Near misses fuel gambling addiction

GAMBLING is extremely popular, with lottery tickets, casinos, slot machines, bingo halls and other forms of the activity generating revenues of more than £80 billion each year in the UK alone. For most people, gambling is nothing more than an entertaining way to pass the time. But for some, it becomes a compulsive and pathological habit – they spend increasing amounts of time gambling, because tolerance builds up quickly, and experience withdrawal symptoms when they aren’t gambling.

The terms “tolerance” and “withdrawal” are normally associated with drug addiction, and indeed pathological gambling is now considered as being akin to substance abuse. We know, for example, that monetary wins activate the brain’s reward circuitry. In pathological gamblers, however, these responses are dampened, so that increasingly larger wins are needed to produce the same rewarding effects. And according to a new study published in the Journal of Neuroscience, near misses fuel the habit in regular gamblers, because they are almost as rewarding as wins.

The mirror movement mutation

MIRROR movements are involuntary movements that mimic, and occur simultaneously with, voluntary movements on the opposite side of the body. The movements are known to occur because of a failure in communication between the two sides of the nervous system. They are thought to be normal during infancy and early childhood, but usually diminish with age and disappear altogether by the age of 10, following maturation of the corpus callosum, the massive bundle of nerve fibres connecting the left and right hemispheres of the brain.

A large genetic study published online in the journal Science now shows that mirror movements are caused by a single genetic mutation. The mutation is located within a gene that encodes a well-known protein involved in guiding growing nerve fibres to their proper destination during development, and gives rise to mirror movements because the connections between the two brain hemispheres fail to form properly.