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1.
J Environ Manage ; 299: 113622, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34479152

RESUMO

Environmental compensation (EC) aims at addressing environmental losses due to development projects and involves a need to compare development losses with compensation gains using relevant metrics. A conceptual procedure for computing no net loss is formulated and used as a point of departure for a comparative analysis of metrics used by five Swedish municipalities as a part of their EC implementation in the spatial planning context of detailed development plans. While Swedish law does not require EC in this context, these municipalities have still decided to introduce EC requirements for development projects that occur on municipality-owned land and to promote voluntary EC among private actors in development projects on private land. There is substantial variation across the municipalities studied with respect to both metrics and attributes subject to measurement, but there are also similarities: The attributes considered when assessing the need for EC in conjunction with development are not only about nature per se, but also about recreational opportunities and other types ecosystem services; semi-quantitative metrics such as scores are common while quantitative or monetary metrics are rare; and metrics are rarely applied to assess compensatory gains, focusing instead on losses from development. Streamlining across municipalities might be warranted for increasing predictability and transparency for developers and citizens, but it also introduces considerable challenges such as a need for developing consistent guidelines for semi-quantitative metrics, and to handle substitutability issues if metrics are not only applied on individual attributes but also on groups of attributes. The broad scope of attributes used by the municipalities is in line with an international tendency to broaden EC to include not only biodiversity aspects but also ecosystem services. Moreover, the EC systems applied by the municipalities are of particular importance for highlighting the crucial role of environmental management for maintaining and enhancing biodiversity and ecosystem services not only in areas having formal protection status but also in the everyday landscape. The municipalities' experience and strengths and weaknesses associated with their EC systems are therefore relevant also in an international perspective.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Benchmarking , Biodiversidade , Cidades , Suécia
2.
J Physiol ; 597(16): 4357-4371, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31342538

RESUMO

KEY POINTS: Parts of the fields of neuroscience and neurology consider the neocortex to be a functionally parcelled structure. Viewed through such a conceptual filter, there are multiple clinical observations after localized stroke lesions that seem paradoxical. We tested the effect that localized stroke-like lesions have on neuronal information processing in a part of the neocortex that is distant to the lesion using animal experiments. We find that the distant lesion degrades the quality of neuronal information processing of tactile input patterns in primary somatosensory cortex. The findings suggest that even the processing of primary sensory information depends on an intact neocortical network, with the implication that all neocortical processing may rely on widespread interactions across large parts of the cortex. ABSTRACT: Recent clinical studies report a surprisingly weak relationship between the location of cortical brain lesions and the resulting functional deficits. From a neuroscience point of view, such findings raise questions as to what extent functional localization applies in the neocortex and to what extent the functions of different regions depend on the integrity of others. Here we provide an in-depth analysis of the changes in the function of the neocortical neuronal networks after distant focal stroke-like lesions in the anaesthetized rat. Using a recently introduced high resolution analysis of neuronal information processing, consisting of pre-set spatiotemporal patterns of tactile afferent activation against which the neuronal decoding performance can be quantified, we found that stroke-like lesions in distant parts of the cortex significantly degraded the decoding performance of individual neocortical neurons in the primary somatosensory cortex (decoding performance decreased from 30.9% to 24.2% for n = 22 neurons, Wilcoxon signed rank test, P = 0.028). This degrading effect was not due to changes in the firing frequency of the neuron (Wilcoxon signed rank test, P = 0.499) and was stronger the higher the decoding performance of the neuron, indicating a specific impact on the information processing capacity in the cortex. These findings suggest that even primary sensory processing depends on widely distributed cortical networks and could explain observations of focal stroke lesions affecting a large range of functions.


Assuntos
Neocórtex/fisiologia , Neurônios/fisiologia , Acidente Vascular Cerebral/patologia , Animais , Masculino , Neocórtex/patologia , Análise de Componente Principal , Ratos , Ratos Sprague-Dawley , Córtex Somatossensorial/patologia , Córtex Somatossensorial/fisiologia
3.
Cerebellum ; 17(5): 683-684, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29931663

RESUMO

In the original version of this paper, the Title should have been written with "A Consensus paper" to read "Cerebellar Modules and Their Role as Operational Cerebellar Processing Units: A Consensus paper".

