کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4934929 1434058 2017 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Load-dependent hyperdeactivation of the default mode network in people with schizophrenia
ترجمه فارسی عنوان
پراکندگی وابسته به بار از شبکه حالت پیش فرض در افراد مبتلا به اسکیزوفرنیا
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب رفتاری
چکیده انگلیسی
Schizophrenia is associated with impairment in a range of cognitive functions. Neuroimaging studies have reported lower, but also higher, task-induced activation accompanying impaired performance. Differences in task-load and the ability of people with schizophrenia (PSZ) to stay engaged in the cognitive operations probed appear to underlie such discrepancies. Similarly, task-induced deactivation of the default mode network (DMN) was weaker in PSZ relative to healthy control subjects (HCS) in most studies, but some reported greater deactivation. An inability to stay engaged in the cognitive operations could account for these discrepancies, too, as it would lead to more time off-task and consequently less deactivation of DMN functions. The present study employed a change detection paradigm with small to moderate set sizes (SSs) of 1, 2, and 4 items. Task training prior to fMRI scanning abolished the group difference in no-response trials. Task-positive regions of interest (ROIs) displayed greater activation with increasing SS in both groups. PSZ showed greater activation relative to HCS at SSs 1 and 2. DMN ROIs displayed greater deactivation with increasing SS in PSZ, but not in HCS, and PSZ tended to hyperdeactivate DMN regions at SS 4. No hypodeactivation was observed in PSZ. In conclusion, when minimizing differences in task-engagement, PSZ tend to over-recruit task-positive regions during low-load operations, and hyperdeactivate DMN functions at higher load, perhaps reflecting heightened non-specific vigilance or effort when dealing with cognitive challenges. This speaks against an inability to down-regulate task-independent thought processes as a primary mechanism underlying cognitive impairment in schizophrenia.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Schizophrenia Research - Volume 185, July 2017, Pages 190-196
نویسندگان
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