scholarly journals Gradients in the cerebellar cortex enable Fourier-like transformation and improve storing capacity

2019 ◽  
Author(s):  
Isabelle Straub ◽  
Laurens Witter ◽  
Abdelmoneim Eshra ◽  
Miriam Hoidis ◽  
Niklas Byczkowicz ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Mossy Fiber ◽  
Low Frequency ◽  
Outer Zone ◽  
Spike Timing ◽  
Vertebrate Brain ◽  
Functional Consequences

AbstractCerebellar granule cells (GCs) making up majority of all the neurons in the vertebrate brain, but heterogeneities among GCs and potential functional consequences are poorly understood. Here, we identified unexpected gradients in the biophysical properties of GCs. GCs closer to the white matter (inner-zone GCs) had higher firing thresholds and could sustain firing with larger current inputs. Dynamic clamp experiments showed that inner- and outer-zone GCs preferentially respond to high- and low-frequency mossy fiber inputs, respectively, enabling to disperse the mossy fiber input into its frequency components as performed by a Fourier transformation. Furthermore, inner-zone GCs have faster axonal conduction velocity and elicit faster synaptic potentials in Purkinje cells. Neuronal network modeling revealed that these gradients improve spike-timing precision of Purkinje cells and decrease the number of GCs required to learn spike-sequences. Thus, our study uncovers biophysical gradients in the cerebellar cortex enabling a Fourier-like transformation of mossy fiber inputs.

scholarly journals Gradients in the mammalian cerebellar cortex enable Fourier-like transformation and improve storing capacity

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Isabelle Straub ◽  
Laurens Witter ◽  
Abdelmoneim Eshra ◽  
Miriam Hoidis ◽  
Niklas Byczkowicz ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Mossy Fiber ◽  
Low Frequency ◽  
Outer Zone ◽  
Spike Timing ◽  
Vertebrate Brain ◽  
Functional Consequences

Cerebellar granule cells (GCs) make up the majority of all neurons in the vertebrate brain, but heterogeneities among GCs and potential functional consequences are poorly understood. Here, we identified unexpected gradients in the biophysical properties of GCs in mice. GCs closer to the white matter (inner-zone GCs) had higher firing thresholds and could sustain firing with larger current inputs than GCs closer to the Purkinje cell layer (outer-zone GCs). Dynamic Clamp experiments showed that inner- and outer-zone GCs preferentially respond to high- and low-frequency mossy fiber inputs, respectively, enabling dispersion of the mossy fiber input into its frequency components as performed by a Fourier transformation. Furthermore, inner-zone GCs have faster axonal conduction velocity and elicit faster synaptic potentials in Purkinje cells. Neuronal network modeling revealed that these gradients improve spike-timing precision of Purkinje cells and decrease the number of GCs required to learn spike-sequences. Thus, our study uncovers biophysical gradients in the cerebellar cortex enabling a Fourier-like transformation of mossy fiber inputs.

Cerebellar Granule Cells and Their Response to Radiation

1970 ◽  
Vol 28 ◽  
pp. 212-213
Author(s):  
Rosita F. de Estable-Puig ◽  
Juan F. Estable-Puig
Keyword(s):  
Cerebellar Cortex ◽  
Granular Layer ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Mossy Fiber ◽  
Molecular Layer ◽  
Synaptic Connections ◽  
Cerebellar Granule ◽  
Peripheral Axon ◽  
Cerebellar Glomerulus

The granular layer of the cerebellar cortex situated between the molecular and medullary layers is built up mainly of the perikarya of small interneurons, the granule cells intermingled with part of their own processes, mossy fiber terminals, fibers of passage and other less numerous intrinsic cells. Ultrastructurally they are characterized by a nucleus which occupies most of the cell body and a rim of cytoplasm. The nucleus exhibits some aggregates of chromatin and in some cells a nucleolus. In the cytoplasm very scarce organelles are observed (Fig.l). Their main synaptic connections are found, first, at the cerebellar glomerulus where granule dendrites are seen in postsynaptic position towards mossy fiber rosettes. Desmosomic attachments are observed between granule dendrites. Second, at the level of the molecular layer where parallel fiber terminals (ramifications of the peripheral axon ) are seen apposing Purkinje dendrite spines.

scholarly journals Efficient generation of reciprocal signals by inhibition

2012 ◽  
Vol 107 (9) ◽  
pp. 2453-2462 ◽  
Author(s):  
Sung-min Park ◽  
Esra Tara ◽  
Kamran Khodakhah
Keyword(s):  
Purkinje Cells ◽  
Granule Cell ◽  
Granule Cells ◽  
Mossy Fiber ◽  
Cell Activity ◽  
Common Mechanism ◽  
Input Output ◽  
Firing Rates ◽  
Neuronal Computation ◽  
The Brain

