Lin Chen

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (45)161.55 Total impact

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    ABSTRACT: Neuronal oscillations are ubiquitous in the brain and contribute to perception and attention. However, most associated evidence derives from post hoc correlations between brain dynamics and behavior. Although a few recent studies demonstrate rhythms in behavior, it remains largely unknown whether behavioral performances manifest spectrotemporal dynamics in a neurophysiologically relevant manner (e.g., the temporal modulation of ongoing oscillations, the cross-frequency coupling). To investigate the issue, we examined fine spectrotemporal dynamics of behavioral time courses in a large sample of human participants (n = 49), by taking a high time-resolved psychophysical measurement in a precuing attentional task. We observed compelling dynamic oscillatory patterns directly in behavior. First, typical attentional effects are demonstrated in low-pass (0-2 Hz) filtered time courses of behavioral responses. Second, an uninformative peripheral cue elicits recurring α-band (8-20 Hz) pulses in behavioral performances, and the elicited α pulses for cued and uncued conditions are in a temporally alternating relationship. Finally, ongoing α-band power is phase locked to ongoing θ-bands (3-5 Hz) in behavioral time courses. Our findings constitute manifestation of oscillations at physiologically relevant rhythms and power-phase locking, as widely observed in neurophysiological recordings, in behavior. The findings suggest that behavioral performance actually consists of rich dynamic information and may reflect underlying neuronal oscillatory substrates. Our data also speak to a neural mechanism for item attention based on successive cycles (θ) of a sequential attentional sampling (α) process.
    Journal of Neuroscience 04/2014; 34(14):4837-44. · 6.91 Impact Factor
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    ABSTRACT: Background & Aims S100A4 has been linked to fibrosis of several organs as a marker for fibroblasts. However, the role of S100A4 itself in fibrosis development has little been investigated. Herein, we determined whether S100A4 regulates liver fibrogenesis and examined its mechanism by focusing on activation of hepatic stellate cells (HSCs). Methods S100A4 deficient mice were used to determine the role of S100A4 in liver fibrogenesis. The effect of S100A4 on HSC activation was estimated by using primary mouse HSCs and human HSC line LX-2 cells. Levels of serum S100A4 in cirrhotic patients were determined by ELISA. Results S100A4 was found to be secreted by a subpopulation of macrophages and promote liver fibrosis development. It accumulated in the liver during progression of liver fibrosis and activated HSCs in mice. In vitro studies demonstrated that S100A4 induced overexpression of alpha-smooth muscle actin through c-myb in HSCs. Both selective depletion of S100A4-expressing cells and knockdown of S100A4 in liver by RNA interference resulted in a reduction of liver fibrosis following injury. Importantly, increased S100A4 levels in both liver tissue and serum correlated positively with liver fibrosis in human. Conclusions S100A4 promotes liver fibrosis by activating HSCs, which may represent a potential target for anti-fibrosis therapies.
    Journal of Hepatology. 01/2014;
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    ABSTRACT: Face perception is integral to human perception system as it underlies social interactions. Saccadic eye movements are frequently made to bring interesting visual information, such as faces, onto the fovea for detailed processing. Just before eye movement onset, the processing of some basic features, such as the orientation, of an object improves at the saccade landing point. Interestingly, there is also evidence that indicates faces are processed in early visual processing stages similar to basic features. However, it is not known whether this early enhancement of processing includes face recognition. In this study, three experiments were performed to map the timing of face presentation to the beginning of the eye movement in order to evaluate pre-saccadic face recognition. Faces were found to be similarly processed as simple objects immediately prior to saccadic movements. Starting ∼ 120 ms before a saccade to a target face, independent of whether or not the face was surrounded by other faces, the face recognition gradually improved and the critical spacing of the crowding decreased as saccade onset was approaching. These results suggest that an upcoming saccade prepares the visual system for new information about faces at the saccade landing site and may reduce the background in a crowd to target the intended face. This indicates an important role of pre-saccadic eye movement signals in human face recognition.
