Brain activity in the prefrontal cortex during cancelation tasks: Effects of the stimulus array

Abstract

Cancelation tasks have been widely used to neurologically assess selective attention and visual search in various clinical and research settings. However, there is still a lack of evidence regarding the effect of differences in array conditions on brain activity in the prefrontal cortex (PFC) and its association with developmental characteristics. This study employed cancelation tasks to investigate the effects of varying array conditions on oxygenated hemoglobin (oxy-Hb) concentrations. Data from 24 healthy adults were analyzed based on performance during two-block-design type of cancelation tasks with different array conditions (i.e., structured array vs. random array). Performance was assessed based on the number of correct responses, incorrect responses, hit ratios, and performance scores (PS); while PFC activity was examined using near-infrared spectroscopy. In addition, characteristics of attention-deficit/hyperactivity disorder (ADHD) were assessed using the ADHD-Rating Scale-IV (ADHD-RS-IV). Results revealed that the numbers of correct responses and PS were higher in the random array, but there was no difference in the incorrect responses and hit ratio. Similarly, we observed that the oxy-Hb concentration in the PFC significantly increased during the task. Additionally, in the structured array, a significant relationship between task performance and characteristics of ADHD was found but not in the random array. Our results regarding the above-mentioned changes in oxy-Hb concentration suggest that the PFC region is involved in selective attention. We also found that cancelation tasks in a structured array may be useful in evaluating the characteristics of ADHD.