Chemical Messengers: Neurotransmitters and Hormones
Neurotransmitters
- Neurotransmitters are chemical messengers that transmit signals across the synapse from one neuron to another.
- Function: They play a critical role in regulating thoughts, emotions , and behaviour.
Serotonin
- Role: Linked to mood regulation, sleep, and appetite.
- Study: Caspi et al. (2003) found that individuals with a short allele of the 5-HTT gene (affecting serotonin transport) were more likely to develop depression after stressful life events.
Dopamine
- Role: Associated with reward, motivation, and pleasure.
- Study: Fisher et al. (2005) demonstrated that dopamine activity increases when individuals view photos of loved ones, explaining feelings of romantic attraction.
Hormones
- Hormones are chemical messengers released by glands into the bloodstream, affecting distant organs and tissues.
- Function: They influence long-term processes like growth , metabolism , and stress responses.
Cortisol
- Role: Known as the stress hormone , it helps the body respond to threats by increasing energy and alertness.
- Study: Newcomer et al. (1999) found that high levels of cortisol impair memory performance , highlighting its impact on cognitive functions.
Mechanisms of Action
Neurotransmitters
- Release: When an electrical impulse reaches the end of a neuron, it triggers the release of neurotransmitters into the synaptic gap.
