Faculty Opinions recommendation of MeCP2 regulates the timing of critical period plasticity that shapes functional connectivity in primary visual cortex.

We investigated the effects of resting state type on blood oxygen level-dependent (BOLD) signal and functional connectivity in two paradigms: participants either alternated between fixation and eyes closed or maintained fixation or eyes closed throughout each scan. The BOLD signal and functional connectivity of lower and higher tiers of the visual cortical hierarchy were found to be differentially modulated during eyes closed versus fixation. Fixation was associated with greater mean BOLD signals in primary visual cortex and lower mean BOLD signals in extrastriate visual areas than periods of eyes closed. In addition, analysis of thalamocortical functional connectivity during scans in which participants maintained fixation showed synchronized BOLD fluctuations between those thalamic nuclei whose mean BOLD signal was systematically modulated during alternating epochs of eyes closed and fixation, primary visual cortex and the attention network, while during eyes closed negatively correlated fluctuations were seen between the same thalamic nuclei and extrastriate visual areas. Finally, in all visual areas the amplitude of spontaneous BOLD fluctuations was greater during eyes closed than during fixation. The dissociation between early and late tiers of visual cortex, which characterizes both mean and functionally connected components of the BOLD signal, may depend on the reorganization of thalamocortical networks. Since dissociated changes in local blood flow also characterize transitions between different stages of sleep and wakefulness (Braun AR, Balkin TJ, Wesenten NJ, Gwadry F, Carson RE, Varga M, Baldwin P, Belenky G, Herscovitch P. Science 279: 91–95, 1998), our results suggest that dissociated endogenous neural activity in primary and extrastriate cortex may represent a general aspect of brain function.

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

10.1101/2020.05.31.126474 ◽

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.

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Altered Functional Connectivity Strength of Primary Visual Cortex in Subjects with Diabetic Retinopathy

Diabetes Metabolic Syndrome and Obesity Targets and Therapy ◽

10.2147/dmso.s311009 ◽

2021 ◽

Vol Volume 14 ◽

pp. 3209-3219

Author(s):

Chen-xing Qi ◽

Xin Huang ◽

Yan Tong ◽

Yin Shen

Keyword(s):

Diabetic Retinopathy ◽

Visual Cortex ◽

Functional Connectivity ◽

Primary Visual Cortex ◽

Functional Connectivity Strength ◽

Connectivity Strength

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Vision is required for the formation of binocular neurons prior to the classical critical period

10.1101/2021.06.15.448591 ◽

2021 ◽

Author(s):

Liming Tan ◽

Dario L. Ringach ◽

S. Lawrence Zipursky ◽

Joshua T. Trachtenberg

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Depth Perception ◽

Critical Period ◽

Visual Stimuli ◽

Cortical Responses ◽

Eye Opening

Depth perception emerges from the development of binocular neurons in primary visual cortex. Vision is required for these neurons to acquire their mature responses to visual stimuli. A prevalent view is that vision does not influence binocular circuitry until the onset of the critical period, about a week after eye opening, and that this relies on inhibition. Here, we show that vision is required to form binocular neurons and to improve binocular tuning and matching from eye opening until critical period closure. Inhibition is not required for this process, but rather antagonizes it. Vision improves the tuning properties of binocular neurons by strengthening and sharpening ipsilateral eye cortical responses. This progressively changes the population of neurons in the binocular pool and this plasticity is sensitive to interocular differences prior to the critical period. Thus, vision guides binocular plasticity from eye opening and prior to the classically defined critical period.

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