Copenhagen Affective Disorder research Centre (CADIC), Psychiatric Centre Copenhagen, Copenhagen University Hospital, Rigshospitalet, Denmark.
Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Denmark; Department of Clinical Medicine, University of Copenhagen, Denmark.
J Affect Disord. 2022 Sep 1;312:235-244. doi: 10.1016/j.jad.2022.06.053. Epub 2022 Jun 26.
Bipolar disorder (BD), and especially the mania phenotype, is characterized by heightened reward responsivity and aberrant reward processing. In this longitudinal fMRI study, we investigated neuronal response during reward anticipation as the computed expected value (EV) and outcome evaluation as reward prediction error (RPE) in recently diagnosed patients with BD.
Eighty remitted patients with BD and 60 healthy controls (HC) underwent fMRI during which they performed a card guessing task. Of these, 41 patients and 36 HC were re-scanned after 16 months. We compared reward-related neural activity between groups at baseline and longitudinally and assessed the impact of mood relapse.
Patients showed lower RPE signal in areas of the ventrolateral prefrontal cortex (vlPFC) than HC. In these regions, the HC showed decrease in RPE signal over time, which was absent in patients. Patients further exhibited decreased EV signal in the occipital cortex across baseline and follow-up. Patients who remained in remission showed normalization of the EV signal at follow-up. Baseline activity in the identified regions was not associated with subsequent relapse.
Follow-up scans were only available in a relatively small sample. Medication status, follow-up time and BD illness duration prior to diagnosis varied.
Lower RPE signal in the vlPFC in patients with BD at baseline and its lack of normative reduction over time may represent a trait marker of dysfunctional reward-based learning or habituation. The increase in EV signal in the occipital cortex over time in patients who remained in remission may indicate normalization of reward anticipation activity.
双相情感障碍（BD），尤其是躁狂症，其特征是奖赏反应性增强和奖赏加工异常。在这项纵向 fMRI 研究中，我们研究了最近诊断为 BD 的患者在奖赏预期期间的神经元反应，作为计算的预期价值（EV）和作为奖赏预测误差（RPE）的结果评估。
80 名缓解期 BD 患者和 60 名健康对照者（HC）接受 fMRI 检查，在此期间他们进行了卡片猜测任务。其中，41 名患者和 36 名 HC 在 16 个月后重新扫描。我们在基线和纵向比较了两组之间的奖赏相关神经活动，并评估了情绪复发的影响。
与 HC 相比，患者的腹外侧前额叶皮层（vlPFC）的 RPE 信号较低。在这些区域，HC 的 RPE 信号随时间下降，而患者则没有。患者在整个基线和随访过程中还显示出枕叶皮层的 EV 信号下降。在随访中保持缓解的患者表现出 EV 信号的正常化。在确定的区域中，基线活动与随后的复发无关。
仅在相对较小的样本中进行了随访扫描。药物状态、随访时间和诊断前 BD 疾病持续时间各不相同。
BD 患者在基线时 vlPFC 中的 RPE 信号较低，且随时间的正常减少缺失，可能代表了功能失调的基于奖赏的学习或习惯形成的特征性标记。在缓解的患者中，随时间的推移，枕叶皮层的 EV 信号增加，可能表明奖赏预期活动的正常化。
