Daijiworld Media Network - Sydney

Sydney, Jan 2: Compulsive behaviours may not arise from entrenched habit loops that override self-control, but could instead be linked to inflammation in a key brain region involved in decision-making, according to a new study conducted on rats, challenging long-held scientific views.

Behaviours in which individuals repeatedly perform certain actions despite being aware of negative consequences, such as excessive handwashing or gambling, have traditionally been thought to stem from deeply ingrained habits that are difficult to break. However, senior author Laura Bradfield, a behavioural neuroscientist at the University of Technology Sydney, said the findings suggest a different underlying mechanism.

Bradfield explained that habits are generally useful as they allow people to function on autopilot, such as brushing teeth or driving a familiar route, freeing up mental space for other tasks. She noted that when unexpected situations arise, such as a child stepping onto the road, people are able to regain conscious control, assess outcomes and alter their behaviour.

The study, published in the journal Neuropsychopharmacology, examined whether inducing inflammation in the striatum, a brain region associated with motor control, habit formation and motivation, would increase habitual behaviour in rats. Contrary to expectations, researchers observed that the animals became more deliberate and goal-oriented in their decision-making.

“Surprisingly, the animals became more goal-directed and continued to adjust their behaviour based on outcomes, even in situations where habits would normally take over,” Bradfield said.

The researchers attributed this shift to astrocytes, star-shaped brain cells that support neurons. Inflammation caused these cells to multiply and disrupt nearby neural circuits involved in movement and decision-making, leading to altered behaviour.

The study concluded that inflammation in the striatum can bias action selection toward excessive goal-directed control due to dysregulated astrocyte function. The authors suggested that treatments targeting astrocytes and reducing neuroinflammation, along with broader anti-inflammatory approaches such as exercise and improved sleep, could open new avenues for managing compulsive behaviours.