scholarly journals Cross-Modal Recruitment of Primary Visual Cortex by Auditory Stimuli in the Nonhuman Primate Brain: A Molecular Mapping Study

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Priscilla Hirst ◽  
Pasha Javadi Khomami ◽  
Amol Gharat ◽  
Shahin Zangenehpour
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Molecular Mapping ◽  
Cortical Activation ◽  
Early Gene ◽  
Implicit Associations ◽  
Initial Exposure ◽  
Short Period ◽  
Increased Activity

Recent studies suggest that exposure to only one component of audiovisual events can lead to cross-modal cortical activation. However, it is not certain whether such crossmodal recruitment can occur in the absence of explicit conditioning, semantic factors, or long-term associations. A recent study demonstrated that crossmodal cortical recruitment can occur even after a brief exposure to bimodal stimuli without semantic association. In addition, the authors showed that the primary visual cortex is under such crossmodal influence. In the present study, we used molecular activity mapping of the immediate early gene zif268. We found that animals, which had previously been exposed to a combination of auditory and visual stimuli, showed increased number of active neurons in the primary visual cortex when presented with sounds alone. As previously implied, this crossmodal activation appears to be the result of implicit associations of the two stimuli, likely driven by their spatiotemporal characteristics; it was observed after a relatively short period of exposure (~45 min) and lasted for a relatively long period after the initial exposure (~1 day). These results suggest that the previously reported findings may be directly rooted in the increased activity of the neurons occupying the primary visual cortex.

scholarly journals How the mechanisms of long-term synaptic potentiation and depression serve experience-dependent plasticity in primary visual cortex

2014 ◽  
Vol 369 (1633) ◽  
pp. 20130284 ◽  
Author(s):  
Sam F. Cooke ◽  
Mark F. Bear
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Learning ◽  
Excitatory Input ◽  
Monocular Deprivation ◽  
Hebbian Plasticity ◽  
Circuit Components ◽  
Cortical Synapses ◽  
Visual Cortical

Donald Hebb chose visual learning in primary visual cortex (V1) of the rodent to exemplify his theories of how the brain stores information through long-lasting homosynaptic plasticity. Here, we revisit V1 to consider roles for bidirectional ‘Hebbian’ plasticity in the modification of vision through experience. First, we discuss the consequences of monocular deprivation (MD) in the mouse, which have been studied by many laboratories over many years, and the evidence that synaptic depression of excitatory input from the thalamus is a primary contributor to the loss of visual cortical responsiveness to stimuli viewed through the deprived eye. Second, we describe a less studied, but no less interesting form of plasticity in the visual cortex known as stimulus-selective response potentiation (SRP). SRP results in increases in the response of V1 to a visual stimulus through repeated viewing and bears all the hallmarks of perceptual learning. We describe evidence implicating an important role for potentiation of thalamo-cortical synapses in SRP. In addition, we present new data indicating that there are some features of this form of plasticity that cannot be fully accounted for by such feed-forward Hebbian plasticity, suggesting contributions from intra-cortical circuit components.

Serotonin inhibits the induction of NMDA receptor-dependent long-term potentiation in the rat primary visual cortex

2006 ◽  
Vol 1103 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Hyun-Sok Kim ◽  
Hyun-Jong Jang ◽  
Kwang-Hyun Cho ◽  
Sang June Hahn ◽  
Myung-Jun Kim ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Nmda Receptor ◽  
Primary Visual Cortex ◽  
Long Term Potentiation ◽  
Term Potentiation

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.

Prior Expectations Evoke Stimulus Templates in the Primary Visual Cortex

2014 ◽  
Vol 26 (7) ◽  
pp. 1546-1554 ◽  
Author(s):  
Peter Kok ◽  
Michel F. Failing ◽  
Floris P. de Lange
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Activity Patterns ◽  
Representational Content ◽  
Specific Pattern ◽  
Specific Stimulus ◽  
Prior Expectation ◽  
Early Visual Cortex ◽  
Actual Stimulus ◽  
Increased Activity

Sensory processing is strongly influenced by prior expectations. Valid expectations have been shown to lead to improvements in perception as well as in the quality of sensory representations in primary visual cortex. However, very little is known about the neural correlates of the expectations themselves. Previous studies have demonstrated increased activity in sensory cortex following the omission of an expected stimulus, yet it is unclear whether this increased activity constitutes a general surprise signal or rather has representational content. One intriguing possibility is that top–down expectation leads to the formation of a template of the expected stimulus in visual cortex, which can then be compared with subsequent bottom–up input. To test this hypothesis, we used fMRI to noninvasively measure neural activity patterns in early visual cortex of human participants during expected but omitted visual stimuli. Our results show that prior expectation of a specific visual stimulus evokes a feature-specific pattern of activity in the primary visual cortex (V1) similar to that evoked by the corresponding actual stimulus. These results are in line with the notion that prior expectation triggers the formation of specific stimulus templates to efficiently process expected sensory inputs.

