Event-related cerebral hemodynamics reveal target-specific resource allocation for both ‘‘go’’ and ‘‘no-go’’ response-based vigilance tasks Tyler H. Shaw a,⇑ , Matthew E. Funke e , Michael Dillard c , Gregory J. Funke b , Joel S. Warm b,d , Raja Parasuraman a a Center of Excellence in Neuroergonomics, Technology, and Cognition (CENTEC), George Mason University, Department of Psychology, 4400 University Drive, Fairfax, VA, United States b Air Force Research Laboratory WPAFB, 711th Human Performance Wing, Wright Patterson Air Force Base, OH, United States c National Research Council, Washington, DC, United States d University of Dayton Research Institute, Dayton, OH, United States e Naval Medical Research Unit – Dayton, Wright Patterson Air Force Base, OH, United States article info Article history: Accepted 5 May 2013 Keywords: Vigilance Sustained attention Event-related Cerebral blood flow velocity Attentional resource theory abstract Transcranial Doppler sonography was used to measure cerebral blood flow velocity (CBFV) in the right and left cerebral hemispheres during the performance of a 50-min visual vigilance session. Observers monitored a simulated flight of unmanned aerial vehicles for cases in which one of the vehicles was flying in an inappropriate direction relative to its cohorts. Two types of vigilance tasks were employed: a tra- ditional task in which observers made button press (‘‘go’’) responses to critical signals, and a modification of the traditional task called the Sustained Attention to Response Task (SART) in which ‘‘go’’ responses acknowledged nonsignal events and response withholding (‘‘no-go’’) signified signal detection. Signal detections and global CBFV scores declined over time. In addition, fine-grained event-related analyses revealed that the detection of signals was accompanied by an elevation of CBFV that was not present with missed signals. As was the case with the global scores, the magnitude of the transient CBFV increments associated with signal detection also declined over time, and these findings were independent of task type. The results support the view of CBFV as an index of the cognitive evaluation of stimulus significance, and a resource model of vigilance in which the need for continuous attention produces a depletion of information-processing assets that are not replenished as the task progresses. Further, temporal declines in the magnitude of event-related CBFV in response to critical signals only is evidence that the decrement function in vigilance is due to attentional processing and not specific task elements such as the required response format. Ó 2013 Published by Elsevier Inc. 1. Introduction The capacity to sustain attention at an efficient level deterio- rates over time in detection and discrimination tasks (Davies & Parasuraman, 1982; Warm, 1984). One explanation for this decline – the vigilance decrement – is that the need for continuous atten- tion results in a depletion of information-processing resources (Norman & Bobrow, 1975) that are not replenished as task perfor- mance progresses (Johnson & Proctor, 2004; Langner, Eickhoff, & Steinborn, 2011; MacLean et al., 2009; Parasuraman, 1979; Para- suraman, Warm, & Dember, 1987; Proctor & Vu, 2010; Smit, Eling, Hopman, & Coenen, 2005; Warm & Dember, 1998; Warm, Parasur- aman, & Matthews, 2008; Wiggins, 2011). Often, the resource interpretation is coupled with a self-regulation approach which suggests that task performance is a function of not only the re- sources available for target detection, but also the effort that is allocated to the task (Humphries & Revelle, 1984; Kahneman, 1973; Matthews & Desmond, 2002). Evidence for the attentional resource model of vigilance has been mainly derived from findings pointing to the adverse impact on vigilance performance of work- ing memory load (Caggiano & Parasuraman, 2004; Helton & Rus- sell, 2012; Parasuraman, 1979), additional processing demands (Smit et al., 2005), and dual-task performance requirements (Para- suraman, 1985), as well as by subjective ratings revealing high mental effort and stress in such tasks (Warm, Dember, & Hancock, 1996; Warm, Matthews, & Finomore, 2008). Resource theories have been criticized for their circularity, gi- ven that resources are typically both inferred from and used to ex- plain changes in behavioral performance, as in dual-task studies (Navon, 1984). A performance-independent resource measure can provide one way of bypassing this criticism. Accordingly, several researchers have turned to neurophysiological measures in seeking 0278-2626/$ - see front matter Ó 2013 Published by Elsevier Inc. http://dx.doi.org/10.1016/j.bandc.2013.05.003 ⇑ Corresponding author. Address: 4400 University Drive, MS3F5, Fairfax, VA 22030-4444, United States. Fax: +1 703 993 1359. E-mail address: tshaw4@gmu.edu (T.H. Shaw). Brain and Cognition 82 (2013) 265–273 Contents lists available at SciVerse ScienceDirect Brain and Cognition journal homepage: www.elsevier.com/locate/b&c