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Journal of Neurophysiology Dec 2022A hedge fund billionaire's children are suffering from cerebellar disease. He invited a group of neuroscientists to plan a search for therapies. What resulted is the... (Review)
Review
A hedge fund billionaire's children are suffering from cerebellar disease. He invited a group of neuroscientists to plan a search for therapies. What resulted is the outline of an implantable neural emulator that might electronically replace the damaged part of the brain.
Topics: Male; Child; Humans; Purkinje Cells; Cerebellum; Cerebellar Diseases
PubMed: 36350062
DOI: 10.1152/jn.00437.2022 -
Cerebellum (London, England) Dec 2018Cerebellar Purkinje neurons are arguably some of the most conspicuous neurons in the vertebrate central nervous system. They have characteristic planar fan-shaped...
Cerebellar Purkinje neurons are arguably some of the most conspicuous neurons in the vertebrate central nervous system. They have characteristic planar fan-shaped dendrites which branch extensively and fill spaces almost completely with little overlap. This dendritic morphology is well suited to receiving a single or a few excitatory synaptic inputs from each of more than 100,000 parallel fibers which run orthogonally to Purkinje cell dendritic trees. In contrast, another type of excitatory input to a Purkinje neuron is provided by a single climbing fiber, which forms some hundreds to thousands of synapses with a Purkinje neuron. This striking contrast between the two types of synaptic inputs to a Purkinje neuron has attracted many neuroscientists. It is also to be noted that Purkinje neurons are the sole neurons sending outputs from the cerebellar cortex. In other words, all computational results within the cortex are transmitted by Purkinje cell axons, which inhibit neurons in the cerebellar or vestibular nucleus. Notably, Purkinje neurons show several forms of synaptic plasticity. Among them, long-term depression (LTD) at parallel fiber synapses has been regarded as a putatively essential mechanism for cerebellum-dependent learning. In this special issue on Purkinje neurons, you will find informative reviews and original papers on the development, characteristics and functions of Purkinje neurons, or related themes contributed by outstanding researchers.
Topics: Animals; Cerebellum; Humans; Purkinje Cells
PubMed: 30284678
DOI: 10.1007/s12311-018-0985-7 -
Neuroscience May 2021In the last 50 years, our vision of the cerebellum has vastly evolved starting with Voogd's (1967) description of extracerebellar projections' terminations and how the... (Review)
Review
In the last 50 years, our vision of the cerebellum has vastly evolved starting with Voogd's (1967) description of extracerebellar projections' terminations and how the projection maps transformed the presumptive homogeneity of the cerebellar cortex into a more complex center subdivided into transverse and longitudinal distinct functional zones. The picture became still more complex with Richard Hawkes and colleagues' (Gravel et al., 1987) discovery of the biochemical heterogeneity of Purkinje cells (PCs), by screening their molecular identities with monoclonal antibodies. Antigens were expressed in a parasagittal pattern with subsets of PCs either possessing or lacking the respective antigens, which divided the cerebellar cortex into precise longitudinal compartments that are congruent with the projection maps. The correlation of these two maps in adult cerebellum shows a perfect matching of developmental mechanisms. This review discusses a series of arguments in favor of the essential role played by PCs in organizing the microzonation of the cerebellum during development (the "matching" hypothesis).
Topics: Antibodies, Monoclonal; Antigens; Cerebellar Cortex; Cerebellum; Purkinje Cells
PubMed: 31982466
DOI: 10.1016/j.neuroscience.2020.01.019 -
Cerebellum (London, England) Oct 2015Great attention has been given so far to cerebellar control of posture and of skilled movements despite the well-demonstrated interconnections between the cerebellum and... (Review)
Review
Great attention has been given so far to cerebellar control of posture and of skilled movements despite the well-demonstrated interconnections between the cerebellum and the autonomic nervous system. Here is a review of the link between these two structures and a report on the recently acquired evidence for its involvement in the world of emotions. In rodents, the reversible inactivation of the vermis during the consolidation or the reconsolidation period hampers the retention of the fear memory trace. In this region, there is a long-term potentiation of both the excitatory synapses between the parallel fibres and the Purkinje cells and of the feed-forward inhibition mediated by molecular layer interneurons. This concomitant potentiation ensures the temporal fidelity of the system. Additional contacts between mossy fibre terminals and Golgi cells provide morphological evidence of the potentiation of another feed-forward inhibition in the granular layer. Imaging experiments show that also in humans the cerebellum is activated during mental recall of emotional personal episodes and during learning of a conditioned or unconditioned association involving emotions. The vermis participates in fear learning and memory mechanisms related to the expression of autonomic and motor responses of emotions. In humans, the cerebellar hemispheres are also involved at a higher emotional level. The importance of these findings is evident when considering the cerebellar malfunctioning in psychiatric diseases like autism and schizophrenia which are characterized behaviourally by emotion processing impairments.
Topics: Animals; Cerebellum; Emotions; Humans; Mental Disorders
PubMed: 25626523
DOI: 10.1007/s12311-015-0649-9 -
Nature Communications Sep 2023Social recognition memory (SRM) is a key determinant of social interactions. While the cerebellum emerges as an important region for social behavior, how cerebellar...
