There are two things that drive human behavior: needs such as food, sleep, and avoiding pain, and rewards. Any object, event, or activity that motivates us, encourages us to learn, or creates pleasurable feelings can be a reward.
So how does our brain calculate the value of a reward and how does it translate into action? In this article, we will go into the details of the brain circuit known as the "reward system" to answer this question.
Motivation is defined as the activation of behavior to achieve a goal and is considered a fundamental element of our interactions with the world and each other.
The nervous system coordinates various motivational behaviors, such as feeding, drinking, and escape, for survival and evolutionary fitness. The precise behaviors required for different motivational behaviors vary, but common brain substrates exist for common features, such as approach or avoidance 1 .
The regulation of motivational behaviors, that is, the mobilization of people to achieve a goal, occurs through the interaction of certain circuits in the brain. These circuits are coordinated by the cooperative work of small particles called molecules.
These molecules include peptides (small proteins), hormones (chemical messengers that are transmitted to different parts of the body), and neurotransmitters (chemicals that transmit signals between nerve cells).
These molecules bring together and process the various signals necessary for complex decisions to be made in the brain. The regulation of motivation occurs through the coordinated action of molecules in the brain.
Neurons in different areas of the brain’s reward system communicate using the neurotransmitter dopamine: For example, dopamine-producing neurons in the ventral tegmental area of the brain communicate with a region called the nucleus accumbens to process rewards and motivate behavior. Neurons that release dopamine are activated when we expect to receive a reward. Therefore, dopamine plays a critical role in motivation .
Neurons that release dopamine are activated when we expect to receive a reward, and dopamine also strengthens memories associated with the reward. Dopamine strengthens the connections between neurons in the hippocampus, the brain's learning and memory center, where neurons transmit messages, thus strengthening memories 3 .
Dopamine signaling creates emotional associations to rewards in the amygdala, which processes emotions, and in the prefrontal cortex, regions involved in planning and reasoning.
Dopamine responses vary from person to person. Some people's brains respond more strongly to rewards than punishments, while others respond more strongly to punishments.
Reward learning and motivation strongly influence the amygdala. Studies have found that highly motivated and goal-focused participants have more dopamine signaling in the striatum and prefrontal cortex, two areas known to influence motivation and reward.
The brain’s reward system is a network that essentially identifies behaviors or experiences that are perceived as pleasant or rewarding. This system encourages the repetition of positive experiences by ensuring the receipt of rewards 2 .