Skip to content

A Model of The Brain

July 9, 2012

If we are to understand the nature of consciousness, thoughts, emotions and human behaviour then we will need to engage in some exploration of the brain.

In attempting to understand the highly complex functionality of the brain it will be helpful to examine its structure from the perspective of 3 interconnected layers, each one extending beyond the area directly below it and transforming the overall character and behaviour of the whole system. These 3 layers are the cerebrum, the limbic system and the hindbrain.

The cerebrum encloses the limbic system which encloses the hindbrain, and each of these 3 layers enhances the functional capacity of the area below it. Despite the complexity of the brain and the high degree of interactivity between its different components, modern neuroscience has established that each of these 3 areas has a particularly significant role to play in specific aspects of human experience.

The Hindbrain

The hindbrain is the lower part of the brainstem and is often referred to as the “primitive” or “reptile brain”. The brainstem is the region at the base of the brain that relays signals between the brain and the spinal cord. It is largely concerned with fundamental life support mechanisms, primal instincts and survival functions. This is a home for automatic, conditioned and habitual responses, hence the “primitive” or “reptile” association.

The Limbic System

The limbic system, sometimes referred to as the “emotional brain”, is a set of structures located on top of the brainstem and beneath the cortex (the surface of the cerebrum). These structures are involved in forming many of our emotions, motivations and memories, particularly those that are related to primal, instinctive drives such as personal safety, reproduction and social bonding. Emotion and memory critically combine to mark behaviours and situations with “positive” or “negative” feelings. This area of the brain is where mostly unconscious value judgements are made. It also plays a role in salience (what gets your attention), spontaneity and creativity.

The Cerebrum

Sometimes viewed as the “rational” brain. The outer layer of the cerebrum is called the cortex, and the neo (new) cortex accounts for 90% of the cortex in humans. When you see a picture of the brain the wrinkled, grey matter is the cortex and it is where the majority of brain cells or neurons reside. We share this part of our brain with other mammals like the primates and dolphins, although in humans the neocortex is the largest. It has the capacity to observe complex patterns and is responsible for cognitive processes such as thought, belief, reasoning, sensory perception and language.

The neocortex is divided into two hemispheres, right and left. The right side of the brain controls the left side of the body and vice versa. The hemispheres are also divided in terms of what kind of thought they process or produce. For example, the right side is more concerned with the artistic, spatial and musical while the left is more concerned with the rational, linear and verbal aspects.

Now that we have established a basic model we can begin to explore the mechanism of thoughts, emotions and physical states. I will address this issue in my next post.

Spencer Joseph

Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: