This short course provides a three-days long introduction to the field of computational neuroscience. Theoretical studies of brain functions have focused on the information processing properties of individual neurons, neural circuits and networks systems. Computational neuroscience seeks to study these functions as revealed by neurophysiological experiments through computational means, and, as such, is high interdisciplinary and cross-disciplinary. Our program brings together experimentalist, modelers, and theoreticians to illustrate the diverse approaches and disciplines that make up computational neuroscience.
The 2019 short course is sponsored by the Chinese Society for Neuroscience (Committee on Computational Neuroscience and Neural Engineering)，CSIAM Mathematical Life Sciences, the SJTU Institute of Natural Sciences, and the SJTU Zhiyuan College.
December 16 ~ 18, 2019
Room 306, No. 5 Science Building, Minhang Campus, Shanghai Jiao Tong University
How to arrive: https://ins.sjtu.edu.cn/contact-us
Please register online.
Preference is given to, but not limited to, applicants with a basic understanding of ordinary differential equations and probability and a working knowledge of Matlab.
No registration fee. Participants should cover their own lodging and meals.
|09:00-10:20||Jianyuan Sun||Large encoding scope of information processing at single synapse|
|10:40-12:00||Jianyuan Sun||Computational model of vesicle recycling at a central synapse|
|14:00-15:20||Guoqiang Bi||Multiscale dynamics and structures from synapse to brain|
|15:40-17:00||Guoqiang Bi||Multiscale dynamics and structures from synapse to brain|
|09:00-10:20||Aihua Chen||The computational rules of cross-modality suppression in the visual posterior sylvian area (VPS)|
|10:40-12:00||Aihua Chen||The computational rules of cross-modality suppression in the visual posterior sylvian area (VPS)|
By Guoqiang Bi, University of Science and Technology of China
The brain consists of myriad neurons innervating one another through even more synapses, forming interacted networks to carry out various function. Within this enormously complex system, dynamic events such as synaptic plasticity occurs over multiple spatiotemporal scales. The first part of the lecture will cover basic findings about synaptic plasticity, with an emphasis on the temporal properties of spike-timing-dependent plasticity (STDP), its potential cellular signaling mechanism, and its network consequences. The lecture will also cover other properties of synaptic plasticity including recent work on the role of mitoflash in the conversion of short-term synaptic change into long-term plasticity.
The second part of the lecture will focus on the multiscale structure of brain circuits, from different types of synapses to the network of neuronal circuits across the entire brain. Emphasis will be on new imaging techniques, including cryo electron tomography and correlative light-electron microscopy that were used to reveal molecular organization inside synapses in their native states, as well as ultra-high speed volumetric imaging method VISoR that was developed to map the connectivity and activity trace of the entire brain at subcellular resolution. Also to be discussed (by the class) are experimental and computational challenges in using these cutting-edge technologies and in understanding the big data they generated.
By Aihua Chen，East China Normal University
The visual posterior sylvian area (VPS) of the macaque brain, also called the parieto-temporal association area T3 in earlier literature, is an area with neurons responding selectively to heading direction in both visual and vestibular modalities. However, since opposite heading preferences strongly dominated in VPS, this area may be not a key site for optimizing perception of self-motion trajectory. To investigate how visual-vestibular interactions happen in VPS, we examined the response of VPS to unimodal as well as congruent and conflicting bimodal stimuli. In contrast to MSTd, bimodal responses in VPS were poorly fit by weighted linear sums of unimodal responses. Instead, a weighted sum of cosine function for vestibular and visual responses provide a significantly improved fit and most VPS neurons require a nonlinear component. The weights from the best model fit typically less than one. Moreover, both modulation depth and neuronal discrimination thresholds impaired for both matched and conflict bimodal compared to unimodal stimuli, which might reduced neural sensitivity during multisensory stimulation, indicating the cross-modal suppression in VPS. These findings about the visual-vestibular cross-modal suppression in VPS might allow a shift of the dominant sensorial weight during self-motion perception from one sensory modality (visual or vestibular) to the other, and can further protect visual perception of self-motion from potential vestibular mismatches caused by involuntary head accelerations during locomotion.
