Altered working memory process in the manganese-exposed brain

Chronic manganese (Mn) exposure often leads to impairments in fine motor and cognitive functions, particularly memory. However, the neural correlates of Mn-induced alterations in memory remain unclear. In the present study, we performed functional MRI (fMRI) with 2-back memory tests to assess the neural correlates of Mn-induced memory impairment in response to subclinical dysfunction in the working memory networks in welders exposed to Mn for extended periods of time. Within-group and between-group analyses revealed that brain activity in working memory networks was increased in welders with chronic Mn exposure during the 2-back verbal working memory task compared to healthy control individuals. Therefore, our fMRI findings indicate that welders might require more neural resources in working memory networks to compensate for subtle deficits in working memory and altered working memory processes, even if they performed the tasks at the same level as healthy control individuals.

Research highlights
► The manuscript describes the result of functional MRI with 2-back memory tests in welders exposed to manganese to assess the neural correlates of manganese-induced memory impairment.
► Within-group and between-group analyses revealed that brain activity in working memory networks was increased in welders with chronic manganese exposure during the 2-back verbal working memory task compared to healthy control individuals.
► Our fMRI findings indicate that welders might require more neural resources in working memory networks to compensate for subtle deficits in working memory and altered working memory processes.