Nan-hui Chen - Academia.edu (original) (raw)
Papers by Nan-hui Chen
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
The pupil size of both human and other animals can be affected by light. Many kinds of psychiatri... more The pupil size of both human and other animals can be affected by light. Many kinds of psychiatrical and psychological disorders, such as drug abuse, associate with abnormal properties of pupillary light reflex. Thus, the properties of pupillary light reflex could serve as an indicator for drug abuse detection. However, the effect of drug abuse on pupillary light reflex is till unclear. To assess the effects of addictive drugs on pupillary light reflex quantificationally, in the present study, we examined the effects of morphine on pupil diameter and pupillary light reflex in rhesus monkeys. By measuring the pupil diameter at different timing points before and after the administration of morphine, we found that morphine administration reduced the diameter of pupil and decreased the constriction rate. Our present results provide an experimental support for applying the properties of pupillary light reflex as a reference in addicts' detection.
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
An effective algorithm for detecting pupil size based on image processing was established. Three ... more An effective algorithm for detecting pupil size based on image processing was established. Three features reflecting differences between opiate addicts and normal subjects in pupillary light reflex were extracted by applying this algorithm, including absolute amplitude of contraction (AAC), relative amplitude of contraction (RAC) and slope of contraction velocity (SCV). Effects of addiction, sex, myopia, aging, sleep deprivation on the three features were studied. None of three features was found significant differences between sexes, myopia, sleep deprived and normal subjects. Only RAC increased significantly in aging subjects in comparison to opiate addicts, The features of pupillary light reflex in opiate addicts decreased significantly not only comparing with normal subjects, but the subjects with potential facts that may alter their pattern of pupil light reflex as well. Our study provided basic data for future establishment of a rapid, non-contact method in distinguishing opia...
Sheng li xue bao : [Acta physiologica Sinica], Jan 25, 2004
In this paper, one method was introduced, which was a combination of the cue-related morphine add... more In this paper, one method was introduced, which was a combination of the cue-related morphine addiction model and a technique for obtaining chronic extracellular recordings of single unit in freely moving rats. With the combination and improvement of this technique, we have successfully applied this new method to study the neuronal activity of the hippocampus CA1 region in morphine withdrawal rats. In all, we found some more accurate and objective cellular characteristics of hippocampal neurons, and considered these characteristics as one of electrophysiological indexes of morphine addiction rats.
Journal of Neuroscience, 2011
The synchronized activity of cortical neurons often features spike delays of several milliseconds... more The synchronized activity of cortical neurons often features spike delays of several milliseconds. Usually, these delays are considered too small to play a role in cortical computations. Here, we use simultaneous recordings of spiking activity from up to 12 neurons to show that, in the cat visual cortex, the pairwise delays between neurons form a preferred order of spiking, called firing sequence. This sequence spans up to ∼ 15 ms and is referenced not to external events but to the internal cortical activity (e.g., beta/gamma oscillations). Most importantly, the preferred sequence of firing changed consistently as a function of stimulus properties. During beta/gamma oscillations, the reliability of firing sequences increased and approached that of firing rates. This suggests that, in the visual system, short-lived spatiotemporal patterns of spiking defined by consistent delays in synchronized activity occur with sufficient reliability to complement firing rates as a neuronal code.
Journal of Shanghai University (english Edition), 2007
The distribution of bursin in sacculus rotundus and gut-associated lymphoid tissues was investiga... more The distribution of bursin in sacculus rotundus and gut-associated lymphoid tissues was investigated in rabbit by immuno-histochemical staining method with anti-bursin monoclonal antibody (McAb)2F9-4. The results indicated that the appearance of the bursin-containing cells coincided with the morphodifferentiation and growth process in rabbit. Bursin immunized cells not only distributed in dome epithelium and mucosal epithelium, but also in follicular germinal center, dome, T-cell area, goblet cell, inter-epithelial lymphocyte and cap-zone of sacculus rotundus. This founding suggested that bursin-containing cells in sacculus rotundus might play an important role in intestinal mucosal immunity.
