SUMMARY The cerebellum contains the majority of neurons in the human brain and is unique for its uniform cytoarchitecture, absence of aerobic glycolysis, and role in adaptive plasticity. Despite anatomical and physiological differences between the cerebellum and cerebral cortex, group-average functional connectivity studies have identified networks related to specific functions in both structures. Recently, precision functional mapping of individuals revealed that functional networks in the cerebral cortex exhibit measurable individual specificity. Using the highly-sampled Midnight Scan Club (MSC) dataset, we found the cerebellum contains reliable, individual-specific network organization that is significantly more variable than the cerebral cortex. The frontoparietal network, thought to support adaptive control, was the only network overrepresented in the cerebellum compared to the cerebral cortex (2.3-fold). Temporally, all cerebellar resting state signals lagged behind the cerebral cortex (125-380ms), supporting the hypothesis that the cerebellum engages in a domain-general function in the adaptive control of all cortical processes.

Highlights d Casting the dominant upper extremity for 2 weeks caused disuse and weakness d Disused brain circuits functionally disconnected from the rest of the motor system d Connectivity within disused circuits was maintained throughout casting d Disuse-driven spontaneous activity pulses propagated through disused circuits

Communication can contribute to the evolution of biodiversity by promoting speciation and reinforcing reproductive isolation between existing species. The evolution of species-specific signals depends on the ability of individuals to detect signal variation, which in turn relies on the capability of the brain to process signal information. Here, we show that evolutionary change in a region of the brain devoted to the analysis of communication signals in mormyrid electric fishes improved detection of subtle signal variation and resulted in enhanced rates of signal evolution and species diversification. These results show that neural innovations can drive the diversification of signals and promote speciation.

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Amyotrophic lateral sclerosis type 4 (ALS4) is a rare, early-onset, autosomal dominant form of ALS, characterized by slow disease progression and sparing of respiratory musculature. Dominant, gain-of-function mutations in the senataxin gene (SETX) cause ALS4, but the mechanistic basis for motor neuron toxicity is unknown. SETX is a RNA-binding protein with a highly conserved helicase domain, but does not possess a low-complexity domain, making it unique among ALS-linked disease proteins. We derived ALS4 mouse models by expressing two different senataxin gene mutations (R2136H and L389S) via transgenesis and knock-in gene targeting. Both approaches yielded SETX mutant mice that develop neuromuscular phenotypes and motor neuron degeneration. Neuropathological characterization of SETX mice revealed nuclear clearing of TDP-43, accompanied by TDP-43 cytosolic mislocalization, consistent with the hallmark pathology observed in human ALS patients. Postmortem material from ALS4 patients exhibited TDP-43 mislocalization in spinal cord motor neurons, and motor neurons from SETX ALS4 mice displayed enhanced stress granule formation. Immunostaining analysis for nucleocytoplasmic transport proteins Ran and RanGAP1 uncovered nuclear membrane abnormalities in the motor neurons of SETX ALS4 mice, and nuclear import was delayed in SETX ALS4 cortical neurons, indicative of impaired nucleocytoplasmic trafficking. SETX ALS4 mice thus recapitulated ALS disease phenotypes in association with TDP-43 mislocalization and provided insight into the basis for TDP-43 histopathology, linking SETX dysfunction to common pathways of ALS motor neuron degeneration.