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Motivation and emotion/Book/2024/Neurohormones and emotion

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Neurohormones and emotion:
How do neurohormones influence emotional states and regulation?

Overview

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Have you ever wondered where your emotions stem from? You may understand why you are feeling the way that you do, maybe you had a bad day at work or you found out your friend is having a baby. These are experiences where we can instantly feel sad or happy. However, have you ever been curious to know why you experience these feelings. Even when they come from doing something as simple as patting a dog, or feeling anxious during a thunderstorm. These emotions can come from your external environment and experiences and knowing where these emotions come from allows you to have a deeper understanding of the extraordinary mechanisms in your brain and how you can use them to your benefit.
Figure 1. Feeling fearful is an emotion that can be experienced when there is a perceived threat such as a thunderstorm
Figure 1. Paul Ekman, theorised 6 basic emotions that are innate and shared by everyone across cultures.

Neurohormones are a type of hormone that is produced and released by neurons in the brain, into the bloodstream, where it acts on distant target cells or organs. They are directly related with the central nervous system and influence cognitive, behavioural and physiological processes. Recent research has explored the relationship between neurohormones and how they influence emotion.

Paul Ekman is one of the earliest researchers of emotion. He identified six basic emotions; anger, surprise, disgust, enjoyment, fear, and sadness. (see Figure 2). Overtime, research of the representation of these emotions in the brain have illuminated the complexity of emotional processes. Many recent studies have revealed that multiple neural structures could be influential for one particular basic emotion, while a specific area could attribute to a number of basic emotions. (Wang et al., 2020). Neurohormones in our brain help regulate our emotional states. Being able to understand the neuropsychological science behind our emotions we can gain greater emotional awareness. Through knowing how our neurohormones influence emotions, individuals can help identify emotional triggers and create strategies to overcome them. It is also important to gain insight in how we can make informed and healthy choices that benefit neurohormone levels to optimise our emotions.

This book chapter will explain the relationship between different neurohormones and their influence on our emotional states and emotional regulation. It will also give insight into effective strategies that can be put in place to help optimise neurohormones for emotional regulation. It is crucial that we gain an understanding on how neurohormones can influence our feelings to enhance emotional awareness, long-term wellbeing outcomes and holistic health.

Zoe's case study
Zoe is a 22 year old early childhood educator who has recently experienced a significant increase in her emotional wellbeing and sense of connectedness with others. She feels that she is more enthusiastic and empathetic in her interactions with her workmates and children that she cares for. Zoe's positive emotional changes could be because of her recent involvement in activities that are likely to boost oxytocin levels such as volunteering at the local dog shelter and participating in community social events such as bingo and trivia night. These self-reported feelings that Zoe is feeling can align with effects of increased oxytocin levels, a neurohormone produced in our brain.
Figure 1. Zoe engaging in a social activity that can increase her oxytocin levels due to positive social bonds.

Focus questions:
  • What are the theories of emotion?
  • What is the relationship between neurohormones and emotions?
  • How can we use our knowledge of neurohormones to optimise positive emotions?

Emotions

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Emotions have been widely studied overtime and despite the critical significance of emotions in our lives, there is currently no scientific consensus on a definition about what emotion is (Gu et al., 2019). However, different theorists have approached the study of emotions from various perspectives, leading to a rich tapestry of theories that capture the complexity of emotional states. These states can be described as psychological processes that are triggered by the comparison between what our internal body needs and the external resources available. They can be characterised by changes physiologically, behaviourally and cognitively (Gu et al., 2019).

Ekman's Six Basic Emotions

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Paul Ekman is an American psychologist best known for his work in the field of emotions and facial expressions, his psychological research on emotions is the strongest evidence to date. Ekman's research has focused on how emotions are expressed through facial expressions and how these expressions can be universally recognised across different cultures. Ekman identified six basic emotions as anger, surprise, disgust, joy, fear, and sadness.

“Emotions are a process, a particular kind of automatic appraisal influenced by our evolutionary and personal past, in which we sense that something important to our welfare is occurring, and a set of psychological changes and emotional behaviours begins to deal with the situation."

Paul Ekman, [Paul Ekman Group, 2003]

Ekman believed that the six basic emotions are the product of our evolution and found that emotions have adaptive value in dealing with fundamental life tasks. He believed that the primary function of emotion is to activate individuals to deal quickly with important interpersonal encounters. (Ekman, 1992.)

Ekman proposed nine characteristics which distinguish basic emotions from each other and other affective states such as moods, emotional traits and attitudes etc.

Table 1.

