Frank A. Kozel

A replication study of the neural correlates of deception.

The authors attempted to replicate prior group brain correlates of deception and improve on the consistency of individual results. Healthy, right-handed adults were instructed to tell the truth or to lie while being imaged in a 3T magnetic resonance imaging (MRI) scanner. Blood oxygen level-dependent functional MRI significance maps were generated for subjects giving a deceptive answer minus a truthful answer (lie minus true) and the reverse (true minus lie). The lie minus true group analysis (n = 10) revealed significant activation in 5 regions, consistent with a previous study (right orbitofrontal, inferior frontal, middle frontal cortex, cingulate gyrus, and left middle frontal), with no significant activation for true minus lie. Individual results of the lie minus true condition were variable. Results show that functional MRI is a reasonable tool with which to study deception.

Serial Vagus Nerve Stimulation Functional MRI in Treatment-Resistant Depression

Vagus nerve stimulation (VNS) therapy has shown antidepressant effects in open acute and long-term studies of treatment-resistant major depression. Mechanisms of action are not fully understood, although clinical data suggest slower onset therapeutic benefit than conventional psychotropic interventions. We set out to map brain systems activated by VNS and to identify serial brain functional correlates of antidepressant treatment and symptomatic response. Nine adults, satisfying DSM-IV criteria for unipolar or bipolar disorder, severe depressed type, were implanted with adjunctive VNS therapy (MRI-compatible technique) and enrolled in a 3-month, double-blind, placebo-controlled, serial-interleaved VNS/functional MRI (fMRI) study and open 20-month follow-up. A multiple regression mixed model with blood oxygenation level dependent (BOLD) signal as the dependent variable revealed that over time, VNS therapy was associated with ventro-medial prefrontal cortex deactivation. Controlling for other variables, acute VNS produced greater right insula activation among the participants with a greater degree of depression. These results suggest that similar to other antidepressant treatments, BOLD deactivation in the ventro-medial prefrontal cortex correlates with the antidepressant response to VNS therapy. The increased acute VNS insula effects among actively depressed participants may also account for the lower dosing observed in VNS clinical trials of depression compared with epilepsy. Future interleaved VNS/fMRI studies to confirm these findings and further clarify the regional neurobiological effects of VNS.