The Role of the BDNF in Spatial and Temporal Working Memory Maintenance: an Eye-Tracking Behavioral Study

The BDNF Val66Met polymorphism is believed to alter neuroplasticity in frontal and hippocampal regions, thus affecting both long-term and working memory (WM). This study examines differences in spatial and temporal WM in two Val66Met genetic groups using behavioral (accuracy and response times) and eye tracking indexes. The participants’ task was to memorize either the spatial location of a stimulus or its position in a sequence. Results revealed that reaction times for both groups were significantly slower in temporal trials than in spatial trials supporting previously stated dichotomy of spatial and temporal processing. Moreover, the primacy-recency effect was found only in the temporal condition, which indicates that stimuli in temporal trials were maintained as a sequence, whereas spatial stimuli were memorized independently. Number of saccades was significantly higher in the spatial condition during stimuli presentation, whereas during the delay it increased considerably in the temporal condition, suggesting that participants tended to use different attentional strategies to memorize temporal and spatial information. Finally, analysis of the interaction of group and block effects on the fixation duration revealed that Met carriers recruit more focused attention, while Val carriers demonstrate more explorative behavior thereby performing more saccades than the Met group. The present study provides the first investigation of differences in temporal and spatial WM between the Val66Met genetic groups using eye tracking techniques and pave the way for future investigation on this highly debated topic.