Special Topic on Brain Science
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2021, 10(5):12-22.
DOI: doi: 10.12146/j.issn.2095-3135.20210324001
Abstract:
Vestibular nuclei (VN) is a sensorimotor structure controlling posture and balance. The anatomy and function of VN is closely related to diseases, such as motion sickness, vestibular migraine, vertigo, postural deficits, and Parkinson’s disease. It has been known that stress imposes effects on the function of VN and the progress of these diseases. Since the locus coeruleus-norepinephrine (LC-NE) system is activated by stress, it would be interesting to know whether there is a connection between LC and VN and its possible function. The experiment results showed that LC neurons project to the VN and they are tyrosine hydroxylase (TH)-positive. After subjected to sleep deprivation stress treatment, the mice showed higher cFos activation in the LC-NE neurons compared with the untreated control group, suggesting the important role LC-NE may play in stress-related VN malfunction. This study provides anatomical basis for further neural circuity studies of LC-VN in balance and then its possible involvement in diseases.
Vestibular nuclei (VN) is a sensorimotor structure controlling posture and balance. The anatomy and function of VN is closely related to diseases, such as motion sickness, vestibular migraine, vertigo, postural deficits, and Parkinson’s disease. It has been known that stress imposes effects on the function of VN and the progress of these diseases. Since the locus coeruleus-norepinephrine (LC-NE) system is activated by stress, it would be interesting to know whether there is a connection between LC and VN and its possible function. The experiment results showed that LC neurons project to the VN and they are tyrosine hydroxylase (TH)-positive. After subjected to sleep deprivation stress treatment, the mice showed higher cFos activation in the LC-NE neurons compared with the untreated control group, suggesting the important role LC-NE may play in stress-related VN malfunction. This study provides anatomical basis for further neural circuity studies of LC-VN in balance and then its possible involvement in diseases.
2021, 10(6):97-110.
DOI: 10.12146/j.issn.2095-3135.20210331002
Abstract:
The spinal cord connects the brain to the peripheral nervous systemand plays an important role in encoding downstream brain commands and peripheral input signals during somatosensory and motor processes. Resolving the relationship between animal behavior and spinal cord neural activity through optical imaging remains a major challenge in neuroscience research. We have developed a method for in vivo imaging of the spinal cord in freely behaving mice using miniaturized two-photon fluorescence microscopy. The image quality and imaging stability of the method were evaluated by imaging the anterior spinal artery vessels, during spontaneous behavior and strenuous movements of freely behaving animals in an unrestrained environment. This physically solves the key problems in previous studies, such as image bias and loss due to the irregular motion of the spinal cord, and it achieves stable imaging of the spinal cordinfreely behaving mice based on miniaturized two-photon fluorescence microscopy. In addition, this method enables real-time imaging of individual neuronal calcium signals in the superficial neuronal activity of the spinal dorsal horn. This will provide technical support to explore the neuronal activity patterns in the spinal cord during somatosensory and motor processes, it’s important for advancing the study of spinal cordrelated functional neural networks.
The spinal cord connects the brain to the peripheral nervous systemand plays an important role in encoding downstream brain commands and peripheral input signals during somatosensory and motor processes. Resolving the relationship between animal behavior and spinal cord neural activity through optical imaging remains a major challenge in neuroscience research. We have developed a method for in vivo imaging of the spinal cord in freely behaving mice using miniaturized two-photon fluorescence microscopy. The image quality and imaging stability of the method were evaluated by imaging the anterior spinal artery vessels, during spontaneous behavior and strenuous movements of freely behaving animals in an unrestrained environment. This physically solves the key problems in previous studies, such as image bias and loss due to the irregular motion of the spinal cord, and it achieves stable imaging of the spinal cordinfreely behaving mice based on miniaturized two-photon fluorescence microscopy. In addition, this method enables real-time imaging of individual neuronal calcium signals in the superficial neuronal activity of the spinal dorsal horn. This will provide technical support to explore the neuronal activity patterns in the spinal cord during somatosensory and motor processes, it’s important for advancing the study of spinal cordrelated functional neural networks.
2022, 11(4):70-79.