    PLoS ONE 01/2014; 9(3):e93112. · 3.73 Impact Factor
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    ABSTRACT: Stromal restraints to cancer are critical determinants of disease but they remain incompletely understood. Here we report a novel mechanism for host surveillance against cancer contributed by S100A4+ (FSP1+) fibroblasts. Mechanistic studies of fibrosarcoma formation caused by subcutaneous injection of the carcinogen methylcholanthrene (MCA) had suggested that interferon-gamma receptor signaling may restrict MCA diffusion by inducing expression of collagen (foreign body reaction). We tested the hypothesis that this reaction encapsulated MCA and limited carcinogenesis by determining whether its ability to induce fibrosarcomas was impaired in the absence of proliferating fibroblasts. We found that S100A4+ fibroblasts accumulated around the carcinogen where they produced collagens, encapsulating MCA and protecting epithelial cells from DNA damage. Ablation of these cells at the site of MCA injection by local administration of Ganciclovir (GCV) in FSP1-TK transgenic mice altered tumor morphology to an epithelial phenotype, indicating that in the absence of encapsulating fibroblasts, MCA targeted epithelial cells. Notably, we showed that destruction of the fibrous capsule around the MCA by local injection of collagenase induced rapid tumor development in mice that were otherwise durably tumor-free. Our findings demonstrate that the S100A4+ fibroblasts prevent epithelial malignancy and that collagen encapsulation of carcinogens protects against tumor development. Together, this study provides a novel mechanism for host surveillance against cancer.
    Cancer Research 03/2013; · 8.65 Impact Factor
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    ABSTRACT: We examined the effects of number magnitude (within vs. outside the subitizable range) and notation (symbolic vs. nonsymbolic number) on neural responses to visual displays in the human brain using fMRI at 7T. We found that the right temporoparietal junction (rTPJ) responded more strongly to small than to larger numbers (2, 4 > 6, 8), while there was greater activity bilaterally within and around the intraparietal sulcus (IPS) as number magnitude increased (6, 8 > 2, 4). The effects of number magnitude were greatest for nonsymbolic stimuli. In addition, there was striking overlap between rTPJ regions responding to small numbers and those most strongly activated by symbolic stimuli, and between IPS regions responding to large numbers and those most activated by nonsymbolic stimuli. The results are consistent with distinct neural processes recruited for the processing of small- and large-number magnitudes. Contributions due to differences in representing exact number (small nonsymbolic arrays and all symbolic numbers, in rTPJ) and overall magnitude (particularly with large nonsymbolic arrays, in IPS), and the associated theoretical implications of the findings, are discussed.
    Cerebral Cortex 03/2013; · 6.83 Impact Factor
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    Jie Li, Lin Chen, Zhihai Qin
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    ABSTRACT: Tumors are highly complex tissues composed of neoplastic cells and different kinds of stromal cells. Tumor stromal cells, especially fibroblasts, play important roles during the multistep development of tumors. In this review, the two-faced characteristics of tumor stromal fibroblasts are discussed in the light of our current knowledge. For one thing, fibroblasts act as an "inflammation regulator" by secretion of cytokines and regulation of tumor immunity; for another, they act as a "damage healer" for cure of wounds by remodeling extracellular matrix or taking a part in the "foreign body reaction". Since the properties of fibroblasts are complicated, both aspects of fibroblasts for tumor development should be considered carefully in clinical studies to target cancer-associated fibroblasts.
    Cancer Microenvironment 05/2012; 5(3):187-93.
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    ABSTRACT: It is well known that emotion can modulate attentional processes. Previous studies have shown that even under restricted awareness, emotional facial expressions (especially threat-related) can guide the direction of spatial attention. However, it remains unclear whether emotional facial expressions under restricted awareness can affect temporal attention. To address this issue, we used a modified attentional blink (AB) paradigm in which masked (Experiment 1) or unmasked (Experiment 2) emotional faces (fearful or neutral) were presented before the AB sequence. We found that, in comparison with neutral faces, masked fearful faces significantly decreased the AB magnitude (Experiment 1), whereas unmasked fearful faces significantly increased the AB magnitude (Experiment 2). These results indicate that effects of emotional expression on the AB are modulated by the level of awareness.
    PLoS ONE 01/2012; 7(9):e46394. · 3.73 Impact Factor
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    ABSTRACT: Mounting psychophysical evidence suggests that early visual computations are sensitive to the topological properties of stimuli, such as the determination of whether the object has a hole or not. Previous studies have demonstrated that the hole feature took some advantages during conscious perception. In this study, we investigate whether there exists a privileged processing for hole stimuli during unconscious perception. By applying a continuous flash suppression paradigm, the target was gradually introduced to one eye to compete against a flashed full contrast Mondrian pattern which was presented to the other eye. This method ensured that the target image was suppressed during the initial perceptual period. We compared the initial suppressed duration between the stimuli with and without the hole feature and found that hole stimuli required less time than no-hole stimuli to gain dominance against the identical suppression noise. These results suggest the hole feature could be processed in the absence of awareness, and there exists a privileged detection of hole stimuli during suppressed phase in the interocular rivalry.