A description of Ekman's nine characteristics which distinguish basic emotions

Characteristic Explanation
Distinctive universal signals Uniqueness in facial expressions, recognised across cultures
Presence in other primates Similar expressions in other primates, indicating evolutionary roots
Distinctive physiology Distinctive physiological responses e.g., fear is related to an increased heart rate
Distinctive universals in antecedent events Certain events/triggers elicit a consistent emotion e.g., death often leads to sadness
Coherence among emotional response Emotion often align in various responses (e.g, happiness may trigger responses such as smiling and laughing)
Quick onset Arise suddenly, without warning
Brief duration E.g: Joy from receiving good news may last only a few moments
Automatic appraisal Emotions arise from quick, unconscious awareness of a situation
Unbidden occurrence Cannot control the emotions we feel, one cannot simply elect when to have which emotion.

Whilst Ekman provided a significant contribution to the theory of emotion there are some criticism. Firstly,  the physiological overlap between different emotions questions the clarity of Ekman's classifications. For instance, both fear and excitement can elicit similar physiological responses, such as increased heart rate and heightened arousal, suggesting that the bodily markers Ekman relies on may not be as distinct as proposed. This contradiction can question the reliability of using physiological indicators to categorise emotions, suggesting the need for other psychological theories such as neuroscientific underpinnings in the classification of certain emotions.

For a deeper understanding see book chapter on Ekman's basic emotions

The James Lang Theory of Emotion

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The James Lang Theory of Emotion is one of the earliest theories of emotion and proposes that physiological arousal with the exclusion of emotional behaviour, determines ones emotional feelings. (Lacasse, 2014) (James, 1890) This theory determined that emotions come from the physiological body changes in the autonomic, hormonal and motor systems (Northoff, 2008). It puts forward that we experience an emotional state after a physiological response has taken place in the body.  

Emotional Regulation

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According to James Gross (2014), emotional regulation refers to shaping which emotions one has, when one has them and how one experiences or expresses these emotions. For instance activities such as pounding your pillow when you’re angry at your boss or playing calming music after a long day at work are examples of ways one can regulate their emotions. Gross proposed three core features of emotion regulation:

  • Activation of a goal
  • Engagement of the processes that are responsible for altering the emotion trajectory
  • Impact on emotion dynamics e.g, the rise time, magnitude, duration and offset of responses in experiential, behavioural or physiological domains, depending on the individual’s goals.

Emotional regulation has been linked to distinct but overlapping neural emotion circuits (Urry & Gross, 2010). Brain regions such as the amygdala, prefrontal cortex and the anterior cingulate cortex are involved in emotional regulation processes such as reappraisal, where one has an active goal of regulating and uses effortful control processes to do so. Therefore highlighting a possible role of neurohormones involved in these neural circuits to help regulate emotions. This is an important area to discuss as  individuals with reduced abilities to regulate their emotions are at higher risk to develop depression or anxiety disorders (Aldao et al., 2010)

Neuroscience of emotion

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Antonio Damasio (1999) suggested that our emotional experiences arise from brain responses and the physiological expressions of those emotions. These brain responses represent unconscious emotions and correlate with subjective feelings (Shafir et al., 2014). This perspective emphasises that the brain plays a central role in shaping our emotional experiences. Rather than viewing emotions as just an aftereffect of physiological changes, we can understand them as part of a dynamic process where neurobiological activity, including hormonal responses, actively contributes to how we experience and interpret our emotions. In this way, the relationship between neurohormones and emotions is more interconnected.

Neurohormones

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Neurohormones are chemical substances that are synthesised by a neuron, act on another neuron and is then released into the bloodstream (Hoyle, 1985). Once a receptor is activated by a neurohormone, a series of reactions occurs that regulates physiology and, ultimately, behavior. However, an increasing number of studies indicate that hormones can impact these processes at a previously underestimated rapid pace. With the potential to function like neurotransmitters, our understanding of hormones and their mechanisms of action is evolving (Calisi & Saldanha, 2015).

Neurohormonal influence on joy

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Joy is a fundamental human emotion and is classified by Ekman in his theory of basic emotions. Our pursuit of happiness drives us to seek out various factors that can enhance our well-being, and neuroscience offers insights into where happiness originates. Understanding the neural mechanisms behind happiness—including the alteration of neural circuitry and the release of neurotransmitters—has deepened our knowledge of happiness and wellbeing (Ghosh, 2018). As Antonio Damasio noted, “we are not thinking machines that feel, but emotional machines that think," emphasising the significance of emotions in our cognitive processes. Key hormones like oxytocin and serotonin play vital roles in fostering joy; oxytocin promotes trust and empathy in social bonding, while serotonin helps regulate mood and emotional stability (Ghosh, 2018). Engaging in everyday activities that stimulate these hormones can enhance our happiness, often without our conscious awareness of their effects on our brain and emotional health.

