a-fine-motor-task-to-study-joint-kinematics-preclinical-model

A Fine Motor Task to Study Joint Kinematics in a Preclinical Model of Neurodegenerative Disease

Motor dysfunction is a critical, yet often underappreciated, component of neurodegenerative diseases such as Alzheimer's disease (AD) and related ...

Arizona State University

Adeno-associated virus (AAV) has great potential as a source of treatments for conditions that might respond to potent and ubiquitous transgene expression. However, among its drawbacks, the genetic "payload" of AAV vectors is limited to <4.9 kb and some commonly used gene promoters are sizeable and susceptible to transcriptional silencing. We recently described a short (404 bp), potent, and persistent promoter obtained from the genome of pseudorabies virus (PrV) called alphaherpesvirus latency-associated promoter 2 (LAP2). Here, we evaluated the biodistribution and potency of transgene expression in mouse peripheral tissues in response to local and systemic administration of AAV8-LAP2 and AAV9-LAP2. We found that administration of these vectors resulted in levels of transgene expression that were similar to the larger EF1α promoter. LAP2 drives potent transgene expression in mouse liver and kidney when administered systemically and in skeletal muscle in response to intramuscular delivery. Notably, in skeletal muscle, administration of vectors with LAP2 and EF1α promoters resulted in preferential transduction of myofibers type 2. A direct side-by-side comparison between LAP2 and the EF1α promoter revealed that, despite its smaller size, LAP2 was equally potent to the EF1α promoter and resulted in widespread gene expression after IV and IM administration of AAV8 or AAV9 vectors. Collectively, these findings suggest that constructs that include LAP2 may have the capacity to deliver large therapeutically effective payloads in support of future gene therapy protocols.

Local and systemic administration of AAV vectors with alphaherpesvirus latency-associated promoter 2 drives potent transgene expression in mouse liver, kidney, and skeletal muscle.

The cerebellum regulates nonmotor behavior, but the routes of influence are not well characterized. Here we report a necessary role for the posterior cerebellum in guiding a reversal learning task through a network of diencephalic and neocortical structures, and in flexibility of free behavior. After chemogenetic inhibition of lobule VI vermis or hemispheric crus I Purkinje cells, mice could learn a water Y-maze but were impaired in ability to reverse their initial choice. To map targets of perturbation, we imaged c-Fos activation in cleared whole brains using light-sheet microscopy. Reversal learning activated diencephalic and associative neocortical regions. Distinctive subsets of structures were altered by perturbation of lobule VI (including thalamus and habenula) and crus I (including hypothalamus and prelimbic/orbital cortex), and both perturbations influenced anterior cingulate and infralimbic cortex. To identify functional networks, we used correlated variation in c-Fos activation within each group. Lobule VI inactivation weakened within-thalamus correlations, while crus I inactivation divided neocortical activity into sensorimotor and associative subnetworks. In both groups, high-throughput automated analysis of whole-body movement revealed deficiencies in across-day behavioral habituation to an open-field environment. Taken together, these experiments reveal brainwide systems for cerebellar influence that affect multiple flexible responses.

Cerebellar contributions to a brainwide network for flexible behavior in mice.

The cerebellum, traditionally associated with motor coordination and balance, also plays a crucial role in various aspects of higher-order function and dysfunction. Emerging research has shed light on the cerebellum's broader contributions to cognitive, emotional, and reward processes. The cerebellum's influence on autonomic function further highlights its significance in regulating motivational and emotional states. Perturbations in cerebellar development and function have been implicated in various neurodevelopmental disorders, including autism spectrum disorder and attention deficit hyperactivity disorder. An increasing appreciation for neuropsychiatric symptoms that arise from cerebellar dysfunction underscores the importance of elucidating the circuit mechanisms that underlie complex interactions between the cerebellum and other brain regions for a comprehensive understanding of complex behavior. By briefly discussing new advances in mapping cerebellar function in affective, cognitive, autonomic, and social processing and reviewing the role of the cerebellum in neuropathology beyond the motor domain, this Mini-Symposium review aims to provide a broad perspective of cerebellar intersections with the limbic brain in health and disease.

Cognitive-Affective Functions of the Cerebellum.

Behavioral and pharmaceutical interventions reverse defects associated with increased cerebellar long-term depression in a mouse model of Fragile X syndrome.

Restoring cerebellar-dependent learning.

The significance of cerebellar contributions in early-life through aging.