Experimental Brain Research, 2001
Previous studies of the dorsomedial frontal cortex (DMF) and the prefrontal cortex (PF) have show... more Previous studies of the dorsomedial frontal cortex (DMF) and the prefrontal cortex (PF) have shown that, when monkeys respond to nonspatial features of a discriminative stimulus (e.g., color) and the stimulus appears at a place unrelated to the movement target, neurons nevertheless encode stimulus location. This observation could support the idea that these neurons always encode stimulus location, regardless of its relevance to an instrumentally conditioned behavior. Past studies, however, leave open the possibility that activity observed during one operant task might reflect the contingencies of a different task, performed at different times. To test these alternatives, we examined the activity of DMF and PF neurons in two rhesus monkeys conditioned to perform an operant eye-movement task in which only the color and shape of visual stimuli served as salient discriminative features. Each of eight stimuli was associated with a response to a different eye-movement target. The location of these stimuli varied from trial to trial but was of no behavioral relevance, and the monkeys did not perform any operant task in which stimulus location controlled behavior. A substantial minority of neurons in both DMF and PF nevertheless encoded stimulus location, which indicates that this property does not depend on its relevance in an instrumentally conditioned behavior.
Cerebral Cortex, 2010
Gamma synchronization has generally been associated with grouping processes in the visual system.... more Gamma synchronization has generally been associated with grouping processes in the visual system. Here, we examine in monkey V1 whether gamma oscillations play a functional role in segmenting surfaces of plaid stimuli. Local field potentials (LFPs) and spiking activity were recorded simultaneously from multiple sites in the opercular and calcarine regions while the monkeys were presented with sequences of single and superimposed components of plaid stimuli. In accord with the previous studies, responses to the single components (gratings) exhibited strong and sustained gamma-band oscillations (30--65 Hz). The superposition of the second component, however, led to profound changes in the temporal structure of the responses, characterized by a drastic reduction of gamma oscillations in the spiking activity and systematic shifts to higher frequencies in the LFP (~10% increase). Comparisons between cerebral hemispheres and across monkeys revealed robust subject-specific spectral signatures. A possible interpretation of our results may be that single gratings induce strong cooperative interactions among populations of cells that share similar response properties, whereas plaids lead to competition. Overall, our results suggest that the functional architecture of the cortex is a major determinant of the neuronal synchronization dynamics in V1.
Frontiers in Computational Neuroscience, 2009
ABSTRACT As most cortical neurons are broadly tuned to various stimulus parameters, it is inevita... more ABSTRACT As most cortical neurons are broadly tuned to various stimulus parameters, it is inevitable that individual neurons participate in the representation of more than one visual object. We asked here whether the prefrontal representation of immediately preceding objects would interfere with the representation of subsequently processed object stimuli, supporting the idea that neuronal processes challenged by more input and compressed in time leads to a degradation of the quality of encoding. In the past, we analyzed simultaneously recorded multi- and single-unit signals derived from arrays of single-ended microelectrodes and tetrodes during a simple visual memory task (Waizel et al., SfN 2007&2008) and found that accurate representations of individual objects require the participation of large neuronal populations. Based on single trial firing rate values, we calculated one-way ANOVAs at 1% significance thresholds and performed subsequent posthoc comparisons (Scheffé) in order to detect stimulus selectivity and stimulus specificity for the activity at each single site, respectively. With tetrodes we were able to detect highly-specific units in PFC with a narrow band of stimulus preferences, which were remarkably stable throughout all stimulus comparisons. In order to increase the probability to find more of these specific units, we sharpened the impact and enhanced the temporal structure of the task. Two monkeys, who were trained to perform the basic task at ~80% performance, were ad hoc presented with a sequence of up to 4 objects that were shown consecutively within a fixed period of 900 ms. Not only the monkeys were able to impromptu generalize from a simple (Load 1) to a demanding task (Load 2-4) (Wildt et al., SfN 2008), they also showed highly selective sites (p< .009- p< 7 × 10-13) in all four load conditions, even for those last objects during load 4 (p<.006) which were presented for less than 250 ms. For all load conditions, highly specific sites could be found (118 pairwise comparisons with p<.01). One group of these sites kept their object preference throughout the entire sequence of all four objects, others responded position-dependent to different objects, but were still highly stable throughout all pairwise comparisons. These results suggest that neuronal ensembles in primate PFC are capable of encoding up to 4 objects without interactions among the activity expressed in relation to other objects in the sequence. In addition, they are able to resolve even very shortly presented objects (<250 ms) showing strong selectivity uniquely for one of them and without superimposing this representation with signals evoked by more recently perceived objects.
