Motivation and emotion/Book/2024/Neurohormones and emotion

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

Multimedia presentation (3 min)

Overview

Figure 1. Feeling fearful is an emotion that can be experienced when there is a perceived threat such as a thunderstorm Have you ever wondered where your emotions stem from? From having a bad day at work to finding 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. The underlying mechanisms of these emotions originate from processes occurring in your brain.

Figure 2. 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.

Emotions are a concept that have been widely researched and theorised (see Figure 2). 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.

This chapter explains the relationship between different neurohormones and their influence on our emotional states and emotional regulation. It also gives insight into effective strategies that can be put in place to help optimise neurohormones for emotional regulation. Understanding how neurohormones can influence feelings can 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. Figure 3. Zoe engaging in a social activity that can increase her oxytocin levels due to positive social bonds. 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.

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

Emotions have been widely studied over time 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

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

Figure 4. The James-Lang Theory of emotion process

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. It puts forward that we experience an emotional state after a physiological response has taken place in the body, for instance when we become aware of physiological bodily changes induced by danger, we feel fear and subjectively experience emotional feelings (see figure 4). Focusing on the body brings up the question of how the environment shapes our emotions. The body is thought to reflect the environment through these sensory and motor experiences, and it's these bodily responses that are key to forming our emotional feelings (Northoff, 2008).

Emotional Regulation

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. The Modal Model of Emotion outlines how emotions are generated and regulated and typically includes the following components in a sequence occurrence:

Table 2.

Modal model of emotion sequence

Component:	Description
Situation	An external or internal event that provokes an emotional response
Attention	Focusing on the situation, influencing how the emotion is experienced
Appraisal	The individual's assessment of what the situation means. Help in interpreting the emotional meaning of the event
Response	Includes the emotional expderience itself and the physiological and behavioural responses that accompany emotion (e.g., crying)

This process is then regulated by strategies used to manage emotional responses which can involve altering the situation, attention and appraisal of the emotion (Gross, 2014).

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)

Neurohormones

Neurohormones are chemical substances that are synthesised by a neuron, act on another neuron and is then released into the bloodstream (Wang, 2020). 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).

Joy

Figure 5. Positive social relationships promotes oxytocin

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 has deepens 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 (see figure 5). 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 (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.

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 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, 2004). 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.

Fear

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 and plays an essential role in the regulation of arousal, attention, cognitive function, and stress reactions (Jiang 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.

Sadness

Figure 6. Sadness can be seen physically through facial expressions

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 (see figure 6) 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., 2009). 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

Neurohormones can impact on 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 (Wolf et al., 2018). Additionally, strong emotional states often accompany impulsive and violent behaviours, 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 optimise emotional states through understanding of neurohormones

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

The beneficial effects of physical exercise on physical, cognitive, and emotional well-being are well documented. Some research 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.

Figure 7. Dance movement therapy can help modulate seratonin

Another type of exercise that research has shown to have benefits for optimising emotional states is dance movement therapy (DMT) (see figure 7). 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

Figure 8. Holding hands can reduce the neural response to threat.

Research suggest that physical touch helps stimulate oxytocin production. Specifically, paternal oxytocin levels increase after skin-to-skin contact with fathers and their newborns. This increase remains heightened for a long period of time (Cong et al., 2015). These findings contradict previous findings 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) (See figure 8). This can suggest that physical touch and norepinephrine have a relationship due to the role that norepinephrine plays in threat detection.

Conclusion

Emotions are multifaceted and involves the integration of a range of theories and insights from neuroscience. Paul Ekman’s foundational work on basic emotions highlights the universality and evolutionary significance of basic emotions, whilst the James-Lange theory emphasises the role of physiological responses in shaping our emotional experiences. Through understanding these theories, relationships are able to be clearly understood between neurohormones such as oxytocin, serotonin, and norepinephrine. These hormones play crucial roles in modulating emotions and influencing states of joy, fear, and sadness. For instance, oxytocin fosters social bonds and positive emotional states, serotonin regulates mood and emotional stability, and norepinephrine impacts arousal and stress responses.

While the relationship between neurohormones and emotions offers valuable insights, many studies rely on specific contexts and populations, which may limit the generalisability of their findings. Additionally, individual differences in biology, environment, and personal experiences can significantly influence emotional responses, making it challenging to establish universally applicable conclusions.

In order to optimise positive emotions, individuals can engage in strategies such as regular physical exercise, which has been linked to increased norepinephrine levels and improved mood, and practices like dance movement therapy that can elevate serotonin levels. Additionally, fostering physical touch whether through affectionate gestures or skin-to-skin contact can enhance oxytocin release and emotional well-being. By incorporating these strategies, we can create environments and lifestyles that promote emotional resilience and enhance our overall emotional health.

See also

• Emotional self-regulation (Book chapter, 2013)
• Neurohquizormones (Wikipedia)
• Norepinphrine (Wikipedia)
• Motivation and emotion/Book/2013/Oxytocin and emotion (Book Chapter, 2013)
• Motivation and emotion/Book/2017/Oxytocin and trust (Book Chapter, 2017)
• Dance therapy (Wikipedia)

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External links

• Paul Ekman Group: What are emotions? (paulekman.com)
• Oxytocin: the love hormone (health.harvard.edu)
• Paul Zak Ted Talk: Trust, morality and oxytocin?(Youtube)