New equipment to assist researchers to shed light on free will question

Dr Dawie van den Heever, Head of BERG, and Llewellyn Groeneveld, a Masters student in Biomedical Engineering, with the new brain imaging equipment, NIRSIT.

Do you have a free will, or not? Is this something you have ever thought about?

If your answer is “yes”, then you are in the company of biomedical engineering researchers at Stellenbosch University who like to grapple with this question.

The thought-provoking issue regarding the human brain and free will no longer has to remain in the sphere of mere intellectual debate. The Biomedical Engineering Research Group (BERG) at Stellenbosch University (SU) recently purchased state-of-the art brain imaging equipment that can possibly shed more light on this interesting topic.

Dr Dawie van den Heever, who now heads BERG, says: “The new piece of equipment is a welcome addition to the already well-equipped research group aiming to be the leading biomedical research institute in South Africa.

“One of the focus areas of BERG is neuroscience and we are currently investigating brain processes during decision making which might leave our common notion of free will in the balance,” he says.

The brain imaging equipment comes from Obelab, in Korea. NIRSIT is a device designed to measure variations in cerebral blood oxygen saturation by radiating a near-infrared light beam into the cerebral cortex.

Software is then used to monitor the distribution of cerebral oxygen saturation via multiple channels.

The device can record up to 204 channels on the prefrontal cortex, the area of the brain believed to be responsible for higher order decision making.

In 1983 the world was shocked with the first neuroscientific evidence against free will.

Benjamin Libet and his team of researchers showed the presence of brain activity in the motor cortex preceding voluntary hand movement up to half a second.

The surprising finding was that this brain activity also preceded the participant’s conscious awareness of this “voluntary” action.

Since then, several variations of the study have been carried out and all seem to confirm the findings with a sufficient degree of reliability. 

Dr Van den Heever elaborates: “However, many people are still sceptical and refute the claims made by some of these researchers and also question the practical relevance of these studies. Thus, research at BERG is currently addressing some of these limitations to the previous studies. 

“Our research shifts the focus to real-life decisions with consequences, while comparing brain activity associated with both arbitrary and deliberate decisions.

“Furthermore, the research tries to determine the neural mechanisms underlying deliberate choices.

“We are investigating the use of machine learning techniques to look for other networks or markers involved in the onset of the action prior to conscious intent and, in doing so, deliver another blow to the argument of free will.”

He continues: “The hypothesis is that there are other signals or markers in the brain that might not be easy and straight forward to discern and therefore the power of machine learning techniques will be used to search for these hidden markers.

Currently a 128-channel electroencephalogram (EEG) system is being used due to its high temporal resolution compared to other imaging modalities.

EEG measures the electrical activity in the brain on millisecond scales.

They will be looking for electrical signals that precede conscious awareness of the decision earlier than Libet, by looking in different areas (like the frontal cortex) and using better techniques.

However, EEG has very poor spatial resolution and might not be able to accurately locate the areas involved.

“Enter the new NIRSIT system with very high spatial resolution, up to 204 channels overlaying the prefrontal cortex, the seat of deliberate decision making.

“The first results of the EEG study can be expected at the end of 2018. Data has been recorded and we are in the process of processing the data and looking for signals that precede decision making.

“In the future we will be using the NIRSIT device to replicate these studies with better spatial resolution, to pin-point the area in the frontal cortex responsible for decision making more accurately and decisively,” Dr Van den Heever says.