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1.
Cell ; 184(14): 3731-3747.e21, 2021 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-34214470

RESUMEN

In motor neuroscience, state changes are hypothesized to time-lock neural assemblies coordinating complex movements, but evidence for this remains slender. We tested whether a discrete change from more autonomous to coherent spiking underlies skilled movement by imaging cerebellar Purkinje neuron complex spikes in mice making targeted forelimb-reaches. As mice learned the task, millimeter-scale spatiotemporally coherent spiking emerged ipsilateral to the reaching forelimb, and consistent neural synchronization became predictive of kinematic stereotypy. Before reach onset, spiking switched from more disordered to internally time-locked concerted spiking and silence. Optogenetic manipulations of cerebellar feedback to the inferior olive bi-directionally modulated neural synchronization and reaching direction. A simple model explained the reorganization of spiking during reaching as reflecting a discrete bifurcation in olivary network dynamics. These findings argue that to prepare learned movements, olivo-cerebellar circuits enter a self-regulated, synchronized state promoting motor coordination. State changes facilitating behavioral transitions may generalize across neural systems.


Asunto(s)
Movimiento/fisiología , Red Nerviosa/fisiología , Potenciales de Acción/fisiología , Animales , Calcio/metabolismo , Cerebelo/fisiología , Sincronización Cortical , Miembro Anterior/fisiología , Interneuronas/fisiología , Aprendizaje , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Neurológicos , Actividad Motora/fisiología , Núcleo Olivar/fisiología , Optogenética , Células de Purkinje/fisiología , Conducta Estereotipada , Análisis y Desempeño de Tareas
2.
Cell ; 180(3): 536-551.e17, 2020 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-31955849

RESUMEN

Goal-directed behavior requires the interaction of multiple brain regions. How these regions and their interactions with brain-wide activity drive action selection is less understood. We have investigated this question by combining whole-brain volumetric calcium imaging using light-field microscopy and an operant-conditioning task in larval zebrafish. We find global, recurring dynamics of brain states to exhibit pre-motor bifurcations toward mutually exclusive decision outcomes. These dynamics arise from a distributed network displaying trial-by-trial functional connectivity changes, especially between cerebellum and habenula, which correlate with decision outcome. Within this network the cerebellum shows particularly strong and predictive pre-motor activity (>10 s before movement initiation), mainly within the granule cells. Turn directions are determined by the difference neuroactivity between the ipsilateral and contralateral hemispheres, while the rate of bi-hemispheric population ramping quantitatively predicts decision time on the trial-by-trial level. Our results highlight a cognitive role of the cerebellum and its importance in motor planning.


Asunto(s)
Cerebelo/fisiología , Toma de Decisiones/fisiología , Tiempo de Reacción/fisiología , Pez Cebra/fisiología , Animales , Conducta Animal/fisiología , Mapeo Encefálico/métodos , Cerebro/fisiología , Cognición/fisiología , Condicionamiento Operante/fisiología , Objetivos , Habénula/fisiología , Calor , Larva/fisiología , Actividad Motora/fisiología , Movimiento , Neuronas/fisiología , Desempeño Psicomotor/fisiología , Rombencéfalo/fisiología
3.
Physiol Rev ; 100(1): 271-320, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31512990

RESUMEN

The vertebrate control of locomotion involves all levels of the nervous system from cortex to the spinal cord. Here, we aim to cover all main aspects of this complex behavior, from the operation of the microcircuits in the spinal cord to the systems and behavioral levels and extend from mammalian locomotion to the basic undulatory movements of lamprey and fish. The cellular basis of propulsion represents the core of the control system, and it involves the spinal central pattern generator networks (CPGs) controlling the timing of different muscles, the sensory compensation for perturbations, and the brain stem command systems controlling the level of activity of the CPGs and the speed of locomotion. The forebrain and in particular the basal ganglia are involved in determining which motor programs should be recruited at a given point of time and can both initiate and stop locomotor activity. The propulsive control system needs to be integrated with the postural control system to maintain body orientation. Moreover, the locomotor movements need to be steered so that the subject approaches the goal of the locomotor episode, or avoids colliding with elements in the environment or simply escapes at high speed. These different aspects will all be covered in the review.


