[Show abstract][Hide abstract] ABSTRACT: This event-related potentials (ERPs) study attempts to trace the time course it takes to extract phonology while reading Chinese pseudocharacters. Participants were asked to passively attend to a set of pseudocharacters, each paired with a spoken syllable. This syllable had either a predicable or an unpredictable pronunciation, which was determined by the constituent phonetic radical of the pseudocharacter. The data showed that pseudocharacters paired with predictable or unpredictable pronunciations elicited different ERPs and suggested that Chinese pseudocharacters are pronounceable. Furthermore, pseudocharacters paired with unpredictable pronunciations elicited two greater frontal positivities, p2a and p2b, and an enhanced N400. P2 component could be used to index the early extraction of phonology in reading Chinese pseudocharacter; N400 was associated with the post-lexical processing. These findings suggest that phonetic radicals could be used to suggest pronunciation in the early stage of Chinese lexical processing.
[Show abstract][Hide abstract] ABSTRACT: Emotional faces are often salient cues of threats or other important contexts, and may therefore have a large effect on cognitive processes of the visual environment. Indeed, many behavioral studies have demonstrated that emotional information can modulate visual attention and eye movements. The aim of the present study was to investigate (1) how irrelevant emotional face distractors affect saccadic behaviors and (2) whether such emotional effects reflect a specific neural mechanism or merely biased selective attention. We combined a visual search paradigm that incorporated manipulation of different types of distractor (fearful faces or scrambled faces) and delivered anodal transcranial direct current stimulation (tDCS) over the superior temporal sulcus and the frontal eye field to investigate the functional roles of these areas in processing facial expressions and eye movements. Our behavioral data suggest that irrelevant emotional distractors can modulate saccadic behaviors. The tDCS results showed that while rFEF played a more general role in controlling saccadic behavior, rSTS is mainly involved in facial expression processing. Furthermore, rSTS played a critical role in processing facial expressions even when such expressions were not relevant to the task goal, implying that facial expressions and processing may be automatic irrespective of the task goal.
[Show abstract][Hide abstract] ABSTRACT: The effect of hand proximity on vision and visual attention has been well documented. In this study we tested whether such effect(s) would also be present in the auditory modality. With hands placed either near or away from the audio sources, participants performed an auditory-spatial discrimination (Experiment 1: left or right side), pitch discrimination (Experiment 2: high, med, or low tone), and spatial-plus-pitch (Experiment 3: left or right; high, med, or low) discrimination task. In Experiment 1, when hands were away from the audio source, participants consistently responded faster with their right hand regardless of stimulus location. This right hand advantage, however, disappeared in the hands-near condition because of a significant improvement in left hand's reaction time (RT). No effect of hand proximity was found in Experiments 2 or 3, where a choice RT task requiring pitch discrimination was used. Together, these results that the perceptual and attentional effect of hand proximity is not limited to one specific modality, but applicable to the entire "space" near the hands, including stimuli of different modality (at least visual and auditory) within that space. While these findings provide evidence from auditory attention that supports the multimodal account originally raised by Reed et al. (2006), we also discuss the possibility of a dual mechanism hypothesis to reconcile findings from the multimodal and magno/parvocellular account.
Frontiers in Psychology 06/2014; 5:527. DOI:10.3389/fpsyg.2014.00527 · 2.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The majority of Chinese characters are composed of a semantic and a phonetic radical. Although pre-lexical involvement of the phonetic radical in Chinese character recognition has been established, there is little agreement on the contribution of the semantic radical. We used magnetoencephalography (MEG) to investigate the temporal dynamics of the priming effect elicited by repetition of phonetic and semantic radicals in the tasks of homophone and synonym judgment, respectively. The behavioral results revealed robust priming induced by both kinds of radicals. As for the MEG results, the repetition effect of phonetic radicals was obtained in the M170, M250 and M350 components. However, the repetition effect of semantic radicals was only marginally interactive with other variables in the M170, M350 and M450 components. The present findings suggest that phonetic radicals play a predominant role in early lexical access and phonological computation of Chinese character recognition, while semantic radicals have relatively weak effect on lexical access and semantic retrieval.
