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Objective@#To study the shift of oVEMP frequency tuning of unilateral Meniere′s disease, by analyzing oVEMP of air-conducted tone bursts in various frequencies.@*Methods@#From May 2016 to October 2017, 33 patients with unilateral Meniere′s from Aerospace Center Hospital were tested for oVEMP in 500 Hz and 1 000 Hz air-conducted tone bursts respectively, and 20 healthy subjects(40 ears), matched for age and sex, were used as healthy control. The amplitudes of the N1-P1 wave and the frequency amplitude ratios of 500/1 000 Hz in affected ears, unaffected ears and normal ears were compared; and receiver operating characteristic curve was analyzed for frequency amplitude ratios of 500/1 000 Hz.@*Results@#By the 500 Hz tone-burst stimulus, the provocation rates of the oVEMP were 84.9%(28/33), 93.9%(31/33) and 97.5%(39/40) in affected ears, contralateral ears and the ears of normal controls, respectively. By the stimulus of 1 000 Hz tone-burst, the provocation rates of the oVEMP were 81.8%(27/33), 87.9%(29/33) and 82.5% (33/40) in affected ears, contralateral ears and normal control ears, respectively. Amplitudes of N1-P1 waveforms in 500 Hz air-conducted tone bursts in affected ears were under normal control ears and contralateral ears. There was significant difference between affected ears and healthy control ears (P<0.05). Amplitudes of N1-P1 waveforms in contralateral ears were also significantly smaller than those in normal control ears (P<0.05). There were no significant differences in amplitudes of N1-P1 waveforms between affected ears, contralateral ears and normal control ears in 1 000 Hz tone bursts stimulus(P>0.05). Frequency amplitude ratios of 500/1 000 Hz in affected ears were significantly under contralateral and normal control ears (P<0.05). According to ROC, the frequency amplitude ratio critical value of frequency tuning was set as 1.17, the positive rate of frequency tuning shift in affected ears was 54.5%(18/33) and significantly higher than in contralateral ears(18.2%, 6/33, χ2=9.429, P=0.002) and normal control ears (7.5%, 3/40, χ2=19.530, P=0.000). In contrast, there was no significant difference in the incidence of frequency tuning shift between contralateral ears and normal ears(χ2=1.909, P=0.167).@*Conclusions@#Frequency tuning oVEMP with Meniere′s disease will be changed.Frequency tuning of oVEMP with Meniere′s disease shifts from low frequency region to high frequency region in comparison with healthy people. Frequency amplitude ratio is helpful for diagnosis of Meniere′s disease.
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BackgroundRecent researches suggested that properties of neurons in the lateral geniculate neuron (LGN) may represent an important neural limitation on the development of basic spatial and temporal vision,and even binocular rivalry.However,previous studies on the properties of spatiotemporal frequency tuning of LGN were rather concentrated on a monkey or cat,whereas little is known about rat.ObjectiveThis study was to examine the development of spatiotemporal frequency tuning in rats LGN.MethodsTwenty Wistar rats were collected and divided into 14-16 day,20-22 day,27-30 day and 60 day groups according to the different ages after their eyes opened and 5 rats were assigned for each group.Extracellular single neuron recording was carried out in the rats to study the spatio-temporal receptive field properties of neurons in LGN by sinusoidal gratings visual stimuli.Dynamic changes of the spatio-temporal receptive field properties of neurons in LGN with the development of Wistar rats were evaluated.ResultsThe differences between band-pass and low-pass distribution of temporal frequency or spatial frequency of rat LGN were not statistically significant (x2 =0.68,0.47,P＞0.05 ).The optimal temporal frequency of receptive field in rat LGN went up to the maximum value until 60 day in Wistar rats.The mean optimal temporal frequencies of neurons in the four different age groups were ( 2.5 ± 1.3 ),( 2.6± 1.2),(2.6± 1.1 ) and ( 3.6± 1.1 ) Hz with significant differences among the 4 groups (F=4.53,P＜0.05 ),and those in the 14-16 day group,20-22 day group,27- 30 day group were significantly lower than in the 60 days group ( q =4.43,4.10,4.03,P ＜ 0.05 ).No significant differences were seen among the 14-16 day group,20-22 day group and 27-30 day group ( P＞0.05 ).The optimal spatial frequency values in the four groups were ( 0.04 ± 0.04 ),( 0.04 ± 0.03 ),( 0.05 ± 0.03 ),( 0.05 ± 0.04 ) cpd,respectively without statistical difference among them ( F =0.58,P ＞ 0.05 ).The temporal and spatial bandwidth values in the various age groups were not statistically significant among the four groups ( F =0.37,1.22,P＞0.05). Conclusions The development of temporal and spatial frequency characteristics of the rat LGN receptive field may be related to its functional visual pathway.
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Objective To study the change of frequency tuning in inferior collicular neurons when added weak noise forward masking.Methods We examined the changes in neuronal frequency tuning resulted from a weak white noise as forward masking relative to 5dB beyond minimum threshold (reMT+5) and different duration (40、60、80、100 ms) under free field stimulation conditions.Results Weak noise forward masking sharpens frequency tuning curves (FTCs) of most neurons (P