4.
Cerebellum ; 17(5): 654-682, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29876802

RESUMO

The compartmentalization of the cerebellum into modules is often used to discuss its function. What, exactly, can be considered a module, how do they operate, can they be subdivided and do they act individually or in concert are only some of the key questions discussed in this consensus paper. Experts studying cerebellar compartmentalization give their insights on the structure and function of cerebellar modules, with the aim of providing an up-to-date review of the extensive literature on this subject. Starting with an historical perspective indicating that the basis of the modular organization is formed by matching olivocorticonuclear connectivity, this is followed by consideration of anatomical and chemical modular boundaries, revealing a relation between anatomical, chemical, and physiological borders. In addition, the question is asked what the smallest operational unit of the cerebellum might be. Furthermore, it has become clear that chemical diversity of Purkinje cells also results in diversity of information processing between cerebellar modules. An additional important consideration is the relation between modular compartmentalization and the organization of the mossy fiber system, resulting in the concept of modular plasticity. Finally, examination of cerebellar output patterns suggesting cooperation between modules and recent work on modular aspects of emotional behavior are discussed. Despite the general consensus that the cerebellum has a modular organization, many questions remain. The authors hope that this joint review will inspire future cerebellar research so that we are better able to understand how this brain structure makes its vital contribution to behavior in its most general form.


Assuntos
Cerebelo/anatomia & histologia , Cerebelo/fisiologia , Animais , Humanos
5.
Cerebellum ; 16(3): 638-647, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28032320

RESUMO

The existence of input plasticity in the deep cerebellar nuclear (DCN) cells of the adult cerebellum could have profound implications for our understanding of cerebellar function. Whereas the existence of plastic changes in mossy fiber (mf) synaptic responses in DCN neurons has been demonstrated in juvenile slices, there has so far been no direct demonstration of this form of plasticity in the adult cerebellum in vivo. In the present paper, we recorded from neurons in the anterior interposed nucleus (AIN) and stimulated the spinocerebellar tracts (SCT) directly or via the skin to obtain mf activation and the inferior olive to activate climbing fibers (cfs) in the nonanesthetized, adult, decerebrated cat. We used three different types of protocols that theoretically could be expected to induce plasticity, each of which involved episodically intense afferent activation lasting for 10 min. These were conjunctive mf-cf activation, which effectively induces plasticity in cortical neurons; mf and cf activation in a pattern resembling the protocol for inducing classical conditioning; and conjunctive activation of two excitatory mf inputs. None of these protocols had any statistically significant effect on the evoked responses in the AIN neurons. We conclude that the input plasticity for excitatory mfs in the AIN cells of the adult cerebellum in vivo is likely to be less effective than that of parallel fiber synaptic inputs in cerebellar cortical cells, at least in the timespan of 1 h.


Assuntos
Córtex Cerebelar/fisiologia , Núcleos Cerebelares/fisiologia , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Animais , Gatos , Fibras Nervosas/fisiologia , Células de Purkinje/fisiologia
6.
Cerebellum ; 16(1): 230-252, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27193702

RESUMO

For many decades, the predominant view in the cerebellar field has been that the olivocerebellar system's primary function is to induce plasticity in the cerebellar cortex, specifically, at the parallel fiber-Purkinje cell synapse. However, it has also long been proposed that the olivocerebellar system participates directly in motor control by helping to shape ongoing motor commands being issued by the cerebellum. Evidence consistent with both hypotheses exists; however, they are often investigated as mutually exclusive alternatives. In contrast, here, we take the perspective that the olivocerebellar system can contribute to both the motor learning and motor control functions of the cerebellum and might also play a role in development. We then consider the potential problems and benefits of it having multiple functions. Moreover, we discuss how its distinctive characteristics (e.g., low firing rates, synchronization, and variable complex spike waveforms) make it more or less suitable for one or the other of these functions, and why having multiple functions makes sense from an evolutionary perspective. We did not attempt to reach a consensus on the specific role(s) the olivocerebellar system plays in different types of movements, as that will ultimately be determined experimentally; however, collectively, the various contributions highlight the flexibility of the olivocerebellar system, and thereby suggest that it has the potential to act in both the motor learning and motor control functions of the cerebellum.


