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Cerebellum (London, England) Dec 2017Surgery of the posterior fossa represents a technical challenge because of the proximity of the vessels of the cerebellum. If the arterial vascularization of the...
Surgery of the posterior fossa represents a technical challenge because of the proximity of the vessels of the cerebellum. If the arterial vascularization of the cerebellum is well known, the main arterial variations and the whole venous vascularization are probably under recognized. We describe the vascular organization and the main variations through photographs of colored latex perfused brains, obtained with a surgical microscope. The arterial vascularization of the cerebellum is based on three arteries which all originate from the vertebrobasilar system: the superior cerebellar artery (SCA), the anterior and inferior cerebellar artery (AICA), and the posterior and inferior cerebellar artery (PICA). The main arterial variations involve essentially the origin of these vessels. Concerning the SCA, its origin depends on the embryology. The AICA can arise from a common trunk AICA-PICA. It can be sometimes doubled and rarely absent. The PICA also can arise from a common trunk AICA-PICA and sometimes from the extradural segment of the vertebral artery. Concerning the venous organization, we distinguish the superficial and deep veins. The superficial veins drain the cerebellar cortex and transit on the surface of the cerebellum. The deep veins refer to the veins transiting in the fissures between the cerebellum and the brainstem. All these veins terminate as bridging veins that we can divide in three groups: a superior group emptying into the great vein, a posterior group emptying into the transtentorial sinus, and a lateral group ending into the superior petrosal sinus. The surgical implications are discussed.
Topics: Arteries; Cerebellum; Humans; Latex; Neurosurgical Procedures; Tissue Fixation; Veins
PubMed: 27766499
DOI: 10.1007/s12311-016-0828-3 -
Nature Reviews. Neuroscience May 2019The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the... (Review)
Review
The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the cerebellum is critical for motor behaviour, it is not surprising that most neurodevelopmental disorders share motor deficits as a common sequela. However, evidence gathered since the late 1980s suggests that the cerebellum is involved in motor and non-motor function, including cognition and emotion. More recently, evidence indicates that major neurodevelopmental disorders such as intellectual disability, autism spectrum disorder, attention-deficit hyperactivity disorder and Down syndrome have potential links to abnormal cerebellar development. Out of recent findings from clinical and preclinical studies, the concept of the 'cerebellar connectome' has emerged that can be used as a framework to link the role of cerebellar development to human behaviour, disease states and the design of better therapeutic strategies.
Topics: Animals; Cerebellum; Connectome; Humans; Nerve Net; Neurodevelopmental Disorders
PubMed: 30923348
DOI: 10.1038/s41583-019-0152-2 -
Proceedings of the National Academy of... Apr 2022
Topics: Cerebellum; Purkinje Cells
PubMed: 35452313
DOI: 10.1073/pnas.2204155119 -
Neuroscience May 2021This article is dedicated to the memory of Masao Ito. Masao Ito made numerous important contributions revealing the function of the cerebellum in motor control. His... (Review)
Review
This article is dedicated to the memory of Masao Ito. Masao Ito made numerous important contributions revealing the function of the cerebellum in motor control. His pioneering contributions to cerebellar physiology began with his discovery of inhibition and disinhibition of target neurons by cerebellar Purkinje cells, and his discovery of the presence of long-term depression in parallel fiber-Purkinje cell synapses. Purkinje cells formed the nodal point of Masao Ito's landmark model of motor control by the cerebellum. These discoveries became the basis for his ideas regarding the flocculus hypothesis, the adaptive motor control system, and motor learning by the cerebellum, inspiring many new experiments to test his hypotheses. This article will trace the achievements of Ito and colleagues in analyzing the neural circuits of the input-output organization of the cerebellar cortex and nuclei, particularly with respect to motor control. The article will discuss some of the important issues that have been solved and also those that remain to be solved for our understanding of motor control by the cerebellum.
