Rauschecker Josef P, Tian Biao
Department of Physiology and Biophysics, Georgetown University School of Medicine, Box 571460, The Research Building WP15, 3970 Reservoir Road NW, Washington, DC 20057, USA.
J Neurophysiol. 2004 Jun;91(6):2578-89. doi: 10.1152/jn.00834.2003.
Neurons in the lateral belt areas of rhesus monkey auditory cortex were stimulated with band-passed noise (BPN) bursts of different bandwidths and center frequencies. Most neurons responded much more vigorously to these sounds than to tone bursts of a single frequency, and it thus became possible to elicit a clear response in 85% of lateral belt neurons. Tuning to center frequency and bandwidth of the BPN bursts was analyzed. Best center frequency varied along the rostrocaudal direction, with 2 reversals defining borders between areas. We confirmed the existence of 2 belt areas (AL and ML) that were laterally adjacent to the core areas (R and A1, respectively) and a third area (CL) adjacent to area CM on the supratemporal plane (STP). All 3 lateral belt areas were cochleotopically organized with their frequency gradients collinear to those of the adjacent STP areas. Although A1 neurons responded best to pure tones and their responses decreased with increasing bandwidth, 63% of the lateral belt neurons were tuned to bandwidths between 1/3 and 2 octaves and showed either one or multiple peaks. The results are compared with previous data from visual cortex and are discussed in the context of spectral integration, whereby the lateral belt forms a relatively early stage of processing in the cortical hierarchy, giving rise to parallel streams for the identification of auditory objects and their localization in space.
用不同带宽和中心频率的带通噪声（BPN）猝发刺激恒河猴听觉皮层外侧带区域的神经元。与单频纯音猝发相比，大多数神经元对这些声音的反应更为强烈，因此在85%的外侧带神经元中能够引发清晰的反应。分析了对BPN猝发的中心频率和带宽的调谐情况。最佳中心频率沿前后方向变化，有2个反转界定了区域之间的边界。我们证实了存在2个与核心区域（分别为R和A1）横向相邻的带区域（AL和ML）以及颞上平面（STP）上与CM区域相邻的第三个区域（CL）。所有3个外侧带区域均呈耳蜗拓扑组织，其频率梯度与相邻STP区域的频率梯度共线。虽然A1神经元对纯音反应最佳，且其反应随带宽增加而降低，但63%的外侧带神经元调谐到1/3至2倍频程之间的带宽，并表现出一个或多个峰值。将这些结果与视觉皮层的先前数据进行了比较，并在频谱整合的背景下进行了讨论，据此外侧带在皮层层次结构中形成了一个相对早期的处理阶段，产生了用于识别听觉对象及其在空间中定位的并行信息流。
