The hypothalamus connects the nervous system to the endocrine system - where hormones are produced - via the pituitary gland. Except for olfaction (sense of smell), every sensory system sends information through the thalamus to the cortex, according to the online textbook, ' Neuroanatomy, Thalamus' (StatPublishing, 2020). The thalamus relays sensory and motor signals to the cortex.

(Image credit: Mark Garlick/Getty Images)Д«etween the cerebrum and brainstem lie the thalamus and hypothalamus. This gives axons (thin strands through which electrical impulses are transmitted between neurons) a white appearance, and so these axons are called the brain's 'white matter.' The brain also has about the same number of non-neuronal cells, such as the oligodendrocytes that insulate neuronal axons with a myelin sheath.

The human brain contains about 86 billion nerve cells (neurons) - called ' gray matter,' according to a 2012 study published in the Proceedings of the National Academy of Sciences. The cerebrum, which is the main part of the brain located in the front area of the skull, makes up 85% of the brain's weight.

The average male has a brain volume of nearly 78 cubic inches (1,274 cubic centimeters), while the average female brain has a volume of 69 cubic inches (1,131 cubic cm). On average, male brains are about 10% larger than female brains, according to Northwestern Medicine in Illinois. (1.4 kilograms) and makes up about 2% of a human's body weight.

Fransson human brain mapping 2005