A hierarchical society within the brain

It always fascinates me to think about how the brain works. It’s incredible how such rudimentary information such as light is converted so intricately into a constantly changing image. So what happens in the brain?

The brain is organised. Very organised. Like a perfectly ordered filing cabinet. As discussed in a previous post, each area of the brain has a particular function and purpose. However, the analogy of a filing cabinet doesn’t give an accurate indication of just how complex the brain is. Not only are there specific areas, but it appears that the initial decoding of information occurs in a separate region of the brain to the more complex processing. There is a hierarchy within the brain.

Thus, to permit this, each area is connected to other areas by many elaborate pathways. This serves as a route to process and fine tune all the information our brain receives, eventually converting the mass of random electrical impulses to vital thoughts and movements.

Stage I

The point of arrival of information in the brain is known as the primary cortex. In this region, we have the primary visual cortex, where all the visual information arrives, and the primary somatosensory cortex. This receives the complicated array of messages, for example impulses from pressure and temperature receptors on our skin. 

I have used this image before, but it really does highlight the key regions of the brain. The primary somatosensory cortex is shown in light green.

Once the data is somewhat analysed, the papers are passed onto those who really know their stuff- the association cortex’s. In here, the complicated integrating and processing occurs, leading to our ability to perceive, understand and attach meaning to the data.

Stage II

Here you can see the association areas, shown in pink. To make this clearer, lets imagine you hear a bird chirp. Initially this sound is sent from the ears to the auditory sensory area (blue). At the moment, we cannot understand the information. Electrical impulses are transmitted from this area to the auditory association area. Here, the brain deciphers the information, creating links between the sound and birds, allowing us to enjoy birdsong and the like.

Different structures, such as those discussed in previous posts, are involved in the higher association areas. This includes the cerebellum, basal ganglia and others.

http://www.indiana.edu/~p1013447/dictionary/assn_cor.htm

http://thebrain.mcgill.ca/flash/a/a_06/a_06_cr/a_06_cr_mou/a_06_cr_mou.html

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