From 3D surface models to the cellular and molecular architecture of the dentate nucleus: characterizing human-typical traits in the cerebellum
Zusammenfassung der Projektergebnisse
The evolutionary process that led to the encephalization of the human brain remains intriguing and current research is unravelling a complex and manifold process of numerous steps that were taken during the 15‐20 million years of ape evolution. A number of subsystems had to be enhanced, including the visual‐spatial faculties, fine motor skills, prefrontal‐executive functions, emotional, language and social skills. The current project studied the cerebellar dentate nucleus which, together with the cerebellar hemispheres, is particularly enlarged in humans and apes and which has therefore been proposed as being important in many of the human‐typically enhanced subsystems. An alternative view that has guided this project is that the dentate and cerebellar hemispheres mainly contribute to specific sensorimotor functions that are linked to the unique cerebellar microcircuitry. According to this view, the cerebellar cortex detects rapid sequences within the sensorimotor system to monitor error in movement execution, thereby triggering processes of plasticity within the dentate and other cerebellar nuclei (DCN) that modify future movements. The longitudinally oriented folds of the dentate nucleus first described and quantified here for humans and other apes, correspond well with a role of the cerebellum in sequence detection. Such an arrangement would minimize convergence of mediolateral parasagittal stripes, thus enabling us to identify different parallel fiber sequences more readily. The increase in the number of these folds in apes compared to the other primates would allow for a larger sequence of independent movement components, such as are required in complex hand movements. Within the framework of this project, we uncovered a higher dendritic wiring density in the phylogenetically newer dentate/lateralis and interpositus posterior nuclei in rodents and primates. We have interpreted this finding along similar lines as the observation of higher connectivity in phylogenetically newer cerebral cortical regions, and propose that this higher wiring allows a prolonged ability to prune connections and thereby to store new information. Finally, our discovery of the presence of dwarf‐like dendritic arbors in the dentate of primates is surprising and does not comply with the general rule of up‐scaling of dendritic arbors in larger brains established earlier. The remarkably thin ape dentate may be the consequence of such limited dendritic arbors. In summary, this project provides a novel explanation for this remarkable dentate morphology.
Projektbezogene Publikationen (Auswahl)
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(2012) Unravelling cerebellar pathways with high temporal precision targeting motor and extensive sensory and parietal networks. Nature communications 3:924.
Sultan F, Augath M, Hamodeh S, Murayama Y, Oeltermann A, Rauch A, Thier P
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(2014) An intact action‐perception coupling depends on the integrity of the cerebellum. J Neurosci 34:6707‐6716.
Christensen A, Giese MA, Sultan F, Mueller OM, Goericke SL, Ilg W, Timmann D
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(2014) Effects of dementia on cueing mechanism in Parkinson’s disease. Frontiers in Aging Neuroscience 5:236
Gräber S, Lieppelt‐Scarfone I, Metzelder W, Sultan F, Berg D
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(2014) From cerebellar texture to movement optimization. Biological Cybernetics 108:677‐688.
Sultan F
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(2014) Systematic analysis of neuronal wiring of the rodent deep cerebellar nuclei reveals differences reflecting adaptations at the neuronal circuit and internuclear level. J Comp Neurol 522:2481‐2497
. Hamodeh S, Sugihara I, Baizer J, Sultan F
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2014) Cerebellum: Anatomy and Physiology In: Brain Mapping: A Comprehensive Reference: Elsevier
Sultan F
