Gambling can be an exciting, yet high-stress activity that can quickly lead to addiction. When money is lost through gambling, your pride or ego may lead you to pursue additional bets in an attempt to recover what was lost (known as “chasing losses”). This behavior should be avoided at all costs.
At Vancouver Coastal Health Research Institute, researchers are employing MRI and PET brain scans to assess the complex neural processes underlying gambling behavior. Gaining insight into these mechanisms will enable researchers to devise more effective preventive and treatment strategies.
The reward system
Brain’s reward system plays a key role in our addictions. In fact, it has been one of the most studied neurological phenomena; and is usually one of the first indicators that people who become addicted are experiencing decline in this system.
James Olds and Peter Milner conducted research in the 1950s by implanting electrodes into rats’ brains, instructing them to press a lever in order to activate specific areas of their cortex for electrical stimulation. Their experiments found that pressing levers was indeed rewarding specific regions of the rat brains.
These areas of the brain, now commonly referred to as the reward system, play an integral role in creating incentive salience, associative learning and positively-valenced emotions – as well as regulating habitual behaviors.
Studies have also demonstrated that pathological gamblers experience greater dopamine release than healthy controls during gambling episodes, reflecting their inability to predict reward occurrence.
The midbrain
The midbrain is an intricate area of the brain with many nuclei, tracts, and nerves with various functions. To best appreciate its complexity, cross-sectional studies are best done. Three regions can be distinguished within this section. The dorsal part is known as the quadrigeminal plate; its ventral counterpart can be distinguished by cerebral aqueducts as well as dark pigmented substantia nigra structures.
The tegmentum of the midbrain extends from the base of the tectum to, but does not encompass, the substantia nigra. It is surrounded by a layer of neuron cell bodies known as the periaqueductal gray that provides protection.
The tegmentum is key for movement and sensory processing, reward, and motivation. Research has shown that near misses stimulate similar reward system responses as wins do; hence the reason gambling addicts can remain immersed in the game for hours at a time even as their debt piles up; gambling provides them with an escape from daily worries, past traumas, responsibilities and duties while becoming increasingly obsessed with winning!
The insula
Researchers from the University of Cambridge recently conducted research to understand how the insula may relate to gambling addiction. They asked people with various forms of brain injuries as well as healthy participants to play roulette-style and slot machine games; those who were brain damaged demonstrated distortions such as gambler’s fallacy — an error-in-logic that suggests losing repeatedly will increase chances that next event will bring victory.
However, scientists also observed that patients with insula damage responded differently than expected when facing near-miss outcomes: They displayed strong motivation to continue playing while their lesion comparison groups displayed classic gambler’s fallacy effects and tendencies to discount future probabilities – suggesting overrecruitment of insula circuitry might contribute to disordered gambling; understanding its roles might provide insight into developing treatments for gambling addiction and other compulsive behaviors.
The striatum
The striatum contains neuronal activity associated with movement and rewards and is involved with goal directed actions and decision making. It can be divided into the lateral core and medial shell subregions. The former merges into the overlying caudate nucleus before projecting onto Pedunculopontine Tegmentum and Lateral Hypothalamus for processing while medial Shell subregion includes Substania Nigra Ventral Pallidum Lateral Habula for decision making.
Studies involving functional magnetic resonance imaging (fMRI) indicate that the striatum plays a vital role in implicit learning. One such function involves “chunking” action sequences into smaller units to make execution simpler and speedier.
Studies have also demonstrated the striatum’s critical role in loss processing. A recent study that demonstrated increased activation of dopaminergic reinforcement pathways among high-impulsive participants also demonstrated divergent coding for winning and near-miss outcomes in ventral striatum, putamen, and amygdala regions based on high impulsivity; winning outcomes generated more positive signals within reward-associated structures but near miss outcomes generated fewer anticipatory signals; this may over time create propensities towards loss chasing behaviors among these individuals.