Age-Dependent Decline in Supragranular Long-Term Synaptic Plasticity by Increased Inhibition During the Critical Period in the Rat Primary Visual Cortex

2009 ◽  
Vol 101 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Hyun-Jong Jang ◽  
Kwang-Hyun Cho ◽  
Hyun-Sok Kim ◽  
Sang June Hahn ◽  
Myung-Suk Kim ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Critical Period ◽  
Excitatory Postsynaptic Potential ◽  
Age Dependent ◽  
Layer 4 ◽  
Old Rats ◽  
Synaptic Model

Supragranular long-term potentiation (LTP) and depression (LTD) are continuously induced in the pathway from layer 4 during the critical period in the rodent primary visual cortex, which limits the use of supragranular long-term synaptic plasticity as a synaptic model for the mechanism of ocular dominance (OD) plasticity. The results of the present study demonstrate that the pulse duration of extracellular stimulation to evoke a field potential (FP) is critical to induction of LTP and LTD in this pathway. LTP and LTD were induced in the pathway from layer 4 to layer 2/3 in slices from 3-wk-old rats when FPs were evoked by 0.1- and 0.2-ms pulses. LTP and LTD were induced in slices from 5-wk-old rats when evoked by stimulation with a 0.2-ms pulse but not by stimulation with a 0.1-ms pulse. Both the inhibitory component of FP and the inhibitory/excitatory postsynaptic potential amplitude ratio evoked by stimulation with a 0.1-ms pulse were greater than the values elicited by a 0.2-ms pulse. Stimulation with a 0.1-ms pulse at various intensities that showed the similar inhibitory FP component with the 0.2-ms pulse induced both LTD and LTP in 5-wk-old rats. Thus extracellular stimulation with shorter-duration pulses at higher intensity resulted in greater inhibition than that observed with longer-duration pulses at low intensity. This increased inhibition might be involved in the age-dependent decline of synaptic plasticity during the critical period. These results provide an alternative synaptic model for the mechanism of OD plasticity.

scholarly journals Vision reconstructs the cellular composition of binocular circuitry during the critical period

2020 ◽  
Author(s):  
Liming Tan ◽  
Elaine Tring ◽  
Dario L. Ringach ◽  
S. Lawrence Zipursky ◽  
Joshua T. Trachtenberg
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Critical Period ◽  
Cellular Composition ◽  
Feature Detectors ◽  
Layer 2 ◽  
Layer 4 ◽  
High Acuity ◽  
Longitudinal Imaging

AbstractHigh acuity binocularity is established in primary visual cortex during an early postnatal critical period. In contrast to current models for the developmental of binocular neurons, we find that the binocular network present at the onset of the critical period is dismantled and remade. Using longitudinal imaging of receptive field tuning (e.g. orientation selectivity) of thousands of layer 2/3 neurons through development, we show most binocular neurons present at critical-period onset are poorly tuned and rendered monocular. These are replenished by newly formed binocular neurons that are established by a vision-dependent recruitment of well-tuned ipsilateral inputs to contralateral monocular neurons with matched tuning properties. The binocular network in layer 4 is equally unstable but does not improve. Thus, vision instructs a new and more sharply tuned binocular network in layer 2/3 by exchanging one population of neurons for another and not by refining an extant network.One Sentence SummaryUnstable binocular circuitry is transformed by vision into a network of highly tuned complex feature detectors in the cortex.

scholarly journals Sensory experience inversely regulates feedforward and feedback excitation-inhibition ratio in rodent visual cortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Nathaniel J Miska ◽  
Leonidas MA Richter ◽  
Brian A Cary ◽  
Julijana Gjorgjieva ◽  
Gina G Turrigiano
Keyword(s):  
Visual Cortex ◽  
Driving Force ◽  
Critical Period ◽  
Visual Experience ◽  
Feedback Inhibition ◽  
Intracortical Inhibition ◽  
Monocular Deprivation ◽  
Long Term Depression ◽  
Layer 4

