Kumar Vijay, Nichenmetla Sonika, Chhabra Harleen, Sreeraj Vanteemar S, Rao Naren P, Kesavan Muralidharan, Varambally Shivarama, Venkatasubramanian Ganesan, Gangadhar Bangalore N
InSTAR Program, Schizophrenia Clinic, Department of Psychiatry, National Institute of mental health and neurosciences (NIMHANS), Bengaluru, India.
InSTAR Program, Schizophrenia Clinic, Department of Psychiatry, National Institute of mental health and neurosciences (NIMHANS), Bengaluru, India.
Asian J Psychiatr. 2021 Feb;56:102507. doi: 10.1016/j.ajp.2020.102507. Epub 2020 Dec 20.
Neurocognitive cognitive deficits including working memory (WM) impairment is a key component of schizophrenia (SCZ). Though a prefrontal cortex (PFC) abnormality is recognised to contribute to WM impairment, the exact nature of its neurobiological basis in SCZ is not well established. Functional near infra-red spectroscopy (fNIRS) is an emerging low-cost neuroimaging tool to study neuro-hemodynamics. In this background, we examined the hemodynamic activity during a WM task in schizophrenia using fNIRS. fNIRS was acquired during computerised N-back (zero-, one- & two-back) task in 15 SCZ patients and compared with 22 healthy controls. Performance in N-back test were calculated using signal detection theory alongside the mean reaction times. Concentration and latencies of oxy-, deoxy-, and totalhaemoglobin, and oxygen saturation were computed from 8*8 optodes positioned over bilateral PFC. SCZ performed poorly as measured by most of the WM parameters (p < 0.05). Lesser deoxyhemoglobin concentration (two > zero, at right BA10, p = 0.006) was noted in the right frontopolar cortex in SCZ surviving multiple-comparison correction. In addition, olanzapine equivalent doses correlated negatively with right frontopolar cortex activation (two > zero back, BA10, ρ = 0.70, p = 0.004) and better performance in two back (false alarm rate, ρ = 0.61, p = 0.015). A delayed but compensatory hyperactivation of right frontopolar cortex noted in SCZ may underlie the WM deficit in SCZ. Future studies are recommended to replicate the role of right frontopolar cortex in WM using larger samples and systematically explore the effect of antipsychotics on them.
神经认知缺陷，包括工作记忆（WM）损害，是精神分裂症（SCZ）的关键组成部分。尽管前额叶皮层（PFC）异常被认为是导致WM损害的原因，但其在SCZ中的神经生物学基础的确切性质尚未完全明确。功能近红外光谱（fNIRS）是一种新兴的低成本神经成像工具，用于研究神经血流动力学。在此背景下，我们使用fNIRS检查了精神分裂症患者在WM任务期间的血流动力学活动。在15名SCZ患者进行计算机化N-back（零、一和二-back）任务期间采集fNIRS，并与22名健康对照进行比较。使用信号检测理论计算N-back测试中的表现以及平均反应时间。从位于双侧PFC上的8×8光极计算氧合血红蛋白、脱氧血红蛋白和总血红蛋白的浓度及潜伏期，以及血氧饱和度。根据大多数WM参数测量，SCZ表现较差（p < 0.05）。在经过多重比较校正后，SCZ患者右侧额极皮层的脱氧血红蛋白浓度较低（二-back > 零-back，右侧BA10，p = 0.006）。此外，奥氮平等效剂量与右侧额极皮层激活呈负相关（二-back > 零-back，BA10，ρ = 0.70，p = 0.004），并且与二-back任务中的更好表现相关（误报率，ρ = 0.61，p = 0.015）。在SCZ中观察到的右侧额极皮层延迟但代偿性的过度激活可能是SCZ中WM缺陷的基础。建议未来的研究使用更大的样本量重复右侧额极皮层在WM中的作用，并系统地探索抗精神病药物对其的影响。
