On 12 September 2017, the IDS project team of Hong Kong Shue Yan University has held an interdisciplinary seminar regarding the role of prefrontal cortex in decision-making. It was our honor to have Dr. Bolton Chau, Assistant Professor of the Department of Rehabilitation Science of The Hong Kong Polytechnic University, to be our guest speaker. The event had attracted audiences from a broad background interested in neuroscience of the daily decision-making process.

 

The Research Methods

Dr. Chau is highly enthusiastic in neuroscience research. He first shared fundamental knowledge in doing neuroscience research, including computer simulations of the human brain and animal experiments. Computer simulations are the use of advanced technology, which models the function of human brains, so as to make predictions under different stimulations and situations. AlphaGo is a case in point.Animal experiments would tell the change of behaviors in different species. Monkeys are commonly used, as we share the same ancestors and origin. The latter is still controversial, yet its contribution to the discipline is undeniable.

 

By conducting research, we explore and learn more about the amazing facts of human brain. Neuroscientists nowadays are making great effort to broaden the applications of the knowledge, for instance, to help make better prediction regarding human behaviors, subsequently help people in making better and more rational choices.

 

About Orbitofrontal Cortex

The orbitofrontal cortex, also known as OFC, is a sub-region of the prefrontal cortex, which is located above our eyeballs. In previous studies, subtle changes in decision-making have been found in patients suffering from brain damages in the orbitofrontal cortex, suggesting that this particular brain region is related to the human decision-making process.

 

Dr. Chau also introduced the three sub-regions of the orbitofrontal cortex in details, namely the medial orbitofrontal cortex, the central orbitofrontal cortex, and the lateral orbitofrontal cortex, and how they contribute to the decision-making process. It indicated that the three parts of the orbitofrontal cortex are responsible for different kinds and stages of the decision-making process.

 

Valuation – The Central Orbitofrontal Cortex

Valuation is one of the most important and used process in decision-making. It is common that when people making decisions, they compare the value of the options, and would choose the best-valued option among. Dr. Chau presented a study, in which monkeys were presented options of different values (i.e. the amount of juice). The result of the study suggested that when neurons in the monkeys’ central orbitofrontal cortex were highly activated, hence, the activities of neuron in the central orbitofrontal cortex are correlated with the valuation of the options. Therefore, the central orbitofrontal cortex is responsive when the decision-making process involves valuation.

 

Learning – The Lateral Orbitofrontal Cortex

Learning is actually an essential process in decision-making. Previous studies working on the impacts of the lateral orbitofrontal cortex to the reversal learning in decision-making reported that patients with orbitofrontal cortex damaged, made significantly more errors in tasks involving reversal learning. Yet, another group of researchers argued that the damage was localized in medial and central orbitofrontal cortex but ignored the lateral orbitofrontal cortex. It left an open question that which regions would be responsive for the reversal learning in decision-making. In an animal study conducted by Dr. Chau, he found that the activities of the lateral orbitofrontal cortex correlates to the learning rate of the monkeys involved in the study.

 

In order to apply the findings on the human being, Dr. Chau had initiated a follow-up study with stroke and brain-damaged patients. Patients with impairment in the lateral orbitofrontal cortex performed weaker in the designated reversal learning tasks, which supports that the lateral orbitofrontal cortex is important in the learning process of decision-making.

 

Competition Between Options – The Medial Orbitofrontal Cortex and The Ventromedial Prefrontal Cortex

Comparison of the options before reaching decisions is required in daily life. There are numerous research studies of the options comparison process involving two options. Dr. Chau has studied the influence of the presence of distractors (i.e. participants faced more than two options). Dr. Chau has found that even the distractor was totally irrelevant to the decision, people would be affected by it. The value of the distractor is positively correlated with the eyeball fixation time. In other words, when there are distractors, people would spend more time mulling over the decision. Also, the value of the distractor is positively correlated with the neuron activities in the ventromedial prefrontal cortex (VMPFC).

 

Dr. Chau generously shared his knowledge and experience in research regarding prefrontal cortex and decision-making, which our audiences have benefited from.
To review Dr. Chau’s seminar, please go to: http://ids.hksyu.edu/irp/news-and-events/events/detail/20170912_bolton-chau