Cerebellar reserve refers to the capacity of the cerebellum to compensate for tissue damage or loss of function resulting from many different etiologies. When the inciting event produces acute focal damage (e.g., stroke, trauma), impaired cerebellar function may be compensated for by other cerebellar areas or by extracerebellar structures (i.e., structural cerebellar reserve). In contrast, when pathological changes compromise cerebellar neuronal integrity gradually leading to cell death (e.g., metabolic and immune-mediated cerebellar ataxias, neurodegenerative ataxias), it is possible that the affected area itself can compensate for the slowly evolving cerebellar lesion (i.e., functional cerebellar reserve). Here, we examine cerebellar reserve from the perspective of the three cornerstones of clinical ataxiology: control of ocular movements, coordination of voluntary axial and appendicular movements, and cognitive functions. Current evidence indicates that cerebellar reserve is potentiated by environmental enrichment through the mechanisms of autophagy and synaptogenesis, suggesting that cerebellar reserve is not rigid or fixed, but exhibits plasticity potentiated by experience. These conclusions have therapeutic implications. During the period when cerebellar reserve is preserved, treatments should be directed at stopping disease progression and/or limiting the pathological process. Simultaneously, cerebellar reserve may be potentiated using multiple approaches. Potentiation of cerebellar reserve may lead to compensation and restoration of function in the setting of cerebellar diseases, and also in disorders primarily of the cerebral hemispheres by enhancing cerebellar mechanisms of action. It therefore appears that cerebellar reserve, and the underlying plasticity of cerebellar microcircuitry that enables it, may be of critical neurobiological importance to a wide range of neurological/neuropsychiatric conditions.
24 October 2015 in Cellular and Molecular Life Sciences
Sensory processing disorders (SPDs) can be described as difficulty detecting, modulating, interpreting, and/or responding to sensory experiences. Because SPDs occur in many individuals with autism spectrum disorder and in other populations with neurodevelopmental disorders, it is important to distinguish between typical and atypical functioning in sensory processes and to identify early phenotypic markers for developing SPDs. This review considers different methods for diagnosing SPDs to outline a multidisciplinary approach useful for developing valid diagnostic measures. In particular, the advantages and limitations of the most commonly used tools in assessment of SPDs, such as caregiver reports, clinical observation, and psychophysical and neuroimaging studies, will be reviewed. Innovative treatment methods such as neuromodulation techniques and virtual reality will also be suggested.
30 January 2017 in Proceedings of the National Academy of Sciences
Medium spiny neurons (MSNs) are a key population in the basal ganglia network, and their degeneration causes a severe neurodegenerative disorder, Huntington9s disease. Understanding how ventral neuroepithelial progenitors differentiate into MSNs is critical for regenerative medicine to develop specific differentiation protocols using human pluripotent stem cells. Studies performed in murine models have identified some transcriptional determinants, including GS Homeobox 2 (Gsx2) and Early B-cell factor 1 (Ebf1). Here, we have generated human embryonic stem (hES) cell lines inducible for these transcription factors, with the aims of (i) studying their biological role in human neural progenitors and (ii) incorporating TF conditional expression in a developmental-based protocol for generating MSNs from hES cells. Using this approach, we found that Gsx2 delays cell-cycle exit and reduces Pax6 expression, whereas Ebf1 promotes neuronal differentiation. Moreover, we found that Gsx2 and Ebf1 combined overexpression in hES cells achieves high yields of MSNs, expressing Darpp32 and Ctip2, in vitro as well in vivo after transplantation. We show that hES-derived striatal progenitors can be transplanted in animal models and can differentiate and integrate into the host, extending fibers over a long distance. Significance We established human embryonic stem (hES) cell-inducible lines to express specific transcription factors [GS Homeobox 2 (Gsx2) and Early B-cell factor 1 (Ebf1)] to improve medium spiny neuron (MSN) differentiation and to study human striatal development in vitro. We also used a nonintegrating system, by utilizing modified mRNAs to transiently overexpress Gsx2 and Ebf1 in a different hES cell line. These data can help to improve the differentiation protocols that aim to produce high-quality cell preparation suitable for cell transplantation in animal models of Huntington’s disease. Finally, we show that hES-derived striatal progenitors can be transplanted in the striatum of animal models and can differentiate and integrate into the host, extending fibers over a long distance (including the substantia nigra, a striatal target).
This study investigated the prevalence and distribution of psychiatric comorbidities in a group of 472 children and adolescents with ASD aged 3–18 years. We examined differences in age, sex, IQ, adaptive skills, and ASD symptom severity by comparing participants with ASD (ASD group) with participants with ASD and a psychiatric disorder (ASD/PSY group). Overall, 32.2% of participants had a comorbid psychiatric condition. Attention deficit/hyperactivity disorder (ADHD) was the most frequent diagnosis among preschoolers (20.4%); among school-age children, ADHD and anxiety/obsessive-compulsive disorders were the most frequent conditions (21% and 10.6%, respectively); finally, adolescents exhibit higher prevalence of anxiety/obsessive-compulsive disorders (21.8%). The ASD/PSY group showed a higher percentage of males, they were older and showed lower adaptive skills than the group with ASD; moreover, their mothers exhibited higher stress levels than mothers of participants in the ASD group. The comparison between age groups in participants within ASD/PSY group revealed that preschoolers had lower IQ than school-age children and adolescents, and worse adaptive skills, more repetitive behaviors, and restricted interests than adolescents. This study highlights the importance of an accurate diagnosis of psychiatric comorbidities in children and adolescents with ASD, also considering individual and family impairment.