Engineering the brain: the promise of neural engineering in medicine

In conversation with Dr. José Zariffa on how the field could address conditions from Alzheimer’s disease to vision loss

Engineering the brain: the promise of neural engineering in medicine

Much of the incredibly complicated human brain remains a mystery to scientists. Despite this complexity, there is new promise for technologies to treat neurological disorders.

A rapidly developing approach is neural engineering, which unites methods of neuroscience and engineering to investigate and repair neural networks.

The discipline has brought together researchers from a diverse array of scientific fields, including biology, chemistry, mathematics, computer science, and engineering. New devices and technologies have arisen from their efforts to help patients with neural disorders, such as epilepsy and Parkinson’s disease.

A new interdisciplinary area of science

Dr. José Zariffa, an associate professor at U of T’s Institute of Biomaterials & Biomedical Engineering, recently co-authored a review paper on the potential clinical applications of neural engineering.

In an interview with The Varsity, Zariffa said that he is mainly working on “decoding signals from the nervous system.” That is to say, his team has focused on analyzing messages sent from the brain to organs and membranes via electrical impulses to guide the development of medical devices.

Such a device could send impulses to a paralyzed muscle to make it contract or relax, which could help patients who have experienced a spinal injury or stroke.

If you were to track the activity of a nerve, you would notice many pathways entering it as “a mix of many different sources.” Zariffa’s team is currently investigating possible ways to separate those signals so that the messages sent to a pathway of interest can be isolated and used for specific medical purposes.

Current applications, promises, and challenges

In recent years, there has been renewed interest in potential applications of neural engineering — as evidenced by prominent enterprises such as the United States’ BRAIN Initiative — which has generated much momentum for the advancement of new technologies developed in the discipline.

The diversity of the possible applications of neural engineering is mind-blowing. For instance, neural technology can potentially reverse memory deterioration resulting from Alzheimer’s disease, restore lost or damaged eyesight, and even make prosthetic limbs move by thought.

Currently, deep brain stimulation, which involves implanting an electrode that sends signals to specific targets in the brain, is used to treat Parkinson’s disease and severe cases of obsessive-compulsive disorder and depression.

Another emerging trend which shows promise in neural engineering is the stimulation of the nervous system to treat various chronic diseases, ranging from epilepsy to conditions indirectly caused by a malfunctioning nervous system, such as hypertension and diabetes.

According to Zariffa, Toronto is a “hotbed” for neural engineering, as its strong pool of engineering and neuroscience research talent combined with a solid hospital network allow for the interdisciplinary research crucial for neural engineering to happen.

The recently-opened Center for Advancing Neurotechnological Innovation to Application launched by U of T and its affiliated University Health Network is an example of a Toronto-based initiative aiming to bring recent advances in neural engineering to clinical settings.

Zariffa’s own research focuses on developing technology to facilitate recovery from damage to the central nervous system resulting, for example, from spinal cord injury or stroke, which may help patients in their day-to-day lives.

Ethics of neural engineering

While a main objective of neural engineering is to develop devices for clinical applications, it is possible that the advances in this area will be used for non-medical purposes.

For instance, certain biotechnology companies are currently looking into ways to enhance the human brain’s processing abilities by creating brain-computer interfaces based on the most recent advances in artificial intelligence.

Such examples of human augmentation, including Elon Musk’s plan to create “human-AI hybrids” and people “upgrading” their bodies by implanting computer chips, are often sensationalized by media outlets.

Yet, according to Zariffa, modern science is still far from implementing such advances on a broader scale. The ethical considerations of the field, he noted, have not differed considerably from those in most areas of technological development.

Even without the sensationalism of the field, the growing applications of neural engineering remain vast and promising in treating medical disorders.

The brain on cannabis

Research rushes to catch up with legalization

The brain on cannabis

Marijuana is set to become legal across Canada this week, and Canadians must be well equipped to confront any downstream effects this historic move may have. 

The Canadian Tobacco, Alcohol and Drugs Survey found 3.6 million — 12 per cent of Canadians — used cannabis in 2015. Of that population, 24 per cent said they used cannabis for medical purposes. 

Following legalization, individuals should be more cognizant of the effects of marijuana, and specifically ways in which it can affect the brain. 

What does marijuana do to your brain? 

The endocannabinoid system is a complex signaling system in the brain and surrounding tissues. Though it is not well understood, it has been shown to play a role in immune functions and the development of the nervous system. It is also the system that processes cannabis and plays a role in producing the associated neurological effects. 

The system consists of endocannabinoids, cannabinoid receptors, and enzymes that transform endocannabinoids in the body. 

Broadly, endocannabinoids like anandamide and 2-arachidonoylglycerol are a class of cannabinoids — chemicals present in cannabis — that bind to receptors in cells. Once bound, endocannabinoids act on CB1, a cannabinoid receptor that is found in the brain. 

Cannabidiol (CBD) and tetrahydrocannabinol (THC) are the two most well described cannabinoids in marijuana. 


CBD does not produce any of the psychoactive effects, and has been found to block some of the effects of THC by interfering with CB1 receptors. 

Structurally, THC is similar to anandamide — a naturally occurring endocannabinoid — and has been shown to activate the endocannabinoid system. 

“[CB1 receptors] are found in many brain regions that control mood, appetite, memory etc. They inhibit the release of an inhibitor transmitter called GABA and this can lead to increased activity of certain brain excitation pathways,” U of T Professor Ruth Ross explained in an email. 

Ross’ research investigates the molecular pharmacology of cannabinoids. 

“There are many unanswered questions about the safety and efficacy of cannabis as a medicine and about the possible harms of cannabis ­— especially for certain people who may be vulnerable to these effects,” Ross added. “We desperately need more solid clinical data from double blind placebo controlled studies on safety and efficacy.” 

Marijuana in other areas of medicine

There is hope that medical research with cannabis and recreational users will benefit from its legalization. 

For example, Ross and her team are working on developing “medicines that target the endocannabinoid system for the treatment of liver disease, pain and brain disorders.”

Ross said that many medical claims are made about cannabis, but it can actually make some conditions worse. 

“It is almost unknown of any person who has overdosed on cannabis,” Andrea Furlan, Associate Professor in the Faculty of Medicine and Staff Physician and Senior Scientist at the Toronto Rehabilitation Institute, wrote to The Varsity. 

According to Ross, “Cannabis even at high doses does not have the type of physiologically dangerous effect that we might see with opioids, which cause respiratory depression and can cause death.” 

However, because of the psychoactive effects associated with marijuana, it could result in “acute psychosis, paranoia, anxiety, or fear,” and such effects could cause harm to individuals or those around them. 

Despite low chances of overdosing on marijuana, several studies have sought to compare long-term use of cannabis versus alcohol in the developing adolescent brain. One study concluded that “lasting effects of adolescent cannabis use can be observed on important cognitive functions and appear to be more pronounced than those observed for alcohol.”

The Canadian Institutes of Health Research is prioritizing research on neurodevelopment, prevention, harm and treatment of problematic cannabis use, potency and product safety, social determinants of health, relationship of cannabis use and mental health, potential applications of cannabis, and pain management. 

“We hope that with legalization there will be more scientists interested in this area, and that Canada will be a leader in research in the world,” Furlan said.