Noreña A J, Eggermont J J
Department of Physiology and Biophysics, Neuroscience Research Group, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4.
Hear Res. 2003 Sep;183(1-2):137-53. doi: 10.1016/s0378-5955(03)00225-9.
Changes in spontaneous activity, recorded over 15-min periods before, immediately after and within hours after an acute acoustic trauma, were studied in primary auditory cortex of ketamine-anesthetized cats. We focused on the spontaneous firing rate (SFR), the peak cross-correlation coefficient (rho) and burst-firing activity. Multi-units (MUs) were grouped according to characteristic frequency (CF): MUs with a CF below the trauma-tone frequency (TF) were labeled as Be, those with a CF within 1 octave above the TF were labeled as Ab1 and those with a CF more than 1 octave above the TF were labeled as Ab2. Immediately after the trauma, the SFR was not significantly changed. The percentage of time that neurons were bursting, the mean burst duration, the number of spikes per burst and the mean inter-spike interval in a burst were enhanced. rho was locally increased in the Ab1-Ab2 and Ab2-Ab2 groups. A few hours post trauma, the SFR was increased in the Be and Ab2 groups, whereas burst-firing returned to pre-exposure levels. Moreover, rho was elevated in the Be-Ab2, Ab1-Ab2 and Ab2-Ab2 groups; this increase was significantly correlated to the changes in SFR. The results are discussed in the context of a neural correlate of tinnitus.
在氯胺酮麻醉的猫的初级听觉皮层中，研究了急性声创伤前15分钟、创伤后即刻以及创伤后数小时内记录的自发活动变化。我们重点关注自发放电率（SFR）、峰值互相关系数（rho）和爆发式放电活动。多单元（MUs）根据特征频率（CF）进行分组：CF低于创伤音调频率（TF）的MUs标记为Be，CF在TF以上1个倍频程内的标记为Ab1，CF在TF以上超过1个倍频程的标记为Ab2。创伤后即刻，SFR无显著变化。神经元爆发的时间百分比、平均爆发持续时间、每次爆发的尖峰数量以及爆发中的平均峰间间隔均增加。rho在Ab1 - Ab2和Ab2 - Ab2组中局部升高。创伤后数小时，Be组和Ab2组的SFR增加，而爆发式放电恢复到暴露前水平。此外，rho在Be - Ab2、Ab1 - Ab2和Ab2 - Ab2组中升高；这种增加与SFR的变化显著相关。在耳鸣的神经相关性背景下对结果进行了讨论。
