Pokorny Victor J, Sponheim Scott R, Olman Cheryl A
University of Minnesota, Department of Psychology, United States of America.
University of Minnesota, Department of Psychology, United States of America; Minneapolis Veterans Affairs Health Care System, United States of America; University of Minnesota, Department of Psychiatry and Behavioral Science, United States of America.
Schizophr Res. 2024 Dec;274:492-500. doi: 10.1016/j.schres.2024.10.021. Epub 2024 Nov 9.
Schizophrenia is associated with weakened contextual modulation of visual contrast perception, which is generally predicted by population average neural firing rates in primary visual cortex (V1). We use high field fMRI and a novel task to assess V1-instrinsic and V1-extrinsic mechanisms of atypical contextual modulation in schizophrenia.
We examined the BOLD responses of individuals with schizophrenia (SCZ = 34), bipolar disorder (BP = 25), unaffected first-degree relatives of SCZ (SREL = 20), unaffected first-degree relatives of BP (BPREL = 13) and healthy controls (CON = 23). Participants were presented with near- and far-surrounds oriented at 20° and 70° relative to center gratings.
We observed orientation-dependent modulation of V1 BOLD activation to near-surrounds across groups. In particular, the SCZ and CON groups showed significant orientation-dependent contextual modulation (Cohen's d SCZ = 0.56; CON = 0.63). Surprisingly, the direction of the modulation was opposite of predicted: greater BOLD activation for the condition that was expected to produce suppression.
Our results differ from previous reports: we observed successful orientation-dependent modulation of V1 activation in SCZ. Furthermore, our results suggest that spatial attention and figure-ground modulation may play an important role in determining the direction and magnitude of orientation-dependent modulation.
精神分裂症与视觉对比度感知的情境调制减弱有关，这通常由初级视觉皮层（V1）中的群体平均神经放电率预测。我们使用高场功能磁共振成像和一项新任务来评估精神分裂症中非典型情境调制的V1内在和V1外在机制。
我们检查了精神分裂症患者（SCZ = 34）、双相情感障碍患者（BP = 25）、未受影响的SCZ一级亲属（SREL = 20）、未受影响的BP一级亲属（BPREL = 13）和健康对照者（CON = 23）的血氧水平依赖（BOLD）反应。向参与者呈现相对于中心光栅以20°和70°定向的近周边和远周边。
我们观察到跨组V1 BOLD激活对近周边的方向依赖性调制。特别是，SCZ组和CON组表现出显著的方向依赖性情境调制（Cohen's d SCZ = 0.56；CON = 0.63）。令人惊讶的是，调制方向与预测相反：预期产生抑制的条件下BOLD激活更大。
我们的结果与先前的报告不同：我们观察到SCZ中V1激活成功的方向依赖性调制。此外，我们的结果表明，空间注意力和图形-背景调制可能在确定方向依赖性调制的方向和幅度方面发挥重要作用。