Asunto(s)
Sistema Nervioso Central/fisiología , Locomoción , Vertebrados/fisiología , Animales , Ganglios Basales/fisiología , Evolución Biológica , Cerebelo/fisiología , Humanos , Lampreas/genética , Lampreas/fisiología , Ratones , Médula Espinal/fisiología , Vertebrados/genética , Pez Cebra/genética , Pez Cebra/fisiología
4.
Nature ; 600(7888): 269-273, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34789878

RESUMEN

The brain is the seat of body weight homeostasis. However, our inability to control the increasing prevalence of obesity highlights a need to look beyond canonical feeding pathways to broaden our understanding of body weight control1-3. Here we used a reverse-translational approach to identify and anatomically, molecularly and functionally characterize a neural ensemble that promotes satiation. Unbiased, task-based functional magnetic resonance imaging revealed marked differences in cerebellar responses to food in people with a genetic disorder characterized by insatiable appetite. Transcriptomic analyses in mice revealed molecularly and topographically -distinct neurons in the anterior deep cerebellar nuclei (aDCN) that are activated by feeding or nutrient infusion in the gut. Selective activation of aDCN neurons substantially decreased food intake by reducing meal size without compensatory changes to metabolic rate. We found that aDCN activity terminates food intake by increasing striatal dopamine levels and attenuating the phasic dopamine response to subsequent food consumption. Our study defines a conserved satiation centre that may represent a novel therapeutic target for the management of excessive eating, and underscores the utility of a 'bedside-to-bench' approach for the identification of neural circuits that influence behaviour.


Asunto(s)
Mantenimiento del Peso Corporal/genética , Mantenimiento del Peso Corporal/fisiología , Cerebelo/fisiología , Alimentos , Biosíntesis de Proteínas , Genética Inversa , Respuesta de Saciedad/fisiología , Adulto , Animales , Regulación del Apetito/genética , Regulación del Apetito/fisiología , Núcleos Cerebelosos/citología , Núcleos Cerebelosos/fisiología , Cerebelo/citología , Señales (Psicología) , Dopamina/metabolismo , Ingestión de Alimentos/genética , Ingestión de Alimentos/fisiología , Conducta Alimentaria/fisiología , Femenino , Homeostasis , Humanos , Imagen por Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos C57BL , Neostriado/metabolismo , Neuronas/fisiología , Obesidad/genética , Filosofía , Adulto Joven
5.
Proc Natl Acad Sci U S A ; 121(17): e2318849121, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38630714

RESUMEN

Neurons in the inferior olive are thought to anatomically organize the Purkinje cells (P-cells) of the cerebellum into computational modules, but what is computed by each module? Here, we designed a saccade task in marmosets that dissociated sensory events from motor events and then recorded the complex and simple spikes of hundreds of P-cells. We found that when a visual target was presented at a random location, the olive reported the direction of that sensory event to one group of P-cells, but not to a second group. However, just before movement onset, it reported the direction of the planned movement to both groups, even if that movement was not toward the target. At the end of the movement if the subject experienced an error but chose to withhold the corrective movement, only the first group received information about the sensory prediction error. We organized the P-cells based on the information content of their olivary input and found that in the group that received sensory information, the simple spikes were suppressed during fixation, then produced a burst before saccade onset in a direction consistent with assisting the movement. In the second group, the simple spikes were not suppressed during fixation but burst near saccade deceleration in a direction consistent with stopping the movement. Thus, the olive differentiated the P-cells based on whether they would receive sensory or motor information, and this defined their contributions to control of movements as well as holding still.