Topics: Cell Nucleus; Cerebellar Nuclei; Cerebellar Vermis; Cerebellum; Memory; Purkinje Cells
PubMed: 32768619
DOI: 10.1016/j.neuroscience.2020.07.051 -
Cerebellum (London, England) Jun 2015The cerebellar cortex exhibits a strikingly high expression of type 1 cannabinoid receptor (CB1), the cannabinoid binding protein responsible for the psychoactive... (Review)
Review
The cerebellar cortex exhibits a strikingly high expression of type 1 cannabinoid receptor (CB1), the cannabinoid binding protein responsible for the psychoactive effects of marijuana. CB1 is primarily found in presynaptic elements in the molecular layer. While the functional importance of cerebellar CB1 is supported by the effect of gene deletion or exogenous cannabinoids on animal behavior, evidence for a role of endocannabinoids in synaptic signaling is provided by in vitro experiments on superfused acute rodent cerebellar slices. These studies have demonstrated that endocannabinoids can be transiently released by Purkinje cells and signal at synapses in a direction opposite to information transfer (retrograde). Here, following a description of the reported expression pattern of the endocannabinoid system in the cerebellum, I review the accumulated in vitro data, which have addressed the mechanism of retrograde endocannabinoid signaling and identified 2-arachidonoylglycerol as the mediator of this signaling. The mechanisms leading to endocannabinoid release, the effects of CB1 activation, and the associated synaptic plasticity mechanisms are discussed and the remaining unknowns are pointed. Notably, it is argued that the spatial specificity of this signaling and the physiological conditions required for its induction need to be determined in order to understand endocannabinoid function in the cerebellar cortex.
Topics: Animals; Arachidonic Acids; Cerebellum; Endocannabinoids; Glycerides; Humans; In Vitro Techniques; Neuronal Plasticity; Purkinje Cells; Receptor, Cannabinoid, CB1; Synaptic Transmission
PubMed: 25520276
DOI: 10.1007/s12311-014-0629-5 -
Handbook of Clinical Neurology 2018In the last few decades, an increasing number of studies have focused on better characterizing the cerebellar functions beyond motor control, including emotional and... (Review)
Review
In the last few decades, an increasing number of studies have focused on better characterizing the cerebellar functions beyond motor control, including emotional and social domains. Anatomic and functional evidence strongly contributes to delineating the cerebellar functional subdivisions and their integration with cerebral functional networks strictly related to emotional regulation and social functioning, thus suggesting a model of cerebellar organization that resembles that of the cerebral cortex. Overcoming the traditional segregation of cerebrocerebellar networks in sensorimotor/cognitive functional modules, during emotional/social processes, the cerebellar activity reflects a domain-specific mentalizing functionality that is strongly connected with corresponding mentalizing networks in the cerebrum. Additionally, the cerebrocerebellar organization has been shown to have a specific functional and maturational trajectory that is only in part dependent on a structural maturational process and that is protracted from an early stage of life through adolescence and adulthood, when the mature control networks involve both segregation and integration of the brain regions that comprise them. Altogether, these findings underscore the importance of regional functional differences within the cerebellum in relation to emotional and social processing and raise questions about the clinical implication of cerebellar injury on emotional/social behaviors, both in the developing and the adult brain.
Topics: Animals; Brain Mapping; Cerebellum; Emotions; Humans; Neural Pathways; Social Behavior
PubMed: 29903453
DOI: 10.1016/B978-0-444-63956-1.00005-9 -
Cell Reports May 2023Within the cerebellar cortex, mossy fibers (MFs) excite granule cells (GCs) that excite Purkinje cells (PCs), which provide outputs to the deep cerebellar nuclei (DCNs)....
