Does the Integration of Haptic and Visual Cues Reduce the Effect of a Biased Visual Reference Frame on the Subjective Head Orientation?

The selection of appropriate frames of reference (FOR) is a key factor in the elaboration of spatial perception and the production of robust interaction with our environment. The extent to which we perceive the head axis orientation (subjective head orientation, SHO) with both accuracy and precision likely contributes to the efficiency of these spatial interactions. A first goal of this study was to investigate the relative contribution of both the visual and egocentric FOR (centre-of-mass) in the SHO processing. A second goal was to investigate humans' ability to process SHO in various sensory response modalities (visual, haptic and visuo-haptic), and the way they modify the reliance to either the visual or egocentric FORs. A third goal was to question whether subjects combined visual and haptic cues optimally to increase SHO certainty and to decrease the FORs disruption effect.Thirteen subjects were asked to indicate their SHO while the visual and/or egocentric FORs were deviated. Four results emerged from our study. First, visual rod settings to SHO were altered by the tilted visual frame but not by the egocentric FOR alteration, whereas no haptic settings alteration was observed whether due to the egocentric FOR alteration or the tilted visual frame. These results are modulated by individual analysis. Second, visual and egocentric FOR dependency appear to be negatively correlated. Third, the response modality enrichment appears to improve SHO. Fourth, several combination rules of the visuo-haptic cues such as the Maximum Likelihood Estimation (MLE), Winner-Take-All (WTA) or Unweighted Mean (UWM) rule seem to account for SHO improvements. However, the UWM rule seems to best account for the improvement of visuo-haptic estimates, especially in situations with high FOR incongruence. Finally, the data also indicated that FOR reliance resulted from the application of UWM rule. This was observed more particularly, in the visual dependent subject. Conclusions: Taken together, these findings emphasize the importance of identifying individual spatial FOR preferences to assess the efficiency of our interaction with the environment whilst performing spatial tasks

The haptic perception of spatial orientations

This review examines the isotropy of the perception of spatial orientations in the haptic system. It shows the existence of an oblique effect (i.e., a better perception of vertical and horizontal orientations than oblique orientations) in a spatial plane intrinsic to the haptic system, determined by the gravitational cues and the cognitive resources and defined in a subjective frame of reference. Similar results are observed from infancy to adulthood. In 3D space, the haptic processing of orientations is also anisotropic and seems to use both egocentric and allocentric cues. Taken together, these results revealed that the haptic oblique effect occurs when the sensory motor traces associated with exploratory movement are represented more abstractly at a cognitive level

The neural substrates and timing of top–down processes during coarse-to-fine categorization of visual scenes: a combined fMRI and ERP study

■ Spatial frequencies in an image influence visual analysis across a distributed, hierarchically organized brain network. Low spatial frequency (LSF) information may rapidly reach high-order areas to allow an initial coarse parsing of the visual scene, which could then be “retroinjected ” through feedback into lower level visual areas to guide finer analysis on the basis of high spatial frequency (HSF). To test this “coarse-to-fine ” processing scheme and to identify its neural substrates in the human brain, we presented sequences of two spatial-frequency-filtered scenes in rapid succession (LSF followed by HSF or vice versa) during fMRI and ERPs in the same participants. We show that for low-to-high sequences (but not for high-to-low sequences), LSF produces a first increase of activity in prefrontal and temporo-parietal areas, followed by enhanced responses to HSF in primary visual cortex. This pattern i

Attention processes and field dependence-independence: a study with portuguese children and adolescents

Este artigo relaciona o estilo cognitivo "dependência-independência de campo" com o desempenho em tarefas envolvendo vários processos e recursos de atenção. Com uma amostra de 98 crianças e 95 adolescentes portugueses, foram aplicadas quatro tarefas de atenção: capacidade de armazenamento (Dígitos em ordem direta); memória de trabalho verbal (Dígitos em ordem inversa); capacidade para dirigir, mudar e manter a atenção (Código); e capacidade de atenção sustentada (Teste de Atenção e Rastreio Visual, VSAT). Recorreu-se, ainda, à aplicação de uma prova de fator g, tendo em vista o controle da inteligência. Os resultados revelam diferenças entre dependentes e independentes de campo, especialmente relevantes no grupo de crianças na prova de VSAT. Esses resultados abrem novas linhas de investigação para explicar a pior execução acadêmica dos indivíduos dependentes de campo.The present study relates the "field dependence-independence" cognitive style to the performance on tasks involving several attention processes and resources. With a 98 Portuguese children and 95 Portuguese adolescents sample, four attention tasks were applied: storage capacity (Digits Forward Test); verbal working memory (Digits Backward Test); capacity to focus, shift, and maintain attention (Digit Symbol Test); and capacity for sustained attention (Visual Search and Attention Test, VSAT). It was also applied a factor g test for intelligence control. Results showed differences on attention processes between field-dependence and field-independence cognitive styles. These differences are more evident in the children subgroup on VSAT. These results open new research topics to explain lowest academic performance of field-dependent children.(undefined