Dopamine System: Learning Associations Between Stimuli and Rewards

This essay delves into the critical role of the dopamine system within the human brain, emphasizing its function as a key neurotransmitter and hormone. The essay explores the dopamine system's structure, including its various branches and their specific functions in areas like working memory and the striatum, which is implicated in Parkinson's disease. It highlights the impact of dopamine on learning, particularly in associating stimuli with rewards and the development of habits, and its role in addiction. The essay discusses how dopamine neurons signal reward prediction errors and how deficiencies can lead to neurodevelopmental disorders. It also examines the role of dopamine in normal behavior and addiction, emphasizing how drugs and alcohol can disrupt dopamine pathways, affecting behavior and cognitive processes. The conclusion reiterates the importance of the dopamine system for overall brain function, learning, and the formation of addictive behaviors, referencing key studies to support the presented arguments.

DOPAMINE SYSTEM AND ITS
ROLE IN LEARNING THE
ASSOCIATIONS BETWEEN
STIMULI AND REWARDS

TABLE OF CONTENTS
INTRODUCTION...........................................................................................................................1
MAIN BODY...................................................................................................................................1
Dopamine system.........................................................................................................................1
Role of dopamine in learning the associations between stimuli and rewards..............................2
Role of dopamine function in normal behavior and in addiction................................................2
CONCLUSION................................................................................................................................3

INTRODUCTION
Dopamine is one of the most important chemical messenger in the brain which helps in
increasing memory of an individual, helps in body movements, increasing motivation within an
individual because it functions as both a neurotransmitter and a hormone within the brain of a
human body. This essay will lay emphasis on role and importance of dopamine system in
learning associated with rewards and stimuli and how it plays a vital role in normal behaviour
and in addiction.
MAIN BODY
Dopamine system
Dopamine system can be defined as a group of nerve cells which originate into two mid
brain and fore brain. out of which most of the cells originate in the mid brain. This dopamine
system send their axons to different parts of fore brain where they plug into particular functions.
These branches of fore brain dopamine system are mainly divided into three parts. One of them
directly foes into frontal cortex which helps in enhancing overall efficiency of working memory
and thinking. Second branch goes to striatum which is mainly implicated in Parkinson disease
(Berke & Hyman, 2000). Last third branch goes to limbic system of the brain. Mid brain
dopamine mostly receives all kinds of processed information from cortex and various other
regions such as dorsal striatum. Out of all these dopamine branches one of the less known
function of dopamine pathways are mainly organized to produce normal organized behavior. If
any problem occurs in the dopamine system then it dies or in other words any kind of neuro
developmental disorder like schizophrenia or Parkinson's disease can occur. It has also been
identified that dopamine impact is way beyond disease treatment. Impact of dopamine can be
seen in patients living with diseases like Parkinson's. So it is important to understand the role of
dopamine in brain as it plays a vital role in brain because its deficiency within a person can
impact their memory, attention, motivation as well as in movement of an individual as well. Due
to this medical records of an individual can also get disturbed and one of the main disease that
occurs due to deficiency of dopamine is Parkinson's disease (Marsden, 2006). So it is important
to maintain and balance the level of dopamine within an individual because if its deficiency can
create chances of mental diseases then its presence can also be used as a treatment for
schizophrenia and other diseases as well.
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Role of dopamine in learning the associations between stimuli and rewards
Dopamine plays a pivotal but a quite complicated role in impacting stimuli and rewards.
It is majorly involved in reward learning. Dopamine allows learning of new association of some
stimuli, rewards. Other than this it also supports association between stimuli and pleasure but
with acquisition of various kinds of new habits which mainly helps in obtaining rewarding
stimulus. These reward system plays a vital role in activating rewards like addictive drugs by
reinforcing stimuli (Hyman & Malenka, 2001). Damage of dopamine neurons within brain can
result in reduction of association between stimuli and rewards due to which pleasure reaction,
feeling, reaction to good taste can be damaged as dopamine involves neurons, due to which
firing rewards to responses can get affected which also affects predictability of rewards. It has
also been observed that this presence of stimuli plays a vital role in addiction. As mainly this
stimuli is related to wanting i.e. there is a strong association between stimuli and wanting. These
stimuli can result in craving for example smoking stimuli can result to craving of smoking, drugs
related stimuli can result in craving of smoking (Nutt & et.al., 2015). So it can be said that this
dopamine plays a vital role in learning association between stimuli and rewards as it helps in
detecting and predicting occurrence of rewards and stimuli associated to dopamine system. Many
times it happens that these dopamine neurons helps in providing reward predicting error signals
which is one of the most useful thing associated with learning mechanism. These rewards
influence behavior of an individual and stimuli results in addiction of something and dopamine
plays a vital role in association of rewards and stimuli.
Role of dopamine function in normal behavior and in addiction
From the above discussion it is quite clear that role of dopamine is quite important in
normal behaviour functioning and in addiction. Dopamine is a neuro transmitter and hormone
which becomes the main reason due to which many things within a brain are affected (Schultz,
2000). It can be a reason for someone's normal behaviour as well as their addiction towards
certain things. Normal functioning of a human brain can happen automatically with proper
presence of dopamine within their system as it is is the main reason for a persons normal
emotional flow within their body but it is also a known fact that dopamine stimuli controls a
persons addiction towards a certain things, their actions as well as their thinking (Volkow &
et.al., 2011). Certain drugs or alcohol increases overall dopamine output within an individual's
brain which directly affects the way brain functions. Some of the drugs affects the way dopamine
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neuro transmitters flows within a human brain or the way they send alternate signals are
bypassed. This directly affects the normal behaviour of a person, their though process, actions
and not only this it also affects their addiction towards the drug as well. This further results in
their normal functioning as due to such drugs or alcohol person need to increase their quantity in
order to feel normal. In order to feel positive or behave normal their need the drug due to which
addiction for the substance increases within those individuals.
CONCLUSION
From the above essay it has been concluded that dopamine system plays a vital role in
human body brain as its deficiency can cause neuro developmental disorder or diseases like
schizophrenia or Parkinson's disease. It plays a vital role in rewards and stimuli which affects the
overall behaviour of an individual as well as their addictions towards certain substances like
drugs or alcohol.
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REFERENCES
Berke, J. D., & Hyman, S. E. (2000). Addiction, dopamine, and the molecular mechanisms of
memory. Neuron.25(3). 515-532.
Hyman, S. E., & Malenka, R. C. (2001). Addiction and the brain: the neurobiology of
compulsion and its persistence. Nature reviews neuroscience.2(10). 695.
Marsden, C. A. (2006). Dopamine: the rewarding years. British journal of
pharmacology.147(S1).S136-S144.
Nutt, D. J. & et.al. (2015). The dopamine theory of addiction: 40 years of highs and lows. Nature
Reviews Neuroscience.16(5). 305.
Schultz, W. (2000). Multiple reward signals in the brain. Nature reviews neuroscience.1(3). 199.
Volkow, N. & et.al. (2011). Food and drug reward: overlapping circuits in human obesity and
addiction. In Brain imaging in behavioral neuroscience (pp. 1-24). Springer, Berlin,
Heidelberg.
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