Neuro Science    





Everybody would frequently use the word 'Emotion' or 'Emotional' and would understand what it mean when others use the words in various context. But you would have difficulties describing in words when somebody ask you 'what is emotion'. I also have same problem.. I think I know what it mean, but I don't think I have good / deep understanding to clearly describe it in words. This is the motivation for me to write this note which is about emotion.

Emotion in dictionary

The first step for the study is to check out some of the definition of emotion from well-known dictionaries.

Merriam-Webster defines :

  • a consciousmental reaction (such as anger or fear) subjectively experienced as strong feeling usually directed toward a specific object and typically accompanied by physiological and behavioral changes in the body
  • a state of feeling
  • the affective aspect of consciousness

Collins defines :

  • a feeling such as happiness, love, fear, anger, or hatred, which can be caused by the situation that you are in or the people you are with defines :

  • An affective state of consciousness in which joy, sorrow, fear, hate, or the like, is experienced, as distinguished from cognitive and volitional states of consciousness.
  • any of the feelings of joy, sorrow, fear, hate, love, etc.
  • any strong agitation of the feelings actuated by experiencing love, hate, fear, etc., and usually accompanied by certain physiological changes, as increased heartbeat or respiration, and often overt manifestation, as crying or shaking.

Emotion in Psychology / Neuroscience

In terms of psychology and neuroscience, emotion can be defined as a complex mental state and physiological response that arises from various stimuli, resulting in cognitive, behavioral, and physiological changes. Emotions play a crucial role in human experience and guide our actions, decision-making, and social interactions.

The article The Neuroscience Behind Emotions states :

  • Emotions arereactions that people have in response to events or situations.. The circumstance that causes the emotion determines the type of emotion the individual feels. There are four major emotions:happiness, sadness, fear, and anger., which are associated with three core affects:reward, punishment, and stress..
  • Emotion is a complex psychological state with three separate components: a subjective experience, a physiological response, and a behavioral or expressive response.

Neural Mechanism for Emotion

The neural mechanisms of emotion involve a complex interplay between various brain regions, neural circuits, and neurotransmitters. These components work together to process, generate, and regulate emotional responses.


Image Source : Discrete Neural Signatures of Basic Emotions

          mPFC, medial prefrontal cortex;

          PCC, posterior cingulate cortex;

          Prec, precuneus; aPFC, anterior prefrontal cortex;

          LOC, lateral occipital cortex;

          post-CG, postcentral gyrus;

          pre-CG, precentral gyrus;

          Ins, insula;

          Amy, amygdala;

          MTG, middle temporal gyrus

Followings are the parts of the brain that are associated with emotions :

  • Amygdala: The amygdala plays a critical role in processing emotional stimuli, particularly in the recognition and processing of fear and other threat-related emotions. The amygdala receives sensory input from the thalamus and the cortex,evaluates the emotional significance of the stimuli,and sends signals to other brain regions to initiate appropriate emotional responses..
  • Prefrontal Cortex (PFC): The PFC is involved in higher-order cognitive functions, including emotional regulation, decision-making, and social behavior. The PFC modulates the activity of the amygdala and other limbic structures, helping to regulate emotional responses and integrate them with cognitiveprocesses. The PFC also plays a role in the experience of complex emotions, such asempathy, guilt, and moral judgment..
  • Hippocampus: The hippocampus is primarily involved in learning and memory. However, it also has a role in emotional processing, particularly in the formation and retrieval of emotional memories. The hippocampusinteracts with the amygdala, connecting emotional experiences with specific contextual information..
  • Insula: The insula, a part of the cerebral cortex, is involved in the processing of bodily sensations and the subjective experience of emotions. It plays a role inthe perception of internal bodily states, such as pain, hunger, and temperature, and contributes to the experience of emotions likedisgust, anger, and empathy..
  • Anterior Cingulate Cortex (ACC): The ACC, located in the medial prefrontal cortex, is involved in a variety of cognitive and emotional processes, including error detection, conflict monitoring, and emotional regulation. The ACC is thought tointegrate cognitive and emotional information to guidedecision-making and behavior..
  • Thalamus: The thalamus is a key relay station in the brain, responsible for transmitting sensory information from the peripheral nervous system to the cerebral cortex. It plays a role in emotional processing byrelaying sensory information to the amygdala and other limbic system structures.. The thalamus is involved in the initial appraisal of emotionalstimuli and helps determine the emotional significance of sensory input. The connections between the thalamus and amygdala enablerapid emotional responses to threatening or salient stimuli, such as the fear response to a sudden, loud noise..
  • Hypothalamus: The hypothalamus is crucial for maintaining the body's homeostasis. It regulates various physiological processes, including temperature, sleep, hunger, thirst, and hormone release. The hypothalamus is involved in emotional processing through its connections with other limbic system structures, such as the amygdala and the hippocampus.It plays a critical role ingenerating and regulating physiological responses to emotions, such as increased heart rate, blood pressure, and stress hormone release during fear or anxiety.. The hypothalamus also influences the autonomic nervous system and the endocrine system, whichmodulate the body's stress response and emotional states..

