the chemistry of emotions part 2

Neurotransmitters play a critical role in modulating emotions in the brain and serious problems can result if neurotransmitter levels are not optimally balanced. Depression, anxiety or mood swings can all be caused by a lack of a balance in neurotransmitters.

Drug therapies given to individuals suffering from these disorders aim to restore that balance. For example, some antidepressants stimulate the midbrain dopaminergic neurons to release dopamine or the raphe nuclei located in the midline of the brainstem to produce serotonin. These drugs can also achieve this by blocking the reabsorption or reuptake of the neurotransmitter, causing it to stay in the brain for longer, therefore raising its apparent levels and therefore, improving mood.

anatomy of emotion

The brain is a large organ weighing in at almost 3 pounds. It is as complex in its anatomy as its function. Various areas of the brain are responsible for eliciting and controlling different emotions. The most important part of your brain for processing emotions is the limbic system comprising the amygdala, hippocampus, thalamus and basal ganglia. The amygdala evaluates the emotional value of incoming sensory inputs. It is also the ‘fear centre’ of the brain and plays a crucial role in deciding the response to fearful stimuli. Many studies have shown that damage to this part of the brain can abolish the perception of fear altogether.

The hypothalamus is another part of the limbic system which controls the involuntary response to emotions. For example, if you are excited or anxious, your heartbeat is increased or your palms are sweaty – these responses are mediated by the hypothalamus.

The hippocampus is responsible for evoking emotions related to certain memories. The nostalgia that you feel when you think about the “good old times” is controlled by the hippocampus. It is also responsible for converting short term memories to long term.

The brain on the whole is composed of two halves or hemispheres, one on each side – left and right. Each of the hemispheres performs different functions and is associated with the processing of different information. For example, the left part of your brain is responsible for drawing more literal conclusions, such as the meanings of words, or mathematical formula while the right side is more creative, feeling-oriented and has a less concrete perspective.

As both sides are working in unison, emotions are pretty well managed. Generally – and this is an oversimplification – the right hemisphere identifies a stimulus and the left brain interprets its meaning. This system works perfectly because the roles of receiving/ identifying and interpretation are clearly designated. But sometimes, if one of the hemispheres is not able to perform its function, the results can be disastrous, such as if there is no left brain to interpret emotions as in the case of a traumatic brain injury, the right brain will be overwhelmed with emotional stimuli and the person would not be able to function.

There is plentiful scientific evidence regarding the effect of damage to either hemisphere. People with damage to their left brain are more prone to depression and suicidal ideas. Their right brains are overwhelmed with feelings, emotions and memories and they don’t have the left brain function to stablilze, interpret or “make sense” of these feelings, emotions and memories.

memory plays a part in perceiving emotion

As we all have experienced, certain memories can evoke a feeling of joy and others can evoke sorrow. These memories, when elicited, can cause the limbic system to perceive them as emotional stimuli and the result is the precipitation of an emotion. As we saw earlier, short term memories are transformed to long term in the hippocampus which can then triggered by certain visual or auditory stimuli.

Many psychologists have successfully used this to treat patients suffering from severe depression. If you can evoke a good memory in a depressed individual, it can lead to the release of dopamine and serotonin and make the patient feel better. We can all do this by using “first aid” tools and techniques such as those described in this blog “happiness hack (first aid)”

something to take home

The brain is like a complicated but very finely tuned system. It plays a crucial role in eliciting and interpreting emotions and feelings. Knowing about how your brain is involved in experiencing emotions, how some disorders affect the balance in brain chemistry (or are affected/caused by it) and learning some first aid techniques, can give you more choices around how you feel.

curated from Life Science, 25 May 2016.

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