000202183 001__ 202183
000202183 005__ 20190509132514.0
000202183 0247_ $$2doi$$a10.5075/epfl-thesis-6299
000202183 02470 $$2urn$$aurn:nbn:ch:bel-epfl-thesis6299-1
000202183 02471 $$2nebis$$a10256122
000202183 037__ $$aTHESIS
000202183 041__ $$aeng
000202183 088__ $$a6299
000202183 245__ $$aIn vivo measurement of excitatory synaptic transmission between identified neurons in layer 2/3 mouse barrel cortex
000202183 269__ $$a2014
000202183 260__ $$bEPFL$$c2014$$aLausanne
000202183 336__ $$aTheses
000202183 502__ $$aProf. W. Gerstner (président) ; Prof. C. Petersen (directeur) ; Prof. M. Hausser,  Dr A. Holtmaat,  Prof. R. Schneggenburger (rapporteurs)
000202183 520__ $$aThe neocortex is the most distinctive feature of the mammalian brain and it is considered to be the substrate of high-order cognitive functions. The nature and the arrangement of the diverse neuronal elements constituting its multiple areas have received longstanding attention. Progressively such anatomical and functional investigations are undertaken in the context of an intact living being. It offers the possibility of examining the role of particular areas, networks or even individual neurons during various behavioral states. Synaptic connectivity and synaptic transmission have been traditionally investigated in reduced preparations. Typically, electrophysiological and optical techniques have been used to control and record the propagation of electrical activity between two or more neurons in acute brain slices in vitro. The purpose of this thesis is the investigation of synaptic connectivity and synaptic transmission within the intact neocortex of the living mouse. Here I took advantage of the recent development of optogenetics, in combination with electrophysiology and two-photon microscopy to systematically and directly record synaptic transmission between a single excitatory neuron and two main types of GABAergic neurons in layer 2/3 of the mouse barrel cortex in vivo. Overall, I discovered stronger excitatory connections onto GABAergic neurons than onto excitatory neurons, irrespective of the absolute or relative locations of the pre- and postsynaptic neurons somas. I further revealed that parvalbumin-expressing (PV) and somatostatin-expressing (Sst) GABAergic neurons received excitatory inputs that were similar in magnitude, but were more reliable and faster in PV neurons than in Sst neurons. Exploring postsynaptic responses to multiple presynaptic action potentials elicited at high frequency, I found a strong short-term facilitation accompanied by significant input summation in Sst neurons, but little short-term dynamics with no summation in PV neurons. Lastly, I compared the amplitude of single action potential-evoked postsynaptic responses as a function of neocortical activity level and found that it was unchanged in both neuron types. Overall, the results of this thesis provide new insights into the functioning of microcircuits in vivo while confirming many findings from reduced preparations. In the future, it will be interesting to extend these initial in vivo measurements to other neuron and synapse types, particularly in awake animals engaged in different behavioral states.
000202183 6531_ $$aNeocortex
000202183 6531_ $$aBarrel cortex
000202183 6531_ $$aExcitatory synaptic transmission
000202183 6531_ $$aGABAergic neurons
000202183 6531_ $$aParvalbumin-expressing neurons
000202183 6531_ $$aSomatostatin-expressing neurons
000202183 6531_ $$aSlow oscillations
000202183 6531_ $$aUP and DOWN states
000202183 6531_ $$aSingle-cell optogenetics
000202183 6531_ $$aWhole-cell patch-clamp in vivo
000202183 700__ $$0243167$$g161374$$aPala, Aurélie
000202183 720_2 $$aPetersen, Carl$$edir.$$g157467$$0243169
000202183 8564_ $$uhttps://infoscience.epfl.ch/record/202183/files/EPFL_TH6299.pdf$$zn/a$$s21237795$$yn/a
000202183 909C0 $$xU10837$$0252149$$pLSENS
000202183 909CO $$pthesis$$pthesis-bn2018$$pDOI$$ooai:infoscience.tind.io:202183$$qDOI2$$qGLOBAL_SET$$pSV
000202183 917Z8 $$x108898
000202183 917Z8 $$x108898
000202183 917Z8 $$x108898
000202183 918__ $$dEDNE$$cBMI$$aSV
000202183 919__ $$aLSENS
000202183 920__ $$b2014$$a2014-10-24
000202183 970__ $$a6299/THESES
000202183 973__ $$sPUBLISHED$$aEPFL
000202183 980__ $$aTHESIS