The development and plasticity of central auditory system can be influenced by the change of peripheral neuronal activity. However, the molecular mechanism participating in the process remains elusive. Brain-derived n...The development and plasticity of central auditory system can be influenced by the change of peripheral neuronal activity. However, the molecular mechanism participating in the process remains elusive. Brain-derived neurotrophic factor(BDNF) binding with its functional receptor tropomyosin receptor kinase B(TrkB) has multiple effects on neurons. Here we used a rat model of auditory deprivation by bilateral cochlear ablation, to investigate the changes in expression of BDNF and Trk B in the auditory cortex after auditory deprivation that occurred during the critical period for the development of central auditory system. Reverse transcription-quantitative polymerase chain reaction(RTqPCR) and immunohistochemistry methods were adopted to detect the m RNA and protein expression levels of BDNF and TrkB in the auditory cortex at 2, 4, 6 and 8 weeks after surgery, respectively. The change in the expression of BDNF and TrkB mRNAs and proteins followed similar trend. In the bilateral cochlear ablation groups, the BDNF-TrkB expression level initially decreased at 2 weeks but increased at 4 weeks followed by the reduction at 6 and 8 weeks after cochlear removal, as compared to the age-matched sham control groups. In conclusion, the BDNF-TrkB signaling is involved in the plasticity of auditory cortex in an activity-dependent manner.展开更多
There is growing evidence suggests that noise-induced cochlear damage may lead to hyperexcitability in the central auditory system(CAS)which may give rise to tinnitus.However,the correlation between the onset of the n...There is growing evidence suggests that noise-induced cochlear damage may lead to hyperexcitability in the central auditory system(CAS)which may give rise to tinnitus.However,the correlation between the onset of the neurophysiological changes in the CAS and the onset of tinnitus has not been well studied.To investigate this relationship,chronic electrodes were implanted into the auditory cortex(AC) and sound evoked activities were measured from awake rats before and after noise exposure.The auditory brainstem response(ABR) was used to assess the degree of noise-induced hearing loss.Tinnitus was evaluated by measuring gap-induced prepulse inhibition(gap-PPI).Rats were exposed monaurally to a high-intensity narrowband noise centered at 12 kHz at a level of 120 dB SPL for 1 h.After the noise exposure,all the rats developed either permanent(>2 weeks) or temporary(<3 days) hearing loss in the exposed ear(s).The AC amplitudes increased significantly 4 h after the noise exposure.Most of the exposed rats also showed decreased gap-PPI.The post-exposure AC enhancement showed a positive correlation with the amount of hearing loss.The onset of tinnitus-like behavior was happened after the onset of AC enhancement.展开更多
Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 1...Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.展开更多
The estrous cycle is a physiological process modulated by hormonal changes associated, in turn, with alterations of the attraction or sensitivity with which females perceive different sensory stimuli. Auditory stimuli...The estrous cycle is a physiological process modulated by hormonal changes associated, in turn, with alterations of the attraction or sensitivity with which females perceive different sensory stimuli. Auditory stimuli play an important role in the social interaction of several mammals, including their sexual behavior and the mother-young relationship. Since the prefrontal cortex (PFC) and nucleus accumbens (Acc) had been associated with the processing and assignation of the incentive value of stimuli, this study was designed to analyze whether electroencephalographic (EEG) activity in the PFC and Acc was modified during the two antagonist phases of the estrous cycle (proestrus-estrus and diestrus) when female rats heard sound recordings with different types of cries emitted by other rats. EEGs were recorded in eight female virgin Wistar rats, 80-100 days old, bilaterally implanted in the PFC and Acc during an awake-quiet state, in three conditions: when hearing 1) cries of pups;2) cries of adult male rats;and, 3) cries of adult female rats. The cries were recorded from pups (2-10 days old) and male and female adult rats after gentle prodding by a human hand. Each auditory stimulus (which included vocalizations up to 22 kHz) was randomly played back through a speaker placed near the female rats. Only upon perceiving the cries of male rats did the females in the proestrus-estrous phase show a lower relative power in the 14-30 Hz band in the Acc and an increased inter-prefrontal correlation in the 8-13 Hz band. It is probable that these EEG changes are associated with the lower activation or non-anxious state that the female rat presents specifically during the proestrus-estrous phase in response to the alarm cries of adult male rats.展开更多