Influence of Neurotransmittors on Emotion

Some neurotransmitters play a role in emotional processing and regulation, affecting various aspects of emotion such as mood, motivation, arousal, and stress response. Here is a list of some key neurotransmitters involved in emotion:

  • Dopamine: Dopamine is associated with reward, pleasure, and motivation. It plays a crucial role in the brain's reward system, contributing tothe experienceof positive emotions and reinforcing behaviorsthat promote survival and well-being.
  • Serotonin: Serotonin is involved in mood regulation, appetite, sleep, and social behavior. Altered serotonin levels are associated with mood disorders such as depression and anxiety. Serotonin also plays a role inimpulse control, aggression, and feelings of well-being and contentment.
  • Norepinephrine (noradrenaline): Norepinephrine is involved in arousal, vigilance, and the body's stress response. It contributes to the"fight or flight" response and is associated with emotions such as fear, anxiety, and excitement. Norepinephrine also plays a role inattention and focus, influencing emotional salience and the ability to respond to emotionally relevant stimuli.
  • GABA (gamma-aminobutyric acid): GABA is the primary inhibitory neurotransmitter in the brain, counteracting the excitatory effects of other neurotransmitters like glutamate. GABA plays a role inemotional regulation by reducing neuronal excitability and promoting relaxation and calmness. Altered GABA levels are associated with anxiety disorders and mood disturbances.
  • Glutamate: Glutamate is the primary excitatory neurotransmitter in the brain and is involved in many aspects of cognitive functioning, including learning and memory. Glutamate also plays a role in emotional processing bymodulatingneuronal activity in brain regions such as the amygdala and prefrontal cortex. Imbalances in glutamate signaling can contribute to mood disorders, anxiety, and stress-related conditions.
  • Endorphins: Endorphins are neuropeptides that function as natural painkillers and mood enhancers. They are released in response to stress, exercise, and other stimuli, producing feelings of pleasure, well-being, and euphoria. Endorphins contribute to theregulation of mood and the body's stress response.
  • Oxytocin: Oxytocin is a neuropeptide that plays a critical role in social bonding, trust, and attachment. It is often referred to as the "love hormone" due to its involvement in forming and maintaining close relationships. Oxytocin also contributes toempathy, compassion, and the regulation of stress and anxiety.

Hormonal Influence on Emotion

In addition to Neurotransmittors, there are some hormones that can affect the emotion. Followings are a list of hormones associated with Emotion. You may see some hormones that are explained in Neurotransmitter section because some chemicals plays multi roles as neurotransmitter and hormone.

