Motivation and emotion/Book/2017/tDCS and motivation

tDCS and motivation:
How tDCS can influence motivation?

Multimedia presentation (3 min)

Overview

The brain is the major networking center for the body, and for all motivations to occur, the brain must transmit all the information the body. Several key areas are known to have significant effects on motivational tendencies, from the dorsolateral prefrontal cortex to the brains reward system of the Ventral Striatum, Nucleus Accumbens and the Ventral Tegmental Area. This provides us with the motivation to complete an action, from drinking water to developing confidence through increased competence. Motivation is defined as a reason or reasons for acting or behaving in a particular way. This chapter looks at the effect of Transcranial direct current stimulation (tDCS) on these motivations, the overarching effects that these increases have on increasing esteem and moving towards self-actualization.

What is Transcranial direct current stimulation

tDCS is an act of modulating the excitability of cortical regions of the brain through non-invasive means (Utz et al., 2010). It is an innovative electronic tool that can help to reduce reaction time and increase pain threshold while being simple enough to use at home (Wexler, 2016). This is accomplished by the attachment of an anode and a cathode to various different places of the skull (depending on the desired effect) to allow a small amount of electrical current to modify brain function (Nitsche et al., 2008). Studies have also shown that this is a safe and prolonged yet reversible method of modulating cortical function (Nitsche et al., 2008).

Studies have found that for tDCS to be effective it must be applied and have stimulation occurring for at least 3 minutes with an intensity minimum of 0.6 milliamps (Paulus, 2011). This means that for tDCS to work a saline solution of roughly 6ml is applied to a pair of sponges (around 25cm2) these are attached to the anode and the cathode which are attached to two different areas of the skull (Zhao et al., 2017). This allows the current to pass through the skull to the desired parts of the brain. This current must be at least 0.6 mA (however, 1-2mA is most commonplace) and be going for a minimum of three minutes however the average time in which tDCS occurs is 10 to 30 minutes (Paulus, 2011; Zhao et al., 2017).

The after-effects of transcranial direct current stimulation can last for up to 1 and a half hours after the session ends. The stimulation from the anode causes the resting of the neuronal membrane potential towards depolarisation while the cathode causes the hyperpolarization of resting membrane. Simply put, tDCS helps increase the speed in which the brain is able to activate the messages it wishes to send, while not providing enough current to force a message to be sent. For example, the current is not strong enough to force twitches in the fingers when placed in certain areas, the participant is still fully in control (Zhao et al., 2017). To summarise, tDCS sends an electric current through the brain to increase the speed at which messages are sent. This brings up an important argument that has been conclusively studied, safety.

How can transcranial direct current stimulation be safe?

There have been countless studies regarding the safe use of tDCS, from short-term pain to long-term side effects, and potential damage to the brain (Paulus, 2011). While the literature has found that the use of tDCS is safe, there are a few potential side effects. Electrodes used in tDCS can cause skin lesions, mild tingling, pain and redness of the skin (Zhao et al., 2017). These side effects are associated with the intensity of the current, duration of the session and the density of the simulation (Zhao et al., 2017). Zhao et al. (2017) outline several studies that correlate these symptoms with the use of tDCS but found that there were no long-term side effects and that the majority of test subjects over a number of studies showed zero side effects.

What is motivation,

Motivation is the reason or reasons for acting or behaving in a particular way. Motivation is involved with the start of a behaviour, the purposefully directed focus of a behaviour which is then sustained over a period of time (Reeve, 2015).

For example, think about a subject sitting in a chair trying to do an assignment. Motivation is required to start that activity. The motivation for this could be extrinsic rewards such as good grades, or a pass mark. Internal motivations like relatedness (seeing friends doing similar) or introjection (trying to alleviate guilt) from watching netflix all week and not doing any work. Another aspect of motivation kicks in when doing the assignment, the need go to the bathroom, refill their water bottle, finish the last few episodes of that show on netflix. It is these pressures that chip at the motivation to finish the assignment, these pressures are known as intervening variables (Reeve, 2015). Eventually, the need to go to the bathroom or get a drink will pull this person away from the computer as these biological functions increase in intensity over time. What finishes is the end of the motivation to complete/do that assignment and move on to something else, maybe they talked themselves into believing they could complete the assignment the morning of or the desire to sleep becomes too much. This is when the strength of the motivation to do the assignment is less than the desire/motivation to do something else, maybe that netflix show ended on a cliffhanger and it became too much and the direct attention to the assignment was lost as they walk away from the computer to eat chips and watch netflix.

What effects motivation

There are multiple factors that affect motivation, some of these include:

• Depression
• Extrinsic rewards
• Goals
• Self-worth

There are many variables to this and allows for many factors and situations that a person can have fluctuations both up, and down in levels of motivation. These can occur before the start of a particular behaviour, which can be influenced by factors such as depression. During a particular behaviour, which can be influenced by internal and external factors such as hunger. Last is the timing of the end of a behaviour, e.g. sleep (Reeve, 2015).