Objective Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) was used to study activation signals in the brain cortex evoked by tone stimulation in patients with tinnitus for its poten...Objective Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) was used to study activation signals in the brain cortex evoked by tone stimulation in patients with tinnitus for its potential utility as an objective indicator of tinnitus. Methods BOLD-fMRI examination was conducted in 7 patients with chronic tinnitus and 15 control subjects. The activation signal in the brain cortex was recorded. Results Significant activation was found in temporal lobe in control subjects, with greater signal volume and intensity on the contralateral than ipsilateral auditory cortex (P < 0.01). However, there was no discernable patterns in the anatomical location, volume and intensity of cortical activation signals in patients with chronic tinnitus. Conclusions Patients with chronic tinnitus may have abnormal neural activities in the auditory cortex.展开更多
Background: Several studies reported on the effectiveness of 1 Hz repeated transcranial magnetic stimulation (rTMS) over the temporoparietal cortex (TPC) on refractory auditory hallucinations (AH) in schizophrenia but...Background: Several studies reported on the effectiveness of 1 Hz repeated transcranial magnetic stimulation (rTMS) over the temporoparietal cortex (TPC) on refractory auditory hallucinations (AH) in schizophrenia but little is known about the long-term therapeutic effect of this tool. Aim: The aim of this study was to evaluate rTMS’ impact on auditory hallucinations (AH) and cognitive functions in patients with schizophrenia with a three-month follow-up. Methods: In a randomized double blind sham controlled study, 26 patients with refractory schizophrenia received 1 Hz rTMS applied on TPC for four weeks. rTMS was given to patients over one month with five rTMS sessions each week. Patients were evaluated via AHRS (Auditory Hallucination Rating Scale, Hoffman et al.), PANSS (Positive and Negative Syndrome Scale, Kay et al. 1988), and CGI (Clinical Global Impression) before treatment by rTMS every week during the first month, and every month until the third month. Results: Neither clinical nor cognitive differences were found between rTMS and placebo. Conclusion: 1 Hz rTMS using parameters mentioned above has no statistically significant effect on AH;although evidences about the potential benefit of rTMS in the treatment of AH negative results suggest the need for further studies in this area.展开更多
The basic morphological aspects of auditory cortex organization in different orders of eutherian mammals are considered in the present review. The modern data describing a partitioning of mammalian auditory cortex int...The basic morphological aspects of auditory cortex organization in different orders of eutherian mammals are considered in the present review. The modern data describing a partitioning of mammalian auditory cortex into subfields are presented. A detailed observation of the structural organization of primary auditory cortex is given, as well as a review of recent morphological data about secondary auditory areas. Another section describes the system of auditory cortical projections. The data are considered from the perspective of possible homologies existing between the auditory cortices in different mammalian species.展开更多
Tinnitus, the phenomenon of ringing or buzzing in the ears without an external sound source is one of the most commonly reported symptoms in otorhinolaryngology and affects 10 - 15% of the general population. Models h...Tinnitus, the phenomenon of ringing or buzzing in the ears without an external sound source is one of the most commonly reported symptoms in otorhinolaryngology and affects 10 - 15% of the general population. Models have been developed to account for neural basis of tinnitus, its pathogenesis and its consequences on mental health （deRidder et al., 2013）. In most cases tinnitus onset follows a partial hearing impairment. Peripheral sensory deprivation due to cochlear damages may prompt increased neuronal activity in the central auditory system in order to adapt the neural sensitivity to the reduced sensory inputs. This central gain could over amplify the ＂neural noise＂ and thus trigger a homeostatic down-regulation of inhib- itory synapses in the auditory cortical map leading to specific reorganization of the cortical representation of the tinnitus percept. Dysfunctional feedback connections from limbic regions to auditory brain areas, interacting at the thalamic level, may account for the psychological impairment.展开更多
Major depressive disorder(MDD),characterized by anhedonia,loss of motivation,behavioral despair,and cognitive abnormalities[1],stands as the second leading cause of disability worldwide[2]owing to its heightened preva...Major depressive disorder(MDD),characterized by anhedonia,loss of motivation,behavioral despair,and cognitive abnormalities[1],stands as the second leading cause of disability worldwide[2]owing to its heightened prevalence,suicide rates,and recurrence[3].Empirical evidence and clinical observations have substantiated the notion that patients with MDD often exhibit compromised auditory perception[4].展开更多