  • Cortisol: Cortisol is a glucocorticoid hormone released by the adrenal glands in response to stress. It is a critical component of the body's "fight or flight" responseand helps mobilize energy resources during stressful situations. High cortisol levels can increase arousal, anxiety, and negative emotions, while chronic stress and elevated cortisol levels have been linked to mood disorders such as depression and anxiety.
  • Adrenaline (epinephrine) and norepinephrine (noradrenaline): These hormones are released by the adrenal glands in response to stress and play a crucial role in the"fight or flight" response. They increase heart rate, blood pressure, and blood flow to muscles, preparing the body for action. Adrenaline and norepinephrine also influence emotions byincreasing arousal, alertness, and feelings of fear, anxiety, or excitement.
  • Oxytocin: Oxytocin is a neuropeptide produced in the hypothalamus and released by the posterior pituitary gland. Often referred to as the "love hormone," oxytocin plays a critical role in social bonding, attachment, trust, and empathy. It canpromote positive emotions such as love, happiness, and contentment, and reduce stress and anxiety.
  • Estrogen: Estrogen is a group of sex hormones primarily associated with female reproductive development and function, though it is also present in males in smaller amounts. Estrogen can influence emotions by modulating the activity of neurotransmitter systems, such as serotonin and dopamine. Fluctuating estrogen levels during the menstrual cycle can affect mood, contributing topremenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) in some women. Estrogen has also been implicated in mood regulation and the prevalence of mood disorders such as depression.
  • Testosterone: Testosterone is a sex hormone primarily associated with male reproductive development and function, though it is also present in females in smaller amounts. Testosterone can influence emotions bymodulatingthe activity of neurotransmitter systems and brain regions involved in emotional processing. High testosterone levels have been linked to increased aggression, risk-taking, and dominance, while low testosterone levels can contribute to mood disturbances and depression.
  • Progesterone: Progesterone is a sex hormone primarily involved in the female reproductive system, regulating menstrual cycles and pregnancy. It also plays a role in mood regulation and can influence emotions bymodulatingthe activity of neurotransmitter systems such as GABA. Similar to estrogen, fluctuations in progesterone levels during the menstrual cycle can affect mood and contribute to PMS and PMDD in some women.

Medical conditions related to Emotion

There are various types of medical conditions associated with Emotion. Followings are some of the examples with neurological and hormonal factors involved in the condition.

Medical Condition

Neurological Factors

Hormonal Factors

Major Depressive Disorder (MDD)

Imbalances in serotonin, dopamine, and norepinephrine; Altered activity in prefrontal cortex, hippocampus, and amygdala

HPA axis dysregulation; Elevated cortisol levels

Generalized Anxiety Disorder (GAD)

Imbalances in GABA, serotonin, and norepinephrine; Altered activity in amygdala, prefrontal cortex, and anterior cingulate cortex

HPA axis dysregulation; Elevated cortisol levels

Bipolar Disorder

Imbalances in dopamine, serotonin, and glutamate; Altered activity in prefrontal cortex, amygdala, and hippocampus

HPA axis dysregulation; Elevated cortisol levels

Post-Traumatic Stress Disorder (PTSD)

Altered activity in amygdala, hippocampus, and prefrontal cortex; Imbalances in norepinephrine and serotonin

HPA axis dysregulation; Elevated cortisol levels

Premenstrual Dysphoric Disorder (PMDD)

Altered serotonin neurotransmission; Changes in brain sensitivity to hormonal fluctuations

Fluctuations in estrogen and progesterone levels

Seasonal Affective Disorder (SAD)

Altered activity in brain regions associated with mood regulation; Changes in serotonin levels

Altered melatonin production


Altered neurotransmitter systems and brain regions involved in mood regulation

Insufficient thyroid hormone production (T4 and T3)

Cushing's Syndrome

Altered activity in brain regions associated with mood regulation; Changes in neurotransmitter systems

High levels of cortisol

Polycystic Ovary Syndrome (PCOS)

Altered neurotransmitter systems and brain regions involved in mood regulation

High levels of androgens; Insulin resistance


Altered activity in brain regions associated with mood regulation; Changes in neurotransmitter systems, such as serotonin

Decline in estrogen and progesterone production

Are Emotion Born or Made ?

Most of the readers would think this is a question with no worth of asking because the answer is so clear. You may say 'Of course, most of (even if not all) emotions are born. Imagine a baby crying when it is in need of something right after the birth'.

Then, let me ask in a little bit different way. Is all the emotions hardwired in the brain when we born. The hardwired circuit simply get triggered by stimulus ? As a non-expert in this field, I am not one hundred sure of this view either.

Now comes the debates comes.

  • Evolutionary psychologists believe that emotions are adaptations that have evolved in response to the challenges faced by our ancestors. They believe that emotions are innate, meaning that we are born with them wired into our brains.
  • However, Some recent researches claim that emotions are not inborn, automatic responses, but ones we learn, based on our experiences and prior knowledge.

Here I don't intend to annouce the win to any specific claims (i.e, bord or made). Instead, I would just try to introduce a few different claims leaving the conclusion to readers or future research.

