scholarly journals Functional ultrasound imaging of deep visual cortex in awake non-human primates

2019 ◽  
Author(s):  
Blaize Kévin ◽  
Gesnik Marc ◽  
Arcizet Fabrice ◽  
Ahnine Harry ◽  
Ferrari Ulisse ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Ocular Dominance ◽  
Functional Responses ◽  
Spatiotemporal Resolution ◽  
Retinotopic Maps ◽  
Visual Areas ◽  
Deep Layers ◽  
Fixation Task ◽  
Passive Fixation ◽  
The Brain

SummaryDeep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed functional Ultrasound (fUS) imaging fUS imaging technique to uncover deep hemodynamic functional responses. Applying fUS imaging on two awake non-human primates performing a passive fixation task, we reconstructed their retinotopic maps down to the deep calcarine and lunate sulci on visual areas (V1, V2 and V3). These maps were acquired in a single hour session with very few stimuli presentation. The spatial resolution of the technology is illustrated by mapping of Ocular Dominance (OD) columns within superficial and deep layers of the primary visual cortex. These acquisitions showed that OD selectivity is mostly present in layer IV but with evidence also in layers II/III and V. The fUS imaging technology therefore provides a new mesoscale approach to map brain activities at high spatiotemporal resolution in awake subjects within the whole depth of the cortex.

scholarly journals Functional ultrasound imaging of deep visual cortex in awake nonhuman primates

2020 ◽  
Vol 117 (25) ◽  
pp. 14453-14463 ◽  
Author(s):  
Kévin Blaize ◽  
Fabrice Arcizet ◽  
Marc Gesnik ◽  
Harry Ahnine ◽  
Ulisse Ferrari ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Nonhuman Primates ◽  
Brain Activity ◽  
Ocular Dominance ◽  
Spatiotemporal Resolution ◽  
Retinotopic Maps ◽  
Visual Tasks ◽  
Deep Layers ◽  
Fixation Task ◽  
Passive Fixation

Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed a functional ultrasound (fUS) technique that enables imaging hemodynamic responses to visual tasks. Using fUS imaging on two awake nonhuman primates performing a passive fixation task, we constructed retinotopic maps at depth in the visual cortex (V1, V2, and V3) in the calcarine and lunate sulci. The maps could be acquired in a single-hour session with relatively few presentations of the stimuli. The spatial resolution of the technology is illustrated by mapping patterns similar to ocular dominance (OD) columns within superficial and deep layers of the primary visual cortex. These acquisitions using fUS suggested that OD selectivity is mostly present in layer IV but with extensions into layers II/III and V. This imaging technology provides a new mesoscale approach to the mapping of brain activity at high spatiotemporal resolution in awake subjects within the whole depth of the cortex.

scholarly journals Homeostatic plasticity mechanisms in mouse V1

2017 ◽  
Vol 372 (1715) ◽  
pp. 20160504 ◽  
Author(s):  
Megumi Kaneko ◽  
Michael P. Stryker
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Neuronal Activity ◽  
Dynamic Range ◽  
Ocular Dominance ◽  
Homeostatic Plasticity ◽  
Ocular Dominance Plasticity ◽  
The Brain

Mechanisms thought of as homeostatic must exist to maintain neuronal activity in the brain within the dynamic range in which neurons can signal. Several distinct mechanisms have been demonstrated experimentally. Three mechanisms that act to restore levels of activity in the primary visual cortex of mice after occlusion and restoration of vision in one eye, which give rise to the phenomenon of ocular dominance plasticity, are discussed. The existence of different mechanisms raises the issue of how these mechanisms operate together to converge on the same set points of activity. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’.

scholarly journals Biological variation in the sizes, shapes and locations of visual cortical areas in the mouse

