Motivation and emotion/Book/2024/Dopamine and learning

Dopamine and learning:
What is the relationship between dopamine and learning?

Overview

Case study 1: When considering dopamine and learning there is a long history of animal studies that served as the foundations to dopamine being crucial for learning and memory formation. The most famous example of this is Pavlov’s dogs (Rehman et al., 2017), where a dog’s reflex to salivate at the presence of food was paired with a neutral stimulus of a bell. After a period of conditioning the bell became a conditioned stimulus and due to the association of the sound and food the dogs would begin to salivate.

Case study 2:

A study conducted by Hollerman et al. (1998) that involved two monkeys that performed a behaviour task under computer control. After a visual instruction that had three different variants was given on the computer the monkey would be rewarded for movement, rewarded for not moving or finally no reward for moving. There were two types of rewards utilised, either apple juice or a sound that indicated a correct response to the instructions was made. By the conclusion of this study the monkey’s demonstrated 95% correct responses to the tasks during the final testing of the experiment.

Figure 1. Skeletal formula of dopamine

Dopamine has been coined “the pleasure drug”[factual?] in the past as many recreational drugs enhance dopamine in the brain. However, Duncan & Shohamy (2022) suggest a more accurate title would be “the learning drug” as dopamine influence more than just negative compulsions and addiction. Dopamine is highly influential in both essential and positive habits such as seeking food, social rewards and gathering of information[factual?].

Through understanding the role dopamine plays in these example case studies, dopamine will be shown to have a vital role in learning. This understanding can provide behavioural insights into why certain behaviours are learned, help attempt to address learning disorders, and help establish the role dopamine plays in neurological and psychiatric disorders[disorders are not relevant to the topic. Focus on dopamine and learning].

Focus questions:

What is dopamine?
How does it[what?] relate to learning?
Can Dopamine Influence Memory Formation and Recall?[use sentence casing]

What Is Dopamine?

Dopamine is a neurotransmitter in the central nervous system (Arias-Carrion and Poppel, 2007). The production of dopamine involves a two step process wherein the amino acid tyrosine is converted into L-dopa. The second stage is when L-dopa is metabolised into dopamine by enzymes (Watson, 2024).

Figure 2. Human brain depicting the location of various components of the brain, in particular the ventral tegmental area and the substantia nigra who are both critical for dopamine supply.

The midbrain is estimated to contain between 400,000 to 600,000 dopaminergic neurons (Duncan and Shohamy, 2022). This may initially appear to be a large number, but in reality dopamine only accounts for around 1% of the total neural cells of the brain, despite the critical influence dopamine holds over brain function (Arias-Carrion and Poppel, 2007)

Within the brain, there are two key areas for the supply of dopamine to learning networks. The first is the ventral tegmental area, and the function of this area of the brain is to regulate reward consumption, learning, memory, and addiction behaviour through mediating dopamine release (Cai and Tong, 2022). The other key area is the substantia nigra, which is a dopaminergic nucleus in the midbrain. This component of the midbrain holds a significant role in modulating motor movement and reward functions as part of the basal ganglia circuitry (Sonne et al., 2022)

See Figure 2 for where the ventral tegmental area and the substantia nigra are located in the brain.

How Does Dopamine Relate to Learning?

Learning is a lifelong journey that transforms curiosity into understanding, shaping not only our knowledge but also our perspectives on the world. Within the context of academia, learning is defined as any process that in living organisms leads to a permanent capacity change and is not solely the result of biological maturation or ageing (Lave, 2009). At its core, learning involves a change in responsiveness to particular stimuli, highlighting how organisms adapt their behaviour based on experiences.

Case study 2 explored further: Hollerman et al’s (1998) study provides a clear example of how the reinforcement learning model can be applied to understand decision-making and behaviour in primates. The monkeys were trained to take certain actions to gain a reward, [grammar?] this model explains reward prediction based on the monkeys developing an expectation for the reward based on the previous trials. This learning was not only in the actions that resulted in a reward but also learning from errors. In the case of a reward being less than expected or withheld entirely, the monkey must modify their responses[grammar?]. Dopamine’s specific role in this study is highlighted by the increased activity levels within the reward prediction process[Dopamine wasn't measured in this study?]. Through an unexpected reward being obtained dopamine activity would increase and this would influence future decision. This depicts the critical role dopamine plays in the reinforcement learning framework.

