Extracellular recordings were made from vestibularnerve afferents innervating the semicircular canals in anesthetized C57BL/6 mice ranging in age from 4-24 weeks. A normalized coefficient of variation was used to divide afferents into regular (CV*G0.1) and irregular (CV*90.1) groups. There were three overall conclusions from this study. First, mouse afferents resemble those of other mammals in properties such as resting discharge rate and dependence of response dynamics on discharge regularity. Second, there are differences in mouse afferents relative to other mammals that are likely related to the smaller size of the semicircular canals. The rotational sensitivity of mouse afferents is approximately threefold lower than that reported for afferents in other mammals. One consequence of the lower sensitivity is that mouse afferents have a larger linear range for encoding head velocity. The long time constant of afferent discharge, which is a measure of low-frequency response dynamics, is shorter in mouse afferents than in other species. Third, juvenile mice (age 4-7 weeks) appear to lack a class of low-sensitivity, highly irregular afferents that are present in adult animals (age 10-24 weeks). By analogy to studies in the chinchilla, these irregular afferents with low sensitivities for lower rotational frequencies correspond to calyx-only afferents. These findings suggest that, although the calyx ending on to type I hair cells is morphologically complete in mice by the age of about 1 month, the physiological response properties in these juvenile animals are not equivalent to those in adults.

Benign paroxysmal positional vertigo (BPPV) is characterized by episodic vertigo and nystagmus provoked by head motions. To study the characteristics of BPPV in a large group of patients in Korea, we retrospectively analyzed clinical features of 1,692 patients (women: 1,146, 67.7%; men: 54.6, 32.3%; mean age: 54.8±14.0 yr), who had been diagnosed as BPPV by trained neuro-otologists Dizziness Clinics. The diagnosis of BPPV was based on typical nystagmus elicited by positioning maneuvers. Posterior semicircular canal was involved in 60.9% of the patients, horizontal canal in 31.9%, anterior canal in 2.2%, and mixed canals in 5.0%. The horizontal canal type of BPPV (HC-BPPV) comprised 49.5% of geotropic and 50.5% of apogeotropic types. We could observe significant negative correlation between the proportion of HC-BPPV of each clinic and the mean time interval between the symptom onset and the first visit to the clinics (r = -0.841, p<0.05). Most patients were successfully treated with canalith repositioning maneuvers (86.9%). The high incidence of HC-BPPV in this study may be explained by relatively shorter time interval between the symptom onset and visit to the Dizziness Clinics in Korea, compared with previous studies in other countries.

We suggest that LL-37 is one of the antimicrobial peptides found in human nasal mucosa and that it participates in the innate immune system of the nasal mucosa.

BackgroundLocomotion involves an integration of vision, proprioception, and vestibular information. The parieto-insular vestibular cortex is known to affect the supra-spinal rhythm generators, and the vestibular system regulates anti-gravity muscle tone of the lower leg in the same side to maintain an upright posture through the extra-pyramidal track. To demonstrate the relationship between locomotion and vestibular function, we evaluated the differences in gait patterns between vestibular neuritis (VN) patients and normal subjects using a gyroscope sensor and long-way walking protocol.MethodsGyroscope sensors were attached to both shanks of healthy controls (n=10) and age-matched VN patients (n = 10). We then asked the participants to walk 88.8 m along a corridor. Through the summation of gait cycle data, we measured gait frequency (Hz), normalized angular velocity (NAV) of each axis for legs, maximum and minimum NAV, up-slope and down-slope of NAV in swing phase, stride-swing-stance time (s), and stance to stride ratio (%).ResultsThe most dominant walking frequency in the VN group was not different compared to normal control. The NAVs of z-axis (pitch motion) were significantly larger than the others (x-, y-axis) and the values in VN patients tended to decrease in both legs and the difference of NAV between both group was significant in the ipsi-lesion side in the VN group only (p=0.03). Additionally, the gait velocity of these individuals was decreased relatively to controls (1.11 ± 0.120 and 0.84 ± 0.061 m/s in control and VN group respectively, p<0.01), which seems to be related to the significantly increased stance and stride time of the ipsi-lesion side. Moreover, in the VN group, the maximum NAV of the lesion side was less, and the minimum one was higher than control group. Furthermore, the down-slope and up-slope of NAV decreased on the impaired side.ConclusionThe walking pattern of VN patients was highly phase-dependent, and NAV of pitch motion was significantly decreased in the ipsi-lesion side. The change of gait rhythm, stance and stride time, and maximum/minimum NAV of the ipsi-lesion side were characteristics of individuals with VN.

The aim of this study was to evaluate the anatomical and clinical relationship between lacunar infarction and the corticospinal tract (CST) in patients with acute lacunar infarction and predict clinical outcome. We examined 28 pyramidal tract stroke patients in the acute phase or early subacute phase (<3 days) with a marked motor deficit. The anatomical location and the extent of CST involvement within the infarcts were visualized on three-dimensional colour-coded diffusion tensor tractography (DTT). With regard to the CST, all patients were divided into three clinical subgroups: Group 1 (intact type), Group 2 (partial involvement type) and Group 3 (whole involvement type). Subsequently, the severity of the motor deficit of each patient was determined according to the National Institutes of Health Stroke Scale (NIHSS) scores at the acute/early subacute phase (<3 days after onset of symptoms), early chronic phase (8-14 days) and outcome (30-60 days). NIHSS scores of Group 1 (12/28) were significantly lower than those of Group 2 (9/28) at the acute phase or early subacute phase (U = -2.816, p<0.01), and those of Group 2 were significantly lower than those of Group 3 (7/28) (U = -3.136, p<0.01). At outcome,NIHSS scores of Group 1 were significantly lower than those of Group 2 (U = -2.846, p<0.01), and scores of Group 2 were significantly lower than those of Group 3 (U = -3.130, p<0.01). At the same time, the NIHSS scores of each group gradually decreased from acute phase to outcome, Neurological improvement was statistically different among the three topographical types of infarction (H = 26.15, p<0.01; H = 11.03, p<0.01; H = 10.05, p<0.01). In conclusion, the three-dimensional colour-coded DTT allows in vivo differentiation of distinct CST stroke subtypes and may help in better establishing the prognosis for patients after CST stroke.