Journal of Neurolinguistics 05/2014; 29(1). DOI:10.1016/j.jneuroling.2013.12.003 · 1.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, we examine the neural substrates underlying Tone 3 sandhi and tone sequencing in Mandarin Chinese using fMRI. Tone 3 sandhi is traditionally described as the substitution of Tone 3 with Tone 2 when followed by another Tone 3 (i.e., 33→23). According to current speech production models, target substitution is expected to engage the posterior inferior frontal gyrus. Since Tone 3 sandhi is, to some extent, independent of segments, which makes it more similar to singing, right-lateralized activation in this region was predicted. As for tone sequencing, based on studies in sequencing, we expected the involvement of the supplementary motor area. In the experiments, participants were asked to produce twelve four-syllable sequences with the same tone assignment (the repeated sequences) or a different tone assignment (the mixed sequences). We found right-lateralized posterior inferior frontal gyrus activation for the sequence 3333 (Tone 3 sandhi) and left-lateralized activation in the supplementary motor area for the mixed sequences (tone sequencing). We proposed that tones and segments could be processed in parallel in the left and right hemispheres, but their integration, or the product of their integration, is hosted in the left hemisphere.
PLoS ONE 01/2014; 9(1):e83126. DOI:10.1371/journal.pone.0083126 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Stimulus-response compatibility effects have been hypothesized to result from a correspondence between the spatial codes associated with the response hand and the stimulus location (i.e., the S-S interpretation of Wallace, 1971) or, alternatively, from a subject’s innate tendency to respond in the direction of the source of stimulation (i.e., the S-R interpretation of Craft & Simon, 1970). Two experiments were conducted to test these two positions. Patterns of response latencies were found that could not be adequately explained by either model.
Bulletin of the Psychonomic Society 12/2013; 10(6):475-477. DOI:10.3758/BF03337702
[Show abstract][Hide abstract] ABSTRACT: The dorsal attentional network is known for its role in directing top-down visual attention toward task-relevant stimuli. This goal-directed nature of the dorsal network makes it a suitable candidate for processing and extracting predictive information from the visual environment. In this review we briefly summarize some of the findings that delineate the neural substrates that contribute to predictive learning at both levels within the dorsal attentional system: including the frontal eye field (FEF) and posterior parietal cortex (PPC). We also discuss the similarities and differences between these two regions when it comes to learning predictive information. The current findings from the literature suggest that the FEFs may be more involved in top-down spatial attention, whereas the parietal cortex is involved in processing task-relevant attentional influences driven by stimulus salience, both contribute to the processing of predictive cues at different time points.
Frontiers in Human Neuroscience 08/2013; 7:404. DOI:10.3389/fnhum.2013.00404 · 2.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Many studies have used event-related potential and neural oscillations to probe the underlying neural mechanisms of inhibitory control in adults, but little has been done in typically developing preschoolers. In this study we tested healthy preschool children between the ages of 5 and 6, and observed better response inhibition in 6-year-olds compared to 5-year-olds. Importantly, this age-related difference could not be explained by the N2 component from event-related potential, but was reflected in an increase in right frontal beta power from electroencephalogram. These results suggest that frontal beta power during the preschool period may reflect neural development of inhibitory control.
[Show abstract][Hide abstract] ABSTRACT: Sixty subjects learned four different 16-word lists in four different conditions. Within each list, every word was repeated. The four conditions were defined by a 2 (whole vs. blocked presentation) by 2 (same order vs. random order repetition) factorial design. An unexpected final free recall followed the immediate free recall of the fourth list. It was found that significantly more reminiscence occurred in the whole-random condition, suggesting that initially imposed organization hindered the subsequent reorganization.
Bulletin of the Psychonomic Society 03/2013; 7(3):337-339. DOI:10.3758/BF03337208
[Show abstract][Hide abstract] ABSTRACT: Inhibitory control, or the ability to suppress planned but inappropriate prepotent actions in the current environment, plays an important role in the control of human performance. Evidence from empirical studies utilizing a sport-specific design has shown that athletes have superior inhibitory control. However, less is known about whether this superiority might (1) still be seen in a general cognitive task without a sport-related context; (2) be modulated differentially by different sporting expertise (e.g., tennis versus swimming).
Here we compared inhibitory control across tennis players, swimmers and sedentary non-athletic controls using a stop-signal task without a sport-specific design. Our primary finding showed that tennis players had shorter stop-signal reaction times (SSRTs) when compared to swimmers and sedentary controls, whereas no difference was found between swimmers and sedentary controls. Importantly, this effect was further confirmed after considering potential confounding factors (e.g., BMI, training experience, estimated levels of physical activity and VO2max), indicative of better ability to inhibit unrequired responses in tennis players.
