COVERT ORIENTING IN THE SPLIT BRAIN REVEALS HEMISPHERIC SPECIALIZATION FOR OBJECT-BASED ATTENTION

Abstract— Theones in cognitive science have debated whether visual selective attention is a space-based or object-based process To investigate this issue, we applied a new experimental paradigm that permits the simultaneous measurement of both space-based and object-based attention to a split-brain patient with disconnected cerebral hemispheres The data demonstrate both space-based and object-based components to the allocation of attention, and reveal that the two processes have different neural substrates These findings are related to previous research on split-brain and unilateral parietal patients     

Expanding MEL response box to accommodate up to 16 external buttons

Micro Experimental Laboratory (MEL) is a widely used software package developed for the automation of psychological experiments. This report presents a simple way to implement and use an expanded MEL response box that accommodates up to 16 external switches. Hardware and software considerations are reviewed, and relevant MEL code is provided. This includes a simple algorithm that permits the reading of multiple responses within a single trial.     

Improvement of mental imagery after prism exposure in neglect: a case study

Previous work has shown that various symptoms of unilateral neglect, including the pathological shift of the subjective midline to the right, may be improved by a short adaptation period to a prismatic shift of the visual field to the right. We report here the improvement of imagined neglect after prism exposure in a patient with a left unilateral neglect. Despite a strong neglect observed for mental images as well as for conventional tests, the mental evocation of left-sided information from an internal image of the map of France map was fully recovered following prism adaptation to the right. This improvement could not be explained by the alteration of visuomotor responses induced by the prism adaptation. Prism adaptation may therefore act not only on sensory-motor levels but also on a higher cognitive level of mental space representation and/or exploration.     

Minds, persons, and space: an fMRI investigation into the relational complexity of higher-order intentionality

Mental state reasoning or theory-of-mind has been the subject of a rich body of imaging research. Although such investigations routinely tap a common set of regions, the precise function of each area remains a contentious matter. With the help of functional magnetic resonance imaging (fMRI), we sought to determine which areas are involved when processing mental state or intentional metarepresentations by focusing on the relational aspect of such representations. Using non-intentional relational representations such as spatial relations between persons and between objects as a contrast, the results ascertained the involvement of the precuneus, the temporal poles, and the medial prefrontal cortex in the processing of intentional representations. In contrast, the anterior superior temporal sulcus and the left temporo-parietal junction were implicated when processing representations that refer to the presence of persons in relational contexts in general. The right temporo-parietal junction, however, was specifically activated for persons entering spatial relations. The level of representational complexity, a previously unexplored factor, was also found to modulate the neural response in some brain regions, such as the medial prefrontal cortex and the right temporo-parietal junction. These findings highlight the need to take into account the critical roles played by an extensive network of neural regions during mental state reasoning.     

Clustering and switching in unconstrained,phonemic and semantic verbal fluency: the role of age and school type

We investigated the role of age and school type on clustering and switching in verbal fluency tasks (VFTs) with Brazilian children. The children were administered unconstrained, phonemic and semantic VFTs with a duration of 150 or 120 s, respectively. Both age and school type influenced all variables and in terms of performance over time. Older children and private school students outperformed the remainder of the sample, with the first 30 s of each VFT usually being the most productive. Although the size of the clusters produced did not differ between groups, the types of clusters did show some variations, with semantic clusters being the most frequent. Our results revealed strong correlations between switching ability and word production in all three VFTs. In conclusion, the executive functions known as planning and cognitive flexibility play a crucial role in word production by organising and facilitating the recall of lexical information from memory.     

Neuropsychological status of French children with developmental dyslexia and/or developmental coordination disorder: Are both necessarily worse than one?

Developmental dyslexia (DD) and developmental coordination disorder (DCD) co-occur frequently, raising the underlying question of shared etiological bases. We investigated the cognitive profile of children with DD, children with DCD, and children with the dual association (DD + DCD) to determine the inherent characteristics of each disorder and explore the possible additional impact of co-morbidity on intellectual, attentional, and psychosocial functioning. The participants were 8- to 12-year-olds (20 DD, 22 DCD, and 23 DD + DCD). Cognitive abilities were assessed by the Wechsler Intelligence Scale for Children – Fourth Edition (WISC-IV) and the Continuous Performance Test – Second Edition (CPT-II) and behavioral impairments were evaluated by the Child Behavior Checklist (CBCL). No differences were found between the three groups on attention testing (CPT-II) or psychosocial characteristics (CBCL), but a higher percentage of DD + DCD children had pathological scores on psychosocial scales. Significant between-group differences were observed on Processing Speed Index scores and the block design and symbol search subtests, where DD children fared better than DCD children. No significant differences were evident between the co-morbid vs. the pure groups. Our results clearly show significant differences between children with DD only and children with DCD only. In particular, visuo-spatial disabilities and heterogeneity of intellectual profile seem to be good markers of DCD. However, it should be noted that despite these distinct and separate characteristics, a common cognitive profile (weaknesses and strengths) is likely shared by both neurodevelopmental disorders. Surprisingly, concerning co-morbidity, DD + DCD association is not associated with a decrease in intellectual or attentional capacities.     

The construction of spatial situation models during reading

Psycholinguistic research faces a major challenge in describing the mental representations readers construct from a text. It is now widely accepted that readers end with a representation of the situation described in the text. However, it is unclear whether this representation allows the activation of elements in accordance with their situation proximity. To answer this question, two experiments were conducted. Participants read texts, sentence by sentence, which gave them instructions about how to arrange items in a layout; they then performed a recognition task. By manipulating the spatial proximity between prime and probe items, this task allowed the measurement of a spatial priming effect. In the first experiment, a larger priming effect was observed for closer items on the spatial layout. The second experiment replicated these findings and showed that the priming effects are better explained by categorical distance than by Euclidean distance.