All Emotions are Born (Innate)

In this theory, it is claimed that all human emotions are inborn(i.e, not learned). These emotions are thought to be cross-cultural and universal, hardwired into our DNA and having evolved over millions of years. Our ancestors needed these emotional responses as survival mechanisms in the harsh environments they lived in. Today, even though we live in vastly different societies than our early ancestors, we've inherited their emotional responses.

The theory draws heavily from studies involving infants and young children, cross-cultural research, and the use of neuroimaging to identify consistent patterns of brain activity associated with specific emotions. Here are the key premises:

  • Evidence from Developmental Psychology: Newborn infants, even without much exposure to cultural and societal teachings, show emotions like distress, disgust, interest, and pleasure. This suggests that certain emotional responses do not require learning but are rather innate.
  • Cross-cultural Studies: Certain basic emotions such as happiness, sadness, fear, surprise, anger, and disgust are recognized universally across different cultures. This suggests that these emotions are not socially constructed or learned but are instead innate.
  • Neurobiological Evidence: Neuroimaging studies have identified consistent patterns of brain activity associated with specific emotions. For instance, fear is associated with activity in the amygdala which is a small almond-shaped structure deep within the brain. This suggests that emotions have a physiological basis and are not just learned behaviors.
  • Evolutionary Psychology Perspective: Emotions are seen as adaptive responses to environmental challenges. For instance, fear triggers a 'fight or flight' response which prepares the body to either confront or flee from danger.

All Emotions are Made (Learned)

This theory often called 'Constructivist Theory' argues that emotions are primarily learned and socially constructed, rather than being universally innate. According to this theory, our brains create emotional experiences and expressions through a process of prediction and categorization based on past experiences. In other words, this theory suggests our brains form emotional experiences and expressions through a process of prediction and categorization of past experiences.

This theory can be summarized in one line by Lisa Feldman Barret in her TED speach : You aren't at the mercy of your emotions


Literally, it implies that Emotions are not built-in(innate, born) but they are just built (aquired, learned). In the same speach, she

  • challenges the traditional understanding of emotions as universally expressed, recognized, and hardwired brain reactions. Instead, she argues that emotions are constructed by our brains based on our past experiences and predictions.
  • explains that our brains do not contain emotion circuits, and emotions are not built into our brains at birth. Instead, our brains construct emotions in the moment, with billions of neurons working together. This process is based on our past experiences and predictions, which are influenced by the context of the situation.

Followings are some of the arguments supporting this theory :

  • Cultural Variation: This refers to the diversity in how emotions are recognized, expressed, and experienced across different cultures. For example, research has shown that people from Western cultures tend to focus on individual emotions, while people from East Asian cultures often consider the emotional context of the group as a whole. Some cultures may have unique emotions that don't exist in other cultures. An example is the Filipino emotion "liget," which is a kind of passionate anger that has no direct translation in English. This suggests that emotions are influenced by cultural learning and social norms.
  • Neurobiological Evidence: Neuroscience has shown that our brain is a dynamic, plastic organ that can change based on our experiences. Unlike certain basic physiological responses (like pulling your hand away from a hot stove), emotions do not have dedicated and exclusive areas in the brain. For instance, the amygdala, often associated with fear, can also be activated in other emotional states such as happiness. This underscores the brain's flexibility in generating a variety of emotional responses based on different contexts and experiences.
  • Emotional Development: As children grow and interact with their surroundings, they learn to understand, express, and regulate their emotions. For instance, a toddler might initially express frustration by crying or throwing a tantrum. Over time, they learn that such behavior is not socially acceptable, and they might instead express their frustration by using words or taking deep breaths to calm down. This shows that our understanding and expression of emotions can change and become more nuanced over time through learning and experience.
  • Role of Language: Language plays a critical role in helping us categorize and understand our emotional experiences. For example, if a child feels unpleasant after their sibling takes away their toy, they might not understand this feeling until a parent or caregiver labels it as "anger". Through such experiences, the child learns to associate their feelings with the word "anger". As they grow up and learn more emotion words, they can recognize and express a wider range of emotions. This demonstrates how language and cultural learning shape our emotional experiences.
  • Somatic Markers: This refers to how our brains associate certain bodily responses with specific emotional experiences. For instance, if your heart rate increases and palms sweat before a big presentation, your brain might recognize these bodily changes as signs of anxiety. The next time you experience similar bodily changes, your brain will predict that you're about to feel anxious, and you might take steps to calm yourself down. This shows how our brains use past experiences and learned associations to predict and guide our emotional responses.

