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Performance deficits in a voluntary saccade task in Chinese "express saccade makers".

Knox PC, Amatya N, Jiang X, Gong Q, Gong Q - PLoS ONE (2012)

Bottom Line: Differences in behaviour and cognition have been observed in different human populations.However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks).These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population.

View Article: PubMed Central - PubMed

Affiliation: Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. pcknox@liv.ac.uk

ABSTRACT
Differences in behaviour and cognition have been observed in different human populations. It has been reported that in various types of complex visual task, eye movement patterns differ systematically between Chinese and non-Chinese participants, an observation that has been related to differences in culture between groups. However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks). These participants are defined as "express saccade makers" (ESMs). We then show using the antisaccade paradigm, which requires the inhibition of reflexive responses and the programming and execution of voluntary saccades, that the performance of ESMs is compromised; they have higher antisaccade directional error rates, and the latency distributions of their error saccades again exhibit a higher proportion of low latency express saccade errors consistent with a reduced ability to inhibit reflexive responses. These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population. They suggest a potential unexpected confound relevant to those studies of Chinese versus other groups which have investigated group differences using oculomotor measures, and explained them in terms of culture. The confirmation of higher numbers of ESMs among Chinese participants provides new opportunities for examining oculomotor control.

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Mean±95%CI distributions for 60 normal subjects (A,B) and 16 ESMs (C,D) for correct antisaccades (A,C) and error prosaccades (B,D).The grey region shows the express saccade latency range (80 ms to 130 ms). The intersubject mean of the individual subject median latencies (±SD), and the intersubject percentage of express saccades is also shown.
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pone-0047688-g005: Mean±95%CI distributions for 60 normal subjects (A,B) and 16 ESMs (C,D) for correct antisaccades (A,C) and error prosaccades (B,D).The grey region shows the express saccade latency range (80 ms to 130 ms). The intersubject mean of the individual subject median latencies (±SD), and the intersubject percentage of express saccades is also shown.

Mentions: We examined the distribution of CorAS and ErrPS latencies in the two groups by plotting mean (±95% CI) distribution histograms for each saccade type in each of the groups (Figure 5). While the distribution of CorrAS latency was identical, the lower mean latency for ESM ErrPS latency was explained by a prominent early peak in the distribution, which (as in overlap tasks) occurred in the express saccade range. The mean proportion of ErrPS with latencies in the express range was 36±26%. This contrasted with the normal group in whom there were fewer errors with latency in the express range (11±11%). The difference between these percentages was statistically significant (t = 5.69, p<0.0001).


Performance deficits in a voluntary saccade task in Chinese "express saccade makers".

Knox PC, Amatya N, Jiang X, Gong Q, Gong Q - PLoS ONE (2012)

Mean±95%CI distributions for 60 normal subjects (A,B) and 16 ESMs (C,D) for correct antisaccades (A,C) and error prosaccades (B,D).The grey region shows the express saccade latency range (80 ms to 130 ms). The intersubject mean of the individual subject median latencies (±SD), and the intersubject percentage of express saccades is also shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3472994&req=5

pone-0047688-g005: Mean±95%CI distributions for 60 normal subjects (A,B) and 16 ESMs (C,D) for correct antisaccades (A,C) and error prosaccades (B,D).The grey region shows the express saccade latency range (80 ms to 130 ms). The intersubject mean of the individual subject median latencies (±SD), and the intersubject percentage of express saccades is also shown.
Mentions: We examined the distribution of CorAS and ErrPS latencies in the two groups by plotting mean (±95% CI) distribution histograms for each saccade type in each of the groups (Figure 5). While the distribution of CorrAS latency was identical, the lower mean latency for ESM ErrPS latency was explained by a prominent early peak in the distribution, which (as in overlap tasks) occurred in the express saccade range. The mean proportion of ErrPS with latencies in the express range was 36±26%. This contrasted with the normal group in whom there were fewer errors with latency in the express range (11±11%). The difference between these percentages was statistically significant (t = 5.69, p<0.0001).

Bottom Line: Differences in behaviour and cognition have been observed in different human populations.However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks).These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population.

View Article: PubMed Central - PubMed

Affiliation: Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. pcknox@liv.ac.uk

ABSTRACT
Differences in behaviour and cognition have been observed in different human populations. It has been reported that in various types of complex visual task, eye movement patterns differ systematically between Chinese and non-Chinese participants, an observation that has been related to differences in culture between groups. However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks). These participants are defined as "express saccade makers" (ESMs). We then show using the antisaccade paradigm, which requires the inhibition of reflexive responses and the programming and execution of voluntary saccades, that the performance of ESMs is compromised; they have higher antisaccade directional error rates, and the latency distributions of their error saccades again exhibit a higher proportion of low latency express saccade errors consistent with a reduced ability to inhibit reflexive responses. These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population. They suggest a potential unexpected confound relevant to those studies of Chinese versus other groups which have investigated group differences using oculomotor measures, and explained them in terms of culture. The confirmation of higher numbers of ESMs among Chinese participants provides new opportunities for examining oculomotor control.

Show MeSH