Transcranial direct current stimulation(tDCS)has been reportedly beneficial for different neurodegenerative disorders.tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallu...Transcranial direct current stimulation(tDCS)has been reportedly beneficial for different neurodegenerative disorders.tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallucination(AVH).This study aims to review the effects of tDCS on AVH in patients with schizophrenia through combining the evidence from randomized clinical trials(RCTs).The databases of PsycINFO(2000–2019),PubMed(2000–2019),EMBASE(2000–2019),CINAHL(2000–2019),Web of Science(2000–2019),and Scopus(2000–2019)were systematically searched.The clinical trials with RCT design were selected for final analysis.A total of nine RCTs were eligible and included in the review.Nine RCTs were included in the final analysis.Among them,six RCTs reported a significant reduction of AVH after repeated sessions of tDCS,whereas three RCTs did not show any advantage of active tDCS over sham tDCS.The current studies showed an overall decrease of approximately 28%of AVH after active tDCS and 10%after sham tDCS.The tDCS protocols targeting the sensorimotor frontal-parietal network showed greater treatment effects compared with the protocols targeting other regions.In this regard,cathodal tDCS over the left temporoparietal area showed inhibitory effects on AVHs.The most effective tDCS protocol on AVHs was twice-daily sessions(2 mA,20-minute duration)over 5 consecutive days(10 sessions)with the anode over the left dorsolateral prefrontal cortex and the cathode over the left temporal area.Some patient-specific and diseasespecific factors such as young age,nonsmoking status,and higher frequencies of AVHs seemed to be the predictors of treatment response.Taken together,the results of tDCS as an alternative treatment option for AVH show controversy among current literatures,since not all studies were positive.However,the studies targeting the same site of the brain showed that the tDCS could be a promising treatment option to reduce AVH.Further RCTs,with larger sample sizes,should be conducted to reach a conclusion on the efficacy of tDCS for AVH and to develop an effective therapeutic protocol for clinical setting.展开更多
Objective:The effect of long term auditory deprivation on Cortical Auditory Evoked Potentials(CAEPs)especially in human models is not well explored.Hence,the current study was aimed to investigate the effects of long-...Objective:The effect of long term auditory deprivation on Cortical Auditory Evoked Potentials(CAEPs)especially in human models is not well explored.Hence,the current study was aimed to investigate the effects of long-term auditory deprivation and stimulability of auditory cortex in non habilitated congenitally deaf adolescents and adults using CAEPs.Methods and Results:A total of 27 non-habilitated congenitally deaf adolescents/adults with age and gender matched normal hearing adolescents/adults participated in the study.The congenitally deaf group was fitted with high gain hearing aids(first fit).Further,the CAEPs were recorded.The obtained CAEP components were assessed for group effect,source and topographical differences.The between group analysis for CAEP responses showed a significant difference only for P2 latency and amplitude.The source analysis revealed that,in the normal hearing group for CAEPs,the sources were within the temporal regions.However,in the congenitally deaf group,along with the temporal cortex,the bilateral prefrontal cortex also was activated.Conclusion:The findings revealed that it is possible to stimulate and evoke a matured CAEP response from a long deprived auditory system with adequate acoustic stimulation.The presence of CAEP responses is indicative of the functionality of the innate auditory pathway and the crossmodal plasticity in long auditory deprived individuals.展开更多
Importance: Clinical observations have implied a central origin for tinnitus and potential therapeutic effects of ascorbic acid (AA);however, the detailed mechanisms remain undetermined. Objective: To investigate chan...Importance: Clinical observations have implied a central origin for tinnitus and potential therapeutic effects of ascorbic acid (AA);however, the detailed mechanisms remain undetermined. Objective: To investigate changes in the AA levels and neural activity in the auditory cortex (AC) during salicylate-induced tinnitus. Methods: Rats were randomly divided into 3 groups: (1) saline group, which received an intraperitoneal saline injection;(2) SS group, which received an intraperitoneal sodium salicylate (SS) injection (350 mg/kg);and (3) SS+Lido group, which received an intraperitoneal SS injection (350 mg/kg) and lidocaine delivered to the AC by microdialysis. For each group, we firstly used an in vivo microdialysis technique to investigate the concentrations of AA in the AC;and secondly, we recorded the neural activity in the AC using a single-unit recording technique. Results: The AA concentration in the SS group significantly increased after SS injection, whereas that of the saline group did not change. The AA concentration in the SS+Lido group also showed an increasing trend but was significantly lower than that in the SS group. In the electrophysiological study, the spontaneous firing rate of the SS group was significantly higher than that of the saline group. In addition, the proportion of short interval discharges was also higher in the SS group than in the saline group. Both differences were reversed by lidocaine treatment. Interpretation: Our data suggest that the elevation of AA levels in the AC may be related to increased neuronal activity, which may represent the mechanism underlying salicylate-induced tinnitus.展开更多
