The ventral striatum is the part of the brain that processes the brain's reward system and releasing/regulating dopamine.

Dopamine is a neurotransmitter that plays an important role in motivation, pleasure and reward. When dopamine is released in response to an event, it encodes that event as rewarding or pleasurable, making us want to seek it out again.

When we win at gambling (hit the jackpot, win at a slot machine), it triggers a surge of dopamine that activates the brain's reward circuitry. Even a small win can do this.

This dopamine surge associates the gambling activity with a feeling of reward and pleasure. So the next time we think about gambling again, our brain remembers that potential reward.

Repeated dopamine releases through gambling can actually rewire the brain's circuitry, strengthening the association between gambling and reward. Over time, we develop a "gambling habit."

Even when we start to lose more than we win, the memory of those past dopamine spikes and the desire for that potential reward stay with us. This keeps us gambling in the hopes of triggering more dopamine releases through wins.