Table 2.
Overview of studies investigating treatment effects of different therapeutic approaches to determine effects on reward processing in MDD.
| Authors | Year | n (total) | n (patient) | n (HC) | Task/Stimulus | Therapeutic Intervention | ROI/Seeds | Observed Effects Decreased (↓)/Increased (↑) FUCO or Activation in fMRI |
|---|---|---|---|---|---|---|---|---|
| Admon | 2017 | 43 | 46 MDD | 43 | Monetary incentive delay | Amisulprid (50mg); MDD: (23*, 23 Pl); HC: (23*, 20Pl) | Caudate, NAc, putamen | ↑: Increased FUCO between striatum and dorsal ACC and midcingulate cortex in response to reward outcomes in MDD treated with Amisulprid vs. placebo |
| Dichter | 2009 | 27 | 12 MDD | 15 | Wheel of fortune | Behavioral Activation Treatment for Depression | - | ↑: Increased dorsal striatal activation during reward anticipation after BATD in MDD |
| Downar | 2014 | 47 | 38 TRD, 9 TRBPD | 0 | None | rTMS (DMPFC), 20 sessions | 516 | ↑: Responders: increased VMPFC connectivity to VTA, left caudate nucleus, left DMPFC, left DLPFC, left Occipital cortex, right anterior insula, and the rigth Precuneus; Non-responders: increased connectivity to the right fusiform gyrus, right DLPFC, right PCC, right Middle temporal gyrus, right frontopolar cortex, left MCC and left Middle paracingulate cortex |
| Quevedo | 2017 | 68 | 38 MDD | 30 | Monetary reward | Various antidepressants in MDD groups | Bilateral VS | ↑: Increased FUCO between VS and midline cortical areas during loss versus reward trials.in MDD; depression severity linked to higher VS to caudate and precuneus connectivity |
| Carl | 2016 | 53 | 33 MDD | 20 | Monetary incentive delay | Brief Behavioral Activation Treatment for Depression | NAc, caudate nucleus, putamen, frontal medial cortex, OFC, and ACC | ↓: Decreased activity in MDD group when comparing first and second run of the task reflecting decreased capacity for sustained activation of the right NAc |
| Redlich | 2015 | 100 | 33 UD, 33 BD | 34 | Car-guessing paradigm | Various medications in all but 2 patients | NAc | ↓: Decreased activity in UD and BD patients compared to HC in the NAc during reward processing |
| Takamura | 2017 | 24 | 12 MDD | 12 | Variable sized monetary reward | Medication for less than 7 days | Left VS. bilateral putamen | ↓: In HC, striatal activity increased in proportion to the size of monetary reward during reward anticipation. This was altered in MDD patients, and significant group-by-reward size interaction effects detected in ROIs |
| Duprat | 2017 | 50 | 50 MDD | 0 | Probabilistic learning | Accelerated intermittent TBS | - | ↑↓: No significant group differences found in treatment vs sham condition. Patients with low anhedonia displayed higher activity in caudate and putamen at baseline and reduced activity in the reward system after one week of treatment. High anhedonia was linked to increased activity in the reward system after one week of treatment. |
Studies including functional MRI and/or functional connectivity analysis in MDD patients receiving pharmacological or non-pharmacological treatment are included.
Abbreviations: ACC, anterior cingulate cortex; BA, broca area; BATD, behavioral activation treatment for depression; BD, bipolar depression; DLPFC, dorsolateral prefrontal cortex; dmPFC, dorsomedial prefrontal cortex; FUCO, functional connectivity; HC, healthy controls; MDD, major depressive diorder; MCC, midcingulate cortex; NAc, nucleus accumbens; OFC, orbitoftrontal cortex; PCC, posterior cingulate cortex; PFC, prefrontal cortex; Pl, placebo; pVMPFC, posterior ventromedial prefrontal cortex; rTMS, repeated transcranial magnetic stimulation; STG, superior temporal gyrus; TRD, treatment-resistant depression; TBS, theta burst stimulation; UD, unipolar depression; VMPFC, ventromedial prefrontal cortex; VS, ventral striatum; VTA, ventral tegmental area.