Bridging the  Gap: The Interplay of Innate Responses and Cultural Learning in the Psychological Constructionist Theory

This view is often called as Psychological Constructionist Theory. It offers a comprehensive perspective on emotions, incorporating elements from both innate and constructed theories. This theory claims that our emotional experiences are not directly hardwired into our brains or universally pre-programmed, nor are they entirely learned or constructed. Instead, emotions emerge from a mix of fundamental psychological processes, which are universal, and our interpretation of these processes, which is largely shaped by our personal experiences and cultural contexts.

This theory / view has some basic principles as below :

  • Basic Psychological Processes: According to this theory, our emotional experiences are constructed from more fundamental psychological processes like attention, perception, memory, and bodily sensations. These processes are not specific or unique to emotions but serve as the building blocks from which our brains construct our emotional experiences.
  • Interpretation and Context: How we interpret these basic psychological processes can significantly shape our emotional experiences. This interpretation is largely influenced by our personal experiences and cultural learning. The same basic process can lead to different emotions depending on the context and our interpretation of it.
  • Innate Biological Responses: While this theory emphasizes the constructed nature of emotions, it also acknowledges that certain biological responses to stimuli are universal and automatic. These responses, such as an increased heart rate when we perceive a threat, can serve as a starting point for the construction of our emotional experiences.
  • Role of Learning and Culture: Our understanding and interpretation of our biological responses are significantly shaped by our personal experiences and cultural learning. For instance, different cultures might teach us to interpret the same bodily response as different emotions.

As an example, Imagine you are about to give a public speech. Your heart rate increases, and you feel a sensation in your stomachthese are basic biological responses to a perceived stressful situation. Depending on your past experiences and cultural context, you might interpret these sensations differently: as fear, excitement, or anticipation. You might label your emotion as "stage fright" or "thrill", thus constructing your specific emotional experience from these universal biological responses and your learned interpretations of them.

Any Evolutionary advantage of Emotion ?

Emotions play a crucial role in evolution, offering several adaptive advantages that have helped shape human behavior and social structures. Emotions have evolved as a complex system that plays a vital role in survival, reproduction, learning, and social interaction. They are not simply irrational responses but rather adaptive mechanisms that have shaped human behavior and contributed to our success as a species.

Enhanced Survival:

  • Rapid Decision-Making: Emotions enable quick responses to threats or opportunities without needing extensive analysis. Fear triggers a fight-or-flight response, while disgust helps avoid harmful substances.
  • Communication and Cooperation: Emotional expressions facilitate communication between individuals, signaling danger, intentions, or needs. This fosters cooperation, essential for social species' survival.
  • Motivation and Action: Emotions motivate actions necessary for survival and well-being. Hunger drives the search for food, while affection strengthens social bonds.

Improved Reproduction:

  • Mate Selection: Emotions play a crucial role in choosing mates. Attraction and love increase the likelihood of reproduction and parental investment.
  • Offspring Care: Emotions like love and protectiveness towards offspring ensure their survival and well-being, increasing the chances of passing on genes.
  • Social Bonding: Emotions facilitate social bonding, which indirectly contributes to reproductive success through increased support and resources.

Learning and Adaptation:

  • Reinforcement Learning: Emotions like pleasure and pain serve as feedback mechanisms, reinforcing beneficial behaviors and deterring harmful ones.
  • Memory Enhancement: Emotionally charged events are more likely to be remembered, aiding in learning and avoiding future mistakes.
  • Adapting to the Environment: Emotions help individuals assess and respond to environmental changes, contributing to adaptability and survival in dynamic conditions.

Social Cohesion and Group Survival:

  • Empathy and Altruism: Emotions like empathy and compassion motivate individuals to help others, strengthening social bonds and cooperation within groups.
  • Moral Emotions: Emotions like guilt and shame regulate social behavior, promoting cooperation and preventing actions that could harm the group.
  • Group Identity: Emotions like pride and belongingness foster a sense of group identity, which can enhance cooperation and defense against threats.

The Heart and Mind of Decision-Making: Understanding Emotion and Logic

Just based on my personal observation and impression, it seems to me that people tend more to be emotional than rational. Is this explainable ?

