Jodi Gilman

Dr. Jodi Gilman is an Associate Professor in Psychiatry at Harvard Medical School and the Director of Neuroscience at the Massachusetts General Hospital Center for Addiction Medicine. Her research uses multi-modal imaging, behavioral and cognitive testing to understand the biological, psychological, and clinical aspects of addiction. Specifically, she uses brain imaging to understand different stages of substance use, including initiation, continuance, and cessation of drug and alcohol use. Currently, she is using brain-imaging paradigms to understand brain activation patterns under acute drug intoxication. Her long-term research goal is to examine risk factors for the development of addiction, with the hope that this information will lead to the development of specific interventions to mitigate this risk.

Dr. Gilman will be leading a discussion on Delta-9-tetrahydrocannabinol intoxication is associated with increased prefrontal activation as assessed with functional near-infrared spectroscopy: A report of a potential biomarker of intoxication. The primary psychoactive compound in cannabis, Δ9-tetrahydrocannabinol (THC), binds to cannabinoid receptors (CB1) present in high concentrations in the prefrontal cortex (PFC). It is unknown whether the PFC hemodynamic response changes with THC intoxication. Her and her team conducted the first double-blind, placebo-controlled, cross-over study of the effect of THC intoxication on functional near infrared spectroscopy (fNIRS) measures of PFC activation. Fifty-four adult, regular (at least weekly) cannabis users received a single oral dose of synthetic THC (dronabinol; 5-50mg, dose individually tailored to produce intoxication) and identical placebo on two visits at least one week apart. fNIRS recordings were obtained during a working memory task (N-Back) at three timepoints: before THC/placebo, at 100 minutes (when peak effects were expected), and at 200 minutes after THC/placebo administration. Functional data were collected using a continuous-wave NIRS device, with 8 sources and 7 detectors arrayed over the forehead, resulting in 20 channels covering PFC regions. Increases in heart rate significantly correlated with intoxication ratings after THC dosing. Results indicated that 100 min after THC administration, oxygenated hemoglobin (HbO) concentration significantly increased from pre-dose HbO levels throughout the PFC in participants who reported significant intoxication. Changes in HbO response significantly correlated with self-reported intoxication at 100 minutes after THC administration. Among those who reported intoxication, HbO response decreased at 200 min after THC, when intoxication had largely resolved, compared to the peak THC time point. This study demonstrates that THC intoxication causes increased PFC activity, and fNIRS of the PFC can measure this effect. Increased neural activation in PFC represents a potential biomarker for cannabis intoxication.