The question must have fascinated everyone? A very simple question — how and why does Emotions come from? The question can be looked from various aspect s— there is a perspective of psychology, we can look through the prism of cognitive science and can also try to find our answer through our “limited” knowledge of our Brain.
Human brain is a very complex organ. It controls and coordinates everything from the movement of your lips to your heart rate. The brain plays the most important role in how we process our emotions. But our knowledge about human brain is limited though evolving every single day. Human brain can never be compartmentalized based on the functions it performs. Similarly we simply cannot pin point one section of the human brain to be dealing with all emotions. MRI data can be used to substantiate this fact. So when we speak of human brain and emotions it better to speak of a “emotional processing network” as this spread across regions of the brain and each section having their role to play. Scientists feel that it’s the limbic system is primarily responsible for behavioral and emotional responses. However we also need the prefrontal cortex — our control unit to process and communicate the emotion. It helps to guide our actions, and therefore is involved during emotion regulation.
The limbic system combines higher mental functions and primitive emotions into one system and is often referred to as Emotional Nervous System. The limbic system is a complex set of structures found on the central underside of the cerebrum comprising inner sections of the temporal lobes and the bottom of the frontal lobe. Some of the important structures of Limbic system includes
Amygdala : This is a small almond shaped structure , one located on each side of the left and right temporal lobes. This is quite famously known as the “Emotional Centre of the brain”. The amygdala helps the brain in evaluating the emotional valence of the situation and recognize potential threats by
coordinating responses to things in our environment, especially those that trigger an emotional response. Thereby it prepares the body for fight or flight reaction by increasing heart rate and breathing rate. This structure plays an important role in fear and anger. Thus amygdala integrates emotions, emotional behavior, and motivation — classical conditioning. It also plays an important part in learning on the basis of reward and punishment. Due to it’s close proximity to the hippocampus , it is involved in the modulation of memory particularly emotion driven memories. Emotional arousal following a learning influences the strength of the subsequent memory of that event, so that greater emotional arousal enhances the person’s memory retention.
Hippocampus : This sea-horse shaped part is found deep inside the temporal lobe. It plays an important role in memory formation and helps preserve and retrieve memories. It also plays a role in how we understand the spatial dimensions of our environment. Damage to hippocampus results in difficulty in formation of new memory or access to past memories.
Hypothalamus : In addition to controlling emotional responses, this region is also involved in regulating our body temperature, hormone release and sexual responses, hunger, combativeness, rage, laughter. It is associated with changes in emotional activity.
Basal Ganglia is a group of nuclei lying deep in the subcortical white matter of the frontal lobe. It organizes motor behavior. The major components of basal ganglia are Caudate, Putamen, Globus pallidus.
Cingulate gyrus and Para hippocampal gyrus or together known as Limbic cortex is located in the medial side of our brain next to the corpus callosum. They impact mood, motivation, and judgement. It is assumed that frontal part of cingulate gyrus links smell and sights with good memories of past emotional reactions to pain and regulation of aggressive behavior.
Other parts of the brain which can be closely linked with emotions are the insula or insular cortex, and a structure in the midbrain called the periaqueductal gray.
The insula is the source of disgust , it is the place where in we develop a strong negative reaction for something — spicy food, a particular smell, just to give some examples. MRI data shows high activity in the insula when someone feels or anticipates pain. Thus scientists think the insula generates subjective feelings linking internal states, feelings, and conscious actions.
The periaqueductal gray, located in the brainstem, is implicated in pain perception. It contains receptors for pain-reducing compounds like morphine and oxycodone, and help quell activity in pain-sensing nerves . This might be the reason why sometimes we distract ourselves from pain so that we don’t feel it. The periaqueductal gray is also involved in defensive and reproductive behaviors, maternal attachment, and anxiety.
What is important to understand is that there are many brain regions involved during emotion processing. All the different regions have their own job and they all work together to identify and control an emotion.
By the way do we know how many emotions do we have? Anthropologist Paul Ekman proposed in 1970 that humans experienced six basic emotions: anger, fear, surprise, disgust, joy, and sadness. However since then scientists are still discussing — some scientists suggesting , there are just 4 emotions while some scientist could classify as many as 27.
We may look at the major emotions and how these play out in our brain.
Fear : It is a very important emotion for humans. It helps us to respond appropriately to threatening situations that can harm us. The response of fear is generated by stimulation of the amygdala, followed by the hypothalamus. And that’s why people with brain damage affecting their amygdala are often found to not respond properly during dangerous scenarios. Amygdala stimulates the hypothalamus, with a fight-or-flight response. The hypothalamus then sends signals to the adrenal glands to produce hormones, such as adrenaline and cortisol. These hormones then enter the bloodstream, and we notice physical changes like alterations of
- heart rate
- breathing rate
- blood sugar
- perspiration
Anger : It is a response to threats or stress in our environment. When we are in a situation that seems dangerous to us and we feel we cannot escape from it , chances are good that we would respond with anger or aggression. Anger response can also be associated to the fight-or-flight response. Frustration can also trigger anger. Anger starts with the amygdala stimulating the hypothalamus. In addition parts of the prefrontal cortex also play a role in anger. Individuals with damage to this area often have trouble controlling their emotions, especially anger and aggression.
Happiness : It refers mental state of satisfaction. When we feel happy, we generally have positive thoughts and feelings. Happiness response originates partly in the limbic cortex. Another area called the precuneus also plays a role. The precuneus is involved in retrieving memories, maintaining our sense of self, and focusing our attention as we move about our environment. A recent study suggests that people with larger gray matter volume in their right precuneus are more happier. Which might suggest that the precuneus processes certain information and converts it into feelings of happiness.
Love : Love is associated with the stress response triggered by hypothalamus. That’s why we feel nervous, excitement or anxiety while falling for someone. The hypothalamus triggers release of other hormones, such as dopamine, oxytocin, and vasopressin. Dopamine is associated with our body’s reward system. This helps make love a desirable feeling. Oxytocin is often referred to as the “love hormone.” Oxytocin increases when we hug someone or have orgasm. It is produced in the hypothalamus and released through our pituitary gland. Oxytocin is also associated with social bonding as does promotion of a feeling of calmness and contentment. This is important for trust and building a relationship. Vasopressin is also produced in our hypothalamus and released by pituitary gland. It is also involved in social bonding with someone.
The brain is a complex organ that we are still trying to understand. The limbic system is one of the main parts of the brain that controls basic emotions. As more and more mysteries about our brain are understood and as technologies evolve we are more likely to learn even more about the origins of more complex emotions.
