Effects of Sensory Modality on Vigilance Performance and Cerebral Hemovelocity

Abstract

Using Transcranial Doppler sonography, cerebral blood flow velocity (hemovelocity, CBFV) was recorded from the middle cerebral arteries during the performance of 40-min auditory and visual vigilance tasks. Reductions in stimulus duration were the critical signals for detection in both tasks, which were equated for stimulus salience and discrimination difficulty. Signal detection responses (correct detections and false alarms) and CBFV declined linearly over time in both modalities. In addition, the overall level of CBFV and the temporal decline in this measure were greater in the right than the left cerebral hemisphere. The results support the view that a right hemispheric system is involved in the functional control of vigilance and that this system operates in a similar manner in the auditory and visual channels.Vigilance or sustained attention concerns the ability of observers to detect infrequent and unpredictable signals over prolonged periods of time. This aspect of human performance is important to human factors/ergonomic specialists because of the critical role that vigilance occupies in automated human-machine systems such as air-traffic control, cockpit monitoring, airport baggage inspection, nuclear power plant regulation, and industrial-process/quality control (Davies & Parasuraman, 1982: Hancock & Hart, 2002Wickens & Hollands, 2000). Hence, knowledge of the factors that control vigilance performance and their underlying neurophysiological mechanisms is critical for system reliability and productivity and for public safety (Nickerson, 1992;Warm & Dember, 1998).Investigations using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) procedures have been successful in demonstrating that changes in cerebral blood flow and glucose metabolism are involved in the performance of sustained attention or vigilance tasks (Parasuraman, Warm, & See, 1998). These studies identified multiple brain regions that are active during the performance of such tasks, including the frontal lobes, the cingulate gyrus, the intralaminar region of the thalamus, and the midbrain reticular formation. However, as Parasuraman et al. (1998) emphasized, an important limitation of these studies is their failure to correlate brain activity with performance efficiency, perhaps due to the high costs and restrictive environments associated with PET and fMRI. Thus, the functional role of the brain systems identified in the imaging studies remains largely unknown. Gazzaniga, Ivry, and Mangun (2002) have also underscored the importance of linking neuroimaging results to performance efficiency for enhanced understanding of research in cognitive neuroscience.The high costs and the restrictions of PET and fMRI may be circumvented in studying brain systems in vigilance by employing transcranial Doppler sonography (TCD) -a relatively inexpensive and noninvasive procedure that allows for continuous monitoring of cerebral blood flow velocity (CBFV) in the main-stem intracranial arteries. When an area of the brain becom...

Cerebral Hemodynamics and Vigilance Performance

“…In addition, several studies have reported that correlations between the two modalities are either low (r < .30) or nonsignificant (Warm & Jerison, 1984). Accordingly, in a recent study (Shaw et al, 2006) we sought to determine the degree to which the vigilance decrement is accompanied by a decline in cerebral blood flow velocity in comparable visual and auditory vigilance tasks.…”

Crossmodal matching

“…This was the case regardless of the initial reference cue intensity. One proposed explanation for this finding would be the longer duration of tactile (haptic) sensory memory (~ 5-10 seconds), compared to visual (iconic, ~300-500 milliseconds), and auditory (echoic, ~3-4 seconds) memory (Colheart, 1980;Gilson & Baddeley, 1969;Sperling, 1960). As a result, participants may have replayed the tactile reference stimuli less often than the visual and auditory ones, and instead relied more on memory than actual perception and relative judgments.…”

“…Brill et al, 2007Brill et al, 2008Brill et al, 2009Garcia et al, 2009Scerra & Brill, 2012Shaw, 2006Terrence et al, 2005 Tables 1 and 2 highlight the lack of an agreed-upon crossmodal matching technique and raise questions about the validity and reliability of the various approaches. For example, given the potential for large intra-individual variability of crossmodal matches (Teghtsoonian & Teghtsoonian, 1983), it may not be sufficient to obtain a single match value from a participant for any given modality pair.…”