Reciprocal Bidirectional Plasticity of Parallel Fiber Receptive Fields in Cerebellar Purkinje Cells and Their Afferent Interneurons

Jörntell, Henrik; Ekerot, Carl‐Fredrik

doi:10.1016/s0896-6273(02)00713-4

Cited by 270 publications

(328 citation statements)

References 33 publications

Supporting

Mentioning

284

Contrasting

Order By: Relevance

“…Unfortunately, most physiological studies to date have used single distinct stimuli (Bower and Woolston 1983;Garwicz et al 1998;Jorntell and Ekerot 2002;Shambes et al 1978). Although for the sake of control and analysis (and eventual comparison to experimental data), we have only extended the current study to paired-pulse responses, recent recordings have demonstrated that activity in the granule cell layer consists of complex ongoing temporal patterns in awake behaving rats (Hartmann and Bower 2001).…”

Section: Functional Consequences For the Cerebellummentioning

confidence: 96%

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

Santamarı́a¹,

Bower²

2005

Journal of Neurophysiology

View full text Add to dashboard Cite

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...

show abstract

Section: Functional Consequences For the Cerebellummentioning

confidence: 96%

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

Santamarı́a¹,

Bower²

2005

Journal of Neurophysiology

View full text Add to dashboard Cite

show abstract

“…Therefore, in eyeblink conditioning, the US will activate both pathways. USrelated mossy fiber-parallel fiber activity may thus contribute to mechanisms of cerebellar cortical plasticity (Jörntell and Ekerot, 2002;Ekerot and Jörntell, 2003). CNQX application suppressed both periocular-evoked mossy and climbing fiber responses in periocular microzones.…”

Section: Periocular Microzones In Lobule Hvi Are Critical For Expressmentioning

confidence: 99%

Electrophysiological Localization of Eyeblink-Related Microzones in Rabbit Cerebellar Cortex

Mostofi¹,

Holtzman²,

Grout³

et al. 2010

Journal of Neuroscience

102

116

View full text Add to dashboard Cite

The classically conditioned eyeblink response in the rabbit is one of the best-characterized behavioral models of associative learning. It is cerebellum dependent, with many studies indicating that the hemispheral part of Larsell's cerebellar cortical lobule VI (HVI) is critical for the acquisition and performance of learned responses. However, there remain uncertainties about the distribution of the critical regions within and around HVI. In this learning, the unconditional stimulus is thought to be carried by periocular-activated climbing fibers. Here, we have used a microelectrode array to perform systematic, high-resolution, electrophysiological mapping of lobule HVI and surrounding folia in rabbits, to identify regions with periocular-evoked climbing fiber activity. Climbing fiber local field potentials and single-unit action potentials were recorded, and electrode locations were reconstructed from histological examination of brain sections. Much of the sampled cerebellar cortex, including large parts of lobule HVI, was unresponsive to periocular input. However, short-latency ipsilateral periocular-evoked climbing fiber responses were reliably found within a region in the ventral part of the medial wall of lobule HVI, extending to the base of the primary fissure. Small infusions of the AMPA/kainate receptor antagonist CNQX into this electrophysiologically defined region in awake rabbits diminished or abolished conditioned responses. The known parasagittal zonation of the cerebellum, supported by zebrin immunohistochemistry, indicates that these areas have connections consistent with an essential role in eyeblink conditioning. These small eyeblink-related areas provide cerebellar cortical targets for analysis of eyeblink conditioning at a neuronal level but need to be localized with electrophysiological identification in individual animals.

show abstract

“…For example, when parallel fiber input is weak or absent (as in the present work), then a substantial proportion of GABAergic signals will be excitatory, thus maintaining a relatively high IN firing rate. If, on the other hand, the parallel fiber input is strongly activated (as it does in vivo after certain stimulation protocols; Jörntell and Ekerot, 2002), GABAergic synapses will turn inhibitory, and the overall effect on IN firing will be dampened. In this way, the ability of GABAergic synapses to change signs adds flexibility to the network and allows it to maintain its mean firing rate in the range in which it reacts best to new information.…”

Section: A Self-regulating Network?mentioning

confidence: 99%

Coexistence of Excitatory and Inhibitory GABA Synapses in the Cerebellar Interneuron Network

Chavas¹,

Marty²

2003

J. Neurosci.

168

164

View full text Add to dashboard Cite

Functional GABA synapses are usually assumed to be inhibitory. However, we show here that inhibitory and excitatory GABA connections coexist in the cerebellar interneuron network. The reversal potential of GABAergic currents (E GABA ) measured in interneurons is relatively depolarized and contrasts with the hyperpolarized value found in Purkinje cells (Ϫ58 and Ϫ85 mV respectively). This finding is not correlated to a specific developmental stage and is maintained in the adult animal. E GABA in interneurons is close to the mean membrane potential (Ϫ56.5 mV, as measured with a novel "equal firing potential" method), and both parameters vary enough among cells so that the driving force for GABA currents can be either inward or outward. Indeed, using noninvasive cell-attached recordings, we demonstrate inhibitory, excitatory, and sequential inhibitory and excitatory responses to interneuron stimulation [results obtained both in juvenile (postnatal days 12-14) and subadult (postnatal days 20 -25) animals]. In hyperpolarized cells, single synaptic GABA currents can trigger spikes or trains of spikes, and subthreshold stimulations enhance the responsiveness to subsequent excitatory stimulation over at least 30 msec. We suggest that the coexistence of excitatory and inhibitory GABA synapses could either buffer the mean firing rate of the interneuron network or introduce different types of correlation between neighboring interneurons, or both.

show abstract

Reciprocal Bidirectional Plasticity of Parallel Fiber Receptive Fields in Cerebellar Purkinje Cells and Their Afferent Interneurons

Cited by 270 publications

References 33 publications

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

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

Electrophysiological Localization of Eyeblink-Related Microzones in Rabbit Cerebellar Cortex

Coexistence of Excitatory and Inhibitory GABA Synapses in the Cerebellar Interneuron Network

Contact Info

Product

Resources

About