By Jianyuan Sun，Chinese Academy of Siences
In the seminal work, Katz and colleagues established the quantal nature of synaptic transmission, whereby the basic unit of neurotransmission is the quantal event detected postsynaptically as a small all-or-none similar sized miniature postsynaptic potential or current (mini), in response to the neurotransmitter release from a single vesicle. However, the quantal nature of minis has never been justified by the study at single synapses, leaving the open question whether minis are identical in size and follow the principle of invariance. We selectively study the quantal transmission from single active zone contained synapses using whole-cell recording and quantitative analysis. It was found that the amplitude of spontaneous and evoked miniature events from single synapses displayed large variation and were integer multiples of a subunit. This phenomenon can be observed in spontaneous mEPSCs at single synaptic boutons of early age developing calyx synapse, micrometer size Ca2+ uncaging induced quantal events at single boutons of juvenile calyx synapse and micrometer size channelrhodopsin-2 activation evoked quantal events at single boutons of mature PB-CeAL synapse. Our study suggests a large encoding scope of synaptic signaling, which may provide a novel insight into the information processing at synapse level.
By Jianyuan Sun，Chinese Academy of Siences
Synaptic transmission at mammalian central synapse is undergoing with stochastic activity at physiological temperature. Synaptic recycling vesicle pool with proper kinetic structure ensures sustained synaptic transmission. However, the kinetic structure of recycling vesicle pool has never been quantitatively analyzed so far and most of the studies were performed at room temperature and under resting neuronal status. With combination of presynaptic capacitance measurement and postsynaptic EPSC recording on the calyx of Held synapse at physiological temperature, we studied the vesicle recycling under sustained presynaptic stimulation at physiological temperature. The kinetics of vesicle reuse was revealed by impeding transmitter refilling with folimycin. It was found that more than 90% vesicles involved in recycling at calyceal terminals but they are not homogeneously competent for reusing. A significant surface pool of vesicles as an additional capacitance increase was detected corresponding to different intensity of stimulations. We proposed a computational model that the group of recycling vesicles can be dissected as kinetically connected subpopulations and obtained the kinetic structure of the recycling vesicle pool in nerve terminal. The sizes and transferring rates among these sub-pools were dynamically regulated by neuronal activity thus to ensure the efficient synaptic transmission. Our work for the first time provides a quantitative description of synaptic vesicles trafficking along a complete recycling pathway and helps to understand the impact of vesicle recycling on stable and reliable synaptic transmission under variant neuronal activities.
Robustness of synaptic transmission under various neuronal activity analyzed dissect the kinetic structure of synaptic vesicles recycling under sustained stimulations. It was found that kinetics and biochemical properties of several steps of the vesicle cycle the Steady state of synaptic transmission under prolonged sustained stimulations at physiological temperature
Kinetics of vesicle reuse revealed by impeding transmitter refilling with folimycin.
Surface pool of synaptic vesicles under sustained stimulations at physiological temperature
Estimation the kinetic structure of synaptic vesicles in calyceal terminal under sustained stimulations
Synaptic transmission under presynaptic firing with fluctuated frequency.
Temperature dependence of kinetics of vesicle recycling
Kinetic dissection of vesicle recycling under various neuronal activities(four-pools model)
Impact of vesicle recycling on synaptic transmission
Robustness of synaptic transmission under various neuronal activity
Molecular mechanisms underling the kinetics of vesicle recycling
1. Clathrin/non-clathrin mediated endocytosis
dynamics and trafficking
of biological membranes biophysical
properties of membranes and
Vesicle recycling ensures synaptic transmission during neuronal activity, but its kinetic details remain poorly understood. Here, we developed an approach to quantitatively dissect the kinetics of vesicle recycling at the calyx of Held synapse at physiological temperature. Under sustained stimulation, excited postsynaptic currents (EPSCs) were recorded and estimated that ~300,000 vesicles were involved in recycling. Presynatic membrane capacitance measurements emphasized that ~16% of vesicles in the recycling pool (RP) remained on the synaptic terminal and contributed to the surface pool (SP). Two kinetic components of RP depletion revealed the heterogeneity of vesicles before the priming stage and these two vesicle pools together with the readily releasable pool (RRP) as well as SP led to a foul-pool kinetic model that assessed the size of subpools of the RP. Thus, we proposed an realistic kinetic model to describe the whole process of vesicle recycling and highlighted the robustness of synaptic transmission under various neuronal activity.