Every day we make a range of choices in the pursuit of pleasure: we do things that make us feel good or work in a specific job because it’s rewarding or pays well. These experiences help shape our perspectives on life and define our personality.
Consequently, problems with our ability to manage or maintain our pursuit of pleasure often lie at the root of many neuropsychiatric disorders such as addiction and depression.
What’s going on in the brain when we experience pleasure?
Pleasure itself – that good feeling you get in response to food, sex and drugs – is driven by the release of a range of neurotransmitters (chemical messengers) in many parts of the brain. But dopamine release in the brain’s reward system is particularly important. Dopamine release tells the brain when to expect something rewarding, modulates how rewarding it will be and drives us to seek rewarding things.
Dopamine is also important for a range of other functions such as voluntary movement and cognition. Disorders such as schizophrenia have too much dopamine release, which causes psychotic symptoms. In neurodegenerative disorders such as Parkinson’s disease, the dopamine cells responsible for motor coordination die prematurely.
All drugs of abuse, no matter their primary mode of action, release dopamine in this system. Other rewarding experiences – sex, food, and gambling – are also associated with increases in dopamine release. Conversely, decreases in dopamine within reward systems are associated with depression, a lack of pleasure or motivation, and withdrawal.
We all experience pleasure differently as a result of individual differences in biology or neurochemistry, but also as a result of past experiences (no longer liking a food that previously made you sick), and differing social and cultural factors.
For example, musical preferences seem to be shaped more by upbringing than by biological factors. So while some may get a greater hit of dopamine from buying a new handbag, others may get it from placing a bet on a sports match.
There are plenty of time-travel movies in existence, but most are either obtrusive "hard sci-fi" yawn-fests or patronising popcorn entertainment. Here are ten time-travel flicks that manage to successfully straddle the divide -- with trailers!
The sighting of a seven-metre shark off the South Australia coast last year excited the world's media with some making reference to the great white that featured in the classic 1975 film Jaws. It was certainly a big shark but there are tales of even bigger beasts lurking in our waters.