Asunto(s)
Cerebelo , Células de Purkinje , Cerebelo/fisiología , Células de Purkinje/fisiología , Neuronas/fisiología , Movimientos Sacádicos , Movimiento
6.
Annu Rev Neurosci ; 41: 233-253, 2018 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-29986160

RESUMEN

Supervised learning plays a key role in the operation of many biological and artificial neural networks. Analysis of the computations underlying supervised learning is facilitated by the relatively simple and uniform architecture of the cerebellum, a brain area that supports numerous motor, sensory, and cognitive functions. We highlight recent discoveries indicating that the cerebellum implements supervised learning using the following organizational principles: ( a) extensive preprocessing of input representations (i.e., feature engineering), ( b) massively recurrent circuit architecture, ( c) linear input-output computations, ( d) sophisticated instructive signals that can be regulated and are predictive, ( e) adaptive mechanisms of plasticity with multiple timescales, and ( f) task-specific hardware specializations. The principles emerging from studies of the cerebellum have striking parallels with those in other brain areas and in artificial neural networks, as well as some notable differences, which can inform future research on supervised learning and inspire next-generation machine-based algorithms.


Asunto(s)
Cerebelo/fisiología , Modelos Neurológicos , Red Nerviosa/fisiología , Neuronas/fisiología , Aprendizaje Automático Supervisado , Algoritmos , Animales , Cerebelo/citología , Humanos , Plasticidad Neuronal/fisiología , Factores de Tiempo
7.
Nat Rev Neurosci ; 22(2): 92-110, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33203932

RESUMEN

Over the past several decades, theories about cerebellar learning have evolved. A relatively simple view that highlighted the contribution of one major form of heterosynaptic plasticity to cerebellar motor learning has given way to a plethora of perspectives that suggest that many different forms of synaptic and non-synaptic plasticity, acting at various sites, can control multiple types of learning behaviour. However, there still seem to be contradictions between the various hypotheses with regard to the mechanisms underlying cerebellar learning. The challenge is therefore to reconcile these different views and unite them into a single overall concept. Here I review our current understanding of the changes in the activity of cerebellar Purkinje cells in different 'microzones' during various forms of learning. I describe an emerging model that indicates that the activity of each microzone is bound to either increase or decrease during the initial stages of learning, depending on the directional and temporal demands of its downstream circuitry and the behaviour involved.


Asunto(s)
Cerebelo/fisiología , Aprendizaje/fisiología , Plasticidad Neuronal/fisiología , Animales , Humanos , Modelos Neurológicos
8.
Proc Natl Acad Sci U S A ; 120(24): e2221641120, 2023 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-37276394

RESUMEN

Both the cerebellum and basal ganglia are involved in rhythm processing, but their specific roles remain unclear. During rhythm perception, these areas may be processing purely sensory information, or they may be involved in motor preparation, as periodic stimuli often induce synchronized movements. Previous studies have shown that neurons in the cerebellar dentate nucleus and the caudate nucleus exhibit periodic activity when the animals prepare to respond to the random omission of regularly repeated visual stimuli. To detect stimulus omission, the animals need to learn the stimulus tempo and predict the timing of the next stimulus. The present study demonstrates that neuronal activity in the cerebellum is modulated by the location of the repeated stimulus and that in the striatum (STR) by the direction of planned movement. However, in both brain regions, neuronal activity during movement and the effect of electrical stimulation immediately before stimulus omission were largely dependent on the direction of movement. These results suggest that, during rhythm processing, the cerebellum is involved in multiple stages from sensory prediction to motor control, while the STR consistently plays a role in motor preparation. Thus, internalized rhythms without movement are maintained as periodic neuronal activity, with the cerebellum and STR preferring sensory and motor representations, respectively.


Asunto(s)
Ganglios Basales , Cerebelo , Animales , Cerebelo/fisiología , Ganglios Basales/fisiología , Núcleos Cerebelosos/fisiología , Cuerpo Estriado/fisiología , Núcleo Caudado , Movimiento/fisiología
9.
J Neurosci ; 44(8)2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38195508

RESUMEN

The olivo-cerebellar system plays an important role in vertebrate sensorimotor control. Here, we investigate sensory representations in the inferior olive (IO) of larval zebrafish and their spatial organization. Using single-cell labeling of genetically identified IO neurons, we find that they can be divided into at least two distinct groups based on their spatial location, dendritic morphology, and axonal projection patterns. In the same genetically targeted population, we recorded calcium activity in response to a set of visual stimuli using two-photon imaging. We found that most IO neurons showed direction-selective and binocular responses to visual stimuli and that the functional properties were spatially organized within the IO. Light-sheet functional imaging that allowed for simultaneous activity recordings at the soma and axonal level revealed tight coupling between functional properties, soma location, and axonal projection patterns of IO neurons. Taken together, our results suggest that anatomically defined classes of IO neurons correspond to distinct functional types, and that topographic connections between IO and cerebellum contribute to organization of the cerebellum into distinct functional zones.