基金supported by National Science Foundation of China (Grant 30600125)National Science Foundation Hebei Province (Grant C2011206036)
文摘The development and plasticity of central auditory system can be influenced by the change of peripheral neuronal activity. However, the molecular mechanism participating in the process remains elusive. Brain-derived neurotrophic factor(BDNF) binding with its functional receptor tropomyosin receptor kinase B(TrkB) has multiple effects on neurons. Here we used a rat model of auditory deprivation by bilateral cochlear ablation, to investigate the changes in expression of BDNF and Trk B in the auditory cortex after auditory deprivation that occurred during the critical period for the development of central auditory system. Reverse transcription-quantitative polymerase chain reaction(RTqPCR) and immunohistochemistry methods were adopted to detect the m RNA and protein expression levels of BDNF and TrkB in the auditory cortex at 2, 4, 6 and 8 weeks after surgery, respectively. The change in the expression of BDNF and TrkB mRNAs and proteins followed similar trend. In the bilateral cochlear ablation groups, the BDNF-TrkB expression level initially decreased at 2 weeks but increased at 4 weeks followed by the reduction at 6 and 8 weeks after cochlear removal, as compared to the age-matched sham control groups. In conclusion, the BDNF-TrkB signaling is involved in the plasticity of auditory cortex in an activity-dependent manner.
文摘There is growing evidence suggests that noise-induced cochlear damage may lead to hyperexcitability in the central auditory system(CAS)which may give rise to tinnitus.However,the correlation between the onset of the neurophysiological changes in the CAS and the onset of tinnitus has not been well studied.To investigate this relationship,chronic electrodes were implanted into the auditory cortex(AC) and sound evoked activities were measured from awake rats before and after noise exposure.The auditory brainstem response(ABR) was used to assess the degree of noise-induced hearing loss.Tinnitus was evaluated by measuring gap-induced prepulse inhibition(gap-PPI).Rats were exposed monaurally to a high-intensity narrowband noise centered at 12 kHz at a level of 120 dB SPL for 1 h.After the noise exposure,all the rats developed either permanent(>2 weeks) or temporary(<3 days) hearing loss in the exposed ear(s).The AC amplitudes increased significantly 4 h after the noise exposure.Most of the exposed rats also showed decreased gap-PPI.The post-exposure AC enhancement showed a positive correlation with the amount of hearing loss.The onset of tinnitus-like behavior was happened after the onset of AC enhancement.
文摘Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.
文摘The estrous cycle is a physiological process modulated by hormonal changes associated, in turn, with alterations of the attraction or sensitivity with which females perceive different sensory stimuli. Auditory stimuli play an important role in the social interaction of several mammals, including their sexual behavior and the mother-young relationship. Since the prefrontal cortex (PFC) and nucleus accumbens (Acc) had been associated with the processing and assignation of the incentive value of stimuli, this study was designed to analyze whether electroencephalographic (EEG) activity in the PFC and Acc was modified during the two antagonist phases of the estrous cycle (proestrus-estrus and diestrus) when female rats heard sound recordings with different types of cries emitted by other rats. EEGs were recorded in eight female virgin Wistar rats, 80-100 days old, bilaterally implanted in the PFC and Acc during an awake-quiet state, in three conditions: when hearing 1) cries of pups;2) cries of adult male rats;and, 3) cries of adult female rats. The cries were recorded from pups (2-10 days old) and male and female adult rats after gentle prodding by a human hand. Each auditory stimulus (which included vocalizations up to 22 kHz) was randomly played back through a speaker placed near the female rats. Only upon perceiving the cries of male rats did the females in the proestrus-estrous phase show a lower relative power in the 14-30 Hz band in the Acc and an increased inter-prefrontal correlation in the 8-13 Hz band. It is probable that these EEG changes are associated with the lower activation or non-anxious state that the female rat presents specifically during the proestrus-estrous phase in response to the alarm cries of adult male rats.
