HOW YOUR BRAIN WORKS
Parts Of The Brain
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A Brief Introduction To The Brain
Neuroscience research reveals how our reaction to stress and emotion can be transformed.
The human brain is a reddish grey mass, with the consistency of firm jelly, which weighs on average the same as three bags of sugar and houses 100 billion individual brain cells called neurones.
- Each neurone has a cell body which houses its processor, the nucleus. Branching from the bodies are numerous finger like dendrites which branch and re-branch, fanning out to extensive, tree like structures that intertwine with dendritic trees of other neurones.
- Each neurone makes up to 1000 different connections with its neighbours and different areas of the brain. This extensive connectivity allows electrical signals, and thus information to travel from one brain processing centre to another in a matter of milliseconds.
The Human Brain Is Organised In A Hierarchical Manner
The oldest parts controlling the more primitive, instinctual behavioural reflexes.
The newest parts controlling the more sophisticated cognitive, sensory and motor functions.
The Human Brain Is Made Up Of Three Main Blocks
- The Forebrain
- The Midbrain
- The Hindbrain
The oldest part of the human brain, the hindbrain, evolved more than 500 million years ago. It closely resembles the brain of a modern reptile, so is sometimes called "the mammalian brain".
- It is responsible for automatic physiological reflexes that control breathing, heart rate and digestion, and coordinate movement and sense perception.
The midbrain contains neurones responsible for temperature control and the fine tuning of movement. It relays sensory information from the bodies sensory organs to the forebrain.
- It also plays an important part of the limbic system, a group of brain structures associated with the expression of emotion.
The most evolved part is the forebrain which is composed of cerebral hemispheres, and is what we most commonly think of as the brain, and the hypothalamus and thalamus.
In the last 100,000 years, the weight of the human brain has tripled, and most of this growth has been in the cerebral hemispheres.
The neurones of the forebrain control cognitive, sensory and motor function, as well as regulating reproductive functions, eating, sleeping and the display of emotion.
Parts Of The Brain
The Different Parts Of The Brain Are Responsible For Various Activities.
Cerebrum - The cerebrum helps the body to move and is responsible for a person’s ability to think. It is also in charge of a person’s senses.
Cerebellum - The cerebellum is responsible for maintaining a person’s balance and helping the body to move.
Hippocampus - A person’s ability to learn and remember things comes from the hippocampus of the brain.
Hypothalamus - The hypothalamus is in charge of many things that happen within the human body.
- For example, it keeps watch over a person’s body temperature to make sure it stays at a normal level. In addition, it tells the body when it is hungry and thirsty.
Medulla - This part of the brain is in charge of making sure that a person breathes without having to think about it.
Midbrain - A person’s vision and ability to hear are controlled by the midbrain.
Spinal cord - The spinal cord allows messages to travel from the brain to other parts of the body.
Brain stem - The brain stem is in charge of helping a person to breathe, as well as helping a person’s heart to beat.
The Neuroscience Of Emotions
Affective Neuroscience is the study of the neural mechanisms of emotion. Emotions are triggered in the brain by thoughts, which are often unconscious.
Emotion is related to a group of structures in the center of the brain called the limbic systems, which includes the hypothalamus, cingulate cortex, hippocampi and other structures.
The Neuroscience Of Emotions
Affective Neuroscience is the study of the neural mechanisms of emotion. Emotions are triggered in the brain by thoughts, which are often unconscious.
Emotion is related to a group of structures in the center of the brain called the limbic systems, which includes the hypothalamus, cingulate cortex, hippocampi and other structures.
The following brain structures are currently thought to be involved in emotion :
Amygdala — The amygdalae are two small, round structures located anterior to the hippocampi near the temporal poles.
- The amygdalae are involved in detecting and learning what parts of our surroundings are important and have emotional significance.
- They are critical for the production of emotion, and may be particularly so for negative emotions, especially fear.
Prefrontal Cortex — The term prefrontal cortex refers to the very front of the brain, behind the forehead and above the eyes.
- It appears to play a critical role in the regulation of emotion and behavior by anticipating the consequences of our actions.
- The prefrontal cortex may play an important role in delayed gratification by maintaining emotions over time and organizing behavior toward specific goals.
Anterior Cingulate — The anterior cingulate cortex (ACC) is located in the middle of the brain, just behind the prefrontal cortex.
- The ACC is thought to play a central role in attention, and may be particularly important with regard to conscious, subjective emotional awareness.
- This region of the brain may also play an important role in the initiation of motivated behavior.
Ventral Striatum — The ventral striatum is a group of subcortical structures thought to play an important role in emotion and behavior.
- One part of the ventral striatum called the nucleus accumbens is thought to be involved in the experience of goal-directed positive emotion.
- Individuals with addictions experience increased activity in this area when they encounter the object of their addiction.
Insula — The insular cortex is thought to play a critical role in the bodily experience of emotion. As it is connected to other brain structures that regulate the body’s autonomic functions (heart rate, breathing, digestion, etc.)
- This region also processes taste information and is thought to play an important role in experiencing the emotion of disgust.
Cerebellum - Recently, there has been a considerable amount of work that describes the role of the cerebellum in emotion as well as cognition, and a "Cerebellar Cognitive Affective Syndrome" has been described.
Both neuroimaging studies as well as studies following pathological lesions in the cerebellum (such as a stroke) demonstrate that the cerebellum has a significant role in emotional regulation.
- Lesion studies have shown that cerebellar dysfunction can attenuate the experience of positive emotions.
- While these same studies do not show an attenuated response to frightening stimuli, the stimuli did not recruit structures that normally would be activated. Such as the amydala.
Rather, alternative limbic structures were activated, such as the ventromedial prefrontal cortex, the anterior cingulate gyrus, and the insula.
- This may indicate that evolutionary pressure resulted in the development of the cerebellum as a redundant fear-mediating circuit to enhance survival.
- It may also indicate a regulatory role for the cerebellum in the neural response to rewarding stimuli, such as money, drugs of abuse, and orgasm.
When we are confronted by a potential threat, this can trigger fear, anger or the urge to flee. Sometimes called "amygdala hyjack". The reaction is often disproportionate to the actual provocation.
When in the grip of these emotions, your capacity for higher "rational brain" thinking is diminished, and you are likely to revert to rote behaviours stored in the basal ganglia.
The practice of mindfulness helps us to recognise and observe our thought patterns.
Practitioners develop the ability to recognise when thoughts arise, and observe them in a detached manner, without the need to become involved in them. Thus not triggering an "emotional" or "automatic" reaction.