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Interhemispheric relations in attention evidenced by the lateralized attention network test (LANT)

100%

Asanowicz D., Wolski P.

Acta Neurobiologiae Experimentalis

2009

tom 69

nr 3

Attention has been convincingly demonstrated to involve anatomically and functionally distinct networks that subserve confl ict resolution, spatial orienting and alerting. On the one hand, partially independent symmetric attention networks can be postulated within the two brain hemispheres (Zaidel 1995). On the other hand, large body of data, mostly clinical, suggests asymmetric control of attention (Heilman and Van Den Abell 1980). Not much is known at present on the nature of interhemispheric relations in attention. To address this issue, the Lateralized Attention Network Test (LANT) was designed. The introductory study of Greene et al. (2007) has suggested some hemispheric independence and similarity but no clear asymmetry. To gain better insight we conducted three consequent experiments recruiting 170 participants. We supplemented the original LANT procedure with modifi cations that allowed comparisons between goal-directed and stimulusdriven control of attention. The results show that interhemispheric relations within the attentional networks do depend on whether the “endogenous” or the “exogenous” control dominates in the task.

Effects of prism adaptation on voluntary and reflexive orienting of attention

80%

Asanowicz D., Michalczyk M., Marzecova A., Wolski P.

Acta Neurobiologiae Experimentalis

2009

tom 69

nr 3

Hemispatial neglect is a failure of attending to the left half-space resulting from lesions of the right hemisphere. It is believed to be an attentional dysfunction, involving defi cits in disengagement of attention from the objects in right visual fi eld, as well as in inhibition of return to the right visual fi eld. Rosetti and Rode (1998) proposed a method of ameliorating symptoms of neglect by means of prismatic lenses, which shift vision (e.g. 15° to the right or left) and thereby trigger changes in visuo-spatial integration. However, it is not clear, which particular cognitive mechanisms are affected by the method. Furthermore, leftward prism adaption in healthy subjects causes an effect similar to hemispatial neglect. Similarly, cognitive and neural mechanisms underlying this effect remain yet to be identifi ed. Two experiments were conducted, which aimed at indicating attentional processes modifi ed by prism adaptation in case of “neglect-like” effect in healthy individuals. Posner’s location-cuing task paradigm was used in order to differentiate processes of endogenous and exogenous orienting of attention, as well as to measure the effect of inhibition of return. Participants performed the task before and after prism adaptation. Results are discussed in light of recent theories of neglect.

Ograniczanie wyników

2 Acta Neurobiologiae Experimentalis

2 Asanowicz D.

2 Wolski P.

1 Marzecova A.

1 Michalczyk M.

2 2009

Wyniki wyszukiwania

Interhemispheric relations in attention evidenced by the lateralized attention network test (LANT)

Effects of prism adaptation on voluntary and reflexive orienting of attention