文摘Objective Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) was used to study activation signals in the brain cortex evoked by tone stimulation in patients with tinnitus for its potential utility as an objective indicator of tinnitus. Methods BOLD-fMRI examination was conducted in 7 patients with chronic tinnitus and 15 control subjects. The activation signal in the brain cortex was recorded. Results Significant activation was found in temporal lobe in control subjects, with greater signal volume and intensity on the contralateral than ipsilateral auditory cortex (P < 0.01). However, there was no discernable patterns in the anatomical location, volume and intensity of cortical activation signals in patients with chronic tinnitus. Conclusions Patients with chronic tinnitus may have abnormal neural activities in the auditory cortex.
文摘Background: Several studies reported on the effectiveness of 1 Hz repeated transcranial magnetic stimulation (rTMS) over the temporoparietal cortex (TPC) on refractory auditory hallucinations (AH) in schizophrenia but little is known about the long-term therapeutic effect of this tool. Aim: The aim of this study was to evaluate rTMS’ impact on auditory hallucinations (AH) and cognitive functions in patients with schizophrenia with a three-month follow-up. Methods: In a randomized double blind sham controlled study, 26 patients with refractory schizophrenia received 1 Hz rTMS applied on TPC for four weeks. rTMS was given to patients over one month with five rTMS sessions each week. Patients were evaluated via AHRS (Auditory Hallucination Rating Scale, Hoffman et al.), PANSS (Positive and Negative Syndrome Scale, Kay et al. 1988), and CGI (Clinical Global Impression) before treatment by rTMS every week during the first month, and every month until the third month. Results: Neither clinical nor cognitive differences were found between rTMS and placebo. Conclusion: 1 Hz rTMS using parameters mentioned above has no statistically significant effect on AH;although evidences about the potential benefit of rTMS in the treatment of AH negative results suggest the need for further studies in this area.
文摘The basic morphological aspects of auditory cortex organization in different orders of eutherian mammals are considered in the present review. The modern data describing a partitioning of mammalian auditory cortex into subfields are presented. A detailed observation of the structural organization of primary auditory cortex is given, as well as a review of recent morphological data about secondary auditory areas. Another section describes the system of auditory cortical projections. The data are considered from the perspective of possible homologies existing between the auditory cortices in different mammalian species.
基金supported by KTS Klaus Tschira Stiftung g Gmb H.And many thanks to Dr.Carrie Ankerstein for stylistic and linguistic improvement of this paper
文摘Tinnitus, the phenomenon of ringing or buzzing in the ears without an external sound source is one of the most commonly reported symptoms in otorhinolaryngology and affects 10 - 15% of the general population. Models have been developed to account for neural basis of tinnitus, its pathogenesis and its consequences on mental health （deRidder et al., 2013）. In most cases tinnitus onset follows a partial hearing impairment. Peripheral sensory deprivation due to cochlear damages may prompt increased neuronal activity in the central auditory system in order to adapt the neural sensitivity to the reduced sensory inputs. This central gain could over amplify the ＂neural noise＂ and thus trigger a homeostatic down-regulation of inhib- itory synapses in the auditory cortical map leading to specific reorganization of the cortical representation of the tinnitus percept. Dysfunctional feedback connections from limbic regions to auditory brain areas, interacting at the thalamic level, may account for the psychological impairment.
基金supported by the Open Project of State Key Laboratory of Natural Medicines(SKLNMKF202209)the National Natural Science Foundation of China(Nos:82074110 and 82274193)。
文摘Major depressive disorder(MDD),characterized by anhedonia,loss of motivation,behavioral despair,and cognitive abnormalities[1],stands as the second leading cause of disability worldwide[2]owing to its heightened prevalence,suicide rates,and recurrence[3].Empirical evidence and clinical observations have substantiated the notion that patients with MDD often exhibit compromised auditory perception[4].