DOI: 10.12146/j.issn.2095-3135.20211104001
Abstract:
Mice are widely used in various physiological, pathological and behavioral experiments. However, it is yet unclear whether or how much spontaneous behavior varies between mice with different genotypes, which may affect experiment design and outcome. In this study, three inbred mice C57BL/6J, C57BL/6N, BALB/c (6J, 6N, BC) were selected, and objectively evaluated for their spontaneous behavior with a hierarchical unsupervised learning framework for 3D animal behavioral characteristics. The results showed that genotype is the most significant factors influencing mice, with the whole list presented as distant genotype＞near genotype＞gender difference. Behavior atlas varies greatly between BC and 6J/6N groups due to obvious differences in body posture, and BC have significantly lower movement speed than 6J and 6N. Although 6J and 6N behavior atlas were relatively similar, 6N sniffed significantly than 6J, and the anxiety levels at 6N were relatively high. The results of this study can be used as a reference for experiment design, strain selection, and determination of N value in future research using mouse model.
Mice are widely used in various physiological, pathological and behavioral experiments. However, it is yet unclear whether or how much spontaneous behavior varies between mice with different genotypes, which may affect experiment design and outcome. In this study, three inbred mice C57BL/6J, C57BL/6N, BALB/c (6J, 6N, BC) were selected, and objectively evaluated for their spontaneous behavior with a hierarchical unsupervised learning framework for 3D animal behavioral characteristics. The results showed that genotype is the most significant factors influencing mice, with the whole list presented as distant genotype＞near genotype＞gender difference. Behavior atlas varies greatly between BC and 6J/6N groups due to obvious differences in body posture, and BC have significantly lower movement speed than 6J and 6N. Although 6J and 6N behavior atlas were relatively similar, 6N sniffed significantly than 6J, and the anxiety levels at 6N were relatively high. The results of this study can be used as a reference for experiment design, strain selection, and determination of N value in future research using mouse model.
2022, 11(5):23-33.
DOI: 10.12146/j.issn.2095-3135.20220217001
Abstract:
Drug addiction is an intractable chronic neuropsychiatric disorder that raises serious social problems. The study of individual susceptibility in drug addiction may contribute to our understanding of neurobiological mechanism underlying addiction and making risk assessment of individual vulnerability. Use the gray-scale analysis evaluate the hair regrowth ability, and assess the addiction susceptibility with conditioned place preference and intravenous self-administration paradigm in rats. The results revealed a significant negative correlation between addiction susceptibility and hair regrowth ability. The rats with fast hair regrowth ability exhibited less CPP score and reduced drug-seeking behavior in the methamphetamine self-administration model. The open field test showed no differences in the locomotor activity and anxiety level between the two groups. The findings may be helpful for predicting drug addiction risk and further exploring the neurobiological mechanisms of addiction susceptibility based on this phenotypic difference.
Drug addiction is an intractable chronic neuropsychiatric disorder that raises serious social problems. The study of individual susceptibility in drug addiction may contribute to our understanding of neurobiological mechanism underlying addiction and making risk assessment of individual vulnerability. Use the gray-scale analysis evaluate the hair regrowth ability, and assess the addiction susceptibility with conditioned place preference and intravenous self-administration paradigm in rats. The results revealed a significant negative correlation between addiction susceptibility and hair regrowth ability. The rats with fast hair regrowth ability exhibited less CPP score and reduced drug-seeking behavior in the methamphetamine self-administration model. The open field test showed no differences in the locomotor activity and anxiety level between the two groups. The findings may be helpful for predicting drug addiction risk and further exploring the neurobiological mechanisms of addiction susceptibility based on this phenotypic difference.
2023, 12(2):1-9.
DOI: 10.12146/j.issn.2095-3135.20220808001
Abstract:
To study the effects of pulse modulated radio frequency electromagnetic field on locomotor activity and neurotransmitter concentration in different brain regions of mice. Wild type C57BL/6J mice were randomly divided into intervention group (n＝9) and control group (n＝6). The intervention group was given pulse modulated RF electromagnetic field stimulation, while the control group was not given stimulation; 30 minutes a day for 5 days. The behavior of mice was recorded by camera, and the concentration of various neurotransmitters in mouse brain was measured by HPLC-MS. After the intervention, the locomotor activity of mice in the intervention group decreased every day compared with that before the intervention (P＜0.05); Intracortical concentrations of γ-aminobutyric acid, acetylcholine and other neurotransmitters, tryptophan and phenylalanine changed significantly (P＜0.05), the level of serotonin exhibited a tendency of decrease, but the concentration of glutamate did not change significantly. There were no significant changes in the locomotor activity, concentration of neurotransmitters, tryptophan and phenylalanine in the brain of control group animals. The 5-day continuous intervention had no negative effect on the anxiety level and autonomous behavior of mice. Pulse modulated RF electromagnetic field could exhibit rapid impact on the locomotor activity of mice, as well as the concentration of various neurotransmitters in different brain regions. The increased level of introcortical γ-aminobutyric acid may be involved in the reduced locomotor activity of mice following such RF electromagnetic field treatment.