Within the cerebellar cortex, mossy fibers (MFs) excite granule cells (GCs) that excite Purkinje cells (PCs), which provide outputs to the deep cerebellar nuclei (DCNs). It is well established that PC disruption produces motor deficits such as ataxia. This could arise from either decreases in ongoing PC-DCN inhibition, increases in the variability of PC firing, or disruption of the flow of MF-evoked signals. Remarkably, it is not known whether GCs are essential for normal motor function. Here we address this issue by selectively eliminating calcium channels that mediate transmission (Ca2.1, Ca2.2, and Ca2.3) in a combinatorial manner. We observe profound motor deficits but only when all Ca2 channels are eliminated. In these mice, the baseline rate and variability of PC firing are unaltered, and locomotion-dependent increases in PC firing are eliminated. We conclude that GCs are indispensable for normal motor performance and that disruption of MF-induced signals impairs motor performance.
Topics: Mice; Animals; Cerebellum; Neurons; Purkinje Cells; Cerebellar Cortex; Signal Transduction
PubMed: 37141091
DOI: 10.1016/j.celrep.2023.112429 -
Neuroscience May 2021Fifty years have passed since David Marr, Masao Ito, and James Albus proposed seminal models of cerebellar functions. These models share the essential concept that... (Review)
Review
Fifty years have passed since David Marr, Masao Ito, and James Albus proposed seminal models of cerebellar functions. These models share the essential concept that parallel-fiber-Purkinje-cell synapses undergo plastic changes, guided by climbing-fiber activities during sensorimotor learning. However, they differ in several important respects, including holistic versus complementary roles of the cerebellum, pattern recognition versus control as computational objectives, potentiation versus depression of synaptic plasticity, teaching signals versus error signals transmitted by climbing-fibers, sparse expansion coding by granule cells, and cerebellar internal models. In this review, we evaluate different features of the three models based on recent computational and experimental studies. While acknowledging that the three models have greatly advanced our understanding of cerebellar control mechanisms in eye movements and classical conditioning, we propose a new direction for computational frameworks of the cerebellum, that is, hierarchical reinforcement learning with multiple internal models.
Topics: Cerebellum; Models, Neurological; Neuronal Plasticity; Purkinje Cells; Synapses
PubMed: 32599123
DOI: 10.1016/j.neuroscience.2020.06.019 -
ELife Aug 2020High-end technical approaches help to untangle the substructure and projection patterns of the cerebellum.
High-end technical approaches help to untangle the substructure and projection patterns of the cerebellum.
Topics: Cerebellum
PubMed: 32812869
DOI: 10.7554/eLife.60852 -
Cerebellum (London, England) Feb 2015"Looking into the future" well depicts one of the most significant concepts in cognitive neuroscience: the brain is constantly predicting future events. Such... (Review)
Review
"Looking into the future" well depicts one of the most significant concepts in cognitive neuroscience: the brain is constantly predicting future events. Such directedness toward the future has been recognized to be relevant to and beneficial for many aspects of information processing in humans, such as perception, motor and cognitive control, decision-making, theory of mind, and other cognitive processes. Because one of the most adaptive characteristics of the brain is to correct errors, the ability to look into the future represents the best chance to avoid repeating errors. Within the structures that constitute the "predictive brain," the cerebellum has been proposed to have a central function, based on its ability to generate internal models. We suggested that "sequence detection" is the operational mode of the cerebellum in predictive processing. According to this hypothesis, the cerebellum detects and simulates repetitive patterns of temporally or spatially structured events and generates internal models that can be used to make predictions. Consequently, we demonstrate that the cerebellum recognizes serial events as a sequence, detects a sequence violation, and successfully reconstructs the correct sequence of events. Thus, we hypothesize that pattern detection and prediction and processing of anticipation are cerebellum-specific functions within the brain and that the sequence detection hypothesis links the multifarious impairments that are reported in patients with cerebellar damage. We propose that this cerebellar operational mode can advance our understanding of the pathophysiological mechanisms in various clinical conditions, such as schizophrenia and autism.
Topics: Anticipation, Psychological; Cerebellum; Humans; Pattern Recognition, Physiological; Serial Learning
PubMed: 25331541
DOI: 10.1007/s12311-014-0616-x