200 Effect of Long-term Feeding of Deoxynivalenol (DON) Contaminated Diets on Performance of Grower-finisher Pigs

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 67-68
Author(s):  
Michael A Bosompem ◽  
Michael O Wellington ◽  
Daniel A Columbus
Keyword(s):  
Feed Intake ◽  
Control Diet ◽  
Average Daily Gain ◽  
Dietary Treatment ◽  
Final Body Weight ◽  
Initial Exposure ◽  
Entire Study ◽  
Short Period ◽  
Dietary Treatments

Abstract Previous studies examining the effects of deoxynivalenol (DON) intake in pigs have largely focused on young animals or have been over a short period of time. The objective of the present study was to determine the effects of long-term feeding of DON contaminated diets on growth performance of grower-finisher pigs. A total of 240 mixed-sex pigs (35.9 ± 1.1 kg) were group housed in 6 pigs/pen (n = 10/treatment) and were randomly assigned to 1 of 4 dietary treatments for 77 d. Diets consisted of a control diet (CON) containing no DON or a diet containing 1, 3, or 5 ppm DON (DON1, DON3, or DON5) achieved by adding DON-contaminated wheat and wheat screenings at the expense of clean wheat. In the grower period, DON5-fed pigs had reduced average daily gain (ADG) compared to CON, with DON1 and DON3-fed pigs being intermediate P < 0.05). There was no effect of dietary treatment on ADG in the finisher period (P > 0.05). Overall the entire study, DON3 and DON5-fed pigs had similar and reduced ADG (P < 0.05) compared to CON and DON1, which did not differ (P > 0.05). Feed intake was reduced in DON-fed pigs in the finisher period (3.12, 2.97, 2.96, and 2.88 ± 0.05; P< 0.05) and in DON3 and DON5-fed pigs overall (2.62, 2.55, 2.47, 2.47 ± 0.03; P < 0.05) compared to CON, with no overall effect observed in the grower period. There was no effect on feed efficiency in any period (P > 0.05). The decrease in performance resulted in reduced final body weight in DON3 and DON5-fed pigs, compared to CON, with DON1-fed pigs being intermediate (P > 0.05). Overall, the effects of DON-intake on performance were variable and generally occurred rapidly after initial exposure and appear to be largely due to the reduction in feed intake.

scholarly journals A comprehensive data-driven model of cat primary visual cortex

2018 ◽  
Author(s):  
Ján Antolík ◽  
Cyril Monier ◽  
Yves Frégnac ◽  
Andrew P. Davison
Keyword(s):  
Visual Cortex ◽  
Computational Modeling ◽  
Primary Visual Cortex ◽  
Systematic Approach ◽  
Data Driven ◽  
Orientation Tuning ◽  
Integrative Modeling ◽  
Functional Features ◽  
Spiking Model

AbstractKnowledge integration based on the relationship between structure and function of the neural substrate is one of the main targets of neuroinformatics and data-driven computational modeling. However, the multiplicity of data sources, the diversity of benchmarks, the mixing of observables of different natures, and the necessity of a long-term, systematic approach make such a task challenging. Here we present a first snapshot of a long-term integrative modeling program designed to address this issue: a comprehensive spiking model of cat primary visual cortex satisfying an unprecedented range of anatomical, statistical and functional constraints under a wide range of visual input statistics. In the presence of physiological levels of tonic stochastic bombardment by spontaneous thalamic activity, the modeled cortical reverberations self-generate a sparse asynchronous ongoing activity that quantitatively matches a range of experimentally measured statistics. When integrating feed-forward drive elicited by a high diversity of visual contexts, the simulated network produces a realistic, quantitatively accurate interplay between visually evoked excitatory and inhibitory conductances; contrast-invariant orientation-tuning width; center surround interactions; and stimulus-dependent changes in the precision of the neural code. This integrative model offers numerous insights into how the studied properties interact, contributing to a better understanding of visual cortical dynamics. It provides a basis for future development towards a comprehensive model of low-level perception.Significance statementComputational modeling can integrate fragments of understanding generated by experimental neuroscience. However, most previous models considered only a few features of neural computation at a time, leading to either poorly constrained models with many parameters, or lack of expressiveness in over-simplified models. A solution is to commit to detailed models, but constrain them with a broad range of anatomical and functional data. This requires a long-term systematic approach. Here we present a first snapshot of such an integrative program: a large-scale spiking model of V1, that is constrained by an unprecedented range of anatomical and functional features. Together with the associated modeling infrastructure, this study lays the groundwork for a broad integrative modeling program seeking an in-depth understanding of vision.

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