Biomedical subjects

Lun Zhao

Publications and source records attributed to Lun Zhao.

11 recordsLinked to original sources

PubMed2026

Development of molecular markers associated with saline-alkali tolerance in rapeseed (Brassica napus L.).

A total of 947 saline-alkaline tolerance-related molecular markers and a 5K cGPS genotyping chipwere developed, providing practical tools for marker-assisted selection and molecular design breeding of saline-alkaline-tolerant rapeseed. Rapeseed (Brassica napus L.) has relatively strong tolerance to saline-alkaline stress and shows great potential for the sustainable utilization and improvement of saline-alkaline soils. However, the breeding of highly tolerant cultivars still mainly depends on conventional hybridization combined with phenotype-based selection, which constrains breeding efficiency. In this study, previously reported saline-alkaline tolerance-related genes from rapeseed, rice, maize, wheat, sorghum, and Arabidopsis were collected. Candidate gene-based association analysis enabled the development of molecular markers and a genotyping chip. A total of 483 significantly associated genes were identified, among which 355 genes contained favorable haplotypes. Molecular markers were successfully developed for 275 genes, including 746 KASP and 201 InDel marker pairs, and four marker pairs were randomly selected for validation. In addition, a 5K cGPS liquid-phase chip (HZSW-cGPS-BRNAP-04), was developed and showed a high call rate and excellent reproducibility in genotyping. These markers and the chip are expected to improve the breeding efficiency of saline-alkaline-tolerant rapeseed cultivars. Overall, this study provides useful tools for early-generation evaluation and marker-assisted selection (MAS), and provides a foundation for molecular design breeding of saline-alkali-tolerant rapeseed.

Brassica napus↗

PubMed2006

Visual mismatch negativity elicited by facial expressions under non-attentional condition.

A modified "cross-modal delayed response" paradigm was used to investigate putative processing of face expression in the absence of focused attention to the face. Neutral, happy and sad faces were presented during intervals occurring between a tone and a response imperative signal (a faint click), while subjects were instructed to discriminate the location of the tone as quickly and accurately as possible and to ignore the faces. A neutral face was presented in 80% of the trials whereas the happy and sad faces were presented in the remaining trials - 10%, respectively. Expression mismatch negativity (EMMN) was obtained by subtracting the ERP elicited by neutral faces from that elicited by sad faces or happy faces. The EMMN started from around 120 ms (sad) and 110 ms (happy) lasting up to 430 ms (sad) and 360 ms (happy) post-stimulus. The EMMN elicited by sad faces was more negative than that elicited by happy faces. Both EMMNs distributed over posterior areas and covered larger areas in the right than in the left hemisphere sites (especially for happy EMMN).

Adult↗

PubMed2005

[ERP correlates of recognition memory for Chinese words].

OBJECTIVE: To study the ERP old/new effects during a recognition task for Chinese words. METHOD: Twenty one healthy right-handed volunteers received a Chinese words recognition task. The stimuli were meaningful words consisting of two Chinese characters. The EEG signals were recorded from 9 scalp sites of the extended 10-20 systems. RESULT: Compared with the new words, the old words elicited larger N320 (the frontal old/new effect) at the frontal brain areas and larger LPC (the parietal old/new effect) at the parietal brain areas. And the peak of LPC appeared significantly earlier in old words ERPs than in new words ERPs. CONCLUSION: The old/new effect is significant for the recognition of Chinese words, which also consists of the frontal old/new effect and the parietal old/new effect. The parietal old/new effect is positive-going, but the frontal old/new effect is negative-going. The frontal old/new effect might be affected by the language and material.

Cognition↗

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↗

PubMed2003

[Effect of extremely low frequency magnetic field on the focal brain injury in rats].

OBJECTIVE: To examine the effect of extremely low frequency magnetic field (ELMF) on the brain trauma in rats. METHOD: Using the focal left-brain cortex contusion model, rats were divided into two groups, ELMF group (3 d and 8 d) and control group (3 d and 8 d), ELMF stimulations were given after the brain trauma provided by a coil (phi 10 cm) which was driven by 15 Hz sinusoidal signals so that ELMF strength of 18 mT at the midpoint was obtained. The morphologic changes were observed in these groups. RESULT: As compared with the control group, the extent of the inflammatory reaction and the neuronal damage was apparently lighter in magnetic field group, especially in 8 d group. At the far away region from the injured brain area, the neuronal shape was changed, and the amount of this special neurocyte was larger in magnetic field group than that in control group, especially in 8 d group. CONCLUSION: ELMF stimulation in the present study may alleviate the brain injury reaction. Attention should be paid to the role of the special neurocyte during the brain injury.

Animals↗

PubMed2003

[WMN: a negative ERPs component related to working memory during non-target visual stimuli processing].

OBJECTIVE: To study non-target stimuli processing in the brain. METHOD: Features of the event-related potentials (ERPs) from non-target stimuli during selective response task (SR) was compared with that during visual selective discrimination (DR) task in 26 normal subjects. The stimuli consisted of two color LED flashes (red and green) appeared randomly in left (LVF) or right (RVF) visual field with same probability. ERPs were derived at 9 electrode sites on the scalp under 2 task conditions: a) SR, making switch response to the target (NT) stimuli from LVF or RVF in one direction and making no response to the non-target (NT) ones; b) DR, making switching response to T stimuli differentially, i.e., to the left for T from LVF and to the right for T from RVF. RESULT: 1) the non-target stimuli in DR conditions, compared with that in SR condition, elicited smaller P2 and P3 components and larger N2 component at the frontal brain areas; 2) a significant negative component, named as WMN (working memory negativity), appeared in the non-target ERPs during DR in the period of 100 to 700 ms post stimulation which was predominant at the frontal brain areas. CONCLUSION: According to the major difference between brain activities for non-target stimuli during SR and DR, the predominant appearance of WMN at the frontal brain areas demonstrated that the non-target stimulus processing was an active process and was related to working memory, i.e., the temporary elimination and the retrieval of the response mode which was stored in working memory.

