Analysis of electrical potentials evoked in the cerebellar anterior lobe by stimulation of hindlimb and forelimb nerves

Jc, Eccles; Provini, L.; Strata, Piergiorgio; Táboríková, H

doi:10.1007/bf00235123

Cited by 147 publications

(55 citation statements)

References 60 publications

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“…Although the characteristic Purkinje cell complex spike is usually activated by a single climbing fibre action potential (Eccles et al 1966), postsynaptic depression may occur during transmission when the olivary neuron fires, not one, but a rapid burst of action potentials. Although our results were obtained at room temperature, it should be noted that olivary neurons can fire at frequencies of around 10 Hz (Llinas & Yarom, 1986), and sustained stimulation at these frequencies results in failure to excite the Purkinje cell in vivo (Eccles, Provini, Strata & T aborikov a, 1968). Thus, it is possible that presynaptic depression at the CF synaptic connection may be acting as a low-pass filter.…”

Section: Quantal Sizementioning

confidence: 81%

Locus of frequency‐dependent depression identified with multiple‐probability fluctuation analysis at rat climbing fibre‐Purkinje cell synapses

Silver

Momiyama

Cull-Candy

1998

The Journal of Physiology

271

309

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1. EPSCs were recorded under whole-cell voltage clamp at room temperature from Purkinje cells in slices of cerebellum from 12-to 14-day-old rats. EPSCs from individual climbing fibre (CF) inputs were identified on the basis of their large size, paired-pulse depression and all-ornone appearance in response to a graded stimulus. 2. Synaptic transmission was investigated over a wide range of experimentally imposed release probabilities by analysing fluctuations in the peak of the EPSC. Release probability was manipulated by altering the extracellular [Ca¥] and [Mg¥]. Quantal parameters were estimated from plots of coefficient of variation (CV) or variance against mean conductance by fitting a multinomial model that incorporated both spatial variation in quantal size and non-uniform release probability. This 'multiple-probability fluctuation' (MPF) analysis gave an estimate of 510 ± 50 for the number of functional release sites (N) and a quantal size (q) of 0·5 ± 0·03 nS (n = 6). 3. Control experiments, and simulations examining the effects of non-uniform release probability, indicate that MPF analysis provides a reliable estimate of quantal parameters. Direct measurement of quantal amplitudes in the presence of 5 mÒ Sr¥, which gave asynchronous release, yielded distributions with a mean quantal size of 0·55 ± 0·01 nS and a CV of 0·37 ± 0·01 (n = 4). Similar estimates of q were obtained in 2 mÒ Ca¥ when release probability was lowered with the calcium channel blocker Cd¥. The non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 1 ìÒ) reduced both the evoked current and the quantal size (estimated with MPF analysis) to a similar degree, but did not affect the estimate of N. 4. We used MPF analysis to identify those quantal parameters that change during frequencydependent depression at climbing fibre-Purkinje cell synaptic connections. At low stimulation frequencies, the mean release probability ( − Pr) was unusually high (0·90 ± 0·03 at 0·033 Hz, n = 5), but as the frequency of stimulation was increased, − Pr fell dramatically (0·02 ± 0·01 at 10 Hz, n = 4) with no apparent change in either q or N. This indicates that the observed 50-fold depression in EPSC amplitude is presynaptic in origin. 5. Presynaptic frequency-dependent depression was investigated with double-pulse and multiple-pulse protocols. EPSC recovery, following simultaneous release at practically all sites, was slow, being well fitted by the sum of two exponential functions (time constants of 0·35 ± 0·09 and 3·2 ± 0·4 s, n = 5). EPSC recovery following sustained stimulation was even slower. We propose that presynaptic depression at CF synapses reflects a slow recovery of release probability following release of each quantum of transmitter. 6. The large number of functional release sites, relatively large quantal size, and unusual dynamics of transmitter release at the CF synapse appear specialized to ensure highly reliable olivocerebellar transmission at low frequencies but to limit transmission at higher frequencies.7697

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Section: Quantal Sizementioning

confidence: 81%

Locus of frequency‐dependent depression identified with multiple‐probability fluctuation analysis at rat climbing fibre‐Purkinje cell synapses

Silver

Momiyama

Cull-Candy

1998

The Journal of Physiology

271

309

View full text Add to dashboard Cite

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“…This suggests that functionally related information is conveyed to the same part of the cerebellar cortex via direct (olivocerebellar) and indirect (cerebropontocerebellar) pathways. This convergence may contribute to the similarity of peripheral receptive fields between climbing fibers and mossy fibers terminating in the same vertical "column" of cerebellar cortex (Eccles et al, 1968;Ekerot and Larson, 1980;Garwicz et al, 1998;Brown and Bower, 2001).…”

Section: Concluding Commentsmentioning

confidence: 92%

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Odeh

Ackerley²,

Bjaalie³

et al. 2005

Journal of Neuroscience

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The cerebropontocerebellar mossy fiber system is a major CNS sensorimotor pathway. We used a double-retrograde axonal tracing technique (red and green beads) to chart in rats the pontocerebellar projection to different electrophysiologically defined climbing fiber zones in the posterior lobe (face-receiving A2 zone and forelimb-and hindlimb-receiving parts of the C1 zone in the paramedian lobule and copula pyramidis, respectively). Individual cortical injection sites were verified as located in a given zone by mapping the pattern of cell labeling in the inferior olive, whereas labeled cells in the pontine nuclei were mapped using computer-aided three-dimensional reconstruction techniques. A number of topographical differences were found for the pontine projection to the individual zones. Projections to the A2 zone were bilateral, whereas to both parts of the C1 zone, the inputs were mainly contralateral. Furthermore, the A2 (face), C1 (forelimb), and C1 (hindlimb) zone projections were centered in progressively more caudal parts of the pontine nuclei with little or no overlap between them. The areas occupied by cell labeling for each zone corresponded closely to territories in the pontine nuclei shown previously to receive projections from somatotopically equivalent regions of the somatosensory cortex. This precise cerebropontocerebellar topography, defined by climbing fiber somatotopy, is a new principle of organization for linking somatosensory and cerebellar cortices. The convergence of direct and indirect sensory projections is likely to have important implications for cerebellar cortical processing.

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“…Ketamine/xylazine anesthesia reduces the N3 component of the extracellular field potentials according to Bengtsson and Jörntell (2007), which represents the activity by the rising axons of the granular cells and their parallel fiber collaterals (Armstrong and Drew 1980;Eccles et al 1968). The same group also demonstrated that ketamine/xylazine anesthesia reduces the climbing fiber-evoked response (Bengtsson and Jörntell 2007).…”

mentioning

confidence: 88%

Differential effects of ketamine/xylazine anesthesia on the cerebral and cerebellar cortical activities in the rat

Ordek

Groth

Şahin

2013

Journal of Neurophysiology

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Analysis of electrical potentials evoked in the cerebellar anterior lobe by stimulation of hindlimb and forelimb nerves

Cited by 147 publications

References 60 publications

Locus of frequency‐dependent depression identified with multiple‐probability fluctuation analysis at rat climbing fibre‐Purkinje cell synapses

Locus of frequency‐dependent depression identified with multiple‐probability fluctuation analysis at rat climbing fibre‐Purkinje cell synapses

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Differential effects of ketamine/xylazine anesthesia on the cerebral and cerebellar cortical activities in the rat

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