The physiology of motivation, motivation and the brain

The brain is the major networking centre for the body, and for all motivations to occur the brain must transmit all the information the body. Several key areas are known to have significant effects on motivational tendencies, from the dorsolateral prefrontal cortex to the brains reward system of The Ventral Striatum, Nucleus Accumbens and the Ventral Tegmental Area.

The Dorsolateral Pre-frontal Cortex

The Prefrontal cortex.

This part of the brain is responsible for the basic sensory rewards system. For example, if someone were to ask you to taste Smiths salt and vinegar potato chip and evaluate it towards terms of preferences your dorsolateral pre-frontal cortex would evaluate the brand of Smiths itself.

One other impact that the dorsolateral prefrontal cortex has is increased importance in the ability to provide effort towards resisting temptation when looking towards completing long-term goals. It is the pre-frontal cortex that allows us to avoid eating an entire bag of chips when trying to get our summer body, however, sometimes other parts of the brain and desire overload that and the entire pack does end up being eaten. It is within this where the link between the dorsolateral prefrontal cortex and motivation can be found. This is the part of the brain that provides impulse control in favour of long-term reward (Reeve, 2015).

The brains reward system.

The Ventral Striatum, Nucleus Accumbens and the Ventral Tegmental Area, It is through the activation of the ventral striatum that we develop the knowledge about what we like, want, and would prefer. When provided with a stimulus i.e. a bag of salt and vinegar chips this system processes the characteristics of the item and the pleasurable feeling, rewarding experience occurs through the release of the neurotransmitter dopamine (Reeve, 2015). One of the primary forms of extrinsic motivation is the act of receiving a reward (Reeve, 2015). The belief that a person will receive a reward is commonly used as an initiative.

Maslow's Hierarchy of Needs

One of the primary theories in motivational psychology is Maslow's hierarchy of needs, as outlined in (Reeve, 2015). This hierarchy can be organised into two clusters, growth motivation and deficiency motivation or growth needs and survival needs. The pyramid starts with physiological needs and then rises through, safety and security needs, love and belongingness needs, esteem needs, and finally self-actualisation needs. To move from one level to the next that need needs to be filled as well as all those before it. For example, a person must fulfil physiological needs and safety and security needs to truly grow to fulfil in love and belongingness.

Maslow's Need Hierarchy

Deficiency and growth

Maslow also highlights the difference between deficiency needs and growth needs (Maslow, 1971). It is argued that disturbances to biological functions, safety, belongingness or self-esteem are deficiency needs. It is characterised by Maslow as a human sickness, this is also seen when the distinction between these needs and vitamins needed for life sustenance are alluded to in (Reeve, 2016).

Esteem and reaching self-actualisation

To focus in on the effects of tDCS we first need to take a deeper look into esteem. There are many differing opinions on the definition of esteem, however, most commonly esteem is viewed as the way in which one self-evaluates their worth (Lönnqvist et al., 2009). There are a number of factors that affect esteem, from perceived competence, achievements, and self-direction, however, these can differ between cultures (Lönnqvist et al., 2009). It is argued that when a person fulfils the needs of esteem that they can grow and develop through self-actualisation which is argued to provide those who reach it an enduring sense of motivation even when high satisfaction levels have been attained (Lönnqvist et al., 2009).

tDCS and self-actualisation

Transcranial direct current stimulation can help increase levels of self-esteem with an increased belief/confidence with an increase in competence with cognitive tasks such as memory (Voarino, Dubljević, & Racine, 2017), motor control (Orban de Xivry & Shadmehr, 2014), and attention (Weiss & Lavdior, 2012). It is through this increased sense of self-esteem that helps an individual reach the self-actualisation tier of Maslow's pyramid which leads to a dramatic increase in motivation towards a person's goals, and furthermore increased motivation even after high levels of satisfaction have been met. In short, tDCS can have a dramatic effect on a persons motivation through simple increases in cognitive tasks such as memory as seen in (Voarino, Dubljevic, & Racine, 2017).

How is Motivation Measured?

The study of psychology is still in its infancy when compared to other scientific disciplines such as physics, biology, and chemistry. Due to the complex nature of the brain and the limited but ever-increasing technology used to study it a number of measures that can be taken to understand the impact of tDCS and its effects on motivation are limited. The most common approach to the study of motivation are self-report measures as seen in (Jones, Gözenman, & Berryhill, 2014), however, there are several avenues to be researched, such as neural imaging scans such as magnetic resonance imaging (MRI) and functional resonance imaging (fMRI) scans.

While self-report measures can be used to provide the researcher with a plethora of information regarding one's feelings towards certain things such as how focused they felt, how motivated the felt about goals etc., the validity of the self-report measure has been argued within the psychological discipline as seen in (Greve et al., 2013) and (Llerena et al., 2013).

Depression, motivation and the impact of tDCS

Depression, a psychological condition that affects an estimated 19 million Americans, when factoring in age, race or gender (Randolph, 2016). While women are the most likely to go through depression it also affects young adults at a significant rate with groups aged 18-25 being 60% more likely to suffer depression than those in the age group of 50 and older (Randolph, 2016). With several forms of depression including major depressive disorder, postpartum depression, and persistent depressive disorder, depression is one of the leading causes of disability and productivity loss with an estimated cost of 17 to $44 billion to American employers (Randolph, 2016). Symptoms of depression such as changes to sleep patterns, lack concentration, and low self-esteem to name a few are often overlooked and untreated (Randolph, 2016).