Assuntos
Cerebelo/fisiologia , Aprendizagem/fisiologia , Atividade Motora/fisiologia , Núcleo Olivar/fisiologia , Animais , Consenso , Humanos , Vias Neurais/fisiologia
7.
Cerebellum ; 14(3): 360-3, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25598536

RESUMO

Climbing fiber receptive fields are a physiological marker that have proven useful to delineate the details of the olivocerebellar circuitry. They have also proven useful as a point of reference to delineate the organization of other parts of the cerebellar circuitry. But what does the location of the climbing fiber receptive field imply and what is its relation to the presumed role of the cerebellum in coordination? Can we expect that all climbing fibers have a peripheral receptive field on the skin? In this short review, we aim to cover these issues.


Assuntos
Cerebelo/citologia , Extremidades/fisiologia , Fibras Nervosas/fisiologia , Vias Neurais/fisiologia , Neurônios/citologia , Animais , Estimulação Física/métodos , Células Receptoras Sensoriais/fisiologia , Pele
8.
J Environ Manage ; 139: 59-68, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24681365

RESUMO

This article addresses the question of how to change individuals' behavior towards more sustainable practices using Information Technology (IT). By following a multidisciplinary and socio-technical perspective, this inquiry is answered by applying a new framework-The Commonality Framework for IT-enabled Change-on a case study of sustainable behavioral change. The framework is grounded in practice theory and is used to analyze the implementation of an IT-system aimed at changing citizens' behavior towards more sustainable transport logistics and procurement in Uppsala, Sweden. The article applies case study research design and the empirical data consists of surveys, in-depth and semi-structured interviews, observations and archival documents. The results show how the change towards sustainable practices is an entanglement of both social and technical-structural elements across time. In this process, structures such as IT are the enablers, and the actors and their social activities are the tipping-point factors that ultimately determine the success of changing individuals' behavior towards a more sustainable direction. This article provides a more balanced view of how both actor and structure related properties interact during the on-going work with change towards greater sustainability practices than earlier research has offered. More specifically, the article offers both a lower-level theory and a method from which we can analyze change processes where technology is seen in its context, and where both technology and the human actor is brought forth to center stage.


Assuntos
Conservação dos Recursos Naturais , Informática , Comportamento , Humanos , Pesquisa , Suécia , Meios de Transporte
9.
iScience ; 27(4): 109338, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38495818

RESUMO

Many studies have suggested that the neocortex operates as a global network of functionally interconnected neurons, indicating that any sensory input could shift activity distributions across the whole brain. A tool assessing the activity distribution across cortical regions with high temporal resolution could then potentially detect subtle changes that may pass unnoticed in regionalized analyses. We used eight-channel, distributed electrocorticogram (ECoG) recordings to analyze changes in global activity distribution caused by single pulse electrical stimulations of the paw. We analyzed the temporally evolving patterns of the activity distributions using principal component analysis (PCA). We found that the localized tactile stimulation caused clearly measurable changes in global ECoG activity distribution. These changes in signal activity distribution patterns were detectable across a small number of ECoG channels, even when excluding the somatosensory cortex, suggesting that the method has high sensitivity, potentially making it applicable to human electroencephalography (EEG) for detection of pathological changes.

10.
Proc Natl Acad Sci U S A ; 106(7): 2389-94, 2009 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-19164536

RESUMO

The computational principles underlying the processing of sensory-evoked synaptic inputs are understood only rudimentarily. A critical missing factor is knowledge of the activation patterns of the synaptic inputs to the processing neurons. Here we use well-defined, reproducible skin stimulation to describe the specific signal transformations that occur in different parallel mossy fiber pathways and analyze their representation in the synaptic inputs to cerebellar granule cells. We find that mossy fiber input codes are preserved in the synaptic responses of granule cells, suggesting a coding-specific innervation. The computational consequences of this are that it becomes possible for granule cells to also transmit weak sensory inputs in a graded fashion and to preserve the specific activity patterns of the mossy fibers.