I am not sure if it can be explained in terms of strict neuroscientific way, but it can be explainable in terms of psychology or behavioral economics. People often rely on emotions as well as rational thought when making decisions and interacting with the world. This interplay between emotion and rationality is a central topic in psychology, behavioral economics, and decision-making studies.

  • Dual-Process Theories: Theories such as the popular "System 1 and System 2" model proposed by Daniel Kahneman suggest that humans have two different ways of thinking: System 1 is fast, intuitive, and emotional, while System 2 is slower, more deliberative, and more logical. People often default to System 1 because it is more efficient and requires less cognitive effort, which means emotions can heavily influence decisions.
  • Emotion's Role in Decision-Making: Emotions are a crucial part of decision-making. They can serve as heuristic shortcuts to make decisions quickly. For instance, fear might deter us from taking dangerous actions, or happiness might lead us to be more cooperative. Emotions also play a critical role in assigning value to different options we might choose.
  • Emotion vs. Rationality in Behavioral Economics: Research in behavioral economics has shown that people do not always act in economically rational ways. Emotions can lead to biases and deviations from what would be considered rational choice. Phenomena like the endowment effect, where people value things more highly simply because they own them, showcase the influence of emotion over strict rational analysis.
  • Cultural and Individual Differences: The preference for emotion or rationality can vary widely among individuals and cultures. Some cultures emphasize emotional expressiveness and interpersonal harmony, while others value restraint and logical analysis more highly.

As high level summary, we can say :

Overall, while people are capable of being rational, emotions often play a significant and sometimes dominant role in decision-making and behavior. This doesn't mean that being emotional is inherently negative; emotions are a fundamental part of human cognition and can contribute positively to creativity, problem-solving, and social interaction. Understanding the balance and interplay between emotion and rationality is a continuing area of research in understanding human behavior.

What is Pros and Cons of Emotion and Rationality ?

Emotions and rationality both play integral roles in human cognition and decision-making, each offering distinct advantages and disadvantages. In other words, Both emotions and rationality are essential aspects of human nature. They offer unique strengths and weaknesses. By understanding their roles and finding a balance between them, we can harness their power to enhance our lives and achieve our full potential.


  • Pros:
    • Rapid Decision-Making: Emotions enable quick responses to situations, especially in times of danger or urgency, when there's no time for extensive analysis.
    • Motivation and Drive: Emotions fuel our passions, ambitions, and desires, motivating us to take action and pursue goals.
    • Social Connection: Emotions facilitate communication, empathy, and bonding with others, creating strong social relationships.
    • Creativity and Intuition: Emotions can inspire creativity and provide intuitive insights that logic alone might miss.
  • Cons:
    • Impulsivity and Irrationality: Emotions can lead to impulsive decisions and actions, clouding judgment and hindering rational thinking.
    • Bias and Prejudice: Emotions can fuel biases and prejudices, leading to unfair or discriminatory behavior towards others.
    • Emotional Turmoil: Uncontrolled emotions can lead to anxiety, depression, anger, and other negative mental health states.
    • Conflict and Misunderstanding: Misinterpreting or overreacting to emotions can lead to conflict and misunderstandings in relationships.


  • Pros:
    • Logical and Critical Thinking: Rationality allows for objective analysis, problem-solving, and decision-making based on facts and evidence.
    • Problem-Solving: Rationality helps identify solutions to complex problems by breaking them down into manageable parts.
    • Planning and Organization: Rationality allows for effective planning and organization, leading to greater efficiency and productivity.
    • Objectivity and Fairness: Rationality helps reduce bias and prejudice, promoting fairness and equality.
  • Cons:
    • Time-Consuming: Rational thought often requires more time to weigh options and analyze data, which can be a disadvantage in situations requiring quick decisions.
    • Lack of Motivation: Excessive reliance on rationality can lead to a lack of motivation and passion, as emotions are often the driving force behind action.
    • Social Disconnect: Overemphasis on rationality can hinder emotional connection and empathy with others, leading to social isolation.
    • Analysis Paralysis: Overthinking and excessive analysis can lead to indecision and inaction.
    • Ignoring Intuition: Relying solely on logic can sometimes lead to ignoring valuable intuitive insights.