brain metabolism and less ability to establish new connections while the patterns of gene expression in the human brain lead to the greater levels of neuronal activity and plasticity across much of the lifespan.

Susceptibility to Neurodegenerative Diseases

Chimpanzee brain is less susceptible to neurodegenerative diseases while human brain is more susceptible to neurodegenerative diseases due to the increased levels of activity. This is another difference between the chimpanzee brain.

Dopamine Production

Dopamine production gene is not expressed in the neocortex of the chimpanzee brain while dopamine production gene is expressed in higher rates in the neocortex and striatum of the human brain.

Abilities

Furthermore, Chimpanzee brain shows the ability to remember symbols to cooperation and tool use while human brain especially shows language abilities and cumulative culture.

Conclusion

Chimpanzee brain is the upper part of their central nervous system. It is comparatively small in size and has symmetrical hemispheres. Due to its comparatively smaller size, it contains a fewer number of neurons. However, chimpanzee brain helps to develop more signs of intelligence, from the ability to remember symbols to cooperation, tool use, and perhaps language. On the other hand, human brain is also the upper part of the central nervous system that occurs inside the skull. It is three times larger than the chimpanzee brain and especially, shows the asymmetrical shape of the two hemispheres. However, the human brain is more advanced compared to the chimpanzee brain. Therefore, the main difference between the chimpanzee brain and human brain is the size, shape, and abilities.

References:

1. “Chimpanzee Brain Facts.” National Chimpanzee Brain Resource, Available Here.
2. Lewis, Tanya. “Humans Evolved Flexible, Lopsided Brains.” LiveScience, Purch, 23 Apr. 2013, Available Here.

Image Courtesy:

1. “Man&chimpbrains” By Gervais, Paul, 1816-1879 (Public Domain) via Commons Wikimedia   
2. “Figure 35 03 02b” By CNX OpenStax (CC BY 4.0) via Commons Wikimedia