The reinforcement learning model illustrates that animals will act to maximise future rewards, with the brain recording the significance of specific actions based on the potential rewards they have yielded in the past. According to Arias-Carrion and Poppel (2007), these previous experiences enable the brain to predict future actions that may lead to either rewards or punishments. The actual reward received after an action is then compared to what was initially expected, a process known as reward prediction error. This feedback mechanism, linked to dopamine activity, plays a crucial role in shaping future behaviour, guiding organisms towards actions that enhance the likelihood of positive outcomes (Arias-Carrion and Poppel, 2007).

Can Dopamine Influence Memory Formation and Recall?

The relationship between dopamine and memory is of great importance to understand [missing something?] to get the most out of learning in a long-term context. Particularly when examining how this neurotransmitter influences memory formation and recall{g}}. Three different aspects of this relationship will be explored as follows. The first is flashbulb memories, which are vivid recollections of emotionally significant events. For instance, many individuals can readily recall their own personal circumstances when learning about the 9/11 attacks[Add link to Wikipedia article], showcasing the intense impact of emotional experiences on memory. This is where dopamine plays a pivotal role in this process by modulating the encoding of such memories based on their emotional weight. Next will be the examination of the long-term potentiation (LTP) and its importance in strengthening synaptic connections essential for memory retention. Finally, we will examine dopamine’s critical function in the retrieval of memories, thereby answering the question of whether dopamine can indeed influence memory formation and recall. Together, these insights will illustrate the multitude of ways in which dopamine shapes one’s memories and overall learning processes.

Flashbulb Memories

Case study 3:

If you were asked, what were you doing when you found out about the tragic events that took place on 9/11/2001, would you be able to recall this information? For many people the answer is yes, and this kind of memory is known as a flashbulb memory. Any memory of personal circumstances when finding out about a surprising and sequential event that are remembered vividly are an example of a flashbulb memory (Conway et al., 1994)

Dopamine plays a pivotal role in memory formation and recall, acting as a key modulator that influences how experiences are encoded and retrieved based on their emotional significance and reward value. An example of the relationship between dopamine and memory recall is the formation and recall of flashbulb memories. As discussed by Conway et al. (1994), these detailed memories are often tied to emotionally significant events, and dopamine’s modulatory effects enhance the encoding of such experiences, particularly in regions like the hippocampus and prefrontal cortex. The article highlights that heightened dopaminergic activity during emotionally charged moments not only strengthens synaptic connections but also aids in the retrieval of these memories later on[Provide more detail]. This underscores the idea that dopamine is vital for ensuring that significant experiences, like those captured in flashbulb memories, are effectively stored and easily accessible, reflecting its critical function in memory processing.

Long-term Potentiation

An additional significant role in memory coding is long-term potentiation (LTP), [grammar?] this is a process that strengthens synaptic connections enhancing connections, enhancing communication between neurons, and is crucial for memory formation (Jay, 2003). Dopaminergic activity facilitates this process by modulating synaptic plasticity, especially in key brain regions like the hippocampus and striatum. Cooke & Bliss (2006) explains when dopamine is released during learning experiences, it not only reinforces the synaptic changes associated with LTP but also helps encode the emotional significance of those memories[Provide more detail]. This connection between dopamine and LTP underscores the importance of dopamine in ensuring that memories are not only stored but also integrated with their contextual and emotional relevance, making them more retrievable in the future. Dopamine serves as a critical regulator in the interplay between synaptic plasticity and memory coding, influencing how experiences are remembered.

Dopamine's role in enhancing memory coding through synaptic plasticity highlights its vital connection to learning, reinforcing how our experiences shape knowledge acquisition and retention. In order to promote learning in all areas of life demonstrating an understanding for how dopamine can be utilised to enhance learning is of significant important for ensuring as much retention of information as possible.

Memory Retrieval

Dopamine holds a critical role in the encoding of memories (Jay, 2003), however, this is not where the relationship between dopamine and learning ends. Witte et al. (2018) found that dopaminergic pathways, particularly in the prefrontal cortex and hippocampus, are essential for modulating synaptic plasticity. This is critical for the not only the formation of memories but critically the retrieval of memories[improve clarity]. The [which?] review reveals evidence from both animal and human studies, indicating that dopamine not only enhances the encoding of emotionally significant experiences but also supports the consolidation and retrieval of these memories[Provide more detail]. These findings highlight dopamine's integral function in learning and memory, linking its mechanisms to neurobiological processes and behavioral outcomes (Witte et al., 2018).

