Impaired prefrontal cortical response by switching stimuli in autism spectrum disorders

Abstract

Working memory (WM) performance is considered to change according to the nature of the task by adequate and prompt activation of corresponding functional connectivity in the brain. In the present study, we examined continuous prefrontal hemodynamic changes depending on reciprocal disposition of WM and non-WM tasks using two-channel near-infrared spectroscopy. To investigate possible functional connectivity deficits in autism spectrum disorder (ASD) during these tasks, relative concentration changes in oxygenated hemoglobin (Hb), deoxygenated Hb, and total Hb were compared between high-functioning ASD subjects (n = 11) and controls (n = 22). Instant evoked cerebral blood oxygenation changes were observed in response to the task switch in controls but not in ASD subjects, although the task performance rate was almost equivalent. Delayed or altered response of functional connectivity to incoming stimuli is considered a characteristic feature of ASD.

Exploring brain functions in autism spectrum disorder: A systematic review on functional near-infrared spectroscopy (fNIRS) studies

“…Nine fNIRS studies have investigated working memory and inhibition in ASD. These studies observed an atypical activation in the PFC during letter-fluency tasks (Iwanami et al, 2011(Iwanami et al, , 2010Kawakubo et al, 2009), working memory tasks (Narita, 2015;Yanagisawa et al, 2016) and task switching/inhibition (Funabiki et al, 2012a(Funabiki et al, , 2012bNarita et al, 2012).…”

“…Studies of working memory conversion showed that a switching tendency of hemodynamic activation in the PFC was obvious in TDC but was not shown instantly in ASD (Narita et al, 2012;Yanagisawa et al, 2016). Regarding inhibitory control ability in ASD, studies showed reduced activation in the right PFC during a Go/No-go task (Funabiki et al, 2012;Xiao et al, 2012) compared to a TDC group and in the left ventrolateral PFC during a stop signal task compared to an ADHD group (Ishii-Takahashi et al, 2014).…”

“…fNIRS studies that investigated working memory and inhibition indicated an atypical activation in the PFC in individuals with ASD. These distinct patterns of neural activation during executive tasks can inform us about the engagement of cognitive control of behaviour in ASD (Corbett et al, 2010;Narita et al, 2012). For instance, Yanagisawa et al, (2016) found lower and delayed weighted separability (WS) values -indexes of quantitative evaluation that evaluate brain activity based on the feature phase of oxy-hemoglobin and its differential value -in the left dorsolateral PFC in ASD compared to TDC participants.…”