Altering dendritic spine shapes in brain neurons can regulate gambling addiction: study

A recent study conducted by Severance Hospital has suggested that modifying the shape of certain dendritic spines in brain neurons can decrease neuronal excitability, potentially providing a novel approach to regulating gambling addiction.

A Severance Hospital and Seoul National University School of Dentistry research team discovered that altering dendritic spine shapes in brain neurons may regulate gambling addiction behaviors. They are, from left, Professors Kim Jeong-hoon, Kim Wha-young and Researcher Kwak Myung-ji at Severance Hospital, and Professor Choi Se-young and Researcher Choi Su-jeong at Seoul National University School of Dentistry.

Addiction is characterized by the tendency to take risks, often disregarding adverse consequences to pursue addictive substances or activities. This trait is evident in both substance addiction and behavioral addictions such as gambling.

However, while most gambling addiction studies have been limited to human subjects, this study is among the first to delve deeply into the neural mechanisms of risk-taking behavior through brain protein manipulation in animal models.

The team, led by Professors Kim Jeong-hoon, Kim Wha-young and Researcher Kwak Myung-ji of the Department of Physiology at Severance Hospital, trained laboratory mice to choose between a low-risk option, which offered small but consistent rewards, and a high-risk option that gave larger but less frequent rewards. Professor Choi Se-young and Researcher Choi Su-jeong of the Department of Physiology at Seoul National University School of Dentistry also participated in the study.

The training separated the mice into two groups -- risk-averse mice, which preferred smaller but more reliable rewards, and risk-seeking mice, which opted for larger, albeit less certain, rewards.

Upon measuring the electrophysiological properties of neurons in the nucleus accumbens of these mice, the researchers found that the cells of risk-seeking mice exhibited reduced excitability compared to those in risk-averse mice.

The researchers then focused on a protein called radixin phosphorylation, known to regulate dendritic spine maturity.

By mimicking the phosphorylation of radixin via a mutated gene delivered through viral vectors, they overexpressed the protein in the nucleus accumbens of risk-averse mice.

This led to changes in the dendritic spine morphology, with the mushroom-shaped spines becoming smaller and neuronal excitability decreasing, similar to the brain structure seen in risk-seeking mice.

Notably, after receiving this radixin intervention, the risk-averse mice displayed an increased tendency toward risk-taking behavior.

“Our findings show that dendritic morphology and electrophysiological properties in the nucleus accumbens vary according to risk-taking behaviors, and that altering these structures can modulate risk choices,” Professor Kim Jeong-hoon said. “This discovery enhances our understanding of the neural mechanisms underpinning decision-making impairments in gambling addiction.”

The results of the research were published in Progress in Neurobiology.