Asunto(s)
Núcleo Olivar , Pez Cebra , Animales , Larva , Núcleo Olivar/fisiología , Neuronas/fisiología , Cerebelo/fisiología
10.
J Neurosci ; 44(6)2024 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-38182420

RESUMEN

Internal models are essential for the production of accurate movements. The accuracy of saccadic eye movements is thought to be mediated by an internal model of oculomotor mechanics encoded in the cerebellum. The cerebellum may also be part of a feedback loop that predicts the displacement of the eyes and compares it to the desired displacement in real time to ensure that saccades land on target. To investigate the role of the cerebellum in these two aspects of saccade production, we delivered saccade-triggered light pulses to channelrhodopsin-2-expressing Purkinje cells in the oculomotor vermis (OMV) of two male macaque monkeys. Light pulses delivered during the acceleration phase of ipsiversive saccades slowed the deceleration phase. The long latency of these effects and their scaling with light pulse duration are consistent with an integration of neural signals at or downstream of the stimulation site. In contrast, light pulses delivered during contraversive saccades reduced saccade velocity at short latency and were followed by a compensatory reacceleration which caused gaze to land on or near the target. We conclude that the contribution of the OMV to saccade production depends on saccade direction; the ipsilateral OMV is part of a forward model that predicts eye displacement, whereas the contralateral OMV is part of an inverse model that creates the force required to move the eyes with optimal peak velocity for the intended displacement.


Asunto(s)
Optogenética , Movimientos Sacádicos , Animales , Masculino , Movimientos Oculares , Cerebelo/fisiología , Macaca nemestrina
11.
J Neurosci ; 44(19)2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38589230

RESUMEN

Animals must distinguish the sensory consequences of self-generated movements (reafference) from those of other-generated movements (exafference). Only self-generated movements entail the production of motor copies (i.e., corollary discharges), which are compared with reafference in the cerebellum to compute predictive or internal models of movement. Internal models emerge gradually over the first three postnatal weeks in rats through a process that is not yet fully understood. Previously, we demonstrated in postnatal day (P) 8 and P12 rats that precerebellar nuclei convey corollary discharge and reafference to the cerebellum during active (REM) sleep when pups produce limb twitches. Here, recording from a deep cerebellar nucleus (interpositus, IP) in P12 rats of both sexes, we compared reafferent and exafferent responses with twitches and limb stimulations, respectively. As expected, most IP units showed robust responses to twitches. However, in contrast with other sensory structures throughout the brain, relatively few IP units showed exafferent responses. Upon finding that exafferent responses occurred in pups under urethane anesthesia, we hypothesized that urethane inhibits cerebellar cortical cells, thereby disinhibiting exafferent responses in IP. In support of this hypothesis, ablating cortical tissue dorsal to IP mimicked the effects of urethane on exafference. Finally, the results suggest that twitch-related corollary discharge and reafference are conveyed simultaneously and in parallel to cerebellar cortex and IP. Based on these results, we propose that twitches provide opportunities for the nascent cerebellum to integrate somatotopically organized corollary discharge and reafference, thereby enabling the development of closed-loop circuits and, subsequently, internal models.


Asunto(s)
Cerebelo , Movimiento , Animales , Ratas , Femenino , Masculino , Movimiento/fisiología , Cerebelo/fisiología , Animales Recién Nacidos , Núcleos Cerebelosos/fisiología , Ratas Sprague-Dawley , Ratas Long-Evans , Potenciales de Acción/fisiología
12.
J Neurosci ; 44(17)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38527808