This suggests that fundamental inhibitory control in athletes can benefit from open skill training. Sport with both physical and cognitive demands may provide a potential clinical intervention for those who have difficulties in inhibitory control.
PLoS ONE 02/2013; 8(2):e55773. DOI:10.1371/journal.pone.0055773 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Twenty Ss learned five 12-word lists. Following the immediate free recall of the fifth list, the Ss were asked to recall and recognize all the 60 words in the previous lists. The Ss in the experimental group were instructed to study each presented word carefully and, after the presentation of every 3 words, to overtly recall the preceding 3 words. Although this intralist retrieval procedure provides a basis for grouping, it has a detrimental effect not only on item accessibility, but also on item availability. A “removal property” of short-term memory was proposed as the locus of this effect. In addition, examination of the response pattern of the final free recall shows that the differential rehearsal interpretation proposed by Cohen (1970) is inappropriate.
[Show abstract][Hide abstract] ABSTRACT: Do the neural circuits for reading vary across culture? Reading of visually complex writing systems such as Chinese has been proposed to rely on areas outside the classical left-hemisphere network for alphabetic reading. Here, however, we show that, once potential confounds in cross-cultural comparisons are controlled for by presenting handwritten stimuli to both Chinese and French readers, the underlying network for visual word recognition may be more universal than previously suspected. Using functional magnetic resonance imaging in a semantic task with words written in cursive font, we demonstrate that two universal circuits, a shape recognition system (reading by eye) and a gesture recognition system (reading by hand), are similarly activated and show identical patterns of activation and repetition priming in the two language groups. These activations cover most of the brain regions previously associated with culture-specific tuning. Our results point to an extended reading network that invariably comprises the occipitotemporal visual word-form system, which is sensitive to well-formed static letter strings, and a distinct left premotor region, Exner's area, which is sensitive to the forward or backward direction with which cursive letters are dynamically presented. These findings suggest that cultural effects in reading merely modulate a fixed set of invariant macroscopic brain circuits, depending on surface features of orthographies.
Proceedings of the National Academy of Sciences 11/2012; 109(50). DOI:10.1073/pnas.1217749109 · 9.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The limits of human visual short-term memory (VSTM) have been well documented, and recent neuroscientific studies suggest that VSTM performance is associated with activity in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively charged electric current through the skull can rapidly and effortlessly improve people's VSTM performance. This artificial improvement, however, comes with an interesting twist: it interacts with people's natural VSTM capability such that low performers who tend to remember less information benefitted from the stimulation, whereas high performers did not. This behavioral dichotomy is explained by event-related potentials around the parietal regions: low performers showed increased waveforms in N2pc and contralateral delay activity (CDA), which implies improvement in attention deployment and memory access in the current paradigm, respectively. Interestingly, these components are found during the presentation of the test array instead of the retention interval, from the parietal sites ipsilateral to the target location, thus suggesting that transcranial direct current stimulation (tDCS) was mainly improving one's ability to suppress no-change distractors located on the irrelevant side of the display during the comparison stage. The high performers, however, did not benefit from tDCS as they showed equally large waveforms in N2pc and CDA, or SPCN (sustained parietal contralateral negativity), before and after the stimulation such that electrical stimulation could not help any further, which also accurately accounts for our behavioral observations. Together, these results suggest that there is indeed a fixed upper limit in VSTM, but the low performers can benefit from neurostimulation to reach that maximum via enhanced comparison processes, and such behavioral improvement can be directly quantified and visualized by the magnitude of its associated electrophysiological waveforms.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 08/2012; 32(31):10554-61. DOI:10.1523/JNEUROSCI.0362-12.2012 · 6.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Witnessing emotional events such as arousal or pain may impair ongoing cognitive processes such as inhibitory control. We found that this may be true only half of the time. Erotic images and painful video clips were shown to men and women shortly before a stop signal task, which measures cognitive inhibitory control. These stimuli impaired inhibitory control only in men and not in women, suggesting that emotional stimuli may be processed with different weights depending on gender.