Studies have shown that depression has a negative impact on intrinsic motivation with declining belief that one can accomplish a goal (Smith, 2012). It is this low self-esteem or belief argued by (Smith, 2012) that can lead to a diminished sense of motivation. This link can also be seen in (Lomelí-Parga, López-Padilla, & Valenzuela-González, 2016). In a physiological sense, there has been a link between certain types of depression and certain parts of the brain. It is argued in (Segrave, et.al., 2014) that there is a link between Major depressive disorder and underactivity of the dorsolateral prefrontal cortex.

It is argued that the use of tDCS can have a positive effect in the reduction of depressive symptoms (Segrave et al., 2015). In this study, tDCS was administered to the dorsolateral prefrontal cortex and found that the use of tDCS and cognitive control therapy (CCT) combined showed stronger results than just the use of CCT alone. While it is to be noted that this used just a small sample size in a small timeframe it puts forth a strong case for the use of tDCS in the severity of major depressive disorder. This could also lead to an increase in self-efficacy, belief and an increase in motivation.

Case study: Jo has had trouble sleeping for a number of months, have had little appetite, low self-worth, and struggle to find the motivation to do anything. Upon seeing their doctor being referred to a psychologist, Jo was diagnosed with major depressive disorder. The implementation of tDCS to the right dorsolateral prefrontal cortex was administered weekly for 30 minutes over a time period of 3 months. This was used to help with the underactivity of the dorsolateral prefrontal cortex. This was administered with cognitive control therapy due to the recent developments in psychological literature. This was used to great effect and helped Jo through depression and to develop esteem and self worth. This allowed Jo to pursue self-actualisation.

What are the effects of transcranial direct current stimulation?

Studies have shown that tDCS can help with:

• depression
• cognitive tasks
• pain threshold
• concentration
• addiction

tDCS is a simple, safe procedure that has a number of benefits. It has also shown that there are a number of ways in which transcranial direct current stimulation can have a measurable effect on motivation, some of these include increased competence, decreased depressive symptoms, and increased belief. The effects of tDCS on perceived competence through an increase in working memory (Jones, Gözenman, & Berryhill, 2014). This perceived competence can lead to an increased sense of belief and help to fulfil the esteem criteria of self-worth as argued in Maslow's hierarchy of needs, this is also shown in (Reeve, 2016).

Conclusion

While the study of the recent technology that is tDCS is still in its infancy there is already strong evidence towards its use in the decrease of depressive symptoms and an overall reduction in the severity of several depressive disorders such as major depressive disorder, while also helping with an increase in cognitive tasks.

Quiz

1 What does tDCS stand for?

	Self-report Questionnaire
	Transcranial direct current stimulation
	Transcranial indirect current stimulation
	Transcranial direct charge stimulant

2 What is the estimated cost of depression to American employers?

	10-25 billion
	14-40 million
	14-40 billion
	10-25 million

3 Which of the following is not a deficiency of Maslow's hierarchy of needs pyramid?

	Esteem
	Safety and security
	Self-actualisation

See also

• Depression and motivation (Book chapter, 2010)
• Biological factors in emotional reactivity (Book chapter, 2017)
• Maslow's hierarchy of needs (Book chapter, 2011)

References

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Jones, K. T., Gözenman, F., & Berryhill, M. E. (2015). The strategy and motivational influences on the beneficial effect of neurostimulation: A tDCS and fNIRS study. Neuroimage, 105, 238-247. doi:10.1016/j.neuroimage.2014.11.012

Llerena, K., Park, S. G., McCarthy, J. M., Couture, S. M., Bennett, M. E., & Blanchard, J. J. (2013). The motivation and pleasure scale-self-report (MAP-SR): Reliability and validity of a self-report measure of negative symptoms. Comprehensive Psychiatry, 54(5), 568-574. doi:10.1016/j.comppsych.2012.12.001

Lomelí-Parga, A. M., López-Padilla, M. G., & Valenzuela-González, J. R. (2016). Self-esteem, motivation, and emotional intelligence: Three factors that influence the successful design of a life project of middle-school young students. Revista Electronic@ Educare, 20(2), 1-22. doi:10.15359/ree.20-2.4

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Llerena, K., Park, S. G., McCarthy, J. M., Couture, S. M., Bennett, M. E., & Blanchard, J. J. (2013). The motivation and pleasure scale-self-report (MAP-SR): Reliability and validity of a self-report measure of negative symptoms. Comprehensive Psychiatry, 54(5), 568-574. doi:10.1016/j.comppsych.2012.12.001

Maslow, A. H. (1971). The farther reaches of human nature. New York: Viking Press.

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Zhao, H., Qiao, L., Fan, D., Zhang, S., Turel, O., Li, Y., . . . He, Q. (2017). Modulation of brain activity with noninvasive transcranial direct current stimulation (tDCS): Clinical applications and safety concerns. Frontiers in Psychology, 8 doi:10.3389/fpsyg.2017.00685