Reciprocal activity between populations of neurons has been widely observed in the brain and is essential for neuronal computation. The different mechanisms by which reciprocal neuronal activity is generated remain to be established. A common motif in neuronal circuits is the presence of afferents that provide excitation to one set of principal neurons and, via interneurons, inhibition to a second set of principal neurons. This circuitry can be the substrate for generation of reciprocal signals. Here we demonstrate that this equivalent circuit in the cerebellar cortex enables the reciprocal firing rates of Purkinje cells to be efficiently generated from a common set of mossy fiber inputs. The activity of a mossy fiber is relayed to Purkinje cells positioned immediately above it by excitatory granule cells. The firing rates of these Purkinje cells increase as a linear function of mossy fiber, and thus granule cell, activity. In addition to exciting Purkinje cells positioned immediately above it, the activity of a mossy fiber is relayed to laterally positioned Purkinje cells by a disynaptic granule cell → molecular layer interneuron pathway. Here we show in acutely prepared cerebellar slices that the input-output relationship of these laterally positioned Purkinje cells is linear and reciprocal to the first set. A similar linear input-output relationship between decreases in Purkinje cell firing and strength of stimulation of laterally positioned granule cells was also observed in vivo. Use of interneurons to generate reciprocal firing rates may be a common mechanism by which the brain generates reciprocal signals.

scholarly journals Purkinje Cells Directly Inhibit Granule Cells in Specialized Regions of the Cerebellar Cortex

Neuron ◽  
2016 ◽  
Vol 91 (6) ◽  
pp. 1330-1341 ◽  
Author(s):  
Chong Guo ◽  
Laurens Witter ◽  
Stephanie Rudolph ◽  
Hunter L. Elliott ◽  
Katelin A. Ennis ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Granule Cells

Feedforward Inhibition Controls the Spread of Granule Cell–Induced Purkinje Cell Activity in the Cerebellar Cortex

2007 ◽  
Vol 97 (1) ◽  
pp. 248-263 ◽  
Author(s):  
Fidel Santamaria ◽  
Patrick G. Tripp ◽  
James M. Bower
Keyword(s):  
Cerebellar Cortex ◽  
Granule Cells ◽  
Functional Organization ◽  
Cerebellar Granule Cells ◽  
Molecular Layer ◽  
Cell Activity ◽  
Excitatory Input ◽  
Cortical Inhibition ◽  
Before And After

Synapses associated with the parallel fiber (pf) axons of cerebellar granule cells constitute the largest excitatory input onto Purkinje cells (PCs). Although most theories of cerebellar function assume these synapses produce an excitatory sequential “beamlike” activation of PCs, numerous physiological studies have failed to find such beams. Using a computer model of the cerebellar cortex we predicted that the lack of PCs beams is explained by the concomitant pf activation of feedforward molecular layer inhibition. This prediction was tested, in vivo, by recording PCs sharing a common set of pfs before and after pharmacologically blocking inhibitory inputs. As predicted by the model, pf-induced beams of excitatory PC responses were seen only when inhibition was blocked. Blocking inhibition did not have a significant effect in the excitability of the cerebellar cortex. We conclude that pfs work in concert with feedforward cortical inhibition to regulate the excitability of the PC dendrite without directly influencing PC spiking output. This conclusion requires a significant reassessment of classical interpretations of the functional organization of the cerebellar cortex.

scholarly journals Cerebellar nuclei excitatory neurons regulate developmental scaling of presynaptic Purkinje cell number and organ growth

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Ryan T Willett ◽  
N Sumru Bayin ◽  
Andrew S Lee ◽  
Anjana Krishnamurthy ◽  
Alexandre Wojcinski ◽  
...  
Keyword(s):  
Purkinje Cell ◽  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Granule Cells ◽  
Postnatal Growth ◽  
Cerebellar Nuclei ◽  
Cell Number ◽  
Conditional Knockout ◽  
Neural Systems ◽  
Scaling Down

For neural systems to function effectively, the numbers of each cell type must be proportioned properly during development. We found that conditional knockout of the mouse homeobox genes En1 and En2 in the excitatory cerebellar nuclei neurons (eCN) leads to reduced postnatal growth of the cerebellar cortex. A subset of medial and intermediate eCN are lost in the mutants, with an associated cell non-autonomous loss of their presynaptic partner Purkinje cells by birth leading to proportional scaling down of neuron production in the postnatal cerebellar cortex. Genetic killing of embryonic eCN throughout the cerebellum also leads to loss of Purkinje cells and reduced postnatal growth but throughout the cerebellar cortex. Thus, the eCN play a key role in scaling the size of the cerebellum by influencing the survival of their Purkinje cell partners, which in turn regulate production of granule cells and interneurons via the amount of sonic hedgehog secreted.

Cerebellar cortex

2020 ◽  
pp. 497-504
Author(s):  
Edmund T. Rolls
Keyword(s):  
Purkinje Cell ◽  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Network Architecture ◽  
Granule Cells ◽  
Feedforward Control ◽  
Synaptic Depression ◽  
Climbing Fibre ◽  
Regular Sampling

The cerebellar cortex appears to be involved in predictive feedforward control to generate smooth movements. There is a beautiful network architecture which suggests that the granule cells perform expansion recoding of the inputs; that these connect to the Purkinje cells via an architecture that ensures regular sampling; and that each Purkinje cell has a single teacher, the climbing fibre, which produces associative long-term synaptic depression as part of perceptron-like learning.

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