Shifts of spatial attention cued by irrelevant numbers: Electrophysiological evidence from a target discrimination task

Fischer et al. demonstrated that a centrally presented number can shift attention to the left/right when its magnitude is small/large. Two electrophysiological studies described these attentional effects as event-related potentials (ERPs) at centro-parietal sites. Since both studies used target detection tasks, it remains currently unknown whether similar results would be obtained with a discrimination task. We used ERPs to test whether digit cues also induce attention shifts when participants perform a feature-discrimination task on targets. ERPs were recorded whereas subjects discriminated the colour of lateral targets that were preceded by a central non-predictive digit. Analysis of cue-locked controlateral vs. ipsilateral ERP activity showed the emergence of early preparatory attention-directing components in parietal and frontal regions. Moreover, target-locked P1 components at occipito-parietal sites were significantly modulated by digit magnitude-target side congruency. These results demonstrate that irrelevant digit cues also bias sensory processing when embedded in a feature-discrimination task.     

Modulation of brain oscillations during fundamental visuo-spatial processing: A comparison between female collegiate badminton players and sedentary controls

ObjectivesThe present study aimed to investigate the difference in fundamental cognitive processing and neural oscillations between badminton players and sedentary controls.DesignA cross-sectional design was adopted to address this issue.MethodsWe compared time-frequency electroencephalographic (EEG) activity from collegiate female badminton players (n = 12, aged 20.58 ± 2.75 years) and age-and gender-matched sedentary non-athletic controls (n = 13, aged 19.08 ± 2.10 years) when they performed a task that involves visuo-spatial attention and working memory.ResultsWe observed that players responded faster than controls on the task without suffering any increase in error responses. Correspondingly, the players, relative to controls, exhibited higher task-related modulations in beta power in the attention condition as well as in theta and beta power in the working memory condition. Notably, the behavior-EEG correlations revealed that better attention performance is associated with lower beta power, while greater working memory is related to higher theta power.ConclusionsOur results shed light on the mechanisms of athletic superiority in fundamental cognitive functioning: the higher theta synchronization points to a greater engagement of attention, whereas the higher beta desynchronization supports the contribution of processing speed (or motor-related processing) to better performance in athletes. This study extends current understanding by suggesting that enhanced neurocognitive function seen in athletes may transfer to fundamental tasks, giving insight into the generalizability of sport experience to neurocognitive functioning.     

Perceptual biases in processing facial identity and emotion

Normal observers demonstrate a bias to process the left sides of faces during perceptual judgments about identity or emotion. This effect suggests a right cerebral hemisphere processing bias. To test the role of the right hemisphere and the involvement of configural processing underlying this effect, young and older control observers and patients with right hemisphere damage completed two chimeric faces tasks (emotion judgment and face identity matching) with both upright and inverted faces. For control observers, the emotion judgment task elicited a strong left-sided perceptual bias that was reduced in young controls and eliminated in older controls by face inversion. Right hemisphere damage reversed the bias, suggesting the right hemisphere was dominant for this task, but that the left hemisphere could be flexibly recruited when right hemisphere mechanisms are not available or dominant. In contrast, face identity judgments were associated most clearly with a vertical bias favouring the uppermost stimuli that was eliminated by face inversion and right hemisphere lesions. The results suggest these tasks involve different neurocognitive mechanisms. The role of the right hemisphere and ventral cortical stream involvement with configural processes in face processing is discussed.     

Effects of primary task predictability and secondary task modality on lane maintenance

The objective of this work was to investigate the effects of auditory and visuo-spatial secondary tasks on variability in lane position in predictable and unpredictable driving conditions. Sixty-six participants drove a simulated vehicle. Predictability was manipulated by adding wind gusts, and the secondary task load by either an auditory task (Experiment 1) or a visuo-spatial task (Experiment 2). Results demonstrated that in the predictable driving condition, lane position variability decreased when auditory secondary task load was given, but it was not affected by visuo-spatial secondary task load. In the unpredictable driving condition; however, while the auditory secondary task load did not affect lane position variability, visuo-spatial secondary task load increased it. The data suggests that the effects of cognitive load on lane maintenance may depend on the type of the secondary task beside predictability of primary task.     