Conclusion

The intricate relationship between dopamine and learning underscores the profound influence this neurotransmitter has on our capacity to acquire, retain, and recall information. Through pivotal case studies, such as Pavlov’s conditioning experiments and Hollerman et al. (1998) research with primates, we observe that dopamine not only reinforces behaviour linked to rewards but also plays a crucial role in error correction and adaptive learning. As dopamine modulates our responses to various stimuli, it enhances our ability to learn from both successes and failures, creating a feedback loop that drives motivation and behaviour.

Furthermore, dopamine's significance extends beyond mere reinforcement, [grammar?] it is integral to the formation of memories, particularly those tied to emotionally charged experiences, known as flashbulb memories. This dynamic interaction between dopamine and memory highlights how our emotional experiences shape our understanding of the world and influence future decision-making. LTP further illustrates dopamine's role in strengthening synaptic connections, ensuring that significant experiences are encoded and retrievable, this in turn facilitates effective learning.

Through the continued to exploration into the nuances of dopamine's role in learning and memory, it becomes evident that this neurotransmitter is not merely the "pleasure drug" it has often been labelled[improve clarity]. Instead, it serves as a key player in our lifelong journey of learning, impacting our behaviour, emotional responses, and cognitive processes. Understanding how dopamine operates can lead to valuable insights into addressing learning disorders and improving educational strategies, ultimately enhancing our ability to learn and adapt in an ever-changing world. By harnessing the power of dopamine, we can unlock greater potential for knowledge acquisition and retention across all facets of life.

References

Arias-Carrión, Ó., & Pöppel, E. (2007). Dopamine, learning, and reward-seeking behavior. Acta Neurobiologiae Experimentalis, 67(4), 481–488. https://doi.org/10.55782/ane-2007-1664

Cai, J., & Tong, Q. (2022). Anatomy and Function of Ventral Tegmental Area Glutamate Neurons. Frontiers in Neural Circuits, 16(867053). https://doi.org/10.3389/fncir.2022.867053

Clos, M., Bunzeck, N., & Sommer, T. (2018). Dopamine is a double-edged sword: dopaminergic modulation enhances memory retrieval performance but impairs metacognition. Neuropsychopharmacology, 44(3), 555–563. https://doi.org/10.1038/s41386-018-0246-y

Conway, M. A., Anderson, S. J., Larsen, S. F., Donnelly, C. M., McDaniel, M. A., McClelland, A. G. R., Rawles, R. E., & Logie, R. H. (1994). The formation of flashbulb memories. Memory & Cognition, 22(3), 326–343. https://doi.org/10.3758/bf03200860

Cooke, S. F., & Bliss, T. V. P. (2006). Plasticity in the human central nervous system. Brain, 129(7), 1659–1673. https://doi.org/10.1093/brain/awl082

Duncan, K., & Shohamy, D. (2007). Dopamine and Learning. Oxford University Press.

Hollerman, J. R., Tremblay, L., & Schultz, W. (1998). Influence of Reward Expectation on Behavior-Related Neuronal Activity in Primate Striatum. Journal of Neurophysiology, 80(2), 947–963. https://doi.org/10.1152/jn.1998.80.2.947

Jay, T. M. (2003). Dopamine: a potential substrate for synaptic plasticity and memory mechanisms. Progress in Neurobiology, 69(6), 375–390. https://doi.org/10.1016/s0301-0082(03)00085-6

Rehman, I., Mahabadi, N., Sanvictores, T., & Rehman, C. I. (2017, December 22). Classical conditioning. Europepmc.org; StatPearls Publishing. https://europepmc.org/article/nbk/nbk470326

Sonne, J., Beato, M. R., & Reddy, V. (2022, October 24). Neuroanatomy, Substantia Nigra. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK536995/

Watson, S. (2021, July 20). Dopamine: The pathway to pleasure. Harvard Health; Harvard Medical School. https://www.health.harvard.edu/mind-and-mood/dopamine-the-pathway-to-pleasure

External links

Case Study 2: Influence of Reward Expectation on Behavior-Related Neuronal Activity in Primate Striatum (Journal of neurophysiology)
Dopamine and Learning (University of Toronto)

	A) To slow down memory retrieval
	B) To enhance the likelihood of positive outcomes based on past experiences on solidarity.
	C) To eliminate unwanted memories
	D) To facilitate biological maturation

	A) Biological maturation
	B) Dopamine production
	C) Synaptic connections between neurons
	D) Memory recall only