Visual attention to motion stimuli and its neural correlates in cannabis users

Attention to motion stimuli and correct motion perception are vital for road safety. Although cannabis use has been associated with increased road crash risks, there is limited research on attentional processing of moving stimuli in cannabis users. This study investigated the neural correlates of the three-stimulus oddball task in cannabis users (n=18) and non-users (n=23) in response to moving stimuli. Stimulus contrast was under 16% against a low luminance background (M luminance<16cd/m(2)). The two groups did not differ in accuracy or in N2 peak amplitude; however, N2 latency was longer for target and standard stimuli in the cannabis group than in the control group. The cannabis group also showed a significantly reduced P3b amplitude in response to target stimuli. The AUDIT score was added as a random factor to the anova to rule out the effects of uneven alcohol consumption in the two groups. A significant group effect was found for N2 latency in response to target and standard stimuli and a significant interaction between the group, and the AUDIT score was found for the P3b peak amplitude for the distractor and standard stimuli, but not for the target stimuli. The results of this study suggest that cannabis use relates to reduced neural activity underlying attention to motion stimuli. Implications for regular early-onset cannabis use road safety are discussed.