As founding scientific director of the Brain Institute, Peter L. Strick, PhD, provides administrative support and research expertise to more than 150 neuroscientists, while maintaining his own highly productive laboratory. Strick is internationally recognized for his pioneering work in unraveling neural networks for movement, cognition and affect in the central nervous system. In 1986, he published a groundbreaking review with Garrett Alexander, MD, PhD, and Mahlon DeLong, MD, in which they proposed that the basal ganglia participate in multiple distinct circuits with motor and non-motor areas of the cerebral cortex.
This review led to a major paradigm shift in concepts about basal ganglia function. Specifically, the basal ganglia were not simply concerned with the generation of movement, but also were involved in the control of cognition and affect. The review remains one of the most highly cited papers in systems neuroscience (> 7,300 citations), in part, because of its implications about the impact of basal ganglia dysfunction on neurologic and neuropsychiatric disorders.
To test this new proposal, Strick pioneered the use of neurotropic viruses as transneuronal tracers in the central nervous system. His studies demonstrated that the cerebellum as well as the basal ganglia form multiple "closed loop" circuits with motor, prefrontal and posterior parietal areas of cortex. Furthermore, he demonstrated that the basal ganglia and cerebellum communicate with each other and form a densely interconnected network with the cerebral cortex. These results have had a profound impact on concepts about the contributions of the basal ganglia and cerebellum to health and disease. Discovery of these connections provide the neural substrate to explain basal ganglia and cerebellar involvement in cognitive processes like working memory, rule-based learning, switching attention and visuo-spatial perception. These connections also provide an explanation why abnormal activity in these circuits contributes to a broad range of neurologic and neuropsychiatric symptoms, including those associated with Parkinson's and Huntington's diseases, attention deficit-hyperactivity disorder, obsessive-compulsive disorder and depression.
Strick was the first to identify the premotor areas in the frontal lobe and demonstrated that they project directly to the spinal cord just like the primary motor cortex. He showed that the number of corticospinal neurons descending from the premotor areas is comparable to the number descending from the primary motor cortex. Thus, descending commands can originate not only from the primary motor cortex, but also from each of the premotor areas. In a recent study he demonstrated that a specific region of posterior parietal cortex can be the source of command signals to generate hand movements. Taken together, these observations have fundamentally altered concepts about the voluntary control of movement by indicating that the central commands for movement can originate from multiple cortical areas as parallel pathways to the spinal cord.
Strick also has interests in applying transneuronal tracing to explore questions of neural development. In collaboration with others, he is using CRISPR to knockout the gene ATM in a non-human primate model of Ataxia Telangiectasia (AT), a childhood disorder that produces progressive cerebellar degeneration and various cancers. ATM is a DNA repair gene; hence, its absence in AT explains the susceptibility to cancer. However, the link between ATM and cerebellar degeneration is unknown. To date, there has never been a systematic analysis of the brain degeneration in children with AT. The kind of whole brain analysis we will create will allow systematic and unbiased assessment of the distribution of changes throughout the cerebellum in children with AT and which brain regions in addition to the cerebellum are involved in AT pathology. This information is critical to designing new treatments to enhance the quality of life of children with AT.
Recently Strick has used virus tracing to provide new insights into a classical problem in neuroscience-- the mind-body connection. He has shown that cortical areas involved in the control of movement, cognition, and affect are sources of central commands to the adrenal medulla, an organ concerned with the control of immediate responses to stress. These findings provide an anatomical basis for psychosomatic illness in which how we move, think and feel has an impact on adrenal function. Overall, Strick's work is helping to dissolve the artificial boundaries between neurology and psychiatry, by demonstrating a common neural substrate for disorders assigned to each discipline.
In addition to heading the Brain Institute, Strick holds multiple administrative positions at Pitt. As Thomas Detre Professor and Chair of the Department of Neurobiology at Pitt, Strick has recruited junior and senior faculty with strengths in systems neuroscience, developmental biology, computation, pain circuitry, sensory systems and neurodegeneration. He also directs the Systems Neuroscience Institute, the Neuroscience Imaging Center, the national Center for Neuroanatomy with Neurotropic Viruses and the regional Center for Neuroscience Research in Non-Human Primates.
A graduate of the University of Pennsylvania with a doctorate in anatomy from Penn, Strick worked at the National Institute of Mental Health and in the departments of neurosurgery and physiology at the State University of New York-Medical Center before joining the Pitt faculty in 2000. Strick was elected to the National Academy of Sciences in 2012 and to the American Academy of Arts and Sciences in 2004.
Strick and his colleagues have developed novel techniques to map connections from the brain to distant regions of the body. Now they intend to create an atlas of neural networks, using transneuronal tracing with viruses. Brain Institute scientists have used transneuronal tracing to discover several important, previously unknown networks that allow the brain to control muscles and visceral organs. In 2016, Strick used this virus tracing to identify neural networks that connect the cerebral cortex to the adrenal medulla, which is responsible for the body’s rapid response in stressful situations. More recently, Strick and his research team showed the first concrete evidence of a suspected neural pathway that enables the fine hand movements needed for a person to recognize, manipulate and use objects. This new information can be expected to lead to development of therapies to restore hand movement after stroke or other brain injury.