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Emotion
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 conscious mental 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
Dictionary.com 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 are reactions 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.
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 as empathy, 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 hippocampus interacts 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 in the 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 to integrate 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 by relaying 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 enable rapid 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 in generating 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, which modulate 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 to the 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 in impulse 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 in attention 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 in emotional 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 by modulatingneuronal 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 the regulation 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 to empathy, 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 by increasing 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 can promote 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 to premenstrual 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 by modulatingthe 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 by modulatingthe 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.
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Medical Condition
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Neurological Factors
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Hormonal Factors
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| 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 |
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Seasonal Affective Disorder (SAD)
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Altered activity in brain regions associated with mood regulation; Changes in serotonin levels
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Altered melatonin production
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Hypothyroidism
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Altered neurotransmitter systems and brain regions involved in mood regulation
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Insufficient thyroid hormone production (T4 and T3)
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Cushing's Syndrome
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Altered activity in brain regions associated with mood regulation; Changes in neurotransmitter systems
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High levels of cortisol
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Polycystic Ovary Syndrome (PCOS)
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Altered neurotransmitter systems and brain regions involved in mood regulation
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High levels of androgens; Insulin resistance
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Menopause
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Altered activity in brain regions associated with mood regulation; Changes in neurotransmitter systems, such as serotonin
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Decline in estrogen and progesterone production
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Reference
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