文摘Transcranial direct current stimulation(tDCS)has been reportedly beneficial for different neurodegenerative disorders.tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallucination(AVH).This study aims to review the effects of tDCS on AVH in patients with schizophrenia through combining the evidence from randomized clinical trials(RCTs).The databases of PsycINFO(2000–2019),PubMed(2000–2019),EMBASE(2000–2019),CINAHL(2000–2019),Web of Science(2000–2019),and Scopus(2000–2019)were systematically searched.The clinical trials with RCT design were selected for final analysis.A total of nine RCTs were eligible and included in the review.Nine RCTs were included in the final analysis.Among them,six RCTs reported a significant reduction of AVH after repeated sessions of tDCS,whereas three RCTs did not show any advantage of active tDCS over sham tDCS.The current studies showed an overall decrease of approximately 28%of AVH after active tDCS and 10%after sham tDCS.The tDCS protocols targeting the sensorimotor frontal-parietal network showed greater treatment effects compared with the protocols targeting other regions.In this regard,cathodal tDCS over the left temporoparietal area showed inhibitory effects on AVHs.The most effective tDCS protocol on AVHs was twice-daily sessions(2 mA,20-minute duration)over 5 consecutive days(10 sessions)with the anode over the left dorsolateral prefrontal cortex and the cathode over the left temporal area.Some patient-specific and diseasespecific factors such as young age,nonsmoking status,and higher frequencies of AVHs seemed to be the predictors of treatment response.Taken together,the results of tDCS as an alternative treatment option for AVH show controversy among current literatures,since not all studies were positive.However,the studies targeting the same site of the brain showed that the tDCS could be a promising treatment option to reduce AVH.Further RCTs,with larger sample sizes,should be conducted to reach a conclusion on the efficacy of tDCS for AVH and to develop an effective therapeutic protocol for clinical setting.
文摘Objective:The effect of long term auditory deprivation on Cortical Auditory Evoked Potentials(CAEPs)especially in human models is not well explored.Hence,the current study was aimed to investigate the effects of long-term auditory deprivation and stimulability of auditory cortex in non habilitated congenitally deaf adolescents and adults using CAEPs.Methods and Results:A total of 27 non-habilitated congenitally deaf adolescents/adults with age and gender matched normal hearing adolescents/adults participated in the study.The congenitally deaf group was fitted with high gain hearing aids(first fit).Further,the CAEPs were recorded.The obtained CAEP components were assessed for group effect,source and topographical differences.The between group analysis for CAEP responses showed a significant difference only for P2 latency and amplitude.The source analysis revealed that,in the normal hearing group for CAEPs,the sources were within the temporal regions.However,in the congenitally deaf group,along with the temporal cortex,the bilateral prefrontal cortex also was activated.Conclusion:The findings revealed that it is possible to stimulate and evoke a matured CAEP response from a long deprived auditory system with adequate acoustic stimulation.The presence of CAEP responses is indicative of the functionality of the innate auditory pathway and the crossmodal plasticity in long auditory deprived individuals.
基金National Science Foundation of China(21272018,90813032)Beijing Municipal Natural Science Foundation(7112144).
文摘Importance: Clinical observations have implied a central origin for tinnitus and potential therapeutic effects of ascorbic acid (AA);however, the detailed mechanisms remain undetermined. Objective: To investigate changes in the AA levels and neural activity in the auditory cortex (AC) during salicylate-induced tinnitus. Methods: Rats were randomly divided into 3 groups: (1) saline group, which received an intraperitoneal saline injection;(2) SS group, which received an intraperitoneal sodium salicylate (SS) injection (350 mg/kg);and (3) SS+Lido group, which received an intraperitoneal SS injection (350 mg/kg) and lidocaine delivered to the AC by microdialysis. For each group, we firstly used an in vivo microdialysis technique to investigate the concentrations of AA in the AC;and secondly, we recorded the neural activity in the AC using a single-unit recording technique. Results: The AA concentration in the SS group significantly increased after SS injection, whereas that of the saline group did not change. The AA concentration in the SS+Lido group also showed an increasing trend but was significantly lower than that in the SS group. In the electrophysiological study, the spontaneous firing rate of the SS group was significantly higher than that of the saline group. In addition, the proportion of short interval discharges was also higher in the SS group than in the saline group. Both differences were reversed by lidocaine treatment. Interpretation: Our data suggest that the elevation of AA levels in the AC may be related to increased neuronal activity, which may represent the mechanism underlying salicylate-induced tinnitus.