RESUMEN

Throughout life, the cerebellum plays a central role in the coordination and optimization of movements, using cellular plasticity to adapt a range of behaviors. Whether these plasticity processes establish a fixed setpoint during development, or continuously adjust behaviors throughout life, is currently unclear. Here, by spatiotemporally manipulating the activity of protein phosphatase 2B (PP2B), an enzyme critical for cerebellar plasticity in male and female mice, we examined the consequences of disrupted plasticity on the performance and adaptation of the vestibulo-ocular reflex (VOR). We find that, in contrast to Purkinje cell (PC)-specific deletion starting early postnatally, acute pharmacological as well as adult-onset genetic deletion of PP2B affects all forms of VOR adaptation but not the level of VOR itself. Next, we show that PC-specific genetic deletion of PP2B in juvenile mice leads to a progressive loss of the protein PP2B and a concurrent change in the VOR, in addition to the loss of adaptive abilities. Finally, re-expressing PP2B in adult mice that lack PP2B expression from early development rescues VOR adaptation but does not affect the performance of the reflex. Together, our results indicate that chronic or acute, genetic, or pharmacological block of PP2B disrupts the adaptation of the VOR. In contrast, only the absence of plasticity during cerebellar development affects the setpoint of VOR, an effect that cannot be corrected after maturation of the cerebellum. These findings suggest that PP2B-dependent cerebellar plasticity is required during a specific period to achieve the correct setpoint of the VOR.


Asunto(s)
Cerebelo , Plasticidad Neuronal , Reflejo Vestibuloocular , Animales , Reflejo Vestibuloocular/fisiología , Plasticidad Neuronal/fisiología , Ratones , Cerebelo/crecimiento & desarrollo , Cerebelo/fisiología , Masculino , Femenino , Células de Purkinje/fisiología , Adaptación Fisiológica/fisiología , Ratones Endogámicos C57BL , Ratones Noqueados
13.
PLoS Comput Biol ; 20(1): e1011008, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38166093

RESUMEN

Complex interactions between brain regions and the spinal cord (SC) govern body motion, which is ultimately driven by muscle activation. Motor planning or learning are mainly conducted at higher brain regions, whilst the SC acts as a brain-muscle gateway and as a motor control centre providing fast reflexes and muscle activity regulation. Thus, higher brain areas need to cope with the SC as an inherent and evolutionary older part of the body dynamics. Here, we address the question of how SC dynamics affects motor learning within the cerebellum; in particular, does the SC facilitate cerebellar motor learning or constitute a biological constraint? We provide an exploratory framework by integrating biologically plausible cerebellar and SC computational models in a musculoskeletal upper limb control loop. The cerebellar model, equipped with the main form of cerebellar plasticity, provides motor adaptation; whilst the SC model implements stretch reflex and reciprocal inhibition between antagonist muscles. The resulting spino-cerebellar model is tested performing a set of upper limb motor tasks, including external perturbation studies. A cerebellar model, lacking the implemented SC model and directly controlling the simulated muscles, was also tested in the same. The performances of the spino-cerebellar and cerebellar models were then compared, thus allowing directly addressing the SC influence on cerebellar motor adaptation and learning, and on handling external motor perturbations. Performance was assessed in both joint and muscle space, and compared with kinematic and EMG recordings from healthy participants. The differences in cerebellar synaptic adaptation between both models were also studied. We conclude that the SC facilitates cerebellar motor learning; when the SC circuits are in the loop, faster convergence in motor learning is achieved with simpler cerebellar synaptic weight distributions. The SC is also found to improve robustness against external perturbations, by better reproducing and modulating muscle cocontraction patterns.


Asunto(s)
Cerebelo , Médula Espinal , Humanos , Cerebelo/fisiología , Médula Espinal/fisiología , Simulación por Computador , Extremidad Superior , Aprendizaje/fisiología
14.
PLoS Comput Biol ; 20(4): e1011277, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38574161