To study the effects of pulse modulated radio frequency electromagnetic field on locomotor activity and neurotransmitter concentration in different brain regions of mice. Wild type C57BL/6J mice were randomly divided into intervention group (n＝9) and control group (n＝6). The intervention group was given pulse modulated RF electromagnetic field stimulation, while the control group was not given stimulation; 30 minutes a day for 5 days. The behavior of mice was recorded by camera, and the concentration of various neurotransmitters in mouse brain was measured by HPLC-MS. After the intervention, the locomotor activity of mice in the intervention group decreased every day compared with that before the intervention (P＜0.05); Intracortical concentrations of γ-aminobutyric acid, acetylcholine and other neurotransmitters, tryptophan and phenylalanine changed significantly (P＜0.05), the level of serotonin exhibited a tendency of decrease, but the concentration of glutamate did not change significantly. There were no significant changes in the locomotor activity, concentration of neurotransmitters, tryptophan and phenylalanine in the brain of control group animals. The 5-day continuous intervention had no negative effect on the anxiety level and autonomous behavior of mice. Pulse modulated RF electromagnetic field could exhibit rapid impact on the locomotor activity of mice, as well as the concentration of various neurotransmitters in different brain regions. The increased level of introcortical γ-aminobutyric acid may be involved in the reduced locomotor activity of mice following such RF electromagnetic field treatment.
2023, 12(2):10-19.
DOI: 10.12146/j.issn.2095-3135.20220606001
Abstract:
Photothrombotic ischemia is a common experimental ischemic stroke model. In response to light stimulation, activated photosensitive dyes produce reactive oxygen species, which in turn induces damage to the vascular endothelial cells, causing platelet adhesion, aggregation and thrombosis. Since the conventional photothrombotic ischemia model produces only a tiny ischemic penumbra which can’t properly represent the clinical pathology, a modified proximal middle cerebral artery occlusion model was established in this study. The mouse proximal middle artery was irradiated by laser for 3 minutes to induce thrombosis following injection with the light-sensitive dye Rose Bengal and subsequently evaluated by 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence, and flow cytometry. The results showed that this model produced a stable infarct area of 9% to 15% in the striatal and cortical regions, which is larger than the conventional photothrombotic ischemia. Resident microglia, infiltrating myeloid cells, and lymphocytes in the infarcted tissue were identified by flow cytometry. It is suggested that the modified proximal middle artery occlusion model can be applied to study the pathological and immune mechanisms after ischemic stroke injury.
Photothrombotic ischemia is a common experimental ischemic stroke model. In response to light stimulation, activated photosensitive dyes produce reactive oxygen species, which in turn induces damage to the vascular endothelial cells, causing platelet adhesion, aggregation and thrombosis. Since the conventional photothrombotic ischemia model produces only a tiny ischemic penumbra which can’t properly represent the clinical pathology, a modified proximal middle cerebral artery occlusion model was established in this study. The mouse proximal middle artery was irradiated by laser for 3 minutes to induce thrombosis following injection with the light-sensitive dye Rose Bengal and subsequently evaluated by 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence, and flow cytometry. The results showed that this model produced a stable infarct area of 9% to 15% in the striatal and cortical regions, which is larger than the conventional photothrombotic ischemia. Resident microglia, infiltrating myeloid cells, and lymphocytes in the infarcted tissue were identified by flow cytometry. It is suggested that the modified proximal middle artery occlusion model can be applied to study the pathological and immune mechanisms after ischemic stroke injury.
2023, 12(2):20-28.