Despite perinatal damage to the cerebellum being one of the highest risk factors for later being diagnosed with autism spectrum disorder (ASD), it is not yet clear how the cerebellum might influence the development of cerebral cortex and whether this co-developmental process is distinct between neurotypical and ASD children. Leveraging a large structural brain MRI dataset of neurotypical children and those diagnosed with ASD, we examined whether structural variation in cerebellar tissue across individuals was correlated with neocortical variation during development, including the thalamus as a coupling factor. We found that the thalamus plays a distinct role in moderating cerebro-cerebellar structural coordination in ASD. Notably, structural coupling between cerebellum, thalamus, and neocortex was strongest in younger childhood and waned by early adolescence, mirroring a previously undescribed trajectory of behavioral development between ASD and neurotypical children. Complementary functional connectivity analyses likewise revealed atypical connectivity between cerebellum and neocortex in ASD. This relationship was particularly prominent in a model of cerebellar structure predicting functional connectivity, where ASD and neurotypical children showed divergent patterns. Interestingly, these functional-structural relationships became more prominent with age, while structural effects were most prominent earlier in childhood, and showed significant lateralization. This pattern may suggest a developmental sequence where early uncoordinated structural growth amongst regions is followed by increasingly atypical functional synchronization. These findings provide multimodal evidence in the living brain for a cerebellar diaschisis model of autism, where both increased cerebellar-cerebral structural coupling and altered functional connectivity in cerebro-cerebellar pathways contribute to the ontogeny of this neurodevelopmental disorder.

Multimodal evidence for cerebellar influence on cortical development in autism: structural growth amidst functional disruption.

In an effort to increase access to neuroscience education in underserved communities, we created an educational program that utilizes a simple task to measure place preference of the cockroach () and the open-source free software, SLEAP Estimates Animal Poses (SLEAP) to quantify behavior. Cockroaches ( = 18) were trained to explore a linear track for 2 min while exposed to either air, vapor, or vapor with nicotine from a port on one side of the linear track over 14 d. The time the animal took to reach the port was measured, along with distance traveled, time spent in each zone, and velocity. As characterizing behavior is challenging and inaccessible for nonexperts new to behavioral research, we created an educational program using the machine learning algorithm, SLEAP, and cloud-based (i.e., Google Colab) low-cost platforms for data analysis. We found that SLEAP was within a 0.5% margin of error when compared with manually scoring the data. Cockroaches were found to have an increased aversive response to vapor alone compared with those that only received air. Using SLEAP, we demonstrate that the - coordinate data can be further classified into behavior using dimensionality-reducing clustering methods. This suggests that the linear track can be used to examine nicotine preference for the cockroach, and SLEAP can provide a fast, efficient way to analyze animal behavior. Moreover, this educational program is available for free for students to learn a complex machine learning algorithm without expensive hardware to study animal behavior.

Low-Cost Approaches in Neuroscience to Teach Machine Learning Using a Cockroach Model.

The cerebellum, identified to be active during cognitive and social behavior, has multisynaptic connections through the cerebellar nuclei (CN) and thalamus to cortical regions, yet formation and modulation of these pathways are not fully understood. Perineuronal nets (PNNs) respond to changes in local cellular activity and emerge during development. PNNs are implicated in learning and neurodevelopmental disorders, but their role in the CN during development is unknown. Connectivity deficits, specifically between lateral CN (LCN) and cortical regions have been found in autism spectrum disorder with patients displaying reduced cognitive flexibility. To examine the role of LCN on cognition, neural activity was perturbed in both male and female mice using designer receptors exclusively activated by designer drugs (DREADDs) from postnatal day 21 to 35. We found that while an adolescent LCN disruption did not alter task acquisition, correct choice reversal performance was dependent on DREADD manipulation and sex. Inhibitory DREADDs improved reversal learning in males (5 d faster to criteria), and excitatory DREADDs improved female reversal learning (10 d faster to criteria) compared with controls. Interestingly, the DREADD manipulation in females regardless of direction reduced PNN intensity, whereas in males, only the inhibitory DREADDs reduced PNNs. This suggests a chronic adolescent LCN manipulation may have sex-specific compensatory changes in PNN structure and LCN output to improve reversal learning. This study provides new evidence for LCN in nonmotor functions and sex-dependent differences in behavior and CN plasticity.

Article	Year
Local and systemic administration of AAV vectors with alphaherpesvirus latency-associated promoter 2 drives potent transgene expression in mouse liver, kidney, and skeletal muscle. Journal of virological methods\| PubMed ID: 36736702	2023
Cerebellar contributions to a brainwide network for flexible behavior in mice. Communications biology\| PubMed ID: 37277453	2023
Cognitive-Affective Functions of the Cerebellum. The Journal of neuroscience : the official journal of the Society for Neuroscience\| PubMed ID: 37940582	2023
Restoring cerebellar-dependent learning. eLife\| PubMed ID: 39012692	2024
The significance of cerebellar contributions in early-life through aging. Frontiers in computational neuroscience\| PubMed ID: 39258107	2024
Multimodal evidence for cerebellar influence on cortical development in autism: structural growth amidst functional disruption. Molecular psychiatry\| PubMed ID: 39390225	2025
Low-Cost Approaches in Neuroscience to Teach Machine Learning Using a Cockroach Model. eNeuro\| PubMed ID: 39653390	2024
Adolescent Cerebellar Nuclei Manipulation Alters Reversal Learning and Perineuronal Net Intensity Independently in Male and Female Mice. The Journal of neuroscience : the official journal of the Society for Neuroscience\| PubMed ID: 39753302	2025

Jessica L. Verpeut

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