2018 ◽  
Author(s):  
Jack Waters ◽  
Eric Lee ◽  
Nathalie Gaudreault ◽  
Fiona Griffin ◽  
Jerome Lecoq ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Biological Variation ◽  
Measurement Noise ◽  
Cortical Areas ◽  
Retinotopic Maps ◽  
Visual Areas ◽  
Visual Cortical ◽  
Cortical Visual Areas ◽  
Processing Of Visual Information

ABSTRACTVisual cortex is organized into discrete sub-regions or areas that are arranged into a hierarchy and serve different functions in the processing of visual information. In our previous work, we noted that retinotopic maps of cortical visual areas differed between mice, but did not quantify these differences or determine the relative contributions of biological variation and measurement noise. Here we quantify the biological variation in the size, shape and locations of 11 visual areas in the mouse. We find that there is substantial biological variation in the sizes of visual areas, with some visual areas varying in size by two-fold across the population of mice.

scholarly journals Sonogenetic stimulation of the brain at a spatiotemporal resolution suitable for vision restoration

2021 ◽  
Author(s):  
Sara Cadoni ◽  
Charlie Demene ◽  
Matthieu Provansal ◽  
Diep Nguyen ◽  
Dasha Nelidova ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Neurological Disorders ◽  
Real Life ◽  
Spatiotemporal Resolution ◽  
Brain Machine Interfaces ◽  
Ultrasound Stimulation ◽  
Wide Range ◽  
The Brain ◽  
Stimulation Of

Remote, precisely controlled activation of the brain is a fundamental challenge in the development of brain machine interfaces providing feasible rehabilitation strategies for neurological disorders. Low-frequency ultrasound stimulation can be used to modulate neuronal activity deep in the brain, but this approach lacks spatial resolution and cellular selectivity and loads the brain with high levels of acoustic energy. The combination of the expression of ultrasound-sensitive proteins with ultrasound stimulation (sonogenetic stimulation) can provide cellular selectivity and higher sensitivity, but such strategies have been subject to severe limitations in terms of spatiotemporal resolution in vivo, precluding their use for real-life applications. We used the expression of large-conductance mechanosensitive ion channels (MscL) with high-frequency ultrasonic stimulation for a duration of milliseconds to activate neurons selectively at a relatively high spatiotemporal resolution in the rat retina ex vivo and the primary visual cortex of rodents in vivo. This spatiotemporal resolution was achieved at low energy levels associated with negligible tissue heating and far below those leading to complications in ultrasound neuromodulation. We showed, in an associative learning test, that sonogenetic stimulation of the visual cortex generated light perception. Our findings demonstrate that sonogenetic stimulation is compatible with millisecond pattern presentation for visual restoration at the cortical level. They represent a step towards the precise transfer of information over large distances to the cortical and subcortical regions of the brain via an approach less invasive than that associated with current brain machine interfaces and with a wide range of applications in neurological disorders.

scholarly journals Prior expectations evoke stimulus-specific activity in the deep layers of the primary visual cortex

PLoS Biology ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. e3001023
Author(s):  
Fraser Aitken ◽  
Georgios Menelaou ◽  
Oliver Warrington ◽  
Renée S. Koolschijn ◽  
Nadège Corbin ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Specific Activity ◽  
Predictive Processing ◽  
Cortical Layers ◽  
Computational Architecture ◽  
Deep Layers ◽  
Flow Through ◽  
The Brain ◽  
The Way

The way we perceive the world is strongly influenced by our expectations. In line with this, much recent research has revealed that prior expectations strongly modulate sensory processing. However, the neural circuitry through which the brain integrates external sensory inputs with internal expectation signals remains unknown. In order to understand the computational architecture of the cortex, we need to investigate the way these signals flow through the cortical layers. This is crucial because the different cortical layers have distinct intra- and interregional connectivity patterns, and therefore determining which layers are involved in a cortical computation can inform us on the sources and targets of these signals. Here, we used ultra-high field (7T) functional magnetic resonance imaging (fMRI) to reveal that prior expectations evoke stimulus-specific activity selectively in the deep layers of the primary visual cortex (V1). These findings are in line with predictive processing theories proposing that neurons in the deep cortical layers represent perceptual hypotheses and thereby shed light on the computational architecture of cortex.