DOI: 10.12146/j.issn.2095-3135.20221013001
Abstract:
Electrical nerve stimulation is an effective method for certain treatments by affecting the central or peripheral nervous system. The instability of electrical nerve stimulation is a critical problem in clinical practice. It is a widely held view that the mechanism of the instability is that the electrical stimulation disturbs the membrane potential of nerve axons. However, due to the lack of a computable macro model for electrical nerve stimulation, it is difficult to effectively study the specific impact of its membrane potential disturbance on electrical stimulation for a long time. Based on the previously proposed circuit-probability theory, this study qualitatively analyzes the instability of electrical nerve stimulation to effectively research the influence of membrane potential disturbance on electrical stimulation. The results show that the current-instability curve of animal experimental data and qualitative simulation is highly consistent, which further indicates that the circuit-probability theory might explain the membrane potential disturbance caused by electrical stimulation and has instructive significance for the practical application of electrical nerve stimulation.
Electrical nerve stimulation is an effective method for certain treatments by affecting the central or peripheral nervous system. The instability of electrical nerve stimulation is a critical problem in clinical practice. It is a widely held view that the mechanism of the instability is that the electrical stimulation disturbs the membrane potential of nerve axons. However, due to the lack of a computable macro model for electrical nerve stimulation, it is difficult to effectively study the specific impact of its membrane potential disturbance on electrical stimulation for a long time. Based on the previously proposed circuit-probability theory, this study qualitatively analyzes the instability of electrical nerve stimulation to effectively research the influence of membrane potential disturbance on electrical stimulation. The results show that the current-instability curve of animal experimental data and qualitative simulation is highly consistent, which further indicates that the circuit-probability theory might explain the membrane potential disturbance caused by electrical stimulation and has instructive significance for the practical application of electrical nerve stimulation.
2018, 7(5):29-35.
DOI: 10.12146/j.issn.2095-3135.201805004
Abstract:
Microglia is one of the important non-neoplastic elements of cerebral glioma. The interaction of glioma and microglia promotes tumor progression. However, the spatiotemporal heterogeneity of the microglia in the context of glioma remains uncertain. In this study, cerebral glioma model was built with C6 cell implantation in 28 SD rats to investigate the distribution of microglia during the tumor progression. T2 weighted magnetic resonance imaging (T2WI) was conducted at the post-operative day 7, 9, 12, 14, 16, 18, 22, 23 and 24 after the model built-up, after which the Hematoxylin-Eosin (HE) and immunofluorescent staining of the brain tissue were prepared. Nine regions of interest (ROI) were defined within the tumor, as the peritumoral and the contralesional areas on the HE sections with the largest tumor expansion. Scale-invariant feature transform (SIFT) algorithm was used to register and fuse the HE-immunofluorescent image pairs. ROIs defined on the HE sections were then translated to the immunofluorescence images. The averaged signal intensity was measured on the T2WI image with the largest tumor diameter. Mean density (MD) of the microglia in the ROIs were measured for each ROI and plotted with the time after C6 cell implantation. It can be observed that MD in the tumor ROI was significantly larger than that of the rest ROIs (P＜0.001). MD increased with time and diameter that best fit to binomial and linear functions, respectively, for all the ROIs with a more precipitous inclination in the tumor MD. The average signal intensity of the ROIs on T2WI were also found positively correlated with the tumor MD. These findings indicate that tumor formation of C6 glioma triggers extensive microglia activation in the tumor and the non-neoplastic brain tissue, necessitating the assessment of microglia in both the local and global scales in performing the aggressiveness characterization and treatment trials targeting microenvironment of cerebral glioma.
