Non-traditional large neurons in the granular layer of the cerebellar cortex.
ABSTRACT The granular layer of the cerebellar cortex is composed of two groups of neurons, the granule neurons and the so-called large neurons. These latter include the neuron of Golgi and a number of other, lesser known neuron types, generically indicated as non-traditional large neurons. In the last few years, owing to the development of improved histological and histochemical techniques for studying morphological and chemical features of these neurons, some non-traditional large neurons have been morphologically well characterized, namely the neuron of Lugaro, the synarmotic neuron, the unipolar brush neuron, the candelabrum neuron and the perivascular neuron. Some types of non-traditional large neurons may be involved in the modulation of cortical intrinsic circuits, establishing connections among neurons distributed throughout the cortex, and acting as inhibitory interneurons (i.e., Lugaro and candelabrum neurons) or as excitatory ones (i.e., unipolar brush neuron). On the other hand, the synarmotic neuron could be involved in extrinsic circuits, projecting to deep cerebellar nuclei or to another cortex regions in the same or in a different folium. Finally, the perivascular neuron may intervene in the intrinsic regulation of the cortex microcirculation.
Full-textDOI: · Available from: Loredana Lorusso, May 30, 2015
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ABSTRACT: Although the basic morphological characteristics of neurons in the cerebellar cortex have been documented in several species, virtually nothing is known about the quantitative morphological characteristics of these neurons across different taxa. To that end, the present study investigated cerebellar neuronal morphology among eight different, large-brained mammalian species comprising a broad phylogenetic range: afrotherians (African elephant, Florida manatee), carnivores (Siberian tiger, clouded leopard), cetartiodactyls (humpback whale, giraffe) and primates (human, common chimpanzee). Specifically, several neuron types (e.g., stellate, basket, Lugaro, Golgi, and granule neurons; N = 317) of the cerebellar cortex were stained with a modified rapid Golgi technique and quantified on a computer-assisted microscopy system. There was a 64-fold variation in brain mass across species in our sample (from clouded leopard to the elephant) and a 103-fold variation in cerebellar volume. Most dendritic measures tended to increase with cerebellar volume. The cerebellar cortex in these species exhibited the trilaminate pattern common to all mammals. Morphologically, neuron types in the cerebellar cortex were generally consistent with those described in primates (Fox et al., 1967) and rodents (Palay and Chan-Palay, 1974), although there was substantial quantitative variation across species. In particular, Lugaro neurons in the elephant appeared to be disproportionately larger than those in other species. To explore potential quantitative differences in dendritic measures across species, MARSplines analyses were used to evaluate whether species could be differentiated from each other based on dendritic characteristics alone. Results of these analyses indicated that there were significant differences among all species in dendritic measures.Frontiers in Neuroanatomy 07/2014; 8:24. DOI:10.3389/fnana.2014.00024 · 4.18 Impact Factor
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ABSTRACT: The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum.Frontiers in Cellular Neuroscience 01/2015; 8(450):1-26. DOI:10.3389/fncel.2014.00450 · 4.18 Impact Factor