224 research outputs found
A biophysical model of endocannabinoid-mediated short term depression in hippocampal inhibition
Memories are believed to be represented in the synaptic pathways of vastly interconnected networks of neurons. The
plasticity of synapses, that is, their strengthening and weakening depending on neuronal activity, is believed to be the basis
of learning and establishing memories. An increasing number of studies indicate that endocannabinoids have a widespread
action on brain function through modulation of synapβtic transmission and plasticity. Recent experimental studies have
characterised the role of endocannabinoids in mediating both short- and long-term synaptic plasticity in various brain
regions including the hippocampus, a brain region strongly associated with cognitive functions, such as learning and
memory. Here, we present a biophysically plausible model of cannabinoid retrograde signalling at the synaptic level and
investigate how this signalling mediates depolarisation induced suppression of inhibition (DSI), a prominent form of shortterm
synaptic depression in inhibitory transmission in hippocampus. The model successfully captures many of the key
characteristics of DSI in the hippocampus, as observed experimentally, with a minimal yet sufficient mathematical
description of the major signalling molecules and cascades involved. More specifically, this model serves as a framework to
test hypotheses on the factors determining the variability of DSI and investigate under which conditions it can be evoked.
The model reveals the frequency and duration bands in which the post-synaptic cell can be sufficiently stimulated to elicit
DSI. Moreover, the model provides key insights on how the state of the inhibitory cell modulates DSI according to its firing
rate and relative timing to the post-synaptic activation. Thus, it provides concrete suggestions to further investigate
experimentally how DSI modulates and is modulated by neuronal activity in the brain. Importantly, this model serves as a
stepping stone for future deciphering of the role of endocannabinoids in synaptic transmission as a feedback mechanism
both at synaptic and network level
Bioinformatics in China: A Personal Perspective
Biochemical Research MethodsMathematical & Computational BiologySCI(E)PubMed3EDITORIAL MATERIAL4e1000020
Measurement of the matrix element for the decay Ξ·β²βΞ·Ο +Ο -
The Dalitz plot of Ξ·ββ²βΞ·Οβ+Οβ- decay is studied using (225.2Β±2.8)Γ106 J/Ο events collected with the BESIII detector at the BEPCII eβ+eβ- collider. With the largest sample of Ξ·ββ² decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ΟβΞ³Ξ·ββ² is determined to be (4.84Β±0.03Β±0.24)Γ10β-3, where the first error is statistical and the second systematic. Β© 2011 American Physical Society.published_or_final_versio
First observation of the decays ΟcJβΟ0Ο0Ο0Ο0
We present a study of the P-wave spin-triplet charmonium Ο cJ decays (J=0, 1, 2) into Ο0Ο0Ο0Ο0. The analysis is based on 106Γ106 Οββ² decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the Ο0Ο0Ο0Ο0 hadronic final state is observed for the first time. We measure the branching fractions B(Ο c0βΟ0Ο0Ο0Ο0)=(3.34Β±0. 06Β±0.44)Γ10β-3, B(Ο c1βΟ0Ο0Ο0Ο0) =(0.57Β±0.03Β±0.08)Γ10β-3, and B(Ο c2βΟ0Ο0Ο0Ο0)=(1.21Β±0.05Β±0.16) Γ10β-3, where the uncertainties are statistical and systematical, respectively. Β© 2011 American Physical Society.published_or_final_versio
Higher-order multipole amplitude measurement in Ο β²βΞ³Ο c2
Using 106Γ106 Ο β² events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition Ο β²βΞ³Ο c2βΞ³Ο +Ο -/Ξ³K +K - are measured. A fit to the Ο c2 production and decay angular distributions yields M2=0.046Β±0. 010Β±0.013 and E3=0.015Β±0.008Β±0.018, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with 4.4Ο statistical significance and is consistent with the charm quark having no anomalous magnetic moment. Β© 2011 American Physical Society.published_or_final_versio
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