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

• Published in: PloS one Vol. 7; no. 10; p. e47688
• Main Authors: Knox, Paul C, Amatya, Nabin, Jiang, Xiaoyu, Gong, Qiyong, Gong, Qyong
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.10.2012; Public Library of Science (PLoS)
• Subjects: Adult; Asian Continental Ancestry Group; Biology; Brain research; China; Cognition; Cognition & reasoning; Experiments; Eye; Eye movements; Female; Human behavior; Human populations; Humans; Latency; Male; Medical imaging; Medical research; Medicine; Middle Aged; Motor neurons; Neural networks; Neurosciences; Physiological aspects; Psychological aspects; Reaction Time; Saccades (Eye movements); Saccades - physiology; Saccadic eye movements; Task Performance and Analysis; Visual tasks; Young Adult; China; United Kingdom > UK
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0047688

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.