Integration by Purkyně cells of mossy and climbing fiber inputs from cutaneous mechanoreceptors

Jc, Eccles; Nh, Sabah; Rf, Schmidt; Táboríková, H

doi:10.1007/bf00236405

Cited by 93 publications

(52 citation statements)

References 31 publications

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“…In the presence of feedforward inhibition, the maximum firing rate, but not the number of extra spikes, linearly encoded the strength of granule cell synaptic input. The finding that Purkinje cells linearly encode the strength of their synaptic input in their firing rate is consistent with recordings of the firing rate of Purkinje cells in vivo that show Purkinje cells linearly sum information (Thach, 1967;Eccles et al, 1972;Allen et al, 1974). We propose that Purkinje cells encode the strength of their granule cell synaptic inputs in their poststimulus maximum firing rate using a linear computational algorithm, although the mechanism by which DCN neurons decode this information remains to be delineated.…”

Section: Discussionsupporting

confidence: 81%

The Linear Computational Algorithm of Cerebellar Purkinje Cells

Walter¹,

Khodakhah²

2006

J. Neurosci.

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The orchestration of simple motor tasks by the cerebellum results in coordinated movement and the maintenance of balance. The cerebellum integrates sensory and cortical information to generate the signals required for the coordinated execution of simple motor tasks. These signals originate in the firing rate of Purkinje cells, each of which integrates sensory and cortical information conveyed by granule cell synaptic inputs. Given the importance of the granule cell input-Purkinje cell output function for cerebellar computation, this algorithm was determined. Using several stimulation paradigms, including those that mimicked patterns of granule cell activity similar to those observed in vivo, we quantified the poststimulus maximum firing rate and number of extra spikes in response to granule cell synaptic input. Both of these parameters linearly encoded the strength of synaptic input when inhibitory synaptic transmission was blocked. This linear algorithm was independent of the location or temporal pattern of synaptic input. With inhibitory synaptic transmission intact, the maximum firing rate, but not the number of extra spikes, encoded the strength of granule cell synaptic input. Furthermore, the maximum firing rate of Purkinje cells linearly encoded the strength of synaptic input whether or not the activation of granule cells resulted in a pause in Purkinje cell firing. On the basis of the data presented, we propose that Purkinje cells encode the strength of granule cell synaptic input in their maximum firing rate with a linear algorithm.

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Section: Discussionsupporting

confidence: 81%

The Linear Computational Algorithm of Cerebellar Purkinje Cells

Walter¹,

Khodakhah²

2006

J. Neurosci.

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“…Thus for example, Bell and Grimm (1969) reported no spiking correlations in Purkinje cells Ͼ100 m apart even though the recorded neurons presumably shared a common set of parallel fiber inputs. In 1972, Eccles and colleagues specifically proposed that parallel fiber synaptic effects were subthreshold when they failed to find elongated beams of activated Purkinje cells after peripheral afferent activation (Eccles et al 1972). This result was confirmed and extended by our own report in 1983 that a focal excitation of the granule cell layer resulted in a restricted activation of only immediately overlying Purkinje cells (Bower and Woolston 1983).…”

Section: Parallel Fiber and Ascending Segment Synapsesmentioning

confidence: 99%

Background Synaptic Activity Modulates the Response of a Modeled Purkinje Cell to Paired Afferent Input

