Bull M S, Berkley K J
Department of Psychology, Florida State University, Tallahassee 32306-1051.
Somatosens Mot Res. 1991;8(2):117-26. doi: 10.3109/08990229109144736.
Neurons in the somatic pretectum receive input from the dorsal column nuclei (DCN) and project to a comparable "somatic" portion of the dorsal accessory nucleus of the inferior olive (DAO). This somatic DAO is reciprocally connected with the anterior interpositus nucleus of the cerebellum. One question that arises is whether this circuitry is further controlled by an output specifically from the anterior interpositus nucleus to the somatic pretectum. Wheatgerm agglutinin conjugated to horseradish peroxidase was injected into various parts of the cat pretectum. Injection sites were interpreted as including the somatic pretectum if neurons in the DCN were retrogradely labeled and if anterograde terminal labeling occurred in somatic DAO. The locations of retrogradely labeled neurons within the deep cerebellar nuclei were then compared in cases in which the injection sites included or excluded the somatic pretectum. In all cases in which the injection site included the somatic pretectum, retrogradely labeled neurons were observed in the anterior interpositus nucleus as well as in the lateral cerebellar nuclei. In some of these cases, neurons in the posterior interpositus and medial nuclei were also labeled. In contrast, in cases in which the pretectal injection site was located outside or at the border of the somatic pretectum, retrogradely labeled neurons were observed only in the lateral, posterior interpositus, and medial nuclei. Thus, the somatic pretectum appears to receive input primarily from neurons in the anterior interpositus nucleus, along with some input from neurons in the lateral nucleus. These results provide additional evidence for a pathway through the DCN in which sequentially processed somatic information has access to and is modulated by cerebellar circuitry. The existence of such a pathway supports the conclusion that neurons in the DCN convey somatic information important not only for cutaneous, kinesthestic, and other bodily sensations, but also for the control of movement.
躯体前顶盖中的神经元接收来自薄束核（DCN）的输入，并投射到下橄榄核背侧副核（DAO）的类似“躯体”部分。这个躯体DAO与小脑前间位核相互连接。出现的一个问题是，这条神经回路是否进一步受到从小脑前间位核到躯体前顶盖的特定输出的控制。将与辣根过氧化物酶结合的麦胚凝集素注入猫前顶盖的各个部位。如果DCN中的神经元被逆行标记，并且在躯体DAO中出现顺行终末标记，则注射部位被解释为包括躯体前顶盖。然后比较注射部位包括或排除躯体前顶盖的情况下，深小脑核内逆行标记神经元的位置。在所有注射部位包括躯体前顶盖的情况下，在前间位核以及小脑外侧核中都观察到了逆行标记的神经元。在其中一些情况下，后间位核和内侧核中的神经元也被标记。相比之下，在前顶盖注射部位位于躯体前顶盖之外或其边界处的情况下，仅在外侧、后间位核和内侧核中观察到逆行标记的神经元。因此，躯体前顶盖似乎主要从前间位核中的神经元接收输入，同时也从外侧核中的神经元接收一些输入。这些结果为通过DCN的一条神经通路提供了额外的证据，在这条通路中，依次处理的躯体信息能够进入小脑神经回路并受到其调节。这样一条通路的存在支持了以下结论：DCN中的神经元传递的躯体信息不仅对皮肤、本体感觉和其他身体感觉很重要，而且对运动控制也很重要。