Microglia is one of the important non-neoplastic elements of cerebral glioma. The interaction of glioma and microglia promotes tumor progression. However, the spatiotemporal heterogeneity of the microglia in the context of glioma remains uncertain. In this study, cerebral glioma model was built with C6 cell implantation in 28 SD rats to investigate the distribution of microglia during the tumor progression. T2 weighted magnetic resonance imaging (T2WI) was conducted at the post-operative day 7, 9, 12, 14, 16, 18, 22, 23 and 24 after the model built-up, after which the Hematoxylin-Eosin (HE) and immunofluorescent staining of the brain tissue were prepared. Nine regions of interest (ROI) were defined within the tumor, as the peritumoral and the contralesional areas on the HE sections with the largest tumor expansion. Scale-invariant feature transform (SIFT) algorithm was used to register and fuse the HE-immunofluorescent image pairs. ROIs defined on the HE sections were then translated to the immunofluorescence images. The averaged signal intensity was measured on the T2WI image with the largest tumor diameter. Mean density (MD) of the microglia in the ROIs were measured for each ROI and plotted with the time after C6 cell implantation. It can be observed that MD in the tumor ROI was significantly larger than that of the rest ROIs (P＜0.001). MD increased with time and diameter that best fit to binomial and linear functions, respectively, for all the ROIs with a more precipitous inclination in the tumor MD. The average signal intensity of the ROIs on T2WI were also found positively correlated with the tumor MD. These findings indicate that tumor formation of C6 glioma triggers extensive microglia activation in the tumor and the non-neoplastic brain tissue, necessitating the assessment of microglia in both the local and global scales in performing the aggressiveness characterization and treatment trials targeting microenvironment of cerebral glioma.
2019, 8(3):19-30.
DOI: 10.12146/j.issn.2095-3135.20190301001
Abstract:
Dorsomedial hypothalamic nucleus (DMH) is an important component of autonomic nervous system, which has extensive connections with limbic system. DMH may participates in the regulation of negative emotions, such as anxiety and fear. However, the cellular mechanisms are still unknown. In this study, elevated plus maze and open filed tests were performed, and a bidirectional effect of optogenetic modulation on behaviors was found. Activating the DMH glutamatergic or gamma-aminobutyric acid (GABAergic) neurons leading to the anxiety-like behavior and increasing of heart rate, while optical inhibition significantly suppressed the anxiety-like behavior and decreased heart rate. These findings may provide new targets for clinical therapy for neuropsychiatric disorders.
Dorsomedial hypothalamic nucleus (DMH) is an important component of autonomic nervous system, which has extensive connections with limbic system. DMH may participates in the regulation of negative emotions, such as anxiety and fear. However, the cellular mechanisms are still unknown. In this study, elevated plus maze and open filed tests were performed, and a bidirectional effect of optogenetic modulation on behaviors was found. Activating the DMH glutamatergic or gamma-aminobutyric acid (GABAergic) neurons leading to the anxiety-like behavior and increasing of heart rate, while optical inhibition significantly suppressed the anxiety-like behavior and decreased heart rate. These findings may provide new targets for clinical therapy for neuropsychiatric disorders.
2019, 8(6):39-47.
DOI: 10.12146/j.issn.2095-3135.20190729005
Abstract:
Ischemic stroke is an acute cerebrovascular disease. Currently, it is treated mainly by timely thrombolysis or mechanical thrombectomy to achieve vascular recanalization, but this process causes serious reperfusion injury to cerebrovasculature, damages the structure and function of the blood-brain barrier (BBB), and increases the risk of cerebral hemorrhage. Studies have shown that the Wnt/β-catenin signaling pathway plays a critical role in regulating the function of BBB, but whether the R-spondin, an agonistic protein of the Wnt/β-catenin signaling pathway, plays a role in regulation of BBB and cerebral injury is unclear. In this study, using mouse recombinant R-spondin-1 protein prepared in vitro, we determined the activation of Wnt/β-catenin signaling pathway induced by combined treatment of the R-spondin-1 protein and Wnt3a protein in mouse primary cerebrovascular endothelial cells, and found that R-spondin1 significantly changed the expression levels of BBB function related genes Cldn3 and Plvap. In a mouse cerebral ischemia/reperfusion model, intravenous injection of recombinant R-spondin-1 protein was inclined to reduce the cerebral infarction and increase mouse survival but did not reach statistical significance compared to phosphate buffer solution controls. Our study reported the molecular mechanisms of BBB function regulation by R-spondin protein, and preliminarily identified its therapeutic effect on cerebral injury following stroke and potential for clinical use.