[Show abstract][Hide abstract] ABSTRACT: The present study examined the use of statistical cues for word boundaries during Chinese reading. Participants were instructed
to read sentences for comprehension with their eye movements being recorded. A two-character target word was embedded in each
sentence. The contrast between the probabilities of the ending character (C2) of the target word (C12) being used as word
beginning and ending in all words containing it was manipulated. In addition, by using the boundary paradigm, parafoveal overlapping
ambiguity in the string C123 was manipulated with three types of preview of the character C3, which was a single-character
word in the identical condition. During preview, the combination of C23′ was a legal word in the ambiguous condition and was
not a word in the control condition. Significant probability and preview effects were observed. In the low-probability condition,
inconsistency in the frequent within-word position (word beginning) and the present position (word ending) lengthened gaze
durations and increased refixation rate on the target word. Although benefits from the identical previews were apparent, effects
of overlapping ambiguity were negligible. The results suggest that the probability of within-word positions had an influence
during character-to-word assignment, which was mainly verified during foveal processing. Thus, the overlapping ambiguity between
parafoveal words did not interfere with reading. Further investigation is necessary to examine whether current computational
models of eye movement control should incorporate statistical cues for word boundaries together with other linguistic factors
in their word processing system to account for Chinese reading.
KeywordsChinese reading–Eye movements–Word processing–Word segmentation cues
Reading and Writing 05/2012; 25(5):1007-1029. DOI:10.1007/s11145-011-9321-z · 1.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Many studies have used static and non-biologically related stimuli to investigate bistable perception and found that the percept is usually dominated by their intrinsic nature with some influence of voluntary control from the viewer. Here we used a dynamic stimulus of a rotating human body, the silhouette spinner illusion, to investigate how the viewers' intentions may affect their percepts. In two experiments, we manipulated observer intention (active or passive), fixation position (body or feet), and spinning velocity (fast, medium, or slow). Our results showed that the normalized alternating rate between two bistable percepts was greater when (1) participants actively attempted to switch percepts, (2) when participants fixated at the spinner's feet rather than the body, inducing as many as 25 switches of the bistable percepts within 1 min, and (3) when they watched the spinner at high velocity. These results suggest that a dynamic biologically-bistable percept can be quickly alternated by the viewers' intention. Furthermore, the higher alternating rate in the feet condition compared to the body condition suggests a role for biological meaningfulness in determining bistable percepts, where 'biologically plausible' interpretations are favored by the visual system.
Vision research 03/2012; 60:34-9. DOI:10.1016/j.visres.2012.03.005 · 1.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To reproduce the duration of an event precisely, one needs to represent the temporal information without being influenced by other magnitude attributes (e.g., size) of the event. In the present study, however, task-irrelevant numerical magnitude automatically affected participants' reproduction of the duration of a stimulus. In Experiment 1, participants made key-press responses to reproduce the duration of numbers. Reproduced durations were shorter for small numbers (e.g., 1) than for large numbers (e.g., 9). In contrast, in Experiment 2, participants' reproductions of a standard duration were longer when their key-press response was accompanied by visual presentation of a small number than when it was accompanied by presentation of a large number. These results clearly demonstrate that number-time interference extends beyond simple mapping between stimulus categories and response alternatives. The findings support the notion that either a common magnitude representation or closely connected magnitude representations underlie numerical and temporal processing.
[Show abstract][Hide abstract] ABSTRACT: Predictability in the visual environment provides a powerful cue for efficient processing of scenes and objects. Recently, studies have suggested that the directionality and magnitude of saccade curvature can be informative as to how the visual system processes predictive information. The present study investigated the role of the right posterior parietal cortex (rPPC) in shaping saccade curvatures in the context of predictive and non-predictive visual cues. We used an orienting paradigm that incorporated manipulation of target location predictability and delivered transcranial magnetic stimulation (TMS) over rPPC. Participants were presented with either an informative or uninformative cue to upcoming target locations. Our results showed that rPPC TMS generally increased saccade latency and saccade error rates. Intriguingly, rPPC TMS increased curvatures away from the distractor only when the target location was unpredictable and decreased saccadic errors towards the distractor. These effects on curvature and accuracy were not present when the target location was predictable. These results dissociate the strong contingency between saccade latency and saccade curvature and also indicate that rPPC plays an important role in allocating and suppressing attention to distractors when the target demands visual disambiguation. Furthermore, the present study suggests that, like the frontal eye fields, rPPC is critically involved in determining saccade curvature and the generation of saccadic behaviors under conditions of differing target predictability.
Human Brain Mapping 11/2011; 32(11):1961-72. DOI:10.1002/hbm.21162 · 5.97 Impact Factor