Science Explains: impaired memory and rewarding feelings associated with alcohol

Ever woken up with a terrible hangover and ‘claimed’ you will never drink again? Yet, somehow you never end up sticking to that claim. What is it about the feelings associated with alcohol that are so rewarding?

Researchers from Brown University have investigated the effects of alcohol addiction in fruit flies on their nerve pathways. The neurones in fruit flies share some core features with the neurones in humans. The regions of the brain which showed activity during alcohol cravings were monitored. They found the key system involved to be the ‘Notch’ pathway, which is involved in the regulation of embryo development, in particular, brain development. However, this pathway is also involved in the formation of memories in adults. Alcohol exposure has been shown to set off a cascade in this pathway and one change in particular is involved in the rewarding feelings.

Alcohol exposure has been shown to set off a cascade in this pathway and one change in particular is involved in the rewarding feelings

This change is in a single building block of a large receptor molecule on nerve cells, and it helps to detect the chemical called dopamine. According to a paper entitled Dopamine controls systemic inflammation through inhibition of NLRP3 inflammasome, dopamine is a neurotransmitter, which can regulate many functions in the body including behaviour and which is involved in a feeling of pleasure and feeling good. The neurotransmitter is responsible for determining whether a memory is perceived as positive or negative and in the case of alcohol, is positive. These positive associations are the reason people still drink despite knowing they will experience a hangover, but are also the reason for more serious issues including the relapse of addicts.

The researchers have suggested that if this pathway works in the same way in humans as it does in fruit flies, then as little as a single glass of wine could activate this pathway, forming the positive association with alcohol. The pathway returns to normal within an hour, however. Comparatively, the consumption of three glasses of wine with an hour break in-between results in the pathway not returning to normal within 24 hours. Persistent and large consumption of alcohol is, therefore, the likely cause of the lack of memory following a night out.

The neurotransmitter is responsible for determining whether a memory is perceived as positive or negative and in the case of alcohol, is positive

These studies show that alcohol manipulates brain processes associated with long-term memory. This effect of alcohol is in likeness with other drugs such as cocaine, methamphetamine, etc. Hence these studies can help us to understand not only how to develop pharmacological targets to treat alcohol addiction but also tackle other drug abuse.

So, that’s the reason you can’t exactly remember those messy nights out, and why they happen again and again…