In this episode, I was able to talk to Dr. Shan Siddiqi, who is an Assistant Professor of Psychiatry at Harvard Medical School and a researcher at the Center for Brain Circuit Therapeutics at Brigham and Women’s Hospital, where he and his lab focuses on brain circuit therapeutics. Shan’s work bridges the gap between neuroimaging and causality, exploring the mechanisms of brain stimulation and lesions in neuropsychiatric disorders such as depression and post-traumatic stress disorder (PTSD). He’s made remarkable strides in understanding the brain circuits involved in these conditions and how we can leverage this knowledge for neuromodulation therapies. Shan has worked on numerous topics that focus at improving transcranial magnetic stimulation (TMS) for psychiatric indications by using brain connectomics. Using various causal sources of information, he was able to show that the same network is associated with changes of depressive symptoms in patients with brain lesions, major depression, epilepsy or Parkinson's disease – and this network could be identified using various types of brain lesions, transcranial magnetic or deep brain stimulation sites. More recently, Shan has worked on identifying a novel TMS target for PTSD based on data from penetrating head trauma lesions and TMS sites. He has worked on conceptual papers that revolve around closing the causality gap in neuroimaging, as well as on how to bring connectomics into clinical practice in psychiatry. His recently launched prospective R01 funded trial will aim at prospectively mapping random cortical stimulation sites to various behavioral and clinical outcomes.