Orienting attention inspace and motor preparation in hearing and deaf subjects

Document Type: 
ASSC Conference Item
Article Type: 
orienting of attention, deaf, motor preparation, manual reaction time, cerebral hemispheres, detection, consciousness
Deposited by: 
Dr. Luiz G Gawryszewski
Date of Issue: 
Luiz G Gawryszewski, Rodrigo A Rocha, Altiere A Carvalho, Erick F Q Conde, Fernanda Ferreira, Antônio Pereira Jr
Event Dates: 
23- 26 June 2006
Event Location: 
Oxford, UK
Event Title: 
10th annual meeting of the Association for the Scientific Study of Consciousness
Event Type: 
ASSC Conference
Presentation Type: 
Number of Pages: 
Official URL: 
Voluntarily orienting attention to a particular location in visual space facilitates target detection at this position and increases the response latency at non-attended positions. Likewise, a preparatory warning signal usually reduces Manual Reaction Time (MRT) to a visual target. These two effects are mediated by distinct neural networks which can be selectively modified by alterations in the early environment. In this work, we measured the effects of attentional orienting and warning signals on the MRT to peripheral visual targets. A visual cue (arrow) appeared above the Fixation Point (FP) and remained on for 1000 ms. Simultaneously, 200, 300 (500) or 1000 ms after cue offset, a target appeared 9 deg to the left or to the right of the FP. Eight deaf and eight hearing subjects voluntered to participate in one session with two blocks of 160 trials. The intervals between cue- offset and target onset were 0,200,300 or 1000 ms in one block and 0,200,500 or 1000 ms in the other block. The target appeared either at the cued position (75% probability) or at a contralateral position. MRT medians were calculated to determine the effects of attention orienting and cue-target interval on manual latency. We found that: 1) for both groups, MRT at 0 ms cue-target interval was 50 ms longer than on the other intervals, which did not differ among them; 2) for hearing subjects, MRT in the valid condition was faster than MRT in the invalid condition for all intervals (cost = 55 ms); 3) for deaf subjects, there is a smaller attentional effect at 0 ms cue-target interval (cost = 24 ms) and no effect at the other intervals and 4) for the deaf subjects, MRT to a right stimulus was longer than that to a left stimulus at 0 and 200 ms cue-target intervals. These results suggest that the deafness has a stronger effect on the orienting of attention in space than on motor preparation to an impending target and that the differences seen between hearing and deaf people may be related to an impairment of the left hemisphere. Financial support: CNPq, CAPES, FAPERJ, PROPP-UFF
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