scholarly journals Linearly Additive Shape and Color Signals in Monkey Inferotemporal Cortex

2009 ◽  
Vol 101 (4) ◽  
pp. 1867-1875 ◽  
Author(s):  
David B. T. McMahon ◽  
Carl R. Olson
Keyword(s):  
Visual Cortex ◽  
Feature Binding ◽  
Neural Representation ◽  
Inferotemporal Cortex ◽  
Visual Areas ◽  
Color Signals ◽  
Color Combinations ◽  
The Brain ◽  
Effective Representation ◽  
Low Order

How does the brain represent a red circle? One possibility is that there is a specialized and possibly time-consuming process whereby the attributes of shape and color, carried by separate populations of neurons in low-order visual cortex, are bound together into a unitary neural representation. Another possibility is that neurons in high-order visual cortex are selective, by virtue of their bottom-up input from low-order visual areas, for particular conjunctions of shape and color. A third possibility is that they simply sum shape and color signals linearly. We tested these ideas by measuring the responses of inferotemporal cortex neurons to sets of stimuli in which two attributes—shape and color—varied independently. We find that a few neurons exhibit conjunction selectivity but that in most neurons the influences of shape and color sum linearly. Contrary to the idea of conjunction coding, few neurons respond selectively to a particular combination of shape and color. Contrary to the idea that binding requires time, conjunction signals, when present, occur as early as feature signals. We argue that neither conjunction selectivity nor a specialized feature binding process is necessary for the effective representation of shape–color combinations.

scholarly journals Stimulus repetition affects both strength and synchrony of macaque inferior temporal cortical activity

2012 ◽  
Vol 107 (12) ◽  
pp. 3509-3527 ◽  
Author(s):  
Dzmitry A. Kaliukhovich ◽  
Rufin Vogels
Keyword(s):  
Firing Rate ◽  
Response Strength ◽  
Visual Images ◽  
Stimulus Repetition ◽  
Short Term ◽  
Know How ◽  
Repetition Suppression ◽  
Deep Layers ◽  
Fixation Task ◽  
Passive Fixation

Repetition of a visual stimulus reduces the firing rate of macaque inferior temporal (IT) neurons. The neural mechanisms underlying this adaptation or repetition suppression are still unclear. In particular, we do not know how the IT circuit is affected by stimulus repetition. To address this, we measured local field potentials (LFPs) and multiunit spiking activity (MUA) simultaneously at 16 sites with a laminar electrode in IT while repeating visual images. Stimulus exposures and interstimulus intervals were each 500 ms. The rhesus monkeys were performing a passive fixation task during the recordings. Induced LFP power decreased with repetition for spectral frequencies above 60 Hz but increased with repetition for lower frequencies, the latter because of a delayed decrease in power when repeating a stimulus. LFP-LFP and MUA-LFP coherences decreased with repetition for frequencies above 60 Hz. This repetition suppression of the MUA-LFP coherence was not due to differences in firing rate since it was present when spike counts were equated for the adapter and repeated stimuli. For frequencies between 15 and 40 Hz, the effect of repetition on synchronization depended on the electrode depth: For the putative superficial layers synchronization was enhanced with repetition, while the LFPs of the putative deep layers decreased their synchrony across layers. The between-site, trial-to-trial covariations in MUA (“noise correlations”) decreased with repetition, but this might have reflected repetition suppression of the firing rate. This work demonstrates that short-term stimulus repetition affects the synchronized activity, in addition to response strength, in IT cortex.

scholarly journals A twisted visual field map in the primate cortex predicted by topographic continuity

