The rat auditory cortex is divided anatomically into several areas, but little is known about the functional differences in information processing among these areas. Three tonotopically organized core fields, namely, the primary (A1), anterior (AAF), and ventral (VAF) auditory fields, as well as one non-tonotopically organized belt field, the dorsal belt (DB), were identified based on their response properties. Compared to neurons in A1, AAF and VAF, units in the DB exhibited little or no response to pure tones but strong responses to white noise. The few DB neurons responded to pure tones with thresholds greater than 60 dB SPL, which was significantly higher than the thresholds of neurons in the core regions. In response to white noise, units in DB showed significantly longer latency and lower peak response, as well as longer response duration, than those in the core regions. Responses to repeated white noise were also examined. In contrast to neurons in A1, AAF and VAF, DB neurons could not follow repeated stimulation at a 300 ms inter-stimulus interval (ISI) and showed a significant steeper ISI tuning curve slope when the ISI was increased from 300 ms to 4.8 s. These results indicate that the DB processes auditory information on broader spectral and longer temporal scales than the core regions, reflecting a distinct role in the hierarchical cortical pathway.

大鼠听觉皮层解剖上分为几个区域，但这些区域之间信息处理的功能差异知之甚少。根据它们的位置，确定了三个以原位排列的核心场，即第一（A1），前（AAF）和腹（VAF）听觉场，以及一个非以原位排列的腰带场，即背带（DB）。响应属性。与A1，AAF和VAF中的神经元相比，DB中的单位对纯音几乎没有响应，但对白噪声的响应却很强。少数DB神经元对纯音的响应阈值大于60 dB SPL，该阈值显着高于核心区域中神经元的阈值。为了响应白噪声，DB中的单元显示出明显更长的延迟和更低的峰值响应，以及更长的响应持续时间，比核心地区的要高。还检查了对重复白噪声的响应。与A1，AAF和VAF中的神经元相反，DB神经元无法在300毫秒刺激间间隔（ISI）进行重复刺激，并且当ISI从300毫秒增加到4.8 s时，ISI调整曲线的斜率明显更陡。这些结果表明，DB在比核心区域更宽的频谱和更长的时间尺度上处理听觉信息，反映出在分层皮层通路中的独特作用。