Biomedical subjects

Yue-jia Luo

Publications and source records attributed to Yue-jia Luo.

8 recordsLinked to original sources

PubMed2006

Semantic and syntactic processing in Chinese sentence comprehension: evidence from event-related potentials.

An ERP experiment was conducted to explore semantic and syntactic processes as well as their interplay in Chinese sentence comprehension. Participants were auditorily presented with Chinese ba sentences, which were either correct, semantically incorrect, syntactically incorrect, or both semantically and syntactically incorrect. The syntactic violation, which was created by eliminating the object-noun phrase from a preposition-object phrase structure, elicited an early starting anterior negativity which merged into a sustained negativity over anterior sites and a temporally limited centro-parietal negativity. The semantic violation elicited an early starting N400 effect. The combined violation in which the syntactic phrase structure violation and the semantic violation were crossed elicited an early staring sustained anterior negativity similar to the pure syntactic effect, and a centro-parietal negativity which was more negative than those of the syntactic condition and the semantic condition. No P600 was obtained neither for the syntactic nor for the combined condition. The results suggest that the syntactic processes (at about 50 ms) appear earlier than the semantic processes (at around 150 ms). They are independent from each other in the early time window (150-250 ms) but interact in a later processing phase (250-400 ms) during Chinese ba sentence comprehension. The broadly distributed negativity, which occurred during the N400 latency range observed in the three violation conditions, is thought to reflect thematic integration processes in the sentence-final position.

Adult↗

PubMed2005

[Effects of switching between neutral and emotional stimuli: an ERP study on "switch cost"].

OBJECTIVE: To investigate if switch cost involved in shifting between neutral and emotional stimuli is reflected by ERPs correlates. METHOD: The subjects were 14 healthy right-handed college students (7 females, 7 males). Garavan's (1998) task paradigm which was important in studying inner attention shifting was used. The subjects were asked to watch a stimulus sequence comprising Schematic line drawings of faces with neutral and emotional expressions, and make counts of them (neutral faces or emotional faces). EEG signals were recorded at 64 sites. RESULT: 1) Switching between stimuli elicited slow responses, increased N2 amplitudes and reduced P300 amplitudes. 2) A negative component (Nd370) was found when ERP wave during non-switching trials was subtracted from that during switching trials, and it was found obviously at extensive parietal area. 3) Nd370 amplitude during switching from emotional stimuli to neutral ones was smaller than that during switching from neutral stimuli to emotional ones. CONCLUSION: Nd370 can be taken as an index of switch cost effect.

Adult↗

PubMed2004

Precuneus contributes to attentive control of finger movement.

AIM: To examine whether precuneus subserves the attentive control of finger movement or whether it mediates the movement preparation and motor inhibition. METHODS: In the Preparation Stage, subjects were shown with a 5-number string in which each number stood for a key-pressing response, the number strings included a complex pattern (eg, 4-1-4-2-3), or a simple one (eg, 2-2-2-2-2), or a null one (ie, x-x-x-x-x). In the Execution Stage, five reaction signs were presented one by one and subjects were required to press the corresponding key to each sign sequentially (eg, in the 4-1-4-2-3 preparation example, subjects press key 4 to the first sign, press key 1 to the second sign, key 4 to the third sign and so on). For the null preparation pattern, five numbers, rather than the reaction signs, were shown at the same pace as in the other two conditions and subjects were to press the corresponding keys. RESULTS: Left medial frontal gyrus (BA 6) and precentral gyrus (BA 6) were involved in both of the Preparation Stage and the Execution Stage, whereas left precuneus (BA 7) was activated only in the Execution Stage. CONCLUSION: Precuneus mediates the attentive control of finger movement, but not the movement preparation or motor inhibition.

Adult↗

PubMed2004

[Aging study of event-related potential on visual spatial attention precued by Chinese words].

OBJECTIVE: Based on the visual experimental paradigm "precue-target", the search range should be affected by different Chinese characters and the dynamic mechanisms of aging in the brain on the visual attention were investigated. METHOD: 16 young and 16 old subjects participated the experiment. Cue was comprised of three Chinese words "Large", or "Median" or "Small." The letter "T" was designed as the target stimulus. When the cue was the "large", "T" may appear within 3 circles. When the cue was the "median", "T" may appear within either the median and small circles. When the cue was small, the target "T" may appear only within the small circle. RESULT: The reaction time (RT) of the two groups of subjects became quick with the reduction of the cue size, while amplitudes of the P1 and N1 component of ERPs increased with the decrease of the cue scale. Old subjects showed longer RT than younger subjects did. The posterior P1 was enhanced significantly and the N1 was inhibited obviously in the old group. The P2 was manifested as significantly inhibitory effect not only in the amplitude but also in the abnormal and unstable waveform. CONCLUSION: The cognitive function of elderly subjects declined in the task of visual spatial attention. We demonstrated for the first time that the P2 was manifested as significantly inhibitory effect, which suggested that the age-related reduction could lead to dysfunction in the anterior scalp to visual spatial attention (voluntary attention).