2019 ◽  
Author(s):  
Hsin-Hao Yu ◽  
Declan P. Rowley ◽  
Nicholas S.C. Price ◽  
Marcello G.P. Rosa ◽  
Elizabeth Zavitz
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Receptive Fields ◽  
Electrode Array ◽  
Extrastriate Cortex ◽  
Complex Type ◽  
Retinotopic Maps ◽  
Visual Areas ◽  
Array Recordings ◽  
Retinotopic Map

AbstractAdjacent neurons in visual cortex have overlapping receptive fields within and across area boundaries, an arrangement which is theorized to minimize wiring cost. This constraint is thought to create retinotopic maps of opposing field sign (mirror and non-mirror representations of the visual field) in adjacent visual areas, a concept which has become central in current attempts to subdivide the cortex. We modelled a realistic developmental scenario in which adjacent areas do not mature simultaneously, but need to maintain topographic continuity across their borders. This showed that the same mechanism that is hypothesized to maintain topographic continuity within each area can lead to a more complex type of retinotopic map, consisting of sectors with opposing field sign within a same area. Using fully quantitative electrode array recordings, we then demonstrate that this type of map exists in the primate extrastriate cortex.

scholarly journals Saccade-based termination responses in macaque V1 and visual perception

2018 ◽  
Vol 35 ◽  
Author(s):  
JAMES E. NIEMEYER ◽  
MICHAEL A. PARADISO
Keyword(s):  
Visual Cortex ◽  
Visual Perception ◽  
Firing Rate ◽  
Visual Stimulation ◽  
Saccadic Eye Movement ◽  
Perceptual Sensitivity ◽  
Neural Correlate ◽  
Visual Areas ◽  
Natural Situation ◽  
The Brain

AbstractNeurons in visual areas of the brain are generally characterized by the increase in firing rate that occurs when a stimulus is flashed on in the receptive field (RF). However, neurons also increase their firing rate when a stimulus is turned off. These “termination responses” or “after-discharges” that occur with flashed stimuli have been observed in area V1 and they may be important for vision as stimulus terminations have been shown to influence visual perception. The goal of the present study was to determine the strength of termination responses in the more natural situation in which eye movements move a stimulus out of an RF. We find that termination responses do occur in macaque V1 when termination results from a saccadic eye movement, but they are smaller in amplitude compared to flashed-off stimuli. Furthermore, there are termination responses even in the absence of visual stimulation. These findings demonstrate that termination responses are a component of naturalistic vision. They appear to be based on both visual and nonvisual signals in visual cortex. We speculate that the weakening of termination responses might be a neural correlate of saccadic suppression, the loss of perceptual sensitivity around the time of saccades.

scholarly journals Retinotopic organization of visual cortex in human infants

2020 ◽  
Author(s):  
C. T. Ellis ◽  
T. S. Yates ◽  
L. J. Skalaban ◽  
V. R. Bejjanki ◽  
M. J. Arcaro ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Extrastriate Cortex ◽  
Human Infants ◽  
Early Maturation ◽  
Retinotopic Mapping ◽  
Retinotopic Maps ◽  
Spatial Frequencies ◽  
Visual Areas ◽  
Retinotopic Organization ◽  
Perceptual Abilities

AbstractVision develops rapidly during infancy, yet how visual cortex is organized during this period is unclear. One possibility is that the retinotopic organization of visual cortex emerges gradually as perceptual abilities improve. This may result in a hierarchical maturation of visual areas from striate to extrastriate cortex. Another possibility is that retinotopic organization is present from early infancy. This early maturation of area boundaries and tuning could scaffold further developmental changes. Here we test the functional maturity of infant visual cortex by performing retinotopic mapping with fMRI. Infants aged 5–23 months had retinotopic maps, with alternating preferences for vertical and horizontal meridians indicative of area boundaries from V1 to V4, and an orthogonal gradient of preferences from high to low spatial frequencies indicative of growing receptive field sizes. Although present in the youngest infants, these retinotopic maps showed subtle agerelated changes, suggesting that early maturation undergoes continued refinement.

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