RESUMEN

According to the motor learning theory by Albus and Ito, synaptic depression at the parallel fibre to Purkinje cells synapse (pf-PC) is the main substrate responsible for learning sensorimotor contingencies under climbing fibre control. However, recent experimental evidence challenges this relatively monopolistic view of cerebellar learning. Bidirectional plasticity appears crucial for learning, in which different microzones can undergo opposite changes of synaptic strength (e.g. downbound microzones-more likely depression, upbound microzones-more likely potentiation), and multiple forms of plasticity have been identified, distributed over different cerebellar circuit synapses. Here, we have simulated classical eyeblink conditioning (CEBC) using an advanced spiking cerebellar model embedding downbound and upbound modules that are subject to multiple plasticity rules. Simulations indicate that synaptic plasticity regulates the cascade of precise spiking patterns spreading throughout the cerebellar cortex and cerebellar nuclei. CEBC was supported by plasticity at the pf-PC synapses as well as at the synapses of the molecular layer interneurons (MLIs), but only the combined switch-off of both sites of plasticity compromised learning significantly. By differentially engaging climbing fibre information and related forms of synaptic plasticity, both microzones contributed to generate a well-timed conditioned response, but it was the downbound module that played the major role in this process. The outcomes of our simulations closely align with the behavioural and electrophysiological phenotypes of mutant mice suffering from cell-specific mutations that affect processing of their PC and/or MLI synapses. Our data highlight that a synergy of bidirectional plasticity rules distributed across the cerebellum can facilitate finetuning of adaptive associative behaviours at a high spatiotemporal resolution.


Asunto(s)
Cerebelo , Simulación por Computador , Condicionamiento Palpebral , Modelos Neurológicos , Plasticidad Neuronal , Plasticidad Neuronal/fisiología , Animales , Cerebelo/fisiología , Condicionamiento Palpebral/fisiología , Células de Purkinje/fisiología , Parpadeo/fisiología , Condicionamiento Clásico/fisiología , Sinapsis/fisiología , Biología Computacional , Ratones , Corteza Cerebelosa/fisiología
15.
Brain ; 147(4): 1412-1422, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-37956080

RESUMEN

Cortical myoclonus is produced by abnormal neuronal discharges within the sensorimotor cortex, as demonstrated by electrophysiology. Our hypothesis is that the loss of cerebellar inhibitory control over the motor cortex, via cerebello-thalamo-cortical connections, could induce the increased sensorimotor cortical excitability that eventually causes cortical myoclonus. To explore this hypothesis, in the present study we applied anodal transcranial direct current stimulation over the cerebellum of patients affected by cortical myoclonus and healthy controls and assessed its effect on sensorimotor cortex excitability. We expected that anodal cerebellar transcranial direct current stimulation would increase the inhibitory cerebellar drive to the motor cortex and therefore reduce the sensorimotor cortex hyperexcitability observed in cortical myoclonus. Ten patients affected by cortical myoclonus of various aetiology and 10 aged-matched healthy control subjects were included in the study. All participants underwent somatosensory evoked potentials, long-latency reflexes and short-interval intracortical inhibition recording at baseline and immediately after 20 min session of cerebellar anodal transcranial direct current stimulation. In patients, myoclonus was recorded by the means of surface EMG before and after the cerebellar stimulation. Anodal cerebellar transcranial direct current stimulation did not change the above variables in healthy controls, while it significantly increased the amplitude of somatosensory evoked potential cortical components, long-latency reflexes and decreased short-interval intracortical inhibition in patients; alongside, a trend towards worsening of the myoclonus after the cerebellar stimulation was observed. Interestingly, when dividing patients in those with and without giant somatosensory evoked potentials, the increment of the somatosensory evoked potential cortical components was observed mainly in those with giant potentials. Our data showed that anodal cerebellar transcranial direct current stimulation facilitates-and does not inhibit-sensorimotor cortex excitability in cortical myoclonus syndromes. This paradoxical response might be due to an abnormal homeostatic plasticity within the sensorimotor cortex, driven by dysfunctional cerebello-thalamo-cortical input to the motor cortex. We suggest that the cerebellum is implicated in the pathophysiology of cortical myoclonus and that these results could open the way to new forms of treatment or treatment targets.