Assuntos
Cerebelo/citologia , Animais , Encéfalo/metabolismo , Gatos , Biologia Computacional , Potenciais Pós-Sinápticos Excitadores/fisiologia , Modelos Biológicos , Modelos Neurológicos , Fibras Nervosas/fisiologia , Rede Nervosa , Inibição Neural/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Técnicas de Patch-Clamp , Software , Transmissão Sináptica/fisiologia
11.
iScience ; 25(4): 104083, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35372805

RESUMO

The spinal cord is engaged in all forms of motor performance but its functions are far from understood. Because network connectivity defines function, we explored the connectivity of muscular, tendon, and tactile sensory inputs among a wide population of spinal interneurons in the lower cervical segments. Using low noise intracellular whole cell recordings in the decerebrated, non-anesthetized cat in vivo, we could define mono-, di-, and trisynaptic inputs as well as the weights of each input. Whereas each neuron had a highly specific input, and each indirect input could moreover be explained by inputs in other recorded neurons, we unexpectedly also found the input connectivity of the spinal interneuron population to form a continuum. Our data hence contrasts with the currently widespread notion of distinct classes of interneurons. We argue that this suggested diversified physiological connectivity, which likely requires a major component of circuitry learning, implies a more flexible functionality.

12.
J Neurosci ; 30(41): 13630-43, 2010 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-20943904

RESUMO

Synaptic gain control and information storage in neural networks are mediated by alterations in synaptic transmission, such as in long-term potentiation (LTP). Here, we show using both in vitro and in vivo recordings from the rat cerebellum that tetanization protocols for the induction of LTP at parallel fiber (PF)-to-Purkinje cell synapses can also evoke increases in intrinsic excitability. This form of intrinsic plasticity shares with LTP a requirement for the activation of protein phosphatases 1, 2A, and 2B for induction. Purkinje cell intrinsic plasticity resembles CA1 hippocampal pyramidal cell intrinsic plasticity in that it requires activity of protein kinase A (PKA) and casein kinase 2 (CK2) and is mediated by a downregulation of SK-type calcium-sensitive K conductances. In addition, Purkinje cell intrinsic plasticity similarly results in enhanced spine calcium signaling. However, there are fundamental differences: first, while in the hippocampus increases in excitability result in a higher probability for LTP induction, intrinsic plasticity in Purkinje cells lowers the probability for subsequent LTP induction. Second, intrinsic plasticity raises the spontaneous spike frequency of Purkinje cells. The latter effect does not impair tonic spike firing in the target neurons of inhibitory Purkinje cell projections in the deep cerebellar nuclei, but lowers the Purkinje cell signal-to-noise ratio, thus reducing the PF readout. These observations suggest that intrinsic plasticity accompanies LTP of active PF synapses, while it reduces at weaker, nonpotentiated synapses the probability for subsequent potentiation and lowers the impact on the Purkinje cell output.


Assuntos
Rede Nervosa/fisiologia , Plasticidade Neuronal/fisiologia , Células de Purkinje/fisiologia , Transmissão Sináptica/fisiologia , Potenciais de Ação/fisiologia , Animais , Cálcio/metabolismo , Caseína Quinase II/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Eletrofisiologia , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia , Estatísticas não Paramétricas , Sinapses/fisiologia
13.
J Neurophysiol ; 103(3): 1329-36, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20032243

RESUMO

Pavlovian eyeblink conditioning is a useful experimental model for studying adaptive timing, an important aspect of skilled movements. The conditioned response (CR) is precisely timed to occur just before the onset of the expected unconditioned stimulus (US). The timing can be changed immediately, however, by varying parameters of the conditioned stimulus (CS). It has previously been shown that increasing the intensity of a peripheral CS or the frequency of a CS consisting of a train of stimuli to the mossy fibers shortens the latency of the CR. The adaptive timing of behavioral CRs probably reflects the timing of an underlying learned inhibitory response in cerebellar Purkinje cells. It is not known how the latency of this Purkinje cell CR is controlled. We have recorded form Purkinje cells in conditioned decerebrate ferrets while increasing the intensity of a peripheral CS or the frequency of a mossy fiber CS. We observe changes in the timing of the Purkinje cell CR that match the behavioral effects. The results are consistent with the effect of CS parameters on behavioral CR latency being caused by corresponding changes in Purkinje cell CRs. They suggest that synaptic temporal summation may be one of several mechanisms underlying adaptive timing of movements.


