Altered intensity coding in the salicylate-overdose animal model of tinnitus.

Tinnitus is one of the leading disorders of hearing with no effective cure as its pathophysiological mechanisms remain unclear. While the sensitivity to sound is well-known to be affected, exactly how intensity coding per se is altered remains unclear. To address this issue, we used a salicylate-overdose animal model of tinnitus to measure auditory cortical evoked potentials at various stimulus levels, and analyzed on single-trial basis the response strength and its variance for the computation of the lower bound of Fisher information.

Dysregulated brain creatine kinase is associated with hearing impairment in mouse models of Huntington disease.

Huntington disease (HD) is a degenerative disorder caused by expanded CAG repeats in exon 1 of the huntingtin gene (HTT). Patients with late-stage HD are known to have abnormal auditory processing, but the peripheral auditory functions of HD patients have yet to be thoroughly assessed. In this study, 19 HD patients (aged 40-59 years) were assessed for hearing impairment using pure-tone audiometry and assessment of auditory brainstem responses (ABRs).

Sound exposure accelerates reflex emergence and development in young rats.

Early sensory experience affects brain development. In rats, most somatic reflexes are not expressed at birth but may take as long as 2 weeks to emerge. Whether sensory enrichment during this early period affects reflex maturation remains unknown.

Anesthesia does not increase the rate of bowel perforation during colonoscopy: a retrospective study.

Objective: To compare the complication rates of bowel perforation during colonoscopy performed with or without anesthesia.

Methods: We retrospectively analyzed 9501 case records of colonoscopy performed at the Chi Mei Medical Center between 2000 and 2004, and compared the rates of bowel perforation between patients receiving anesthesia during the procedure versus those that did not receive anesthesia. Poisson distribution was used for statistical analysis.

The effect of midazolam on mouse Leydig cell steroidogenesis and apoptosis.

The peripheral-type benzodiazepine receptor (PBR), a putative receptor in Leydig cells, modulates steroidogenesis. Since benzodiazepines are commonly used in regional anesthesia, their peripheral effects need to be defined. Therefore, this study set out to investigate in vitro effects of the benzodiazepine midazolam (MDZ) on Leydig cell steroidogenesis, and the possible underlying mechanisms.

Enlargement of neuronal size in rat auditory cortex after prolonged sound exposure.

Prolonged sound exposure produces functional changes in the auditory neurons. It remains unclear whether such changes are detectable with morphometric measures like cell size. Here, after exposing juvenile rats (starting on week-4) to a monotone for 7 days, we measured the size of their cortical neurons.

Nuclear size of c-Fos expression at the auditory brainstem is related to the time-varying nature of the acoustic stimuli.

Acoustic stimulation is known to induce c-Fos expression in the auditory system but how the expression might be related to the time-variance of the sound (e.g., steady or frequency-varying) is unclear.

A new mask designed for patients implanted with a nasogastric tube.

Pulmonary ventilation of patients implanted with a nasogastric tube is often difficult for medical personnel, since air leakage through the facemask and nasogastric tube interface is inevitable. Here we designed and tested a special facemask to improve ventilation in these patients. Forty patients with ASA class I-II were randomly assigned to two groups (study and control, n=20 each patients/group).

A new method for adjusting neural response jitter in the STRF obtained by spike-trigger averaging.

Sensitivity of central auditory neurons to frequency modulated (FM) sound is often characterized based on spectro-temporal receptive field (STRF), which is generated by spike-trigger averaging a random stimulus. Due to the inherent property of time variability in neural response, this method erroneously represents the response jitter as stimulus jitter in the STRF. To reveal the trigger features more clearly, we have implemented a method that minimizes this error.

High frequency block of selected axons using an implantable microstimulator.

Currently, the majority of neural stimulation studies are limited to acute animal experiments due to lack of suitable implantable microstimulation devices. As an initial step to observe the long-term effects of neural stimulation, a system consisting of an external wireless controller and an implantable dual-channel microcontroller-based microstimulator for tripolar high frequency blocking was developed. The system is not only small in size, and thus suitable for short-term implantation, but also has sufficient current output parameter ranges to meet the demand for high frequency blocking experiments.

Responses of central auditory neurons modeled with finite impulse response (FIR) neural networks.

To simulate central auditory responses to complex sounds, a computational model was implemented. It consists of a multi-scale classification process, and an artificial neural network composed of two modules of finite impulse response (FIR) neural networks connected to a maximum network. Electrical activities of single auditory neurons were recorded at the rat midbrain in response to a repetitive pseudo-random frequency modulated (FM) sound.