Neuroergonomics Lab

The Center of Excellence in Neuroergonomics, Technology, and Cognition (CENTEC) was officially launched at George Mason University on July 15, 2010, with Raja Parasuraman as Director. CENTEC is funded by the Air Force Office of Scientific Research (AFOSR) and by the Air Force Research Laboratory (AFRL) for a period of five years (July 15, 2010 - July 14, 2015).

The neuroscience methods used in the Neuroergonomics Lab include:

• Functional magnetic resonance imaging (fMRI)
• Structural MRI (Diffusion Tensor Imaging)
• Event-related brain potentials (ERPs)
• Functional Near Infrared Spectroscopy (fNIRS)
• Molecular genetic assays of single nucleotide polymorphisms
• Transcranial Direct Current Stimulation (TDCS)
• MRI-guided Transcranial Magnetic Stimulation (TMS)

Molecular Genetics of Individual Differences in Human Performance

A molecular genetic approach to individual differences in human performance capitalizes on the breakthroughs provided by the success of the Human Genome Project in decoding the entire human genome and on neuroimaging studies that have linked cognitive functions to the activation of specific cortical networks (Parasuraman, 2009). In our work we have focused on variants of neurotransmitter genes and examined their associations with attention, working memory, and decision making. We have used both basic cognitive tasks as well as more complex simulations of work tasks.

Two recent studies have focused on genes that influence dopamine pathways in the brain. In the first study, we examined the association between the dopamine beta hydroxylase (DBH) gene and decision making in a semi-automated command and control task (Parasuraman et al., 2012). Automation can assist human decision makers in complex tasks but can impair performance when they provide incorrect advice that humans erroneously follow, a phenomenon known as ‘‘automation bias.’’ Individual differences in this bias may reflect inter-individual variation in the capacity of working memory and the efficiency of executive function, both of which are highly heritable and under dopaminergic and noradrenergic control in prefrontal cortex. The DBH gene is thought to regulate the differential availability of dopamine and norepinephrine in prefrontal cortex. We examined decision-making performance under imperfect computer aiding in 100 participants performing a simulated command and control task. Based on two single nucleotide polymorphism (SNPs) of the DBH gene, 21041 C/T (rs1611115) and 444 G/A (rs1108580), participants were divided into groups of low and high DBH enzyme activity, where low enzyme activity is associated with greater dopamine relative to norepinephrine levels in cortex. Compared to those in the high DBH enzyme activity group, individuals in the low DBH enzyme activity group were more accurate and speedier in their decisions when incorrect advice was given and verified automation recommendations more frequently. These results indicate that a gene that regulates relative prefrontal cortex dopamine availability, DBH, can identify those individuals who are less susceptible to bias in using computerized decision-aiding systems.

In a second study, we examined the role of another dopamine gene, COMT, in individual differences in multitasking performance in a supervisory control task. Executive function, a key factor in multitasking, is known to be highly heritable and dependent on dopaminergic activation in prefrontal cortex. We examined whether the Met allele of the dopaminergic gene COMT is associated with training-related effects in supervisory control of multiple unmanned vehicles (UVs). Healthy adults were genotyped for the COMT Val158Met variant and divided into Met/Met, Val/Met, and Val/Val groups. Participants supervised six UVs in an air defense mission under conditions of low and high task load (numbers of enemy aircraft). Training effects were examined over four blocks of trials in each task load condition. Compared to the Val/Met and Val/Val groups, Met/Met individuals exhibited a greater increase in enemy targets destroyed and greater reduction in enemy red zone incursions over training blocks. The results have implications for the development of individualized training for developing executive function skill in supervisory control.

Effects of Non-Invasive Brain Stimulation on Cognition and Skill Acquisition

Developing expertise in occupations such as medical diagnosis, intelligence analysis, or military aviation typically requires extensive practice and training. Accordingly, there is a need for examining ways in which skill acquisition can be accelerated in complex cognitive tasks. Non-invasive brain modulation techniques such as Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) have been shown to enhance performance in different perceptual, cognitive, and motor tasks (Coffman et al., 2014). To address the potential of brain modulation as a training method, however, studies with more complex tasks and multiple sessions are needed to examine whether tDCS can accelerate learning. 

In one recent study in the Neuroergonomics lab, Falcone et al. (2012) had participants perform a complex military threat detection task requiring the detection of threats such as a concealed roadside bomb or a hidden sniper. The threats were very difficult to identify and participants initially performed at chance levels (d’ = 0). Two groups were compared, one receiving active 2mA tDCS and a control group receiving “sham” 0.1 mA stimulation. To assess retention, participants were tested without tDCS immediately after the first session and again in a second session a day later. Anodal stimulation of right inferior frontal cortex with 2 mA increased perceptual sensitivity (d’) on the task, compared to the 0.1 mA control, with no effect on response criterion ß. Participants in the 2 mA group had a much steeper learning curve compared to the control group. On completion of training, these participants had more than double the perceptual sensitivity of the control group. Furthermore, the performance enhancement was maintained for 24 hours. These findings indicate that tDCS augments both skill acquisition and retention in a complex detection task and that the benefits are rooted in an improvement in sensitivity (d’), rather than changes in response bias (ß).

Effects of Cognitive Training on Brain Structure and Function

Recent studies have shown that cognitive and videogame training can enhance performance on many tasks, although whether such performance improvements transfer to other tasks remains debatable. The ultimate goal of cognitive enhancement is transfer to cognitive functioning in everyday settings or at work.  In our studies we used cognitive training to test the hypothesis that far transfer is associated with altered attentional control demands mediated by the modulatory effects of top-down signals in parietal cortex (Strenziok et al., 2013). Healthy adults were assigned to six weeks of training on Brain Fitness (BF: auditory perception), Space Fortress  (SF: visuomotor/working memory), or Rise of Nations (RON: strategic reasoning).  Before and after training, cognitive performance, diffusion tensor imaging-derived white matter integrity, and functional connectivity of the superior parietal cortex (SPC) were assessed.  We found the strongest effects from BF training, which transferred to everyday problem solving and reasoning and selectively changed integrity of occipito-temporal white matter associated with improvement on untrained everyday problem solving.  These results show that cognitive gain from auditory perception training depends on heightened white matter integrity in the ventral attention network.  In BF and SF (which also transferred positively), a decrease in functional connectivity between SPC and inferior temporal lobe (ITL) was observed compared to RON, which did not transfer to untrained cognitive function. Altered brain connectivity—observed in the two training tasks that showed far transfer effects—may be a marker for training success.