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
The pupil size of both human and other animals can be affected by light. Many kinds of psychiatri... more The pupil size of both human and other animals can be affected by light. Many kinds of psychiatrical and psychological disorders, such as drug abuse, associate with abnormal properties of pupillary light reflex. Thus, the properties of pupillary light reflex could serve as an indicator for drug abuse detection. However, the effect of drug abuse on pupillary light reflex is till unclear. To assess the effects of addictive drugs on pupillary light reflex quantificationally, in the present study, we examined the effects of morphine on pupil diameter and pupillary light reflex in rhesus monkeys. By measuring the pupil diameter at different timing points before and after the administration of morphine, we found that morphine administration reduced the diameter of pupil and decreased the constriction rate. Our present results provide an experimental support for applying the properties of pupillary light reflex as a reference in addicts' detection.
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
An effective algorithm for detecting pupil size based on image processing was established. Three ... more An effective algorithm for detecting pupil size based on image processing was established. Three features reflecting differences between opiate addicts and normal subjects in pupillary light reflex were extracted by applying this algorithm, including absolute amplitude of contraction (AAC), relative amplitude of contraction (RAC) and slope of contraction velocity (SCV). Effects of addiction, sex, myopia, aging, sleep deprivation on the three features were studied. None of three features was found significant differences between sexes, myopia, sleep deprived and normal subjects. Only RAC increased significantly in aging subjects in comparison to opiate addicts, The features of pupillary light reflex in opiate addicts decreased significantly not only comparing with normal subjects, but the subjects with potential facts that may alter their pattern of pupil light reflex as well. Our study provided basic data for future establishment of a rapid, non-contact method in distinguishing opia...
Sheng li xue bao : [Acta physiologica Sinica], Jan 25, 2004
In this paper, one method was introduced, which was a combination of the cue-related morphine add... more In this paper, one method was introduced, which was a combination of the cue-related morphine addiction model and a technique for obtaining chronic extracellular recordings of single unit in freely moving rats. With the combination and improvement of this technique, we have successfully applied this new method to study the neuronal activity of the hippocampus CA1 region in morphine withdrawal rats. In all, we found some more accurate and objective cellular characteristics of hippocampal neurons, and considered these characteristics as one of electrophysiological indexes of morphine addiction rats.
Journal of Neuroscience, 2011
The synchronized activity of cortical neurons often features spike delays of several milliseconds... more The synchronized activity of cortical neurons often features spike delays of several milliseconds. Usually, these delays are considered too small to play a role in cortical computations. Here, we use simultaneous recordings of spiking activity from up to 12 neurons to show that, in the cat visual cortex, the pairwise delays between neurons form a preferred order of spiking, called firing sequence. This sequence spans up to ∼ 15 ms and is referenced not to external events but to the internal cortical activity (e.g., beta/gamma oscillations). Most importantly, the preferred sequence of firing changed consistently as a function of stimulus properties. During beta/gamma oscillations, the reliability of firing sequences increased and approached that of firing rates. This suggests that, in the visual system, short-lived spatiotemporal patterns of spiking defined by consistent delays in synchronized activity occur with sufficient reliability to complement firing rates as a neuronal code.
Journal of Shanghai University (english Edition), 2007
The distribution of bursin in sacculus rotundus and gut-associated lymphoid tissues was investiga... more The distribution of bursin in sacculus rotundus and gut-associated lymphoid tissues was investigated in rabbit by immuno-histochemical staining method with anti-bursin monoclonal antibody (McAb)2F9-4. The results indicated that the appearance of the bursin-containing cells coincided with the morphodifferentiation and growth process in rabbit. Bursin immunized cells not only distributed in dome epithelium and mucosal epithelium, but also in follicular germinal center, dome, T-cell area, goblet cell, inter-epithelial lymphocyte and cap-zone of sacculus rotundus. This founding suggested that bursin-containing cells in sacculus rotundus might play an important role in intestinal mucosal immunity.
