Neurosalience Episode 15: A conversation with Dimitri Kullman & Vince Calhoun

Interview by Peter Bandettini, production by Nils Muhlert and Niall Duncan ​

This podcast idea was precipitated by Dimitri Kullman’s 2020 editorial in Brain, causing a stir in the community. It leveled criticism about the clinical validity of fMRI. Some of it was outdated but some was indeed on point.  In this podcast we had a great discussion on all things fMRI -  what it can and cannot measure, and how it can continue to proceed. We also discuss some of the scientific culture surrounding fMRI. Overall, the discussion was useful in bringing some of the flaws as well as some of the outstanding innovations to light. We ended up agreeing that fMRI is in fact, an extremely useful tool that allows penetrating insight into the brain at a specific temporal and spatial scale. We feel that there is still considerable hope yet also considerable challenge in increasing its clinical relevance. ​

​Guests: 

Dr. Dimitri Kullmann is a professor of Neurology at UCL Queen Square Institute of Neurology.

Dimitri received his doctorate from the University of Oxford in 1984 and his Bachelor of Medicine/Surgery from the University of London in 1986. He alternated between research in synaptic transmission and post graduate medical training in London. In 1992, he started his lab at the Institute of Neurology and in 2000, he became a fellow of the Royal College of Physicians. 

Dimitri's interests span the fundamental mechanisms of synaptic transmission, the computational properties of small neuronal circuits, and alterations in neuronal and circuit excitability in epilepsy and other neurological disorders. The core methods in his lab are in vitro electrophysiology and pharmacology, but he also applies confocal and two-photon laser scanning microscopy, computational simulations, molecular genetic methods, and heterologous expression of mutated ion channels. His laboratory has contributed to the discovery of silent synapses, glutamate spillover, presynaptic GABAA receptors in the cortex, human epilepsy caused by K+ and Ca2+ channel mutations, tonic inhibition in the hippocampus, and Hebbian and anti-Hebbian LTP in hippocampal interneurons. 

One of Dimitri's goals is to understand how phenomena that he has studied at the cellular level interact to regulate the excitability of small neuronal circuits. He is integrating studies on hippocampal circuit function with knowledge of how interneurons and principal cells fire during different behaviours. This is being approached both experimentally and with computational simulations. He also aims to apply his lab's recent insights into the cellular consequences of inherited mutations of ion channels (channelopathies) to develop new ways to diagnose and treat neurological diseases.

Dimitri was editor of the journal Brain from 2013 to 2020. He brings to the table the perspective of a clinician neuroscientist who does research at the neuronal scale. 

Dr. Vince Calhoun is the director, since 2019, of Translational Research in Neuroimaging and Data Science (TReNDS), which includes three universities: Georgia State, Georgia Tech, and Emory.  

In 2002, Vince received his Ph.D. in Electrical Engineering from the University of Maryland Baltimore County, and then became an assistant clinical professor at Yale, Director of the Medical Image Analysis laboratory Institute of Living, in Hartford. He moved on in 2006 to the University of New Mexico, Albuquerque as an associate professor, and moved up to become a Distinguished Professor at The University of New Mexico and as a leader in various forms of the Mind Research Network in Albuquerque. 

Vince is an expert on brain imaging acquisition and analysis and has created numerous algorithms for making sense of complex brain imaging data. He is the creator of the group independent component analysis algorithm, which has become widely used for extracting 'networks' of coherent activity from functional magnetic resonance imaging (fMRI) data. He was an early innovator in approaches to characterize the dynamics of brain connectivity. He has also developed techniques to link many different types of data, called 'data fusion' including various types of brain imaging (structural, functional, connectivity) with genomic and epigenomic data. A key focus of Calhoun's work is the development of tools to identify brain imaging markers to help identify and potentially treat various brain disorders including schizophrenia, bipolar disorder, autism, and Alzheimer's disease. He has recently served as President of the OHBM and has been truly prolific in his work to push the methodology of fMRI. 
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The Neurosalience production team consists of Anastasia Brovkin, Katie Moran, Nils Muhlert, Kevin Sitek, and Rachael Stickland.