scholarly journals Weak Coupling Between Spontaneous Local Cortical Activity State Switches Under Anesthesia Leads to Strongly Correlated Global Cortical States

2021 ◽  
Author(s):  
Ethan B. Blackwood ◽  
Brenna P. Shortal ◽  
Alex Proekt
Keyword(s):  
Cortical Activity ◽  
State Transitions ◽  
Strongly Correlated ◽  
Canonical Correlations ◽  
Thalamic Input ◽  
Pairwise Interactions ◽  
Layer 4 ◽  
Small Set ◽  
Activity State ◽  
Granular Layers

Under anesthesia, neural dynamics deviate dramatically from those seen during wakefulness. During recovery from this perturbation, thalamocortical activity abruptly switches among a small set of metastable intermediate states. These metastable states and structured transitions among them form a scaffold that guides the brain back to the waking state. Here, we investigate the mechanisms that constrain cortical activity to discrete states and give rise to abrupt transitions among them. If state transitions were imposed onto the thalamocortical system by changes in the subcortical modulation, different cortical sites should exhibit near-synchronous state transitions. To test this hypothesis, we quantified state synchrony at different cortical sites in anesthetized rats. States were defined by compressing spectra of layer-specific local field potentials (LFPs) in visual and motor cortices. Transition synchrony, mutual information, and canonical correlations all demonstrate that most state transitions in the cortex are local and that coupling between sites is weak. Fluctuations in the LFP in the thalamic input layer 4 were particularly dissimilar from those in supra- and infra-granular layers. Thus, our results suggest that the discrete global cortical states are not imposed by the ascending modulatory pathways but emerge from the multitude of weak pairwise interactions within the cortex.

scholarly journals Leaf Spectra and Weight of Species in Canopy, Subcanopy, and Understory Layers in a Venezuelan Andean Cloud Forest

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Miguel F. Acevedo ◽  
Michele Ataroff
Keyword(s):  
Unit Area ◽  
Cloud Forest ◽  
Strongly Correlated ◽  
Linear Discriminant ◽  
Canonical Correlations ◽  
Leaf Mass ◽  
High Resolution Spectrometer ◽  
Species Groups ◽  
Resolution Spectrometer ◽  
Nm Range

We characterize the leaf spectra of tree species of an Andean cloud forest in Venezuela, grouped according to position in canopy, subcanopy and understory. We measured leaf reflectance and transmittance spectra in the 400–750 nm range using a high-resolution spectrometer. Both signals were subtracted from unity to calculate the absorbance signal. Nine spectral variables were calculated for each signal, three based on wide-bands and six based on features. We measured leaf mass per unit area of all species, and calculated efficiency of absorbance, as ratio of absorbance in photosynthetic range over leaf mass. Differences among groups were significant for several absorbance and transmittance variables, leaf mass, and efficiency of absorbance. The clearest differences are between canopy and understory species. There is strong correlation for at least one pair of band variables for each signal, and each band variable is strongly correlated with at least one feature variable for most signals. High canonical correlations are obtained between pairs of the three canonical axes for bands and the first three canonical axes for features. Absorbance variables produce species clusters having the closest correspondence to the species groups. Linear discriminant analysis shows that species groups can be sorted by all signals, particularly absorbance.

Dynamically coupled synfire chains induce a self-sustained cortical activity state

2010 ◽  
Vol 68 ◽  
pp. e211
Author(s):  
Chris Trengove ◽  
Cees van Leeuwen ◽  
Markus Diesmann
Keyword(s):  
Cortical Activity ◽  
Synfire Chains ◽  
Activity State

scholarly journals Pathway-, layer- and cell-type-specific thalamic input to mouse barrel cortex

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
B Semihcan Sermet ◽  
Pavel Truschow ◽  
Michael Feyerabend ◽  
Johannes M Mayrhofer ◽  
Tess B Oram ◽  
...  
Keyword(s):  
Thalamic Nucleus ◽  
Barrel Cortex ◽  
Sensory Information ◽  
Cell Types ◽  
Excitatory Input ◽  
Higher Order ◽  
Inhibitory Neurons ◽  
Thalamic Nuclei ◽  
Thalamic Input ◽  
Layer 4

