cerebellar glomerulus MA XuFriedman amp WG Regehr JNeurosci 2003 J Hamori amp J Somogyi JCompNeurology 1983 claws Purkinje cells are at the midpoint of a massive convergence ID: 913859
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Slide1
Cerebellar Club
Session 2. Mossy fibers and granule cells
cerebellar glomerulus
M.A. Xu-Friedman & W.G.
Regehr
, J.Neurosci, 2003
J.
Hamori & J. Somogyi, J.Comp.Neurology, 1983
=“claws”
Slide2Purkinje cells are at the midpoint of a massive convergence
From data summarized in KWT Caddy and TJ Biscoe (1979)
Phil Trans Roy Soc Lond Ser B
287:167-201. Additional measurements from BB Gould and P Rakic (1981)
Exp Brain Res
44:195-206, R Alvarez and R Anadón (1987)
J Hirnforsch
28:133-137, RJ Harvey and RMA Napper(1991)
Prog Neurobiol
36:437-463, JA Heckroth (1994)
J Comp Neurol 343:173-182, and R Alvarez-Otero et al (1996) J Comp Neurol 368:487-502.
JC Eccles (1969)
Naturwissenschaften
56:525-534
Slide3Cerebellar Structure and Anatomy
Slide4Slide5The cerebellum: between sensation and action
Sensory surprise / error signals
Sensory teaching signal
Slide6Jinno et al. (2004)
Cerebellum
3:83-88
The cerebellum:
modules for
multisensory learning
Slide7Slide8Vestibulocerebellar
fibers- coordinate head and eye movement.
Mossy fiber Inputs
Flocculonodular
lobe
Pyramidal cells
contralateral cerebellar
B. Spinocerebellar (reticulo-cerebellar and cuneate-cerebellar) fibers- makes cerebellum aware of ongoing movements via proprioceptive input from muscle spindles and joint receptors.
C.
Cerebro
-ponto-cerebellar fibers - alerts cerebellum regarding anticipated movements.C
Slide9Slide10Patches/Receptive fields
R
. Apps & R. Hawkes,
Nat.Reviews
, 2009
Slide11- Hippocampal mossy fiber (DG-CA3)
endbulb of Heldthe calyx of Held
nigrothalamic synapsesribbon-associated and ribbon-free goldfish bipolar synapses
M.A. Xu-Friedman & W.G. Regehr, Physiol
Rev, 2004Mossy fibers and granule cells synapses
size
69–200 μm2; Xu-Friedman & Regehr, 2003 ; 168–266 μm2; Hamori & Somogyi, 1983
surface area of the AZ - 0.13 μm2
number and density of AZs 113-440
the nearest neighbor distance 0.46 μmnumber of synaptic vesicles 200,000over ∼330 release sites number of synaptic vesicles per AZ ∼600 The mossy fiber terminal contacts the dendrites of as many as 50 granule cells, 400-800 (Sugihara &
Shinoda), with 1–10 release sites per granule cellglomerulus- site of information redistribution
Slide12Gao Z. et al,
Nat.Reviews, 2012
Glutamate and GABA spillover drive E/I balance
to edge The permissive “time window” lasts about 8–10 ms, due to feed-forward/feed-back inhibition, so that granule cells have time to fire just 1–3 spikes
Glomerular
Functions
Mapelli J & D'Angelo E.
,
J.Neurosci, 2007
Slide13The ‘window-matching’ hypothesis
Slide14Granule cells
smallest cell ~5µm in diameter
Rancz
EA et al, Nature,2007
Chadderton
P. et al, Nature,2014
Fire 100-200Hz bursts to punctuate stimulation
Time-window matching
hypothsis
:
- May need activation of several dendrites by MF(coincidence detector?)- First spike delay determination
Powell et al, Elife,2015
Slide15Golgi cell, spatiotemporal organization of granular layer
activity
low-frequency
pacemaking
current injection result in high-frequency spike discharge followed by hyperpolarization and a silent pause
hyperpolarizing current injection result in sagging inward rectification followed by a post-inhibitory rebound
repetitive activity cycles during locomotion
Golgi cell activity in vivo EMG of a limb muscle during walking
Single-unit activity
The Golgi cell shows background activity, over which punctate sensory stimulation elicits bursts of
activity (2–3
spikes)followed by a long-lasting inhibitory period Holtzman et al., 2006Golgi Cell-Golgi Cell Communication through Dendritic Gap Junctions in vivo remains largely to be determined
neuroelectro.org
Slide16Cerebellar interneurons
Schilling K. et al,
Histochem
Cell Biol
, 2008candelabrum cell(only Mol. markers, no ephys)
glob-LugarocI-Lugaro
stellateunipolar brush cells
Slide17Parallel fibers and PCs synapses
Gao Z. et al,
Nat.Reviews
, 2012
Carl-Fredrik Ekerot and Henrik Jorntell, 2001 (E.J.Neurosci) and 2002 (Neuron)
Mittmann W. & Häusser M, J.Neurosci, 2007
Slide18Learning-based theories of cerebellar function
The cerebellum as a perceptron (Marr 1969
et seq.)Eyeblink conditioningDynamic control
Forward and inverse modelsAdaptive learning
Sensory subtractionPerceptron (from Ito 2011)
Slide19Cerebellar cortical circuitry
Slide20To control its output accurately, the brain needs an internal control policy
efference
copy
Slide21General feedback-error-learning model
Cerebellar feedback-error-learning model
Slide22What might the cerebellum do?
Contain learned information in both input and output
Dynamically control brain activity elsewhere
Do this in adult life and development
Slide23Thanks!!!
Slide24