Oxytocin is a peptide hormone of the hypothalamic nuclei that accumulates in the posterior pituitary gland of the brain and from there it is released into the blood (Florea et al., 2022). It is widely known as the ‘love-hormone’ as it facilitates the relationship with others and is associated with positive social behaviours. It is also released from the female reproductive system and facilitates lactation (Kurokawa et al., 2021). Much research has found a strong relationship between oxytocin and emotional states associated with feelings of joy. In particular, experimentally administered oxytocin have produced significant findings, for instance, administered oxytocin is associated with increased sustained attention to happy faces during an attention bias task in depressed patients (Domes et al., 2016) and an increased sensitivity to positive facial cues in healthy patients (Tollenaar et al., 2013). The findings indicate that oxytocin may enhance the processing of positive emotional cues, suggesting a relationship between oxytocin and positive emotions, but they do not establish causality due to potential individual differences and contextual influences. A study by Human and their colleagues (2018) found that administered oxytocin is associated with increased prosocial behaviours, considering research has found significant positive relationships between prosocial behaviour and happiness (Gupta & Sahai, 2019) it can be deduced that oxytocin promotes happy emotional states.

Neuroscientist Paul J. Zak stated that oxytocin baseline levels in humans are near 0 without a stimulus to cause a release. This is supported by research that found that perceived pleasantness of affective touch and a relationship with increased oxytocin (Chen et al., 2020). Zak also found in his studies that oxytocin can have a 3 minute life when released (Zak, 2011). This finding strengthens the understanding of the relationship between oxytocin and happy emotional states as theory states that emotions have only a brief duration (Ekman, 2003) Together, these findings suggest that while perceived pleasantness of touch has a transient effect on oxytocin, its short half-life aligns with the theory that emotions are fleeting; however, the brief duration of oxytocin's action raises questions about its long-term role in sustaining positive emotional states, indicating that additional factors may be necessary to maintain emotional well-being over time.

Neurohormonal influence on fear

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Fear is one of Ekman's basic emotions, and it arises with the threat of harm, either physical, emotional, psychological, real or imagined. The amygdala plays a major role in the fear-defense system which is an innate system that organises defensive responses such as an increased heart rate and hormonal release to promote survival (Kerahrodi & Michal, 2020).

Norepinephrine is a neurotransmitter and neurohormone produced in the neurons in the locus coeruleus in the pons while it is released to the blood by adrenal glands (Jiang et al., 2022). Norepinephrine’s major function is inducing “fight or flight” behaviour (Jiang et al., 2022) and plays an essential role in the regulation of arousal, attention, cognitive function, and stress reactions (Hussain et al., 2022). However, it is important to note whether the arousal triggers negative or positive emotional states. A study found that norepinephrine regulates neuronal excitability in the basolateral amygdale by facilitation of GABA release which can be linked to happiness. (Harrison et al., 2010) These findings suggest that norepinephrine plays a dual role in regulating arousal, influencing both fear and happiness depending on the context and specific neural circuits involved. While its primary function in the "fight or flight" response highlights its connection to fear and stress reactions, the ability of norepinephrine to enhance GABA release in the basolateral amygdala suggests that it can also promote neuronal excitability linked to positive emotional states, indicating that the overall emotional outcome may depend on factors such as individual differences, environmental context, and the balance of neurotransmitter activity.

Neurohormonal influence on sadness

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Experiencing emotional sadness has an impact on both the mind and body and may last anywhere from a few seconds to several hours (Arias et al., 2020). In humans, sadness can be characterised by specific behaviours such as social withdrawal ,facial expressions such as drooping eyelids and physiological changes such as a change in heart rate (Arias et al., 2020).

Serotonin is a neurohormone and neurotransmitter found in the central nervous system, however about 90-95% of the body’s serotonin is located in the periphery system, more specifically in the gastrointestinal tract (Mohammad-Zadeh & Gwaltney-Brant, 2008). Serotonin's role is important in most brain functions, and the dysregulation of the serotonergic system is linked to many mental health and neurological disorders (Berger et al., 2018). Although it is widely regarded as a neurotransmitter, it also can act as a hormone as it is released into the blood and modulates behavioural and neuropsychological processes (Bakshi & Tadi, 2022). Low levels of serotonin are associated with feelings of sadness and depression. When serotonin is deficient, it can lead to negative thinking patterns, difficulty experiencing pleasure, and increased vulnerability to sadness (Hasler, 2010). Thus, maintaining healthy serotonin levels is important for emotional well-being and reducing feelings of sadness.