Social recognition memory (SRM) is a key determinant of social interactions. While the cerebellum emerges as an important region for social behavior, how cerebellar activity affects social functions remains unclear. We selectively increased the excitability of molecular layer interneurons (MLIs) to suppress Purkinje cell firing in the mouse cerebellar vermis. Chemogenetic perturbation of MLIs impaired SRM without affecting sociability, anxiety levels, motor coordination or object recognition. Optogenetic interference of MLIs during distinct phases of a social recognition test revealed the cerebellar engagement in the retrieval, but not encoding, of social information. c-Fos mapping after the social recognition test showed that cerebellar manipulation decreased brain-wide interregional correlations and altered network structure from medial prefrontal cortex and hippocampus-centered to amygdala-centered modules. Anatomical tracing demonstrated hierarchical projections from the central cerebellum to the social brain network integrating amygdalar connections. Our findings suggest that the cerebellum organizes the neural matrix necessary for SRM.
Topics: Mice; Animals; Cerebellar Vermis; Cerebellum; Purkinje Cells; Interneurons; Memory Disorders
PubMed: 37752149
DOI: 10.1038/s41467-023-41744-2 -
Neuron May 2023In this issue of Neuron, Xiao et al. reported that inhibitory and excitatory neurons in the pontine central gray encode and transmit opposite valences of sensory...
In this issue of Neuron, Xiao et al. reported that inhibitory and excitatory neurons in the pontine central gray encode and transmit opposite valences of sensory stimuli through parallel circuits to a distributed brain network.
Topics: Pons; Neurons; Pontine Tegmentum; Cerebellar Nuclei
PubMed: 37141860
DOI: 10.1016/j.neuron.2023.04.009 -
Cerebellum (London, England) Dec 2011
Topics: Animals; Cerebellar Nuclei; Cerebellum; Humans; Purkinje Cells; Vestibular Nuclei
PubMed: 21279491
DOI: 10.1007/s12311-010-0245-y -
Cerebellum (London, England) Oct 2022After decades of study, a comprehensive understanding of cerebellar function remains elusive. Several hypotheses have been put forward over the years, including that the... (Review)
Review
After decades of study, a comprehensive understanding of cerebellar function remains elusive. Several hypotheses have been put forward over the years, including that the cerebellum functions as a forward internal model. Integrated into the forward model framework is the long-standing view that Purkinje cell complex spike discharge encodes error information. In this brief review, we address both of these concepts based on our recordings of cerebellar Purkinje cells over the last decade as well as newer findings from the literature. During a high-dimensionality tracking task requiring continuous error processing, we find that complex spike discharge provides a rich source of non-error signals to Purkinje cells, indicating that the classical error encoding role ascribed to climbing fiber input needs revision. Instead, the simple spike discharge of Purkinje cells carries robust predictive and feedback signals of performance errors, as well as kinematics. These simple spike signals are consistent with a forward internal model. We also show that the information encoded in the simple spike is dynamically adjusted by the complex spike firing. Synthesis of these observations leads to the hypothesis that complex spikes convey behavioral state changes, possibly acting to select and maintain forward models.
Topics: Action Potentials; Biomechanical Phenomena; Cerebellum; Movement; Purkinje Cells
PubMed: 35471627
DOI: 10.1007/s12311-022-01406-3 -
Acta Medica Portuguesa 2010Cerebellar hypoplasias are cerebellar malformations with small but completely formed cerebellum. They can be divided in focal and in diffuse or generalized. It is... (Review)
Review
Cerebellar hypoplasias are cerebellar malformations with small but completely formed cerebellum. They can be divided in focal and in diffuse or generalized. It is sometimes difficult to make distinction between cerebellar atrophy (progressive condition) and hipoplasia (not progressive condition). Focal hypoplasias are restricted to one cerebellar hemisphere or to the vermis. Diffuse hypoplasias refer to both cerebellar hemispheres and vermis. If there is associated IVth ventricle enlargement, hypoplasias occur in the context of Dandy-Walker complex, a continuum of posterior fossa cystic anomalies. A revision of cerebellar hypoplasias and associated pathology is done, illustrated with 22 cases tha include focal and diffuse cerebellar hypoplasias, Dandy-Walker malformations and its variant, persistent Blake's pouch cyst, megacisterna magna, PEHO síndrome (progressive encephalopathy with oedema, hipsarrhythmia and optic atrophy), Joubert syndrome, congenital disorder of glycosylation type Ia, pontocerebellar hipoplasias Barth type I and II, diffuse subcortical heterotopia. The imaging finding of structural cerebellar anomalies frequently leads to diagnostic incertainty as the anomalies are mostly unspecific, implying an extenuating analytical and genetic workup. Their knowledge and classification may be useful to decide the patient adjusted laboratorial workup.
Topics: Abnormalities, Multiple; Cerebellum; Humans; Pons
PubMed: 21144325
DOI: No ID Found -
Nature Neuroscience Sep 2023The vast expansion from mossy fibers to cerebellar granule cells (GrC) produces a neural representation that supports functions including associative and internal model...
The vast expansion from mossy fibers to cerebellar granule cells (GrC) produces a neural representation that supports functions including associative and internal model learning. This motif is shared by other cerebellum-like structures and has inspired numerous theoretical models. Less attention has been paid to structures immediately presynaptic to GrC layers, whose architecture can be described as a 'bottleneck' and whose function is not understood. We therefore develop a theory of cerebellum-like structures in conjunction with their afferent pathways that predicts the role of the pontine relay to cerebellum and the glomerular organization of the insect antennal lobe. We highlight a new computational distinction between clustered and distributed neuronal representations that is reflected in the anatomy of these two brain structures. Our theory also reconciles recent observations of correlated GrC activity with theories of nonlinear mixing. More generally, it shows that structured compression followed by random expansion is an efficient architecture for flexible computation.
Topics: Cerebellum; Brain; Pons; Learning; Neurons
PubMed: 37604889
DOI: 10.1038/s41593-023-01403-7