Dipartimento di Medicina e Chirurgia, Unità di Neuroscienze, Università di Parma, 43100 Parma, Italy,
Dipartimento di Medicina e Chirurgia, Unità di Neuroscienze, Università di Parma, 43100 Parma, Italy.
J Neurosci. 2022 Sep 14;42(37):7060-7076. doi: 10.1523/JNEUROSCI.0071-22.2022. Epub 2022 Aug 11.
In nonhuman primates, major input to the striatum originates from ipsilateral cortex and thalamus. The striatum is a target also of crossed corticostriatal (CSt) projections from the contralateral hemisphere, which have been so far somewhat neglected. In the present study, based on neural tracer injections in different parts of the striatum in macaques of either sex, we analyzed and compared qualitatively and quantitatively the distribution of labeled CSt cells in the two hemispheres. The results showed that crossed CSt projections to the caudate and the putamen can be relatively robust (up to 30% of total labeled cells). The origin of the direct and the crossed CSt projections was not symmetrical as the crossed ones originated almost exclusively from motor, prefrontal, and cingulate areas and not from parietal and temporal areas. Furthermore, there were several cases in which the contribution of contralateral areas tended to equal that of the ipsilateral ones. The present study is the first detailed description of this anatomic pathway of the macaque brain and provides the substrate for bilateral distribution of motor, motivational, and cognitive signals for reinforcement learning and selection of actions or action sequences, and for learning compensatory motor strategies after cortical stroke. In nonhuman primates the striatum is a target of projections originating from the contralateral hemisphere (crossed CSt projections), which have been so far poorly investigated. The present study analyzed qualitatively and quantitatively in the macaque brain the origin of the crossed CSt projections compared with those originating from the ipsilateral hemisphere. The results showed that crossed CSt projections originate mostly from frontal and rostral cingulate areas and in some cases their contribution tended to equal that from ipsilateral areas. These projections could provide the substrate for bilateral distribution of motor, motivational, and cognitive signals for reinforcement learning and action selection, and for learning compensatory motor strategies after cortical stroke.
在非人类灵长类动物中，纹状体的主要输入来自同侧的皮层和丘脑。纹状体也是来自对侧半球的交叉皮质纹状体（CSt）投射的靶点，但迄今为止，这方面的研究还不够充分。在本研究中，我们基于恒河猴两性不同纹状体部位的神经示踪剂注射，定性和定量地分析和比较了双侧半球标记的 CSt 细胞的分布。结果表明，向尾状核和壳核的交叉 CSt 投射可能相对较强（可达总标记细胞的 30%）。直接和交叉 CSt 投射的起源并不对称，因为交叉投射几乎完全来自运动、前额叶和扣带回区域，而不是来自顶叶和颞叶区域。此外，有几个案例中，对侧区域的贡献趋于与同侧区域相当。本研究首次详细描述了恒河猴大脑中的这一解剖通路，为运动、动机和认知信号的双侧分布提供了基础，这些信号用于强化学习和选择动作或动作序列，以及在皮质卒中后学习补偿性运动策略。在非人类灵长类动物中，纹状体是来自对侧半球（交叉 CSt 投射）的投射靶点，而这些投射至今研究甚少。本研究在恒河猴大脑中分析了与同侧半球起源相比，交叉 CSt 投射的起源，从定性和定量两个方面进行了分析。结果表明，交叉 CSt 投射主要起源于额极和前扣带回区域，在某些情况下，其贡献趋于与同侧区域相当。这些投射可以为强化学习和动作选择过程中运动、动机和认知信号的双侧分布以及皮质卒中后学习补偿性运动策略提供基础。