Ischemic stroke is an acute cerebrovascular disease. Currently, it is treated mainly by timely thrombolysis or mechanical thrombectomy to achieve vascular recanalization, but this process causes serious reperfusion injury to cerebrovasculature, damages the structure and function of the blood-brain barrier (BBB), and increases the risk of cerebral hemorrhage. Studies have shown that the Wnt/β-catenin signaling pathway plays a critical role in regulating the function of BBB, but whether the R-spondin, an agonistic protein of the Wnt/β-catenin signaling pathway, plays a role in regulation of BBB and cerebral injury is unclear. In this study, using mouse recombinant R-spondin-1 protein prepared in vitro, we determined the activation of Wnt/β-catenin signaling pathway induced by combined treatment of the R-spondin-1 protein and Wnt3a protein in mouse primary cerebrovascular endothelial cells, and found that R-spondin1 significantly changed the expression levels of BBB function related genes Cldn3 and Plvap. In a mouse cerebral ischemia/reperfusion model, intravenous injection of recombinant R-spondin-1 protein was inclined to reduce the cerebral infarction and increase mouse survival but did not reach statistical significance compared to phosphate buffer solution controls. Our study reported the molecular mechanisms of BBB function regulation by R-spondin protein, and preliminarily identified its therapeutic effect on cerebral injury following stroke and potential for clinical use.
2020, 9(1):1-11.
DOI: 10.12146/j.issn.2095-3135.20191013001
Abstract:
Glioma is a serious brain disease that seriously endangers human health. Early diagnosis and therapy of glioma play a vital role in improving the survival of glioma patients. Currently, the diagnosis of brain glioma mainly relies on advanced instruments such as magnetic resonance imaging and computed tomography, which is difficult to accurately identify the margin of brain tumor and guide intraoperative surgical resection of the lesion. Moreover, due to the limitation of blood-brain barrier, the concentration of drugs into the brain tissue is very low, which is difficult to achieve good therapeutic effect and has serious side effects. In recent years, the rapid development of nanotechnology has brought new hope for accurate diagnosis and therapy of glioma. With the advantages of high sensitivity, high specificity and multifunction, the new functional nanoprobe has been successfully applied in the research of multimodality diagnosis and treatment of glioma. This article mainly introduces the recent advances of nanoprobe for precise diagnosis and treatment of glioma, focusing on the nanoprobes passing through the blood-brain barrier, multimodality imagingguided glioma margin identification and imaging guided precision glioma treatment. The preparation and surface functionalization modification of nanoprobe, as well as for glioma imaging and treatment are further discussed. Finally, the opportunities and challenges faced by functional nanoprobes in the clinical application are prospected.
Glioma is a serious brain disease that seriously endangers human health. Early diagnosis and therapy of glioma play a vital role in improving the survival of glioma patients. Currently, the diagnosis of brain glioma mainly relies on advanced instruments such as magnetic resonance imaging and computed tomography, which is difficult to accurately identify the margin of brain tumor and guide intraoperative surgical resection of the lesion. Moreover, due to the limitation of blood-brain barrier, the concentration of drugs into the brain tissue is very low, which is difficult to achieve good therapeutic effect and has serious side effects. In recent years, the rapid development of nanotechnology has brought new hope for accurate diagnosis and therapy of glioma. With the advantages of high sensitivity, high specificity and multifunction, the new functional nanoprobe has been successfully applied in the research of multimodality diagnosis and treatment of glioma. This article mainly introduces the recent advances of nanoprobe for precise diagnosis and treatment of glioma, focusing on the nanoprobes passing through the blood-brain barrier, multimodality imagingguided glioma margin identification and imaging guided precision glioma treatment. The preparation and surface functionalization modification of nanoprobe, as well as for glioma imaging and treatment are further discussed. Finally, the opportunities and challenges faced by functional nanoprobes in the clinical application are prospected.
2020, 9(1):28-35.
DOI: 10.12146/j.issn.2095-3135.20191129001
Abstract:
The auditory brainstem response (ABR) is an objective method to detect hearing loss. Generally, the ABR induced by click is considered as the gold standard. However, the click-induced ABR is mainly used to assess high-frequency hearing due to the delayed characteristics of human cochlear basilar membrane. In order to compensate for the limitation of the ABR induced by click, a swept-tone stimulus that adjusts the occurrence time of different frequency components was proposed and used to evoke the ABR in this study. The swept-tone evoked ABR was compared with the click evoked ABR at different test levels and different stimulus rates. The experimental results show that the waveform morphology of the swept-tone ABR is better than that of the click ABR. In addition, the swept-tone ABR and the click ABR after different sweeps were also calculated under a different number of sweeps, and the results show that the swept-tone ABR could save recording time compared to the click ABR. These results suggest that the proposed swept-tone ABR could be more sensitive than the commonly used click ABR in the detection of hearing loss.