Asunto(s)
Mioclonía , Estimulación Transcraneal de Corriente Directa , Humanos , Anciano , Estimulación Transcraneal de Corriente Directa/métodos , Estimulación Magnética Transcraneal/métodos , Potenciales Evocados Motores/fisiología , Cerebelo/fisiología
16.
Proc Natl Acad Sci U S A ; 119(14): e2118954119, 2022 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-35349338

RESUMEN

SignificanceThe information that one region of the brain transmits to another is usually viewed through the lens of firing rates. However, if the output neurons could vary the timing of their spikes, then, through synchronization, they would spotlight information that may be critical for control of behavior. Here we report that, in the cerebellum, Purkinje cell populations that share a preference for error convey, to the nucleus, when to decelerate the movement, by reducing their firing rates and temporally synchronizing the remaining spikes.


Asunto(s)
Cerebelo , Células de Purkinje , Potenciales de Acción/fisiología , Cerebelo/fisiología , Movimiento , Neuronas/fisiología , Células de Purkinje/fisiología
17.
Proc Natl Acad Sci U S A ; 119(45): e2210645119, 2022 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-36322758

RESUMEN

Thyroid hormones (THs) regulate gene expression by binding to nuclear TH receptors (TRs) in the cell. THs are indispensable for brain development. However, we have little knowledge about how congenital hypothyroidism in neurons affects functions of the central nervous system in adulthood. Here, we report specific TH effects on functional development of the cerebellum by using transgenic mice overexpressing a dominant-negative TR (Mf-1) specifically in cerebellar Purkinje cells (PCs). Adult Mf-1 mice displayed impairments in motor coordination and motor learning. Surprisingly, long-term depression (LTD)-inductive stimulation caused long-term potentiation (LTP) at parallel fiber (PF)-PC synapses in adult Mf-1 mice, although there was no abnormality in morphology or basal properties of PF-PC synapses. The LTP phenotype was turned to LTD in Mf-1 mice when the inductive stimulation was applied in an extracellular high-Ca2+ condition. Confocal calcium imaging revealed that dendritic Ca2+ elevation evoked by LTD-inductive stimulation is significantly reduced in Mf-1 PCs but not by PC depolarization only. Single PC messenger RNA quantitative analysis showed reduced expression of SERCA2 and IP3 receptor type 1 in Mf-1 PCs, which are essential for mGluR1-mediated internal calcium release from endoplasmic reticulum in cerebellar PCs. These abnormal changes were not observed in adult-onset PC-specific TH deficiency mice created by adeno-associated virus vectors. Thus, we propose the importance of TH action during neural development in establishing proper cerebellar function in adulthood, independent of its morphology. The present study gives insight into the cellular and molecular mechanisms underlying congenital hypothyroidism-induced dysfunctions of central nervous system and cerebellum.


Asunto(s)
Hipotiroidismo Congénito , Células de Purkinje , Ratones , Animales , Células de Purkinje/metabolismo , Potenciación a Largo Plazo/fisiología , Depresión Sináptica a Largo Plazo/fisiología , Calcio/metabolismo , Receptores de Hormona Tiroidea/metabolismo , Depresión , Hipotiroidismo Congénito/metabolismo , Sinapsis/metabolismo , Cerebelo/fisiología
18.
J Neurosci ; 43(20): 3708-3717, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-37037608

RESUMEN

The role of the posterior cerebellum in social cognition is well established; however, it is still unclear whether different cerebellar subregions contribute to different social cognitive processes by exerting specific functions. Here, we employed transcranial magnetic stimulation (TMS) in male and female healthy humans to test the hypothesis of the existence of a medial-to-lateral gradient in the functional organization of the posterior cerebellum, according to which the phylogenetically newer cerebellar hemispheres are involved in tasks requiring higher-level social inferences whereas vermal/medial sectors are involved in basic perceptual emotional mechanisms. We found that interfering via TMS with activity of the medial cerebellum significantly impaired basic emotional recognition/discrimination. In turn, only TMS over the lateral cerebellum affected a task requiring recognizing an emotion considering the social context in which it was experienced. Overall, our data support the existence of a medial-to-lateral gradient in the posterior cerebellum, with medial sectors supporting basic emotion recognition and lateral sectors being recruited when the task taps on higher inferential processing/mentalizing. Interestingly, the contribution of the cerebellum in these different processes seems to be restricted to negative emotional stimuli.SIGNIFICANCE STATEMENT The cerebellum has been recently recognized as a critical component of the social brain, however, the functional topography of this structure in relation to social and emotional processes is still debated. By adopting a causative approach through the use of transcranial magnetic stimulation (TMS), the present study critically insights into the functional organization of the posterior cerebellum by testing the hypothesis of a medial-to-lateral gradient that reflects increasing complexity of social cognitive processes. Our findings demonstrate that lateral and medial cerebellar regions exert partially distinguishable functions in the social cognitive domain, with the medial cerebellum that mainly mediates basic perceptual emotional mechanisms while the lateral cerebellum, although supporting more basic functions, further subserves higher-level social operations.