    PLoS ONE 01/2012; 7(3):e33053. · 3.73 Impact Factor
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    ABSTRACT: To evaluate the clinical practicability of integration of functional magnetic resonance imaging (fMRI) data into neuronavigation as a tool to localize the language area and their relationship with the lesion for the preoperative planning, intraoperative guidance and postoperative follow-up study of brain functions during minimally invasive surgeries in or adjacent to functional areas. Eighty eight patients with intracranial lesions located in or adjacent to the functional language area underwent fMRI (including examinations of lingual and visual function, and motor functions of the limbs and tongue). fMRI data was entered into a neuronavigation system for image fusion and preoperative registration and correction; minimally invasive neurosurgery was performed with fMRI navigation. The shortest distance between the lesion and the functional cortex was less than 5 mm in 6 patients and was more than 5 mm but less than 10 mm in another 10 patients, respectively. 10 patients were recovered and improved in another 6 between 3 - 6 months after surgery, The follow-up time was between 3 months and 1 year. The morbidity rate was 6.8% (6/88). There was no postoperative mortality. Various brain areas were widely activated when the patients were reading and understanding the Chinese words. The unilateral speech functional maps were located in left Brodmann's 9, 46, 17, 18 and 19 areas. fMRI-integrated neuronavigation can locate functional language areas and played an important role in intraoperative protection of functional lingual areas, execution of individualized therapeutic regimens, minimization of surgical complications and determination of prognosis. Total surgical resection was safe for lesions > 10 mm from functional lingual areas.
    Zhonghua yi xue za zhi 11/2011; 91(41):2907-11.
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    Xiaoming Du, Lin Chen, Ke Zhou
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    ABSTRACT: Converging evidence from neuroimaging as well as lesion and transcranial magnetic stimulation (TMS) studies has been obtained for the involvement of right ventral posterior parietal cortex (PPC) in exogenous orienting. However, the contribution of dorsal PPC to attentional orienting, particularly endogenous orienting, is still under debate. In an informative peripheral cueing paradigm, in which the exogenous and endogenous orienting can be studied in relative isolation within a single task, we applied TMS over sub-regions of dorsal PPC to explore their possible distinct involvement in exogenous and endogenous processes. We found that disruption of the left posterior intraparietal sulcus (pIPS) weakened the attentional effects of endogenous orienting, but did not affect exogenous processes. In addition, TMS applied over the right superior parietal lobule (SPL) resulted in an overall increase in reaction times. The present study provides the causal evidence that the left pIPS plays a crucial role in voluntary orienting of visual attention, while right SPL is involved in the processing of arousal and/or vigilance. Hum Brain Mapp 33:2477-2486, 2012. © 2011 Wiley Periodicals, Inc.
    Human Brain Mapping 09/2011; 33(10):2477-86. · 6.88 Impact Factor
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    ABSTRACT: The human visual system is tuned to the motions of biological entities, which provide potentially vital information for survival. The current study examines the interplay between motion speed and motion direction perception. Following a brief presentation of a point-light walker walking straight ahead or slightly leftward or rightward, observers were asked to quickly judge the walking direction (left or right). Participants showed better direction discrimination when the walker walked at a fast pace compared to a natural or slow pace, and this was not simply due to a difference in motion cycles. Moreover, walking direction sensitivity could be enhanced by increasing the feet motion speed alone, so long as the direction of feet movement was consistent with that of the other body parts. These findings demonstrate that our perception of walking direction is influenced by local motion speed, and highlight the role of the feet in biological motion perception. Keywordsbiological motion–motion speed–walking direction–discrimination
    Chinese Science Bulletin 01/2011; 56(19):2025-2030. · 1.32 Impact Factor
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    ABSTRACT: It is known that small and large numbers facilitate left/right respectively (the SNARC effect). Recently, it has been proposed that numerical magnitude is just one example of a range of quantities, which have a common cognitive/neural representation. To investigate this proposition, response congruency effects were explored for stimuli which differed according to their: (a) numerical size, (b) physical size, (c) luminance, (d) conceptual size and (e) auditory intensity. In a series of experiments, groups of undergraduate participants made two-alternative forced choice discriminations with their left or right hands. There were clear interactions between magnitude and responding hand whereby right hand responses were faster for stimuli with (a) large numbers, (b) large physical size, (c) low luminance, and (d) a reference to large objects. There was no congruency effect for the auditory stimuli. The data demonstrate that the response congruency effect observed for numbers also occurs for a variety of other non-numerical visual quantities. These results support models of general magnitude representation and suggest that the association between magnitude and the left/right sides of space may not be related to culture and/or directional reading habits.