Adult↗

PubMed2003

[Differential visual attention scales directed by location versus semantic cue].

OBJECTIVE: To compare the cortical mechanisms associated with visual spatial attention directed by location cues and Chinese character cues. METHOD: Eleven healthy adults (mean age=19) with normal vision served as the subjects. In experiment I, the cue was a circle with black solid line. There were three cue sizes: small, medium and large. In experiment II, three black concentric circles were presented as background, their diameters were the same as the three cues used in experiment I. The cue was one of three Chinese characters small, medium or large respectively. The task of the subjects was to discriminate the target's orientation. RESULT: RT in experiment II was longer with short ISI. The anterosuperior N1 amplitude elicited by the cue in experiment II was larger than that in experiment I. The inferoposterior P1 latency in experiment II was longer than that in experiment I. Comparing the target evoked ERP, the inferoposterior P1 and N1, latency of experiment II was longer than that in experiment I, the inferoposterior P2 amplitude in experiment II was larger than that in experiment I. CONCLUSION: The processing of Chinese cue takes place at higher level functional brain regions compared to processing of location cue. The later requires more resource in the earlier stage of cue process and less in the subsequent stage of the task.

Adolescent↗

PubMed2003

[Early scale effects of the visual spatial attention].

OBJECTIVE: To investigate the visual attention mechanisms of brain, the "cue-target" experimental paradigm was adopted, and the attended range was cued by different Chinese characters. METHOD: Sixteen healthy young participants (8 male and 8 female, 19-24 years old with an average of 21) served as the subjects. The stimulus sequence was "background-cue-target". The background was comprised of three homocentric white circles. Cue was the Chinese character " large", "median" and " small ". There were 8 capital English letters in each circle, which formed three homocentric circles. "T" was designed as the target stimulus. When the cue was large, the target "T" appeared within the three circles. When the cue was medium, "T" appeared within the medium and small circles. When the cue was small, the T maybe appeared only within the small circle. RESULT: The reaction time became short with the decrease of the cue scale, while P1 and N1 components amplitudes increased. CONCLUSION: These results not only provided the electrophysiological evidence for the spot light theory, but also indicated that the spot-light effect happened at the early period of the information processing.

Adult↗

PubMed2002

[The mechanism of gain in scale of visual attention].

Objective. To compare the cortical mechanisms associated with the visual spatial attention directed by fixed location cues. Method. The subjects were 12 healthy right-handed young volunteers. The visual stimuli were presented with the sequence as: background-cue-target. The cue was a black circle varied in three different sizes randomly. The foci of the circles were always at the center of the screen. The task of the subjects was to search the target within the cue circle and discriminate its orientation. Electroencephalogram (EEG) was recorded from 128 scalp sites. Result. The reaction time (RT) to the targets in the same location shortened when the cue size enlarged. The target evoked P1 and N1 components were not affected by the attentive region size, while the amplitudes of the inferoposterior P2 and anterosuperior N2 enlarged when the attentive region size enlarged. Conclusion. 1) The P1 and N1 components under visual attention were related to the spatial location processes mainly. 2) Cue-evoked P2 and N2 components were related to the size of attentive region. 3) The processes of spatial location information were earlier than attentive scale information, which supported the theory that spatial selection is a prerequisite for correct processes of visual object information.

Adolescent↗

PubMed2002

[Brain processing component during face cognition--N170 revealed by event-related potentials].

Objective. To observe features of early component N170 during face recognition. Method. Scalp distribution, amplitude, and latency of N170 was recorded during face recognition tasks in 16 normal subjects. Result. N170 was elicited by the face stimuli in only half of the subjects and the amplitude was modulated by cognitive tasks. Conclusion. N170 reflects not only face structure encoding unit but also direct visual processing unit. Whether N170 reflects the specialty in face recognition needs further study. The latency of N170 showed left hemisphere dominance and the amplitude showed right hemisphere dominance, indicating that it is not pure right hemisphere dominance in face recognition.

Adult↗