23 January 2009
What is dopamine?
This is a first draft, I need a better microphone and I'm not sure about the text. Any constructive criticism?
Transcript: Dopamine is a very important chemical that regulates thought, movement, attention, motivation and learning. It's synthesized by neurons in the middle of the brain but is released all over, in small and large doses.
In small doses, it activates D2 receptors, which reinforces ongoing thoughts and movements. If you're eating pizza, the pleasant taste will activate dopamine neurons, raise dopamine concentrations in your brain, and you'll feel motivated and keep on eating. If you're experiencing something new or expecting something good, dopamine levels can rise up to 100% and you feel excited and completely focused. Being unfocused and easily distracted means your brain is low on dopamine - that's why Ritalin, amphetamine and coffee helps people with attention deficit disorder concentrate.
When something important, unexpected or rewarding happens, large amounts of dopamine are released, which activate D1 receptors and stimulate learning and the formation of new connections between neurons. Memories and habits are formed this way. All addictive drugs release large amounts of dopamine in the brain, but so does good food and drink, and sex, social pleasure, and money.. everything you want releases dopamine, and you want it because it releases dopamine. Things are important and valuable only if they activate your dopamine neurons; if you're still watching this video it's because it's releasing dopamine; and whatever you do when this movie stops will be what releases most dopamine.
More on dopamine: http://www.iplant.eu/monoamine.html
Subscribe to:
Post Comments (Atom)
4 comments:
In the last line you say that whatever you do when this video stops will be what releases most dopamine. I would argue that this statement is not entirely accurate since the actions we decide to take are not wholly dependent on dopamine. For example, I just watched the video and I'm hungry. What would release the most DA would probably be eating some very calorie rich food but I forego lunch and finish some email that I need to send out, or alternatively, I eat a healthy lunch which I would anticipate would release less DA than the calorie rich lunch. Something to think about.
Wrong. The prefrontal cortex allows long-term thinking and planning: it can directly activate the dopamine system and also inhibit impulsive choices.
Indeed, the prefrontal cortex is capable of modulating the dopamine system, and one of its primary functions is inhibitory control, but I am unable to see that what follows is the notion that one's actions necessarily lead to greatest DA release. Please refer to your source for this statement.
You're right, it's not fully established that behaviors compete exclusively in terms of dopamine, but it seems like the best paradigm available at the moment. It's possible that, say, the prefrontal cortex inhibits impulsivity by directly strengthening dopaminergically weak behaviors/cell assemblies rather than providing them with more dopamine, but that's not how I think about it. I also left out the role of other monoamines, an oversimplification for sure but I think it works. Good dopamine references here, Cools & Robbins (2004) and Gruber et al (2006) may be particularly relevant.
Post a Comment