    PLoS ONE 01/2011; 6(8):e23553. · 3.73 Impact Factor
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    ABSTRACT: What is a perceptual object? This question seems to be straightforward yet its answer has become one of the most central and also controversial issues in many areas of cognitive sciences. The“global-first” topological approach ties a formal definition of perceptual objects to invariance over topological transformation, and the core intuitive notion of a perceptual object - the holistic identity preserved over shape-changing transformations - may be precisely characterized as topological invariants, such as connectivity and holes. The topological definition of objects has been verified by a fairly large set of behavioral experiments, including, for example, MOT and attention blink, which consistently demonstrated that while object identity can survive various non-topological changes, the topological change disturbs its object continuity, being perceived as an emergence of a new object. Companion fMRI experiments revealed the involvement of anterior temporal lobe, a late destination of the visual form pathway, in the topological perception and the formation of perceptual objects defined by topology. This contrast of global-first in behavior and late destination in neuroanatomy raises far-reaching issues regarding the formation of object representations in particular, and the fundamental question of “where to begin” in general.
    Brain Informatics - International Conference, BI 2011, Lanzhou, China, September 7-9, 2011. Proceedings; 01/2011
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    ABSTRACT: Cancer development is often associated with increased fibroblast proliferation and extensive fibrosis; however, the role of fibroblasts during carcinogenesis remains largely unknown. Using the 7,12-dimethylbenz-(a)anthracene and 12-O-tetradecanoylphorbol-13-acetate-induced two-stage skin carcinogenesis model, we demonstrated here that there was a massive accumulation and proliferation of fibroblasts in the skin shortly after application of carcinogen. Selective abatement of these cells during the promotion stage drastically decreased incidence and progression of papillomas. This correlated well with reduced macrophage infiltration and impaired cytokine storm in the affected skin. 12-O-tetradecanoylphorbol-13-acetate stimulated skin fibroblasts, secreting high levels of monocyte chemotactic protein-1, and neutralization of this chemokine eliminated almost completely the fibroblast-induced chemotaxis of macrophages. These results strongly suggest that fibroblasts promote skin tumor development by producing monocyte chemotactic protein-1 and maintaining chronic inflammation.
    American Journal Of Pathology 01/2011; 178(1):382-90. · 4.52 Impact Factor
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    ABSTRACT: Recent data indicate that unconscious masked priming can be mediated by top-down attentional set, so that priming effects of congruence between a masked prime and a subsequent probe vanish when the congruence ceases to be task relevant. Here, we show that, while the attentional set determines masked priming for color and orientation features, it does not fully determine priming based on the topological properties of stimuli. Specifically, across a series of different choice-RT tasks, we find that topological congruence between prime and probe stimuli affects RTs for the probes even when other stimulus information (e.g., color or orientation) is required for the response, whereas congruence priming effects of color or orientation occur only when these features are response relevant. Our results suggest that changes in topological properties take precedence over task-directed top-down attentional modulation in masked priming.
    Journal of Vision 01/2011; 11(12). · 2.48 Impact Factor
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    ABSTRACT: The question of what is a perceptual object is one of the most central and also controversial issues in cognitive science. According to the topological approach to perceptual organization, the core intuitive notion of an object--the holistic identity preserved over shape-changing transformations--may be characterized precisely as topological invariance. Here we show that, across a series of multiple-object tracking tasks, performance was not disrupted when the moving items underwent massive featural changes. However, performance was significantly impaired when the items changed their topological properties of holes, demonstrating that topological invariance constrains what counts as an object in the first place. Consistent with previous findings, fMRI studies indicated that the anterior temporal lobe may be involved in the formation of object representation defined by topological constraints.
    Proceedings of the National Academy of Sciences 11/2010; 107(50):21920-4. · 9.74 Impact Factor
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    Zhiguang Li, Lin Chen, Zhihai Qin
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    ABSTRACT: Interleukin (IL)-4 is a crucial cytokine in tumor immunology. In the initial murine experiments, IL-4 exhibited potent anti-tumor ability. Tumors genetically modified to produce IL-4 were rejected, while parental tumors grew progressively. Mice rejected IL-4-producing tumors got long-lasting anti-tumor immunity. The comparative study showed that IL-4 induced the most effective immune response among several cytokines in both prophylactic and therapeutic models. All of these indicate IL-4 has strong potential as a tumor therapy agent. However, contrary evidence indeed exists, and is becoming more and more abundant which shows IL-4 is a tumor-promoting molecule. IL-4 amounts are usually elevated in human cancer patients. IL-4 knockout mice are more resistant to tumor challenge than IL-4 competent mice. Furthermore, tumor cells of various histological origins often express increased levels of IL-4 receptor in comparison to their normal counterparts. By carefully examining presently available data, we found the effects of IL-4 in tumor immunity are closely related to its sources, expressing time and dose, as well as the molecular and cellular environments. In this mini-review, we concentrate on illustrating the paradoxical roles and underlying mechanisms of IL-4 in tumor immunity and try to understand how one molecule has opposite effects.
