“Shutdown” pemerintah amerika serikat dan obamacare (harian pelita 3 oktober 2013 halaman 1 19) by taruna ikrar 2013 10-02 hal 01

•

0 j'aime•364 vues

Contenu connexe

Plus de Taruna Ikrar

Earlysensoryexperienceinstructsthematurationofneuralcircuitry in the cortex1,2. This has been studied extensively in the primary visualcortex,inwhichlossofvisiontooneeyepermanentlydegrades corticalresponsivenesstothateye3,4,aphenomenonknownasocular dominance plasticity (ODP). Cortical inhibition mediates this process4–6,butthepreciseroleofspecificclassesofinhibitoryneurons in ODP is controversial. Here we report that evoked firing rates of binocular excitatory neurons in the primary visual cortex immediatelydropbyhalfwhenvisionisrestrictedtooneeye,butgradually return to normal over the followingtwenty-four hours, despite the fact that vision remains restricted to one eye. This restoration of binocular-like excitatory firing rates after monocular deprivation resultsfromarapid,althoughtransient,reductioninthefiringrates of fast-spiking, parvalbumin-positive (PV) interneurons, which in turncanbeattributedtoadecreaseinlocalexcitatorycircuitinput onto PV interneurons.This reduction in PV-cell-evoked responses after monocular lid suture is restricted to the critical period for ODPandappearstobenecessaryforsubsequentshiftsinexcitatory ODP. Pharmacologically enhancing inhibition at the time of sight deprivation blocks ODP and, conversely, pharmacogenetic reduction of PV cell firing rates can extend the critical period for ODP. Thesefindingsdefinethemicrocircuitchangesinitiatingcompetitive plasticityduringcriticalperiodsofcorticaldevelopment.Moreover, they show that the restoration of evoked firing rates of layer 2/3 pyramidal neurons by PV-specific disinhibition is a key step in the progression of ODP.

A disinhibitory microcircuit initiates critical period plasticity in the visu...

Taruna Ikrar

Abstract In the mammalian neocortex, excitatory neurons provide excitation in both columnar and laminar dimensions, which is modulated further by inhibitory neurons. However, our understanding of intracortical excitatory and inhibitory synaptic inputs in relation to principal excitatory neurons remains incomplete, and it is unclear how local excitatory and inhibitory synaptic connections to excitatory neurons are spatially organized on a layer-by-layer basis. In the present study, we combined whole cell recordings with laser scanning photostimulation via glutamate uncaging to map excitatory and inhibitory synaptic inputs to single excitatory neurons throughout cortical layers 2/3–6 in the mouse primary visual cortex (V1). We ﬁnd that synaptic input sources of excitatory neurons span the radial columns of laminar microcircuits, and excitatory neurons in different V1 laminae exhibit distinct patterns of layer-speciﬁc organizationofexcitatoryinputs.Remarkably,thespatialextentofinhibitoryinputsofexcitatory neurons for a given layer closely mirrors that of their excitatory input sources, indicating that excitatory and inhibitory synaptic connectivity is spatially balanced across excitatory neuronal networks. Strong interlaminar inhibitory inputs are found, particularly for excitatory neurons in layers 2/3 and 5. This differs from earlier studies reporting that inhibitory cortical connections to excitatory neurons are generally localized within the same cortical layer. On the basis of the functional mapping assays, we conducted a quantitative assessment of both excitatory and inhibitory synaptic laminar connections to excitatory cells at single cell resolution, establishing precise layer-by-layer synaptic wiring diagrams of excitatory neurons in the visual cortex.

Primary visual cortex shows laminar speciﬁc and balanced circuit organization...

Taruna Ikrar

A characteristic of the developing mammalian visual system is a brief interval of plasticity, termed the “critical period,” when the circuitry of primary visual cortex is most sensitive to perturbation of visual experience. Depriving one eye of vision (monocular deprivation [MD]) during the critical period alters ocular dominance (OD) by shifting the responsiveness of neurons in visual cortex to favor the nondeprived eye. A disinhibitory microcircuit involving parvalbumin-expressing (PV) interneurons initiates this OD plasticity. The gene encoding the neuronal nogo-66-receptor1(ngr1/rtn4r) is required to close the critical period.Herewecombinedmousegenetics, electrophysiology,andcircuitmapping with laser-scanning photostimulation to investigate whether disinhibition is confined to the critical period by ngr1.We demonstrate that ngr1 mutant mice retain plasticity characteristic of the critical period as adults, and that ngr1 operates within PV interneurons to restrict the loss of intracortical excitatory synaptic input following MD in adult mice, and this disinhibition induces a “lower PV network configuration” in both critical-period wild-type miceandadult ngr1/mice.Wepropose that ngr1 limits disinhibition to close the critical period forODplasticityand that a decrease in PV expression levels reports the diminished recent cumulative activity of these interneurons.

