Human risk taking and metabolic state: No credible evidence for desacyl-ghrelin modulation of neural or behavioural effects.

Traditionally viewed as a motor structure, the human cerebellum is now recognized to support a broad range of cognitive, social, and emotional functions (; ; ; ). Both anatomical and functional (MRI) of the cerebellum play an increasingly important role in studies of neurodevelopmental, neurological, and psychiatric disorders (; ). However, imaging the cerebellum remains challenging, as its surface is highly folded and tightly compacted within a small volume (). Furthermore, different regions of the human cerebellum subserve different functions, which are spatially located quite close together (; ; ). Cerebellar cortical lesions, therefore, can have dramatically different consequences depending on their exact location. To address this problem, we introduced a high-resolution cerebellum-only template—the (SUIT)—together with a spatial normalization framework, to improve the inter-subject alignment of cerebellar structures (). The analysis pipeline was shown at that time to outperform a common whole-brain normalization pipeline (, implemented in SPM99). Since then, the SUIT toolbox has been widely adopted and used across a broad range of cerebellar imaging applications, including functional MRI (; ; ), lesion (), and voxel-based morphometric studies (; ). The SUIT pipeline employs a continuous voxel-wise approach, providing higher-resolution characterization than traditional lobular segmentation methods (; ). This is especially important because cerebellar functional organization does not align with anatomical lobular boundaries (). Despite its methodological advantages, the cerebellar isolation algorithm in the original SUIT toolbox does not always work robustly. For example, voxels belonging to the abutting neocortex or the transverse sinus are frequently misclassified as cerebellar tissue. In turn, inferior cerebellar regions are sometimes not included in the mask. This poses challenges for accurate anatomical analysis, as the volume of cerebellar tissue would not be accurately estimated. The incorrect isolation also biases the normalization to the cerebellum-only template, which propagates errors to subsequent analyses. The isolation mask, therefore, requires manual correction, limiting its applicability to large population-based MRI studies. Importantly, SUIT was originally developed using only data from healthy young adults, the algorithm performs poorly on developmental, aging, and clinical populations, where cerebellar anatomy deviates substantially from the normative template.