Previous work demonstrated that individuals are able to self-regulate their ventral tegmental area (VTA) activity using real-time biofeedback. The current study expands this approach to a larger sample with repeated training sessions to more robustly characterize the effects of VTA modulation. The study will assess change in mood and motivation-related measures, as well as neural activity and connectivity changes.
Major depressive disorder (MDD) is one of the world's largest health problems with current treatments that are ineffective for a substantial proportion of individuals. There is a critical need for mechanistically informed interventions that are individualized and that aim to target core symptoms. Converging evidence from animal and human research in the field has implicated the ventral tegmental area (VTA), a key component of the brain's dopamine system, in regulating motivation and reward-related behaviour. Previous work has demonstrated that participants can successfully train to self-regulate their VTA activity using cognitive strategies while receiving real-time feedback. This shows that VTA self-regulation is feasible in humans. The current study builds on this previous work to further investigate the relationships between VTA activity modulation and mood and motivation related changes in individuals with MDD. Specifically, this study will aim to extend on prior findings by increasing the sample size and incorporating repeated training sessions to enhance and characterize training effects over time. A total of 60 participants with MDD will be recruited and will be randomized in a 1:1 ratio to receive either active biofeedback or sham (control) feedback. Participants will complete two training sessions with real-time 7T-MRI biofeedback. During functional MRI (fMRI) scanning, participants will be trained to use self-generated cognitive strategies to modulate their VTA activity while viewing a visual representation of their brain signal (active condition) or a yoked control signal (sham condition). The primary objective of this study is to determine how VTA modulation influences mood and motivation related measures over time. Secondary objectives include assessing changes in VTA activation and functional connectivity over time, as well as examining how neural changes relate to mood and motivation-related changes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
60
The active biofeedback session will be done within the 7T MRI. It will include MOTIVATE and active rest trials. During each MOTIVATE trial, subjects will be instructed to generate a heightened state of motivation. Subjects will simultaneously view a progress bar on the screen during MOTIVATE trials that represents their VTA activity and they will be trained to try to increase the level of the bar by motivating themselves.
The sham biofeedback session resembles the active condition, however, the progress bar seen during the MOTIVATE trials will represent yoked sham values.
Oxford Centre for Integrative Neuroimaging (OxCIN) FMRIB, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital
Oxford, United Kingdom
RECRUITINGMood and Motivation Related Measures
A single composite metric will be derived by factor analysis of a battery of validated mood and motivation related instruments (e.g. PANAS-SF, POMS-SF, PHQ-9, MAP-SR), providing one expected latent mood and motivation factor. Modelling the instruments jointly avoids nominating any single scale as the outcome, and controls for multiple comparisons. Unit of measure: standardized latent factor score (z / SD units).
Time frame: Pre to post biofeedback training, within a 6-week timeframe.
VTA Connectivity
Functional connectivity between the VTA seed and whole-brain (voxelwise), measured with 7-Tesla fMRI. Unit of measure: Fisher z-transformed correlation coefficient.
Time frame: Pre to post biofeedback training, within a 4-week timeframe.
VTA Activation
Blood-oxygen-level-dependent (BOLD) signal in the bilateral ventral tegmental area (VTA) region of interest for MOTIVATE versus active rest trials, measured with task-based 7-Tesla fMRI. Unit of measure: percent BOLD signal change.
Time frame: Pre to post biofeedback training, within a 4-week timeframe.
Association between change in VTA measures and change in the mood and motivation factor
The standardized VTA activation and connectivity measure will each be tested for an association with change in the mood and motivation factor. One coefficient is reported per VTA measure. Unit of measure: standardized regression coefficient (dimensionless, from -1 to 1).
Time frame: Pre to post biofeedback training, within a 6-week timeframe.
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