Santamarı́a¹,

Bower²

2005

Journal of Neurophysiology

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Santamaria, Fidel and James M. Bower. Background synaptic activity modulates the response of a modeled Purkinje cell to paired afferent input. J Neurophysiol 93: [237][238][239][240][241][242][243][244][245][246][247][248][249][250] 2005. First published August 11, 2004; doi:10.1152/jn.00458.2004. We studied the possible effects of background excitatory and inhibitory synaptic activity on Purkinje cell responses to paired pulse inputs using a morphologically and physiologically detailed compartmental model. Paired-pulse inputs were provided via synapses associated with the ascending segment of the granule cell axon in the presence of variable amounts of background synaptic input provided by parallel fibers and inhibitory interneurons. The results predict the amplitude and dynamics of the somatic and dendritic responses to paired ascending segment inputs are modulated by the level of background synaptic activity, the basal somatic firing rate of the Purkinje cell model does not indicate the type or degree of modulation, and the modulatory effects are mediated through dendritic calcium and calcium-activated potassium currents. These results have important consequences for the functional organization of cerebellar cortex as well as the more general issue of the modulatory as distinct from driving effects of synapses now also being considered in other regions of the mammalian brain including the cerebral cortex. I N T R O D U C T I O NIn recent years, there has been a continually growing interest in the interaction between the active electrical properties of neuronal dendrites and the responses of those dendrites to synaptic input (Chance et al. 2002;Euler and Denk 2001;Hausser and Mel 2003;Migliore and Shepherd 2002). Although neuronal dendrites have traditionally most often been modeled as spatial and temporal summing devices (see London and Segev 1999;Rall 1999), it is clear that the presence of active conductances in dendrites substantially affects how these structures integrate synaptic inputs (Cook and Johnston 1999;De Schutter and Bower 1994c;London and Segev 2001;Poirazi et al. 2003;Williams and Stuart 2002). In fact, model (Chance et al. 2002)-and experimental-based (Frick et al. 2004) studies of the functional consequences of active dendritic membranes are starting to raise questions about whether all synapses are fundamentally "driving" in nature. Specifically, it is now being suggested that some synapses might be more involved in regulating dendritic dynamics than in directly influencing the spiking output of neurons (Chance et al. 2002;De Schutter and Bower 1994b;Jaeger and Bower 1999;Jaeger et al. 1997;Rhodes and Llinas 2001;Santamaria et al. 2002;Sherman and Guillery 1998).The cerebellar Purkinje cell was one of the first mammalian neurons in which experimental studies demonstrated substantial voltage-dependent dendritic conductances (Llinas and Sugimori 1980). Using an articulated set of modeling and experimental studies, we have engaged in a series of experiments intended to better understand the f...

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“…It was observed by Eccles et al (1972d) that CF responses were almost always evoked by only the phasic activity arising from cutaneous inputs. This was confirmed in the present study for Purkyn6 cells tested by applying maintained pressure to the foot pads (Fig.…”

Section: Cutaneous Convergence On To Climbing Fibres 605 Nerves)mentioning

confidence: 99%

Cutaneous convergence on to the climbing fibre input to cerebellar Purkyně cells

Leicht¹,

Rowe²,

Schmidt³

1973

The Journal of Physiology

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SUMMARY1. In cats anaesthetized with Nembutal, the cutaneous receptive fields of individual cerebellar climbing fibres were assessed by recording the climbing fibre responses of single Purkyn6 cells following controlled mechanical stimulation (air jets, vibration, taps, pressure) of the foot pads of all four limbs and of the hairy skin of the limbs and the body.2. Three major types of cutaneous receptive fields of individual climbing fibres were recognized: (a) restricted fields generally confined to the distal areas of one limb only; (b) circumscribed fields on the distal areas of two to four limbs (discontinuous fields); and (c) widespread continuous fields extending over all or almost all of the body surface. A fourth group appears to receive cutaneous inputs from one limb and sensory input from deeper structures in other limbs.3. Thresholds for tapping of the foot pads were often quite low (< 100,um indentation), and there was no noticeable difference in the distribution of thresholds between the climbing fibres having restricted or more widespread cutaneous receptive fields. Similarly, the latencies of climbing fibre responses evoked by vibration and tapping were in the same ranges for climbing fibres with receptive fields restricted to one limb only and for those having more widespread fields. 4. In regard to location in the anterior lobe of the cerebellum it was found that those climbing fibres receiving inputs only from the ipsilateral forelimb projected to Purkyn6 cells located almost entirely in lobule V, whereas all other climbing fibres with restricted or more widespread receptive fields projected to Purkyn6 cells distributed widely within lobules II to V.

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Integration by Purkyně cells of mossy and climbing fiber inputs from cutaneous mechanoreceptors

Cited by 93 publications

References 31 publications

The Linear Computational Algorithm of Cerebellar Purkinje Cells

The Linear Computational Algorithm of Cerebellar Purkinje Cells

Background Synaptic Activity Modulates the Response of a Modeled Purkinje Cell to Paired Afferent Input

Cutaneous convergence on to the climbing fibre input to cerebellar Purkyně cells

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