# Sex-Related Variations in the Brain Motor-Network Connectivity at Rest during Puberty
## 4 Discussion
### Asymmetry of the cerebellar-mouth and cerebellar-hand MsN  
The cerebellar-mouth MsN showed higher node strength values in the right hemisphere at both ages and sexes. The right lateralization in the cerebellar-mouth MsN was attributed to right and left node asymmetry; with two postcentral regions in each hemisphere and an additional posterior insula region in the right. The insula is involved in somatosensory, vestibular, and motor integration [42] and is activated during swallowing [43], therefore, it is a region with high functionality in cerebellar-mouth MsN even when the subject is registered at rest. Additionally, the cerebellar regions that were selected in the atlas of this study activate during lip and tongue movement [44], hence, they have a functional relationship with the insula, strengthening right subnetwork connectivity. The cerebellar-hand MSN showed higher node strength values in the left hemisphere at both ages and sexes. The left lateralization was related to the greater number of node connections of the hand subnetwork. The cerebellar nodes (HVI and VI areas) used in this study are not related to hand and finger movement, except for the vermis, which is associated with contralateral motor activity in right-handed individuals. Therefore, the contralateral dorsolateral premotor cortex and primary motor cortex activity support our findings of greater connectivity of right-handers in the resting state, as expected and previously seen [45]. (4) The centrality variation of the regions in the MsN by age and sex. The most relevant MsN brain areas for leverage centrality were the Cerebellum _6.L1, Vermis_6.1, Precuneus.L1, Cingulum_Post.L1, and Supp_Motor_Area.R1. The Precuneus consistently exhibits high leverage values in the 4 groups studied. According to studies done in macaque, this region has substantial connections in both hemispheres with the dorsal premotor area [46], the supplementary motor area (SMA), and the anterior cingulate cortex [47]. The precuneus's major subcortical connections include corticostriatal projections to the dorsolateral caudate nucleus and putamen (basal ganglia), as well as different projections to brainstem structures with connections to the pontine nuclei (PN). Because PN projections reach a specific set of cerebellar regions, the precuneus gains access to multiple cerebellar circuits. Myelination of afferent connections from the PN to the cerebellum is one of the last to develop and is completed during puberty and flows through the Middle Cerebellar Peduncle, establishing somatomotor network connectivity [15]. Precuneus function has been found to be more responsive during motor imagery than during real-world movement execution [48]. More recently, using fMRI to compare the functional neuroanatomy of motor execution and motor imagery, subjects were required to perform sequential finger-tapping as either a movement execution or an imagery mode in response to visually presented stimuli. The frontal precentral sulcus zone and the posterior superior parietal cortex, which extended bilaterally to the precuneus, were imagery-dominant areas [49]. It has been observed that the precuneus has no connections with the sensory thalamic nuclei, implying that the precuneus does not share thalamic connectivity pattern of the parietal somatosensory cortical regions. This implies adolescent subjects exposed to fMRI in a resting state are actively engaged in virtual movement execution without sensory input. Therefore, it is expected that this region will function as an influencer node in all groups. The Cingulum_Post.L1 and Supp_Motor_Area.R1 showed high leverage values and similar dynamics when compared by sex and age. The dorsal anterior cingulate cortex is hypothesized to play a role in behavior regulation by serving as a primary interface between sensory and cognitive processing [50]. Motor control is an important and distinct type of control that supports a variety of complex activities, particularly the integration of motor responses with cognitive assessment.