Experimental Brain Research, 2001
Previous studies of the dorsomedial frontal cortex (DMF) and the prefrontal cortex (PF) have show... more Previous studies of the dorsomedial frontal cortex (DMF) and the prefrontal cortex (PF) have shown that, when monkeys respond to nonspatial features of a discriminative stimulus (e.g., color) and the stimulus appears at a place unrelated to the movement target, neurons nevertheless encode stimulus location. This observation could support the idea that these neurons always encode stimulus location, regardless of its relevance to an instrumentally conditioned behavior. Past studies, however, leave open the possibility that activity observed during one operant task might reflect the contingencies of a different task, performed at different times. To test these alternatives, we examined the activity of DMF and PF neurons in two rhesus monkeys conditioned to perform an operant eye-movement task in which only the color and shape of visual stimuli served as salient discriminative features. Each of eight stimuli was associated with a response to a different eye-movement target. The location of these stimuli varied from trial to trial but was of no behavioral relevance, and the monkeys did not perform any operant task in which stimulus location controlled behavior. A substantial minority of neurons in both DMF and PF nevertheless encoded stimulus location, which indicates that this property does not depend on its relevance in an instrumentally conditioned behavior.
Cerebral Cortex, 2010
Gamma synchronization has generally been associated with grouping processes in the visual system.... more Gamma synchronization has generally been associated with grouping processes in the visual system. Here, we examine in monkey V1 whether gamma oscillations play a functional role in segmenting surfaces of plaid stimuli. Local field potentials (LFPs) and spiking activity were recorded simultaneously from multiple sites in the opercular and calcarine regions while the monkeys were presented with sequences of single and superimposed components of plaid stimuli. In accord with the previous studies, responses to the single components (gratings) exhibited strong and sustained gamma-band oscillations (30--65 Hz). The superposition of the second component, however, led to profound changes in the temporal structure of the responses, characterized by a drastic reduction of gamma oscillations in the spiking activity and systematic shifts to higher frequencies in the LFP (~10% increase). Comparisons between cerebral hemispheres and across monkeys revealed robust subject-specific spectral signatures. A possible interpretation of our results may be that single gratings induce strong cooperative interactions among populations of cells that share similar response properties, whereas plaids lead to competition. Overall, our results suggest that the functional architecture of the cortex is a major determinant of the neuronal synchronization dynamics in V1.
Frontiers in Computational Neuroscience, 2009
ABSTRACT As most cortical neurons are broadly tuned to various stimulus parameters, it is inevita... more ABSTRACT As most cortical neurons are broadly tuned to various stimulus parameters, it is inevitable that individual neurons participate in the representation of more than one visual object. We asked here whether the prefrontal representation of immediately preceding objects would interfere with the representation of subsequently processed object stimuli, supporting the idea that neuronal processes challenged by more input and compressed in time leads to a degradation of the quality of encoding. In the past, we analyzed simultaneously recorded multi- and single-unit signals derived from arrays of single-ended microelectrodes and tetrodes during a simple visual memory task (Waizel et al., SfN 2007&2008) and found that accurate representations of individual objects require the participation of large neuronal populations. Based on single trial firing rate values, we calculated one-way ANOVAs at 1% significance thresholds and performed subsequent posthoc comparisons (Scheffé) in order to detect stimulus selectivity and stimulus specificity for the activity at each single site, respectively. With tetrodes we were able to detect highly-specific units in PFC with a narrow band of stimulus preferences, which were remarkably stable throughout all stimulus comparisons. In order to increase the probability to find more of these specific units, we sharpened the impact and enhanced the temporal structure of the task. Two monkeys, who were trained to perform the basic task at ~80% performance, were ad hoc presented with a sequence of up to 4 objects that were shown consecutively within a fixed period of 900 ms. Not only the monkeys were able to impromptu generalize from a simple (Load 1) to a demanding task (Load 2-4) (Wildt et al., SfN 2008), they also showed highly selective sites (p< .009- p< 7 × 10-13) in all four load conditions, even for those last objects during load 4 (p<.006) which were presented for less than 250 ms. For all load conditions, highly specific sites could be found (118 pairwise comparisons with p<.01). One group of these sites kept their object preference throughout the entire sequence of all four objects, others responded position-dependent to different objects, but were still highly stable throughout all pairwise comparisons. These results suggest that neuronal ensembles in primate PFC are capable of encoding up to 4 objects without interactions among the activity expressed in relation to other objects in the sequence. In addition, they are able to resolve even very shortly presented objects (<250 ms) showing strong selectivity uniquely for one of them and without superimposing this representation with signals evoked by more recently perceived objects.