Mouse primary somatosensory barrel cortex (wS1) processes whisker sensory information, receiving input from two distinct thalamic nuclei. The first-order ventral posterior medial (VPM) somatosensory thalamic nucleus most densely innervates layer 4 (L4) barrels, whereas the higher-order posterior thalamic nucleus (medial part, POm) most densely innervates L1 and L5A. We optogenetically stimulated VPM or POm axons, and recorded evoked excitatory postsynaptic potentials (EPSPs) in different cell-types across cortical layers in wS1. We found that excitatory neurons and parvalbumin-expressing inhibitory neurons received the largest EPSPs, dominated by VPM input to L4 and POm input to L5A. In contrast, somatostatin-expressing inhibitory neurons received very little input from either pathway in any layer. Vasoactive intestinal peptide-expressing inhibitory neurons received an intermediate level of excitatory input with less apparent layer-specificity. Our data help understand how wS1 neocortical microcircuits might process and integrate sensory and higher-order inputs.

scholarly journals Textures vs Non-Textures: A Simple Computational Method for Classifying Perceived ‘Texturality’ in Natural Images

i-Perception ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 204166952110545
Author(s):  
Fumiya Kurosawa ◽  
Taiki Orima ◽  
Kosuke Okada ◽  
Isamu Motoyoshi
Keyword(s):  
Visual System ◽  
Computational Method ◽  
Natural Images ◽  
Strongly Correlated ◽  
Original Image ◽  
Perceived Similarity ◽  
Image Region ◽  
Discriminant Model ◽  
Small Set ◽  
Highly Correlated

The visual system represents textural image regions as simple statistics that are useful for the rapid perception of scenes and surfaces. What images ‘textures’ are, however, has so far mostly been subjectively defined. The present study investigated the empirical conditions under which natural images are processed as texture. We first show that ‘texturality’ – i.e., whether or not an image is perceived as a texture – is strongly correlated with the perceived similarity between an original image and its Portilla-Simoncelli (PS) synthesized image. We found that both judgments are highly correlated with specific PS statistics of the image. We also demonstrate that a discriminant model based on a small set of image statistics could discriminate whether a given image was perceived as a texture with over 90% accuracy. The results provide a method to determine whether a given image region is represented statistically by the human visual system.

scholarly journals An inhibitory gate for state transition in cortex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Stefano Zucca ◽  
Giulia D’Urso ◽  
Valentina Pasquale ◽  
Dania Vecchia ◽  
Giuseppe Pica ◽  
...  
Keyword(s):  
Inhibitory Control ◽  
Large Scale ◽  
State Transition ◽  
Nrem Sleep ◽  
Cortical Activity ◽  
Electrophysiological Recording ◽  
State Transitions ◽  
Cellular Mechanisms ◽  
Quiet Wakefulness ◽  
Inhibitory Regulation

Large scale transitions between active (up) and silent (down) states during quiet wakefulness or NREM sleep regulate fundamental cortical functions and are known to involve both excitatory and inhibitory cells. However, if and how inhibition regulates these activity transitions is unclear. Using fluorescence-targeted electrophysiological recording and cell-specific optogenetic manipulation in both anesthetized and non-anesthetized mice, we found that two major classes of interneurons, the parvalbumin and the somatostatin positive cells, tightly control both up-to-down and down-to-up state transitions. Inhibitory regulation of state transition was observed under both natural and optogenetically-evoked conditions. Moreover, perturbative optogenetic experiments revealed that the inhibitory control of state transition was interneuron-type specific. Finally, local manipulation of small ensembles of interneurons affected cortical populations millimetres away from the modulated region. Together, these results demonstrate that inhibition potently gates transitions between cortical activity states, and reveal the cellular mechanisms by which local inhibitory microcircuits regulate state transitions at the mesoscale.

scholarly journals Binocular matching of thalamocortical and intracortical circuits in the mouse visual cortex

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Yu Gu ◽  
Jianhua Cang
Keyword(s):  
Cortical Neurons ◽  
Critical Period ◽  
Individual Layer ◽  
Adult Mice ◽  
Thalamic Input ◽  
Intracortical Circuits ◽  
Layer 4 ◽  
Binocular Matching ◽  
Cortical Inputs ◽  
Visual Cortical

Visual cortical neurons are tuned to similar orientations through the two eyes. The binocularly-matched orientation preference is established during a critical period in early life, but the underlying circuit mechanisms remain unknown. Here, we optogenetically isolated the thalamocortical and intracortical excitatory inputs to individual layer 4 neurons and studied their binocular matching. In adult mice, the thalamic and cortical inputs representing the same eyes are similarly tuned and both are matched binocularly. In mice before the critical period, the thalamic input is already slightly matched, but the weak matching is not manifested due to random connections in the cortex, especially those serving the ipsilateral eye. Binocular matching is thus mediated by orientation-specific changes in intracortical connections and further improvement of thalamic matching. Together, our results suggest that the feed-forward thalamic input may play a key role in initiating and guiding the functional refinement of cortical circuits in critical period development.

