Zani Zartashah1, Aastha Relan2, Ryan Ziae3
1Honours Life Sciences, Class of 2022, McMaster University, email@example.com
2Honours Health Sciences, Class of 2023, McMaster University, firstname.lastname@example.org
3Honours Life Sciences, Class of 2022, McMaster University, email@example.com
Dopamine is a chemical messenger that influences brain pathways that promote motivation and reward-driven behaviour.1 Any object, event or activity can act as a reward if it causes one to learn or feel content.2 The brain’s reward system, or mesolimbic pathway, is the circuitry that modulates dopamine release to translate the value of the reward into actions accordingly.3 First, dopamine-releasing neurons in the ventral tegmental area (A) are activated when one expects to receive a reward.3 These signals are sent to the nucleus accumbens (B), the interface for motivation and action.2 Reward-related memories are enhanced by strengthening synaptic connections between neurons in the hippocampus (C), which is the brain’s learning and memory centre.2 Emotional associations are also made when dopamine signaling occurs in decision-making centers such as the amygdala (D) and prefrontal cortex (E).2 It is not the reward itself but the anticipation of the reward that powerfully induces such emotional reactions and memories.2 The more the anticipation there is, the more dopamine signaling occurs, resulting in a stronger drive to perform a behaviour.2 For example, the caffeine within coffee acts as a reward that increases the availability of dopamine receptors in the brain, and consequently, dopamine signalling.4 Regular consumption of coffee and associated dopamine release can promote habit-building behaviour.5 Consuming more coffee increases dopamine signaling, further reinforcing anticipation for the reward.5 Caffeine-induced dopamine activity can create dependence on coffee, a demonstration of the reward system’s effect on behaviour.6
- Rice ME. Closing in on what motivates motivation. Nature. 2019 May 22;570(7759): 40-2
- Schultz W. Neural reward and decision signals: From theories to data. Physiological Reviews. 2015 Jul 1;9(3):853-951.
- Aberg KC, Muller J, Schwartz S. Trial-bytrial modulation of associative memory formation by reward prediction error and reward anticipation as revealed by a biologically plausible computational model. Frontiers in Human Neuroscience. 2017 Feb 15;11:56.
- Volkow ND, Wang G-J, Logan J, Alexoff D, Fowler JS, Thanos PK, et al. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain. Transl Psychiatry. 2015 Apr 14;5(4):e549.
- Volkow ND, Wang G-J, Fowler JS, Tomasi D, Telang F. Addition: Beyond dopamine reward circuitry. Proc Natl Acad Sci USA. 2011 Sep 13;108(37):15037-42.
- Neredith SE, Juliano LM, HUghes JR, Griffiths RR. Caffeine use disorder: A comprehensive review and research agenda. J Caffeine Res. 2013 Sep;3(3):114-30