As reported by researchers at the Natural History Museum in California, and coordinated by Jeff Morgan Stibel, past climate changes would have led to a decrease in the size of the human brain. In particular, the brains of 298 Homo specimens were examined and how their size has changed in the last 50,000 years in relation to global temperature, humidity and rainfall.
As the weather got warmer, average brain size decreased significantly compared to when it was colder. Jeff Morgan Stibel explained: "The most important thing to understand is that the human brain continues to evolve. We found macroevolutionary trends in brain size that occurred in as little as 5-17 thousand years.
The Holocene warming period brought to a reduction of more than 10% in brain size in modern humans. If global temperatures continue to rise this could put greater evolutionary pressure on the human brain. Given recent trends in global warming, it is crucial to understand the impact, if any of climate change on human brain size and ultimately human behavior." The brain is contained and protected by the braincase.
The telencephalon is the largest part of the human brain and is divided into two cerebral hemispheres. The cerebral cortex is an outer layer of gray matter, which covers the white matter nucleus. The cortex is divided into the neocortex and the allocortex which is much smaller.
The neocortex is made up of six neuronal layers, while the allocortex has three or four. Each hemisphere is conventionally divided into four lobes: the frontal lobe, the parietal lobe, the occipital lobe and the temporal lobe.
The frontal lobe is responsible for executive functions, such as self-control, planning, reasoning and abstract thinking, while the occipital lobe is dedicated to vision. Within each lobe, cortical areas are associated with specific functions, such as sensory, motor, and association regions.
Although the left and right hemispheres are broadly similar in form and function, some functions are associated with one side, such as language in the left side and visual-spatial abilities in the right. The hemispheres are connected by commissural nerve tracts, the largest of which is the corpus callosum.