Developmental Regulation of Plasticity in the Forepaw Representation of Ferret Somatosensory Cortex

2003 ◽  
Vol 89 (4) ◽  
pp. 2289-2298 ◽  
Author(s):  
Debra F. McLaughlin ◽  
Sharon L. Juliano
Keyword(s):  
Spatial Distribution ◽  
Somatosensory Cortex ◽  
Ulnar Nerve ◽  
Cortical Activity ◽  
Cortical Response ◽  
Nerve Lesions ◽  
Long Latency ◽  
Cortical Responses ◽  
Layer 4 ◽  
Neonatal Lesions

This study characterized the spatiotemporal responses in ferret somatosensory cortex after sensory deprivation at different phases of cortical development. We hypothesized that cortical responses to stimulation of intact superficial radial nerve in adults will vary systematically according to maturation of thalamocortical relationships at the time of an ulnar nerve transection. Depending on the age of the animal at the time of the lesion, we found differential effects on the spatial distribution of the short- and long-latency components of the cortical response. In animals lesioned at postnatal days 5–7, when thalamic projections are not yet stabilized and layer 4 is not yet formed, we found that initial (short-latency) cortical responses are widespread and fragmented. Ulnar nerve transections performed at postnatal day 20 or 21, when thalamocortical afferents are more stabilized and layer 4 is clearly identifiable, yield moderate expansions in the distribution of short- and long-latency components of the cortical response. Nerve lesions in adults lead to a wider distribution of long-latency cortical activity. Neonatal lesions broaden the spatial distribution and increase the latency of the initial cortical response; interruption of nerve input in older juveniles alters both the early and later components; and nerve lesions in adult animals expand the distribution of later cortical activity only. These findings demonstrate correlation between developmental phase at the time sensory input is interrupted and the latency of affected components of the cortical response. This supports the hypothesis that differential response changes are regulated by functional reorganization of thalamocortical connections after neonatal lesions and alteration of corticocortical dynamics after adult lesions.

GABAergic Inhibitory Control of the Transient and Sustained Components of Orientation Selectivity in a Model Microcolumn in Layer 4 of Cat Visual Cortex

1998 ◽  
Vol 10 (4) ◽  
pp. 855-867 ◽  
Author(s):  
Paul Bush ◽  
Nicholas Priebe
Keyword(s):  
Experimental Data ◽  
Visual Cortex ◽  
Sine Wave ◽  
Orientation Tuning ◽  
Dendritic Field ◽  
Thalamic Input ◽  
Layer 4 ◽  
Dc Component ◽  
Sine Wave Gratings ◽  
Theoretical Analyses

Recently proposed models of orientation tuning in layer 4 of cat primary visual cortex (Somers, Nelson, & Sur, 1995; Douglas, Koch, Mahowald, Martin, & Suarez, 1995) rely on widespread inhibitory intracortical connections to suppress the nonoptimal component of a broadly tuned thalamic input, while local excitatory intracortical connections amplify the optimal component. However, new experimental data (Ferster, Chung, & Wheat, 1996) and theoretical analyses (Ferster, 1987; Krukowski, Priebe, & Miller, 1996) show that the temporally modulated component of thalamic input is well tuned and that the cortical circuitry must simply subtract an unmodulated DC component at nonoptimal orientations to obtain sharp tuning. In addition, within a single hypercolumn in layer 4, inhibitory and excitatory layer 4 neurons have approximately equal-sized axonal fields, making the most of their synapses within their own dendritic field (Kisvarday, Martin, Whitteridge, & Somogyi, 1985; Martin & Whitteridge, 1984). We have constructed a model of a single microcolumn in which GABAB inhibition subtracts the DC and controls the sustained response, while GABAA inhibition controls the response to transient and suprathreshold inputs. The model fits experimental data based on stimulation with drifting sine-wave gratings as well as flashed bars, explains a counterintuitive property of the GABAB K+ conductance, and at suboptimal orientations and submaximal contrasts produces an exponential distribution of firing frequencies.

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