Assuntos
Condicionamento Clássico/fisiologia , Furões/fisiologia , Células de Purkinje/fisiologia , Animais , Estado de Descerebração/fisiopatologia , Estimulação Elétrica , Eletromiografia , Eletrofisiologia , Membro Anterior/inervação , Membro Anterior/fisiologia , Masculino , Movimento/fisiologia , Fibras Nervosas/fisiologia
14.
Front Cell Neurosci ; 13: 140, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31031596

RESUMO

Whereas functional localization historically has been a key concept in neuroscience, direct neuronal recordings show that input of a particular modality can be recorded well outside its primary receiving areas in the neocortex. Here, we wanted to explore if such spatially unbounded inputs potentially contain any information about the quality of the input received. We utilized a recently introduced approach to study the neuronal decoding capacity at a high resolution by delivering a set of electrical, highly reproducible spatiotemporal tactile afferent activation patterns to the skin of the contralateral second digit of the forepaw of the anesthetized rat. Surprisingly, we found that neurons in all areas recorded from, across all cortical depths tested, could decode the tactile input patterns, including neurons of the primary visual cortex. Within both somatosensory and visual cortical areas, the combined decoding accuracy of a population of neurons was higher than for the best performing single neuron within the respective area. Such cooperative decoding indicates that not only did individual neurons decode the input, they also did so by generating responses with different temporal profiles compared to other neurons, which suggests that each neuron could have unique contributions to the tactile information processing. These findings suggest that tactile processing in principle could be globally distributed in the neocortex, possibly for comparison with internal expectations and disambiguation processes relying on other modalities.

15.
J Neurosci ; 27(10): 2493-502, 2007 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-17344387

RESUMO

Associative learning in the cerebellum underlies motor memories and probably also cognitive associations. Pavlovian eyeblink conditioning, a widely used experimental model of such learning, depends on the cerebellum, but the memory locus within the cerebellum as well as the underlying mechanisms have remained controversial. To date, crucial information on how cerebellar Purkinje cells change their activity during learning has been ambiguous and contradictory, and there is no information at all about how they behave during extinction and reacquisition. We have now tracked the activity of single Purkinje cells with microelectrodes for up to 16 h in decerebrate ferrets during learning, extinction, and relearning. We demonstrate that paired peripheral forelimb and periocular stimulation, as well as paired direct stimulation of cerebellar afferent pathways (mossy and climbing fibers) consistently causes a gradual acquisition of an inhibitory response in Purkinje cell simple spike firing. This conditioned cell response has several properties that matches known features of the behavioral conditioned response. The response latency varies with the interstimulus interval, and the response maximum is adaptively timed to precede the unconditioned stimulus. Across training trials, it matches behavioral extinction to unpaired stimulation and also the substantial savings that occur when paired stimulation is reinstated. These data suggest that many of the basic behavioral phenomena in eyeblink conditioning can be explained at the level of the single Purkinje cell.


Assuntos
Córtex Cerebral/fisiologia , Extinção Psicológica/fisiologia , Aprendizagem/fisiologia , Memória/fisiologia , Potenciais de Ação , Animais , Piscadela/fisiologia , Condicionamento Psicológico/fisiologia , Estimulação Elétrica , Furões , Membro Anterior/fisiologia , Fibras Nervosas/fisiologia , Núcleo Olivar/fisiologia , Órbita/fisiologia , Células de Purkinje/fisiologia , Fatores de Tempo
16.
Front Cell Neurosci ; 12: 210, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30108485

RESUMO

How the brain represents the external world is an unresolved issue for neuroscience, which could provide fundamental insights into brain circuitry operation and solutions for artificial intelligence and robotics. The neurons of the cuneate nucleus form the first interface for the sense of touch in the brain. They were previously shown to have a highly skewed synaptic weight distribution for tactile primary afferent inputs, suggesting that their connectivity is strongly shaped by learning. Here we first characterized the intracellular dynamics and inhibitory synaptic inputs of cuneate neurons in vivo and modeled their integration of tactile sensory inputs. We then replaced the tactile inputs with input from a sensorized bionic fingertip and modeled the learning-induced representations that emerged from varied sensory experiences. The model reproduced both the intrinsic membrane dynamics and the synaptic weight distributions observed in cuneate neurons in vivo. In terms of higher level model properties, individual cuneate neurons learnt to identify specific sets of correlated sensors, which at the population level resulted in a decomposition of the sensor space into its recurring high-dimensional components. Such vector components could be applied to identify both past and novel sensory experiences and likely correspond to the fundamental haptic input features these neurons encode in vivo. In addition, we show that the cuneate learning architecture is robust to a wide range of intrinsic parameter settings due to the neuronal intrinsic dynamics. Therefore, the architecture is a potentially generic solution for forming versatile representations of the external world in different sensor systems.

