[Music]
[Female announcer speaking]
Deep within the brain is a set of structures
called the limbic system. The limbic system
contains the brain’s reward circuit or pathway.
The reward circuit links together a number
of brain structures that control and regulate
our ability to feel pleasure. Feeling pleasure
motivates us to repeat behaviors.
When the reward circuit is activated, each
individual cell in the circuit relays electrical
and chemical signals.
The small gap between the sending and receiving
cells is called the synapse.
In the reward circuit, dopamine neurons release
the neurotransmitter dopamine. The released
dopamine molecules travel across the synapse
and link up with proteins called dopamine
receptors on the surface of the receiving
cell.
When dopamine binds to the exterior of the
dopamine receptor this causes proteins attached
to the interior part of the receptors to carry
the signal onward within the cell.
Some dopamine molecules re-enter the sending
cell
via dopamine transporters and can be re-released.
When a reward is encountered the pre-synaptic
cell releases a larger amount of dopamine
in a sudden burst,
Dopamine transporters will then quickly remove
the excess.
Dopamine surges in response to natural rewards
help the brain learn and adapt to a complex
world. However, drugs are able to hijack this
process contributing to unhealthy behaviors
and consequences.