Nogo receptor1confinesadisinhibitorymicrocircuittothe criticalperiodinvisualc...

Taruna Ikrar

Ikrar taruna disandera paman sam (fajar 1 februari 2016 hal 1 dan 2)

Taruna Ikrar

Terobosan pencegahan banjir dan pengelolaan air yang benar (harian pelita jan...

Taruna Ikrar

Ilmuwan indonesia buktikan regenerasi sel otak jadi pengobatan alzheimer an...

Taruna Ikrar

Rakyat merdeka (12 15-2013)

Taruna Ikrar

Ilmuwan indonesia membuktikan terjadinya regenerasi sel sel otak, dan menjadi...

Taruna Ikrar

MalPraktik dan Solidaritas Dokter Indonesia

Taruna Ikrar

2013 11 11 hal 01

Taruna Ikrar

2013 11 11 hal 23

Taruna Ikrar

Teror penembakan anggota polri dan kondisi keamanan nasional (harian pelita 2...

Taruna Ikrar

Teror penembakan anggota polri dan kondisi keamanan nasional (harian pelita 2...

Taruna Ikrar

Idul fitri dan konsolidasi umat islam di daratan amerika (harian pelita 12 ag...

Taruna Ikrar

Idul fitri dan konsolidasi umat islam di daratan amerika (harian pelita 12 ag...

Taruna Ikrar

(Geta Merdeka) Dr Taruna Ikrar Phd Menghar

Taruna Ikrar

Harian Nasional Pelita 23 November 2012 Halaman 19

Taruna Ikrar

Cermin Dunia Kedokteran (Profil Dr Taruna Ikrar Ilmuwan Penemu Mekanisme Tera...

Taruna Ikrar

Cover Cermin Dunia Kedokteran & Profil Dr Taruna Ikrar Bersama Penerima N...

Taruna Ikrar

Harian Pelita Jumat 16 November 2012 Halaman 1

Taruna Ikrar

Plus de Taruna Ikrar (20)

A disinhibitory microcircuit initiates critical period plasticity in the visu...

Primary visual cortex shows laminar speciﬁc and balanced circuit organization...

Nogo receptor1confinesadisinhibitorymicrocircuittothe criticalperiodinvisualc...

Ikrar taruna disandera paman sam (fajar 1 februari 2016 hal 1 dan 2)

Terobosan pencegahan banjir dan pengelolaan air yang benar (harian pelita jan...

Ilmuwan indonesia buktikan regenerasi sel otak jadi pengobatan alzheimer an...

Rakyat merdeka (12 15-2013)

Ilmuwan indonesia membuktikan terjadinya regenerasi sel sel otak, dan menjadi...

MalPraktik dan Solidaritas Dokter Indonesia

2013 11 11 hal 01

2013 11 11 hal 23

Teror penembakan anggota polri dan kondisi keamanan nasional (harian pelita 2...

Idul fitri dan konsolidasi umat islam di daratan amerika (harian pelita 12 ag...

(Geta Merdeka) Dr Taruna Ikrar Phd Menghar

Harian Nasional Pelita 23 November 2012 Halaman 19

Cermin Dunia Kedokteran (Profil Dr Taruna Ikrar Ilmuwan Penemu Mekanisme Tera...

Cover Cermin Dunia Kedokteran & Profil Dr Taruna Ikrar Bersama Penerima N...

Harian Pelita Jumat 16 November 2012 Halaman 1

“Shutdown” pemerintah amerika serikat dan obamacare (harian pelita 3 oktober 2013 halaman 1 19) by taruna ikrar 2013 10-02 hal 01

Recommandé

Recommandé

Contenu connexe

Plus de Taruna Ikrar

Plus de Taruna Ikrar (20)