17.
Neuroreport ; 18(14): 1479-82, 2007 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-17712278

RESUMO

Learning of classically conditioned eyeblink responses depends on mechanisms within the cerebellum. It has been suggested that climbing fibres from the inferior olive transmit the unconditioned stimulus signal to the cerebellum. We have previously shown that the pathway from the deep cerebellar nuclei to the inferior olive inhibits olivary activity. It is known that repeated presentation of the conditioned stimulus on its own leads to extinction of the conditioned response. If the unconditioned stimulus signal is transmitted to the cerebellum via the inferior olive - climbing fibre system then stimulation of the nucleo-olivary pathway just before the unconditioned stimulus in a trained animal should lead to extinction. The results from this investigation confirm this.


Assuntos
Cerebelo/fisiologia , Condicionamento Palpebral/fisiologia , Extinção Psicológica/fisiologia , Núcleo Olivar/fisiologia , Potenciais de Ação/fisiologia , Animais , Comportamento Animal , Furões , Masculino , Vias Neurais/fisiologia
18.
Sci Rep ; 8: 45898, 2017 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-28374841

RESUMO

Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models.


Assuntos
Mecanorreceptores/fisiologia , Neocórtex/fisiologia , Neurônios/fisiologia , Percepção do Tato/fisiologia , Potenciais de Ação/fisiologia , Animais , Dedos/fisiologia , Humanos , Modelos Animais , Estimulação Física , Ratos , Fenômenos Fisiológicos da Pele
19.
eNeuro ; 3(1)2016.
Artigo em Inglês | MEDLINE | ID: mdl-26839917

RESUMO

It has been known for a long time that GABAergic Purkinje cells in the cerebellar cortex, as well as their target neurons in the cerebellar nuclei, are spontaneously active. The cerebellar output will, therefore, depend on how input is integrated into this spontaneous activity. It has been shown that input from climbing fibers originating in the inferior olive controls the spontaneous activity in Purkinje cells. While blocking climbing fiber input to the Purkinje cells causes a dramatic increase in the firing rate, increased climbing fiber activity results in reduced Purkinje cell activity. However, the exact calibration of this regulation has not been examined systematically. Here we examine the relation between climbing fiber stimulation frequency and Purkinje cell activity in unanesthetized decerebrated ferrets. The results revealed a gradual suppression of Purkinje cell activity, starting at climbing fiber stimulation frequencies as low as 0.5 Hz. At 4 Hz, Purkinje cells were completely silenced. This effect lasted an average of 2 min after the stimulation rate was reduced to a lower level. We also examined the effect of sustained climbing fiber stimulation on overt behavior. Specifically, we analyzed conditioned blink responses, which are known to be dependent on the cerebellum, while stimulating the climbing fibers at different frequencies. In accordance with the neurophysiological data, the conditioned blink responses were suppressed at stimulation frequencies of ≥4 Hz.


Assuntos
Potenciais de Ação , Condicionamento Palpebral/fisiologia , Células de Purkinje/fisiologia , Vias Aferentes/fisiologia , Animais , Furões , Masculino
20.
PLoS One ; 9(1): e84616, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24416251

RESUMO

Many mossy fiber pathways to the neurons of the deep cerebellar nucleus (DCN) originate from the spinal motor circuitry. For cutaneously activated spinal neurons, the receptive field is a tag indicating the specific motor function the spinal neuron has. Similarly, the climbing fiber receptive field of the DCN neuron reflects the specific motor output function of the DCN neuron. To explore the relationship between the motor information the DCN neuron receives and the output it issues, we made patch clamp recordings of DCN cell responses to tactile skin stimulation in the forelimb region of the anterior interposed nucleus in vivo. The excitatory responses were organized according to a general principle, in which the DCN cell responses became stronger the closer the skin site was located to its climbing fiber receptive field. The findings represent a novel functional principle of cerebellar connectivity, with crucial importance for our understanding of the function of the cerebellum in movement coordination.


Assuntos
Núcleos Cerebelares/citologia , Fibras Nervosas/metabolismo , Animais , Gatos , Núcleos Cerebelares/fisiologia , Espaço Extracelular/metabolismo , Espaço Intracelular/metabolismo , Estimulação Física , Pele
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