Neural effects of auditory distraction on visual attention in schizophrenia

Abstract

Sensory flooding, particularly during auditory stimulation, is a common problem for patients with schizophrenia. The functional consequences of this impairment during cross-modal attention tasks, however, are unclear. The purpose of this study was to examine how auditory distraction differentially affects task-associated response during visual attention in patients and healthy controls. To that end, 21 outpatients with schizophrenia and 23 healthy comparison subjects performed a visual attention task in the presence or absence of distracting, environmentally relevant "urban" noise while undergoing functional magnetic resonance imaging at 3T. The task had two conditions (difficult and easy); task-related neural activity was defined as difficult - easy. During task performance, a significant distraction (noise or silence) by group (patient or control) interaction was observed in the left dorsolateral prefrontal cortex, right hippocampus, left temporoparietal junction, and right fusiform gyrus, with patients showing relative hypoactivation during noise compared to controls. In patients, the ability to recruit the dorsolateral prefrontal cortex during the task in noise was negatively correlated with the effect of noise on reaction time. Clinically, the ability to recruit the fusiform gyrus during the task in noise was negatively correlated with SANS affective flattening score, and hippocampal recruitment during the task in noise was positively correlated with global functioning. In conclusion, schizophrenia may be associated with abnormalities in neural response during visual attention tasks in the presence of cross-modal noise distraction. These response differences may predict global functioning in the illness, and may serve as a biomarker for therapeutic development.

Figure 1. % Signal Change (Noise-Silence) in Task-Associated Right Hippocampal Response in Patients and Controls.

Left: Statistical parametric map. Map was thresholded at p<0.01 and overlaid onto the SPM8 canonical single subject T1 image for visualization. Data are shown in the neurologic convention (R on R). Right: Extracted right hippocampus response, based on the cluster circled in red on the parametric map (peak coordinate: x = 30, y = −13, z = −23). A relative increase in task-associated response in noise (compared to silence) in controls and a decrease in response in patients was observed.

Figure 2. % Signal Change (Noise-Silence) in Task-Associated Left DLPFC Response in Patients and Controls.

Left: Statistical parametric map. Map was thresholded at p<0.01 and overlaid onto the SPM8 canonical single subject T1 image for visualization. Data are shown in the neurologic convention (R on R). Right: Extracted left DLPFC response (peak coordinate: x = −39, y = 20, z = 40). A relative increase in task-associated response in noise (compared to silence) in controls and a decrease in response in patients was observed.

Figure 3. % Signal Change (Noise-Silence) in Task-Associated Left TPJ Response in Patients and Controls.

Left: Statistical parametric map. Map was thresholded at p<0.01 and overlaid onto the SPM8 canonical single subject T1 image for visualization. Data are shown in the neurologic convention (R on R). Right: Extracted left TPJ response (peak coordinate: x = −57, y = −46, z = 28). A relative increase in task-associated response in noise (compared to silence) in controls and a decrease in response in patients was observed.

Figure 4. % Signal Change (Noise-Silence) in Task-Associated Right Fusiform Response in Patients and Controls.

Left: Statistical parametric map. Map was thresholded at p<0.01 and overlaid onto the SPM8 canonical single subject T1 image for visualization. Data are shown in the neurologic convention (R on R). Right: Extracted right fusiform response, based on the cluster circled in red on the parametric map (peak coordinate: x = 39, y = −76, z = −14). A relative increase in task-associated response in noise (compared to silence) in controls and a decrease in response in patients was observed.

Figure 5. Negative Correlation between % Signal Change (Noise-Silence) in Task-Associated Left DLPFC Response and the Effect of Noise on Reaction Time during the Task in Patients.

Figure 6. Negative Correlation between % Signal Change (Noise-Silence) in Task-Associated Right Fusiform Response and Patient SANS Affective Flattening Score.

Figure 7. Positive Correlation between % Signal Change (Noise-Silence) in Task-Associated Right Hippocampal Response and Patient GAF Score.