Working Memory Load and Facial Emotional Stimuli in Individuals With High Genetic Risk of Schizophrenia

Sandra L. Quiñones-Beltrán¹, Geisa B. Gallardo-Moreno¹, Jacobo J. Brofman-Epelbaum², Fabiola R. Gómez-Velázquez¹, Julieta Ramos-Loyo¹, Fernando A. Barrios³ & Andrés A. González-Garrido^1*

¹Instituto de Neurociencias, Universidad de Guadalajara, México
²Escuela de Pedagogía, Universidad Panamericana, México
³Instituto de Neurobiología, Universidad Nacional Autónoma de México, México

Andrés A. González-Garrido, Instituto de Neurociencias, Universidad de Guadalajara, México.

Keywords: Schizophrenia; Working Memory Load; Facial Emotion; fMRI; n-back

Abstract

Working Memory (WM) deficits have been suggested as an endophenotypic marker for schizophrenia. This neurocognitive marker proposal has been supported by evidence of WM deficits also observed in unaffected high-risk relatives (HR) of patients with schizophrenia. Furthermore, empirical evidence suggests that working memory (WM) load and the implicit facial-emotional processing are interdependent. However, the underlying neurofunctional correlates of several intervening factors, such as WM load and the emotional salience of the information being processed, remain unclear. The present study assessed HR relatives and healthy controls while performing two tasks with different WM load using facial emotional stimuli. The fMRI block paradigm consisted of n-back tasks (1 and 2-back) in which participants had to detect angry facial expressions among neutral and happy ones. The HR group and controls showed similar behavioral accuracy, but they differed in their reaction times. The control group had significantly faster responses when performing the 2-back task, while the HR showed faster responses during the 1-back task. The contrast analysis between groups (controls > HR participants for both 1 and 2-back) were not statistically significant, however, when analyzing each groups’ activation separately, the HR group showed a significantly higher activation in the angular and supramarginal gyri, also involving the superior parietal lobule in the contrast 2-back > 1-back. These results indicate that HR individuals achieve relatively similar behavioral performances than controls, in conditions that demand higher WM load, implying that since they do not benefit from the emotional salience of the stimuli require supplementary parietal activations. The distinctly higher activation observed in the supramarginal and angular gyri, along with the superior parietal lobules during the higher WM load task, could be denoting an additional recruitment of resources to complete the task. Furthermore, these results suggest that the distinct brain activation patterns which have been described in the literature in schizophrenia patients are probably not deterministic preceding the illness.

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