Delano Paul H, Elgueda Diego, Ramirez Fernando, Robles Luis, Maldonado Pedro E
Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
J Physiol Paris. 2010 May-Sep;104(3-4):190-6. doi: 10.1016/j.jphysparis.2009.11.023. Epub 2009 Dec 1.
We studied single and multi-unit activity recorded with tetrodes, from the left auditory cortex of awake chinchillas while they performed a frequency discrimination task. Auditory stimuli were preceded by a silent visual cue. We examined firing rates and first-spike latencies of 181 units in the presence and absence of the visual cue. To discard possible auditory artifacts produced by the visual cue, cochlear potentials were simultaneously recorded by an electrode positioned at the round window of the right cochlea. We found that the visual stimulus altered the firing rate and the mean first-spike latency of 9% and 18% of the recorded auditory-cortex cells, respectively. Furthermore, we found that the subset of neurons in which the firing rate was modulated by the visual cue was distinct from the subset of neurons that changed their latency in the presence of the visual cue. Adding both groups, a visual-stimulus modulated the firing characteristics of 27% of the recorded auditory-cortex neurons in the awake chinchilla. Our results imply that in the auditory cortex, latency and firing rate can be independently altered by visual stimuli, and that both types of analysis must be considered in order to fully understand neural cross-modal interactions.
我们研究了在清醒的毛丝鼠执行频率辨别任务时，用四极管从其左听觉皮层记录到的单单元和多单元活动。听觉刺激之前有一个无声的视觉提示。我们检查了在有和没有视觉提示的情况下181个单元的放电率和首次放电潜伏期。为了排除视觉提示产生的可能的听觉伪迹，通过放置在右耳蜗圆窗处的电极同时记录耳蜗电位。我们发现视觉刺激分别改变了9%和18%的所记录的听觉皮层细胞的放电率和平均首次放电潜伏期。此外，我们发现其放电率受视觉提示调节的神经元子集与在有视觉提示时改变潜伏期的神经元子集不同。将这两组相加，视觉刺激调节了清醒毛丝鼠中27%的所记录的听觉皮层神经元的放电特征。我们的结果表明，在听觉皮层中，潜伏期和放电率可以被视觉刺激独立改变，并且为了充分理解神经跨模态相互作用，必须考虑这两种类型的分析。