Brief (2-3d) monocular deprivation (MD) during the critical period induces a profound loss of responsiveness within binocular (V1b) and monocular (V1m) regions of rodent primary visual cortex. This has largely been ascribed to long-term depression (LTD) at thalamocortical synapses, while a contribution from intracortical inhibition has been controversial. Here we used optogenetics to isolate and measure feedforward thalamocortical and feedback intracortical excitation-inhibition (E-I) ratios following brief MD. Despite depression at thalamocortical synapses, thalamocortical E-I ratio was unaffected in V1b and shifted toward excitation in V1m, indicating that thalamocortical excitation was not effectively reduced. In contrast, feedback intracortical E-I ratio was shifted toward inhibition in V1m, and a computational model demonstrated that these opposing shifts produced an overall suppression of layer 4 excitability. Thus, feedforward and feedback E-I ratios can be independently tuned by visual experience, and enhanced feedback inhibition is the primary driving force behind loss of visual responsiveness.

scholarly journals Layer 4 in Primary Visual Cortex of the Awake Rabbit: Contrasting Properties of Simple Cells and Putative Feedforward Inhibitory Interneurons

2013 ◽  
Vol 33 (28) ◽  
pp. 11372-11389 ◽  
Author(s):  
J. Zhuang ◽  
C. R. Stoelzel ◽  
Y. Bereshpolova ◽  
J. M. Huff ◽  
X. Hei ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Inhibitory Interneurons ◽  
Simple Cells ◽  
Layer 4

Map of the synapses onto layer 4 basket cells of the primary visual cortex of the cat

1997 ◽  
Vol 380 (2) ◽  
pp. 230-242 ◽  
Author(s):  
Bashir Ahmed ◽  
John C. Anderson ◽  
Kevan A.C. Martin ◽  
J. Charmaine Nelson
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Basket Cells ◽  
Layer 4

scholarly journals Levetiracetam Reduced the Basal Excitability of the Dentate Gyrus without Restoring Impaired Synaptic Plasticity in Rats with Temporal Lobe Epilepsy

2020 ◽  
Vol 10 (9) ◽  
pp. 634
Author(s):  
Guillermo González-H ◽  
Itzel Jatziri Contreras-García ◽  
Karla Sánchez-Huerta ◽  
Claudio M. T. Queiroz ◽  
Luis Ricardo Gallardo Gudiño ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Temporal Lobe Epilepsy ◽  
Dentate Gyrus ◽  
Temporal Lobe ◽  
Focal Epilepsy ◽  
Chronic Phase ◽  
Long Term Potentiation ◽  
Excitatory Postsynaptic Potential ◽  
Output Curve

Temporal lobe epilepsy (TLE), the most common type of focal epilepsy, affects learning and memory; these effects are thought to emerge from changes in synaptic plasticity. Levetiracetam (LEV) is a widely used antiepileptic drug that is also associated with the reversal of cognitive dysfunction. The long-lasting effect of LEV treatment and its participation in synaptic plasticity have not been explored in early chronic epilepsy. Therefore, through the measurement of evoked field potentials, this study aimed to comprehensively identify the alterations in the excitability and the short-term (depression/facilitation) and long-term synaptic plasticity (long-term potentiation, LTP) of the dentate gyrus of the hippocampus in a lithium–pilocarpine rat model of TLE, as well as their possible restoration by LEV (1 week; 300 mg/kg/day). TLE increased the population spike (PS) amplitude (input/output curve); interestingly, LEV treatment partially reduced this hyperexcitability. Furthermore, TLE augmented synaptic depression, suppressed paired-pulse facilitation, and reduced PS-LTP; however, LEV did not alleviate such alterations. Conversely, the excitatory postsynaptic potential (EPSP)-LTP of TLE rats was comparable to that of control rats and was decreased by LEV. LEV caused a long-lasting attenuation of basal hyperexcitability but did not restore impaired synaptic plasticity in the early chronic phase of TLE.

Man's Triune Conscious Mind: Part III

1995 ◽  
Vol 81 (2) ◽  
pp. 463-466
Author(s):  
Carl G. Aurell
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Conscious Mind ◽  
Perceptual Model ◽  
Cortex Area ◽  
Layer 4

The perceptual model, discussed previously in Part II, is applied to the organization of the visual cortex in a search for “consciousness neurons,” i.e., sources of sensations, images, and percepts. It is hypothesized that these three conscious phenomena emerge in the primary visual cortex, Area VI, possibly from neurons in its Layer 4.

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