Monitoring of anesthetic effect based on auditory response time / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes of auditory parameters during anesthesia and establish the assessment indicators for anesthesia monitoring in animal experiments.</p><p><b>METHODS</b>BALB/c mice of 4 to 6 weeks were given a single intraperitoneal dose of urethane, and the auditory evoked potential in the surgically exposed inferior colliculus in response to pure tone stimulation was recorded during urethane metabolism. The latency and amplitude data of the waves were extracted using Matlab software to analyze their variations during urethane metabolism.</p><p><b>RESULTS</b>The latency of the auditory evoked potential showed slight variation and was well correlated to time. The latency decreased progressively during urethane metabolism, fast in the initial 2 h and tending to stabilize afterwards.</p><p><b>CONCLUSION</b>The latency of the auditory evoked potential can be more suitable indicators than the amplitude for anesthetic effect monitoring.</p>

Response properties of cochlear nucleus neurons: a digital model-based study / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanisms of different response patterns of the cochlear nucleus neurons based on a digital model.</p><p><b>METHODS</b>Based on the platform of Matlab7.0 and the integrate-and-fire model, we constructed the temporal coding model.</p><p><b>RESULTS</b>The model well simulated the response types of the primary-like, chopper, onset and buildup neurons by changing the settings of some parameters related to the properties of the neurons.</p><p><b>CONCLUSIONS</b>The properties of the neurons dictate the response patterns of the cochlear nucleus neurons. The simulation results are consistent with the literature. Understanding of the response properties of the cochlear nucleus neurons can provide assistance in the study of the auditory system.</p>

Effect of bicuculline on first spike latency of the neurons in the inferior colliculus of mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of bicuculline on the first spike latency of the neurons in the inferior colliculus of mice and investigate the role of GABA inhibition in sound signal processing of the neurons.</p><p><b>METHODS</b>In vivo extracellular recording was performed on the inferior colliculus of 13 BALB/c mice (4 to 5 weeks old) to record the neuronal response to pure tones. Bicuculline, a GABA-A receptor antagonist, was applied to the neurons iontophoretically through one channel in the three-barrel glass-pipettes. The first spike latency and other response properties of the characteristic frequency were recorded for analysis.</p><p><b>RESULTS</b>A total of 30 well-isolated single neurons were recorded. Increased spike counts characterized 96% of the neurons, with either increased (40%) or decreased (60%) latency of neuronal responses. Characteristic frequency alterations occurred in 50% of the neurons with increased spike latency, and the minimum threshold showed linear changes.</p><p><b>CONCLUSION</b>GABAergic inhibition may participate in the latency formation and increased frequency selectivity of mouse inferior colliculus neurons by lateral inhibition. The changes in the first spike latency can be indicative of the information integration in GABAergic neurons at the synaptic level.</p>