Adolescent↗

PubMed2002

[Effects of task load on early and late components of auditory event-related brain potentials].

OBJECTIVE: To study the effects of task load on early and late components of auditory event-related potentials. METHOD: The subjects were 12 healthy right-handed volunteers aged 20-23 years. The stimuli were auditory signals of two kinds of tones and appeared randomly from four speakers located on the left-front, left-rear, right-front and right-rear over the head of the subject. Tasks included: a) pressing the button in response to all signals (AR); b) making location discrimination to tones from left or right (DR); c) making location discrimination to target signals (T, high-tone or low-tone) from the four sides, and make no response to non-target signals (NT). The event-related potentials (ERPs) of three tasks were compared with each other. RESULT: 1) The early components include P1, N1 and P2, and the late components include N2 (N2a/N2b), P3 and SW (slow wave). 2) P1 wave amplitude increased with the increase of the task load. N1 wave amplitude of SR(T)-ERPs decreased markedly compared with that of AR-ERPs and DR-ERPs, and P2 wave amplitude of AR-ERPs increased significantly compared with that of DR-ERPs and SR(T)-ERPs. P2 wave latency shortened with increase of the task load. 3) N2 (N2a/N2b), P3 and SW wave amplitudes increased with the increase of the task load. CONCLUSION: These data indicate that not only the late components but also the early components of auditory event-related potentials were affected by task load. The effects on the late components may be related to the change of the early component (P1) which may reflect the early activity process of the brain.

Acoustic Stimulation↗

PubMed2002

[N2 effect on non-target event-related brain potentials during auditory selective response task].

Objective. To study N2 effect and its feature on non-target event-related brain potentials during auditory selective attention. Method. The subjects were 16 healthy right-handed male volunteers aged 23.2 +/- 2.1 years. The stimuli were male voice of one-digit numbers (2 to 7), which were single syllable pronunciated in Chinese, and appeared randomly with equal probability. The subjects were asked to press a switch as soon as the target signal (odd or even number) was heard but make no response to the non-target signal. EEG signals at 9 locations were recorded. Result. 1) A negative component N280 (N2 effect) was found after non-target stimuli as compared to target stimuli, which was significant in the frontal brain locations; 2) P3 was smaller and its peak appeared later in non-target ERPs than in target ERPs. Conclusion. N2 effect was also elicited by non-target stimuli during auditory modality. We assume that N2 effect might reflect the readjusting of model stored in working memory at the frontal brain.

Adult↗

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↗

PubMed2002

[Two types of event-related brain slow potentials in auditory location discrimination (correction of dicrimination) task].

Objective. To study the difference between two types of event-related brain potentials (ERPs) in auditory location discrimination task. Method. Event-related potentials (ERPs) in auditory location discrimination task were recorded in 14 normal subjects and were compared with head-down tilt (HDT) and head-up tilt (HUT) conditions. Result. 1) The subjects could be divided into group I (n=7) and group II (n =7) according to the feature of the target ERPs component (P3). The difference between the two groups was mainly that there was a negative slow wave after 150 ms in the ERPs of group II subjects, and that the reaction time and error rate in II group was higher than in I group. These data indicated that the psychological load on group II was larger than that on group I. 2) The reduction of mean slow potential amplitude during HDT was more significant in group II than in group I. Conclusion. The slow potential amplitude of ERPs may reflect the psychological load and the brain function state. Attention should be paid to the feature of auditory ERPs in space medical practice.

Acoustic Stimulation↗

PubMed2002

[Effects of different frequency electromagnetic fields on the differentiation of midbrain neural stem cells].

Objective. To examine the effect of electromagnetic fields (EMF) (20 Hz, 8 mT; 5 Hz, 8 mT) on the neuron-orientated differentiation of neural stem cells (NSCs) from midbrains of new-bom rats. Method. Differentiated NSCs were exposed to EMF for 2 x 15 min per day lasting for I d, 5 d, or 10 d. The sham-exposure controls were correspondingly established. Cells were fixed and processed for immunofluorescent staining using the antibody against neuron-specific marker MAP2, then the percentage of MAP2+ cells was calculated. Result. The two EMFs promoted the differentiation of a neuronal fate in different ways. Both of them came into effect even after 1 d exposure. When cells exposed to the 20 Hz EMF, the percentage of neuron-orientated cells gradually increased with longer-term exposure and the most significant effect appeared in 10 d group while that happened in 5 d group under the condition of 5 Hz EMF. The effect contrasted horizontally, significant differences between the two EMFs were observed only at 10 d groups, 20 Hz EMF having more favorable effect than 5 Hz EMF. Conclusion. 20 Hz and 5 Hz EMF could promote the differentiation of midbrain NSCs to a neuronal phenotype in different ways, suggesting that the physical induction might be another strategy to manipulate the differentiation of NSCs.

Animals↗