    Cellular & molecular immunology 12/2009; 6(6):415-22. · 3.42 Impact Factor
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    ABSTRACT: Participants judged the number of dots in visual displays with brief presentations (200 msec), such that the numerosity judgment was based on an instantaneous impression without counting. In some displays, pairs of adjacent dots were connected by line segments, whereas, in others, line segments were freely hanging without touching the dots. In Experiments 1, 2A, and 2B, connecting pairs of dots by line segments led to underestimation of dot numbers in those patterns. In Experiment 3, we controlled for the number of freely hanging line segments, whereas Experiment 4 showed that line segments that were merely attached to dots without actually connecting them did not produce a considerable underestimation effect. Experiment 5 showed that a connectedness effect existed when stimulus duration was reduced (50 msec) or extended (1,000 msec). We conclude that connectivity affects dot numerosity judgments, consistent with earlier findings of a configural effect in numerosity processing. Implications of the role of connectedness in object representation are discussed.
    Psychonomic Bulletin & Review 07/2009; 16(3):509-17. · 2.61 Impact Factor
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    ABSTRACT: Do spatial attention and object attention modulate visual processing in similar ways? Previously we have found a dissociation between these two forms of attention on ERP measures of sensory processing under conditions of peripheral cueing, with spatial attention effects associated with changes over anterior scalp regions and object attention effects associated with changes over posterior regions (He, X., Fan, S., Zhou, K., Chen, L., 2004. Cue validity and object-based attention. J. Cogn. Neurosci. 16, 1085-1097). However, under conditions of central cueing recent data suggest that spatial and object attention have similar effects over posterior cortical areas (e.g., Martínez, A., Teder-Sälejärvi, W., Hillyard, S.A., 2007. Spatial attention facilitates selection of illusory objects: evidence from event-related brain potentials. Brain Res. 1139, 143-152). In the present study we present further evidence for dissociation between spatial and object-based attention under conditions in which spatial attention effects were enhanced by increasing the cue validity and the task load. The data replicated our previous results, with the effects of spatial attention found in an enhanced anterior N1, while the effects of object-based attention emerged in an enhanced posterior N1. Analyses of attention effect maps and current source density maps confirmed the distinct scalp distributions. These results support the proposal that, under peripheral cueing, spatial attention and object attention are associated with activity respectively in anterior and posterior brain structures, and further suggest a distinction between how attention modulates processing under conditions of central cueing and peripheral cueing.
    Brain research 01/2009; 1245:116-25. · 2.46 Impact Factor
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    ABSTRACT: The “global-first” topological approach considers that long-range apparent motion (AM) works by abstracting global form invariants, and hence is actually associating with form perception rather than motion perception. This hypothesis has been verified by the behavioral finding of motion affinity between topologically equivalent figures as well as the fMRI finding of neural correlation of AM at the anterior temporal lobe (ATL). Such interaction of behavior and brain imaging continues to impact on efforts towards a theory on perceptual objects: the topological definition of objects and the ATL neural correlation of the formation of object representation.
    Brain Imaging and Behavior 11/2008; 2(4):309-317. · 2.67 Impact Factor

Publication Stats

390 Citations
161.55 Total Impact Points

Institutions

  • 2002–2014
    • Chinese Academy of Sciences
      • Institute of Biophysics
      Peping, Beijing, China
  • 2002–2012
    • Northeast Institute of Geography and Agroecology
      • • Institute of Biophysics
      • • Graduate School
      Peping, Beijing, China
  • 2011
    • Kunming Institute of Zoology CAS
      Yün-nan, Yunnan, China
    • Capital Medical University
      • Department of Neurosurgery
      Beijing, Beijing Shi, China
  • 2001–2006
    • University of Electronic Science and Technology of China
      • School of Life Science and Technology
      Chengdu, Sichuan Sheng, China
  • 1999–2003
    • University of Science and Technology of China
      • School of Life Sciences
      Luchow, Anhui Sheng, China
  • 1997
    • University of Rochester
      • Center for Visual Science
      Rochester, NY, United States
    • China University of Mining & Technology Beijing Graduate School
      Peping, Beijing, China