Asunto(s)
Cognición Social , Estimulación Magnética Transcraneal , Humanos , Masculino , Femenino , Cerebelo/fisiología , Emociones/fisiología , Cognición/fisiología
19.
J Neurosci ; 43(34): 6035-6045, 2023 08 23.
Artículo en Inglés | MEDLINE | ID: mdl-37507229

RESUMEN

Unipolar brush cells (UBCs) in the cerebellum and dorsal cochlear nucleus (DCN) perform temporal transformations by converting brief mossy fiber bursts into long-lasting responses. In the cerebellar UBC population, mixing inhibition with graded mGluR1-dependent excitation leads to a continuum of temporal responses. In the DCN, it has been thought that mGluR1 contributes little to mossy fiber responses and that there are distinct excitatory and inhibitory UBC subtypes. Here, we investigate UBC response properties using noninvasive cell-attached recordings in the DCN of mice of either sex. We find a continuum of responses to mossy fiber bursts ranging from 100 ms excitation to initial inhibition followed by several seconds of excitation to inhibition lasting for hundreds of milliseconds. Pharmacological interrogation reveals excitatory responses are primarily mediated by mGluR1 Thus, UBCs in both the DCN and cerebellum rely on mGluR1 and have a continuum of response durations. The continuum of responses in the DCN may allow more flexible and efficient temporal processing than can be achieved with distinct excitatory and inhibitory populations.SIGNIFICANCE STATEMENT UBCs are specialized excitatory interneurons in cerebellar-like structures that greatly prolong the temporal responses of mossy fiber inputs. They are thought to help cancel out self-generated signals. In the DCN, the prevailing view was that there are two distinct ON and OFF subtypes of UBCs. Here, we show that instead the UBC population has a continuum of response properties. Many cells show suppression and excitation consecutively, and the response durations vary considerably. mGluR1s are crucial in generating a continuum of responses. To understand how UBCs contribute to temporal processing, it is essential to consider the continuous variations of UBC responses, which have advantages over just having opposing ON/OFF subtypes of UBCs.


Asunto(s)
Núcleo Coclear , Ratones , Animales , Fibras Nerviosas/fisiología , Neuronas/fisiología , Corteza Cerebelosa/fisiología , Cerebelo/fisiología
20.
J Neurosci ; 43(45): 7554-7564, 2023 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-37940582

RESUMEN

The cerebellum, traditionally associated with motor coordination and balance, also plays a crucial role in various aspects of higher-order function and dysfunction. Emerging research has shed light on the cerebellum's broader contributions to cognitive, emotional, and reward processes. The cerebellum's influence on autonomic function further highlights its significance in regulating motivational and emotional states. Perturbations in cerebellar development and function have been implicated in various neurodevelopmental disorders, including autism spectrum disorder and attention deficit hyperactivity disorder. An increasing appreciation for neuropsychiatric symptoms that arise from cerebellar dysfunction underscores the importance of elucidating the circuit mechanisms that underlie complex interactions between the cerebellum and other brain regions for a comprehensive understanding of complex behavior. By briefly discussing new advances in mapping cerebellar function in affective, cognitive, autonomic, and social processing and reviewing the role of the cerebellum in neuropathology beyond the motor domain, this Mini-Symposium review aims to provide a broad perspective of cerebellar intersections with the limbic brain in health and disease.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Trastorno del Espectro Autista , Trastornos del Neurodesarrollo , Humanos , Cognición/fisiología , Cerebelo/fisiología , Trastornos del Neurodesarrollo/patología
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