The role of working memory components and visuospatial abilities in route learning within a virtual environment

An experiment was run to complete our understanding of the involvement of working memory (WM) components in the construction of a spatial model from visual input, considering some of the visuospatial abilities known to modulate performance. In addition, to allow for consideration of the flexibility of the spatial representation, routes in a virtual environment were presented with a route perspective, and tests were presented with route and survey perspectives. The results indicate that the verbal and spatial WM are only involved in the memorisation of certain types of information, and that their involvement depends on the change of perspective necessitated by the task. Thus, even when the learning material and the tests used to assess performance are only visual, a verbal recoding of some information is necessary. Moreover, individual differences modulate the involvement of WM; an individual with higher visuospatial capacities uses more spatial WM than an individual with lower spatial capacities.     

Abilities and strategies of blind and sighted subjects in visuo-spatial imagery

An active visuo-spatial memory task was used in order to determine the characteristics of mental imagery in subjects with and without visual experience. Subjects were instructed to generate a mental representation of verbally presented 2D patterns that were placed in a grid and to indicate how many pattern elements were in corresponding positions in the two halves of the grid according to a specific grid axis (vertical or horizontal). Unexpectedly, results showed a similar performance in early blind, late blind and sighted subjects. However, subjects' debriefing showed that the three groups used different strategies. The sighted and the late blind subjects took advantage of a visuo-spatial strategy. They generated a mental image of the matrix and they simplified this image to maintain only the relevant information in memory. In contrast, the early blind subjects encoded each pattern element by its location in a (X,Y) coordinate system without visual representation. This indicates that both early and late blind subjects are able to perform an active visuo-spatial imagery task as well as sighted subjects although they use different strategies.     

Visuo-spatial processing in congenitally blind people: is there a gender-related preference?

Several studies have shown that blind and sighted individuals are equally able to generate and process visuo-spatial images. However, differences emerge when active manipulation of information is required. A similar distinction has been reported in studies investigating gender-related preferences in visuo-spatial tasks indicating a male advantage in active tasks only. The present study investigates gender-related visuo-spatial preference in congenitally blind people by using active and passive working memory tasks. The results show significant effects due to gender and blindness; nevertheless, gender effects are more pronounced in the blind group and maximised in the active task. These data are interpreted within a theoretical framework that accounts for the different factors modulating the development of visuo-spatial abilities.     

The association of physical activity to neural adaptability during visuo-spatial processing in healthy elderly adults: A multiscale entropy analysis

Physical activity has been shown to benefit brain and cognition in late adulthood. However, this effect is still unexplored in terms of brain signal complexity, which reflects the level of neural adaptability and efficiency during cognitive processing that cannot be acquired via averaged neuroelectric signals. Here we employed multiscale entropy analysis (MSE) of electroencephalography (EEG), a new approach that conveys important information related to the temporal dynamics of brain signal complexity across multiple time scales, to reveal the association of physical activity with neural adaptability and efficiency in elderly adults. A between-subjects design that included 24 participants (aged 66.63 ± 1.31 years; female = 12) with high physical activity and 24 age- and gender-matched low physical activity participants (aged 67.29 ± 1.20 years) was conducted to examine differences related to physical activity in performance and MSE of EEG signals during a visuo-spatial cognition task. We observed that physically active elderly adults had better accuracy on both visuo-spatial attention and working memory conditions relative to their sedentary counterparts. Additionally, these physically active elderly adults displayed greater MSE values at larger time scales at the Fz electrode in both attention and memory conditions. The results suggest that physical activity may be beneficial for adaptability of brain systems in tasks involving visuo-spatial information. MSE thus might be a promising approach to test the effects of the benefits of exercise on cognition.     

Gaze direction affects visuo-spatial short-term memory

Hemispheric asymmetries were investigated by changing the horizontal position of stimuli that had to be remembered in a visuo-spatial short-term memory task. Observers looked at matrices containing a variable number of filled squares on the left or right side of the screen center. At stimulus offset, participants reproduced the positions of the filled squares in an empty response matrix. Stimulus and response matrices were presented in the same quadrant. We observed that memory performance was better when the matrices were shown on the left side of the screen. We distinguished between recall strategies that relied on visual or non-visual (verbal) cues and found that the effect of gaze position occurred more reliably in participants using visual recall strategies. Overall, the results show that there is a solid enhancement of visuo-spatial short-term memory when observers look to the left. In contrast, vertical position had no influence on performance. We suggest that unilateral gaze to the left activates centers in the right hemisphere contributing to visuo-spatial memory.