The auditory brainstem response (ABR) is an objective method to detect hearing loss. Generally, the ABR induced by click is considered as the gold standard. However, the click-induced ABR is mainly used to assess high-frequency hearing due to the delayed characteristics of human cochlear basilar membrane. In order to compensate for the limitation of the ABR induced by click, a swept-tone stimulus that adjusts the occurrence time of different frequency components was proposed and used to evoke the ABR in this study. The swept-tone evoked ABR was compared with the click evoked ABR at different test levels and different stimulus rates. The experimental results show that the waveform morphology of the swept-tone ABR is better than that of the click ABR. In addition, the swept-tone ABR and the click ABR after different sweeps were also calculated under a different number of sweeps, and the results show that the swept-tone ABR could save recording time compared to the click ABR. These results suggest that the proposed swept-tone ABR could be more sensitive than the commonly used click ABR in the detection of hearing loss.
2020, 9(4):11-24.
DOI: 10.12146/j.issn.2095-3135.20200509001
Abstract:
Selection and decision-making involve a series of complex cognitive processes, and time-frequency analysis of electroencephalogram (EEG) signals can help understand brain activity in different cognitive tasks. In this study, a decision-making cognitive task related to the rock-paper-scissors game was designed. By setting the selection probability of the computer (rock 66%, scissors 33%, paper 1%), the subjects are able to make safe or risky decisions. The complete and complex decision task was divided into three stages (planning stage, confirmation stage and feedback stage). During the entire experiment, the NeuroscanQuikCap EEG measurement system recorded data with 64 EEG signal channels in real time. By extracting the characteristics of the change of the average spectral power and the phase synchronization value of each EEG frequency band (δ, θ, α, and β), a comparative analysis of the EEG waves at different task stages was realized. The results show that in the planning stage, the subject’s decision-making activities that want to win or do not want to lose are related to the enhanced activity effects of the parietal lobe α wave and the forehead θ wave. The order in which the brain waves appear may indicate that the subjects will make different types of decision plans. In the confirmation stage, the α wave spectrum power suppression effect and the δ wave phase synchronization enhancement activity show that the subject will increase attention after confirming the choice. In the feedback stage, the θ and β wave power spectrum increase effect and the α wave power spectrum decrease effect are related to different feed back results. And the effects are most obvious in the feedback that the subject finds the game lost. This preliminary study shows that, combined with a complete cognitive task, time-frequency analysis of EEG signals may be an important tool for visualizing brain activity in response to different cognitive functions. It also contributes to the further development for objective cognitive assessment solutions.
Selection and decision-making involve a series of complex cognitive processes, and time-frequency analysis of electroencephalogram (EEG) signals can help understand brain activity in different cognitive tasks. In this study, a decision-making cognitive task related to the rock-paper-scissors game was designed. By setting the selection probability of the computer (rock 66%, scissors 33%, paper 1%), the subjects are able to make safe or risky decisions. The complete and complex decision task was divided into three stages (planning stage, confirmation stage and feedback stage). During the entire experiment, the NeuroscanQuikCap EEG measurement system recorded data with 64 EEG signal channels in real time. By extracting the characteristics of the change of the average spectral power and the phase synchronization value of each EEG frequency band (δ, θ, α, and β), a comparative analysis of the EEG waves at different task stages was realized. The results show that in the planning stage, the subject’s decision-making activities that want to win or do not want to lose are related to the enhanced activity effects of the parietal lobe α wave and the forehead θ wave. The order in which the brain waves appear may indicate that the subjects will make different types of decision plans. In the confirmation stage, the α wave spectrum power suppression effect and the δ wave phase synchronization enhancement activity show that the subject will increase attention after confirming the choice. In the feedback stage, the θ and β wave power spectrum increase effect and the α wave power spectrum decrease effect are related to different feed back results. And the effects are most obvious in the feedback that the subject finds the game lost. This preliminary study shows that, combined with a complete cognitive task, time-frequency analysis of EEG signals may be an important tool for visualizing brain activity in response to different cognitive functions. It also contributes to the further development for objective cognitive assessment solutions.
