How the Neurosurgical Suite Has Become an Active Laboratory for Research at Mount Sinai

This issue of the FBI newsletter is focused on what we call “The Human Brain Laboratory,” broadening and deepening efforts to study our patients’ brains, which is a unique challenge in neuroscience. In contrast to all other organ systems where biopsies are routine, access to our patients’ brain tissue historically has been severely limited. Virtually all access has had to wait until an individual’s death, when brain tissue is then examined postmortem, and where results are confounded by a focus on dead tissue.

This limitation is being overcome at Mount Sinai and certain other leading institutions by morphing the neurosurgical suite into an active laboratory. For example, today, patients undergo routine surgical implantation of electrodes deep into the brain for treatment of movement disorders (Parkinson’s disease and tremor) and, increasingly, for a range of other brain disorders (such as depression, obsessive-compulsive disorder, and Tourette syndrome).

These same electrodes also record local brain activity, which makes it possible to directly measure deep brain activity while a patient performs a motor, emotional, or cognitive task. During surgical implantation of the electrodes, it is also possible to obtain direct measures of neurotransmitters, such as serotonin and dopamine, in the vicinity of the electrodes, through in vivo voltammetry. These studies must be complemented by investigations of nonhuman primates that have homologous regions of frontal cortex, the most complex parts of the brain that are mostly absent in rodents. Nonhuman primates, thereby, enable causal, mechanistic insight into brain functions—work that is not possible in humans.

Before electrodes are placed into the brain during surgery, a small (rice-grain-size) bevel must be created on the surface of the brain to enable the electrodes to enter the brain safely. These bevels are routinely created by cauterizing surface brain tissue, but a recent innovation is to excise that tissue and preserve it for research, making it possible to obtain molecular measures (such as RNA sequencing and proteomics) of living human brain tissue for the very first time. This innovation is called the Living Brain Project.

As well, neuroimaging methods are evolving rapidly and providing increasingly more windows into the structure and function of the brain that were not possible even a few years ago. Functional magnetic resonance imaging with 7-Tesla magnets, for example, is providing high-resolution images of the functioning brain while individuals are engaged in emotional or cognitive tasks.

Finally, as our neuroscientists and physicians make progress in deciphering the codes through which interneuronal communication in the brain underlies its sensory and motor functions, major strides are being made in an entirely new field of study—what is known as “brain-computer interface.” Such approaches are offering promise to individuals who have lost brain function due to trauma or disease to regain the ability to move an arm or even walk again—raising the specter of revolutionary advances in treating people living with these severe impairments.

Each of these novel components of The Human Brain Laboratory, in which Mount Sinai’s FBI is playing a leading role, is highlighted in this newsletter. Written by world leaders in their fields, who are engaged in unique collaborations across their areas of expertise, we believe these approaches will vastly accelerate our understanding and treatment of a number of brain conditions.