Caffeine is a stimulatory drug belonging to a class of chemicals called methylxanthines. Caffeine is bitter in taste and occurs naturally in such foods as chocolate, kona nuts and coffee beans. As a stimulant, caffeine affects the central nervous system by making you feel more alert. However, consuming too much caffeine can cause you to feel anxious and irritable. Irregular heart rhythms, insomnia and headaches may also result from the over-use of caffeine, notes MedlinePlus.
Dorsal Striatum
The dorsal striatum is a region of the brain that is involved with controlling your body's motor functions. Caffeine has been shown to act in the dorsal striatum to increase motor activity in rats and mice. It is thought to do this by interfering with or changing the activity of two other neurotransmitters, dopamine and adenosine, that normally regulate motor activity in this region of the brain, according to Bertil B. Fredholm et al. in an article in Pharmcological Reviews.
Nucleus Accumbens
The nucleus accumbens is found in a part of the brain sometimes referred to as the limbic system. This region is involved in regulating behavior associated with pleasure and reward. Caffeine is thought to interrupt the activities of adenosine and dopamine in this region, resulting in a net decrease of neuronal activity here. Conversely, other drugs of addiction such as amphetamines have been shown to increase neuronal activity in this region of the brain.
Olfactory Bulb
The olfactory bulb is the part of the brain that receives sensory input related to smell. It is also known to play an important part in processing information related to reward-linked behavior. Neurons in the olfactory bulb communicate with other areas of the brain involved in the brain's reward pathway, including those that are involved in emotion, learning and memory. Caffeine has been shown to alter the activity of serotonin, norepinephrine and dopamine in the olfactory bulb of mice, writes M. Gary Hadfield in an article in Molecular Neurobiology.
Cortex and Hippocampus
The cortex and hippocampus of the brain are regions that are functionally important in information processing, learning and memory. Caffeine interferes with the activity of the neurotransmitter adenosine in these regions to produce effects such as increased awareness and attention.
References
- MedlinePlus: Caffeine
- "Pharmacological Reviews"; Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use; Bertil B. Fredholm et al.; March 1999
- National Institute on Deafness and Other Communication Disorders: The Enigmatic Olfactory Tubercle
- "Molecular Neurobiology"; Caffeine and the Olfactory Bulb; M. Gary Hadfield; August 1997
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