1 Seratonin triggers a "fight or flight" response in the body:

True
False

2 Oxytocin is considered the "love hormone"

True
False


Neurohormones and Emotional Regulation

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Neurohormones can have an impact on an individual's emotional regulation. It refers to processes that govern the type, occurrence and intensity of felt and expressed emotions that are inextricably linked to distinct but overlapping neural emotion circuits (Alexander et al., 2021). Serotonin (5-HT) plays a crucial role in emotional regulation, particularly in the context of impulse control and aggressive behaviour. Research indicates that alterations in central nervous system 5-HT signalling can lead to significant dysfunctions in cognitive control and emotional regulation, which are evident in various neuropsychiatric disorders, including anxiety disorders, obsessive-compulsive disorder, depression, bipolar disorder, antisocial personality disorder, and schizophrenia (Lesch, 1998; Mahmood & Silverstone, 2001; Bond, 2005; Gaber et al., 2015). The use of selective serotonin reuptake inhibitors (SSRIs) has shown beneficial effects for patients struggling with disorders related to social and emotional control, highlighting the importance of 5-HT in these areas (Siever, 2008; Elliott et al., 2011). Additionally, strong emotional states often accompany impulsive and violent behaviors, as individuals with these tendencies frequently exhibit irritability, temper outbursts, and heightened emotional responsiveness (Krakowski, 2003). This indicates that impaired emotional self-regulation due to impaired 5-HT can contribute to violent actions. Moreover, serotonin's influence on psychological characteristics and social interactions further underscores its role in emotional regulation, as these factors can also affect serotonergic function and the relationship between serotonin and aggression (Krakowski, 2003).

Strategies to take control of neurohormones to optimise emotional states

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It is evident that neurohormones play a vital role in regulating emotions. Therefore, understanding how you can optimise neurohormone release in your brain to your bloodstream can be of great benefit.

Exercise

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The beneficial effects of physical exercise on physical, cognitive, and emotional well-being are well documented in healthy individuals. There is some research that has found a significant relationship between exercise and neurohormones. For instance, one study found that norepinephrine increases during exercise (Zouhal et al., 2008). As norepinephrine has been associated with feelings of happiness, it can show the importance of exercise for individual’s to optimise their well-being and emotional states. More specifically, a study found that martial arts increased oxytocin production. This study found that oxytocin increased immediately after high-intensity training, however returning to baseline level after the cool down period (Rassovsky et al., 2019). The short lived release of oxtytocin can be linked to Ekman’s theory of emotions being of a brief duration, further solidifying the influence that neurohormones have on emotional states.

Another type of exercise that research has shown to have benefits for optimising emotional states is dance movement therapy (DMT). A study designed to measure the effects of DMT on the psychological symptoms and plasma concentrations of neurohormones in adolescent female students with mild depression, found that  negative psychological symptoms were improved by 12 weeks of DMT. Furthermore, there were significant changes in the participants seratonin levels (Jeong et al., 2005). These findings suggest that DMT can effectively alleviate negative psychological symptoms in adolescent females with mild depression, potentially through the modulation of serotonin levels. However, while the study demonstrates promising results, it is important to consider the need for a larger sample size to better establish generalisability of these outcomes.

Physical touch

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Research suggest that physical touch helps stimulate oxytocin production. Specifically, paternal oxytocin levels increase after skin-to-skin contact with fathers and their new borns. This increase remains heightened for a long period of time (Cong et al., 2015). These findings contradict previous findings that found that oxytocin release was short lived. The contrasting findings regarding the duration of oxytocin release being short-lived increases following high-intensity martial arts training versus prolonged elevation after skin-to-skin contact between fathers and newborns suggest that situational context plays a crucial role in mediating neurohormonal responses, highlighting the complexity of oxytocin's role in emotional bonding and physical activity. There has also been research that holding hands with a romantic partner can reduce the neural response to threat (Coan et al., 2006). This can suggest that physical touch and norepinephrine have a relationship due to the role that norepinephrine plays in threat detection.

Conclusion

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  • Neurohormones originate from regions in the brain that release hormones that influence emotional processes.
  • Norepinephrine and oxytocin are two main neurohormones that play a vital role in emotional states and regulation in the human brain. Norepinephrine plays a role in how our body responds to fear and anxiety which can then influence how we manage and recognise stress. On the other hand, oxytocin can promote feelings of empathy and trust which can in return lead to greater emotional regulation in social contexts.
  • We can increase our neurohormone levels through physical activity, physical touch and interaction with animals.

See also

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References

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