scholarly journals Functional MRI reveals spatially specific attentional modulation in human primary visual cortex

1999 ◽  
Vol 96 (4) ◽  
pp. 1663-1668 ◽  
Author(s):  
D. C. Somers ◽  
A. M. Dale ◽  
A. E. Seiffert ◽  
R. B. H. Tootell
Keyword(s):  
Visual Cortex ◽  
Functional Mri ◽  
Primary Visual Cortex ◽  
Attentional Modulation

Increasing mean airway pressure reduces functional MRI (fMRI) signal in the primary visual cortex

2001 ◽  
Vol 19 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Ingo H. Lorenz ◽  
Christian Kolbitsch ◽  
Christoph Hörmann ◽  
Michael Schocke ◽  
Christian Kremser ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Functional Mri ◽  
Primary Visual Cortex ◽  
Airway Pressure ◽  
Mean Airway Pressure ◽  
Fmri Signal

scholarly journals Dynamic communication of attention signals between the LGN and V1

2018 ◽  
Vol 120 (4) ◽  
pp. 1625-1639 ◽  
Author(s):  
Vanessa L. Mock ◽  
Kimberly L. Luke ◽  
Jacqueline R. Hembrook-Short ◽  
Farran Briggs
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Local Field ◽  
Visual Information ◽  
Local Field Potentials ◽  
Field Potentials ◽  
Information Communication ◽  
Attentional Modulation ◽  
Visual Thalamus ◽  
The Impact

Correlations and inferred causal interactions among local field potentials (LFPs) simultaneously recorded in distinct visual brain areas can provide insight into how visual and cognitive signals are communicated between neuronal populations. Based on the known anatomical connectivity of hierarchically organized visual cortical areas and electrophysiological measurements of LFP interactions, a framework for interareal frequency-specific communication has emerged. Our goals were to test the predictions of this framework in the context of the early visual pathways and to understand how attention modulates communication between the visual thalamus and primary visual cortex. We recorded LFPs simultaneously in retinotopically aligned regions of the visual thalamus and primary visual cortex in alert and behaving macaque monkeys trained on a contrast-change detection task requiring covert shifts in visual spatial attention. Coherence and Granger-causal interactions among early visual circuits varied dynamically over different trial periods. Attention significantly enhanced alpha-, beta-, and gamma-frequency interactions, often in a manner consistent with the known anatomy of early visual circuits. However, attentional modulation of communication among early visual circuits was not consistent with a simple static framework in which distinct frequency bands convey directed inputs. Instead, neuronal network interactions in early visual circuits were flexible and dynamic, perhaps reflecting task-related shifts in attention. NEW & NOTEWORTHY Attention alters the way we perceive the visual world. For example, attention can modulate how visual information is communicated between the thalamus and cortex. We recorded local field potentials simultaneously in the visual thalamus and cortex to quantify the impact of attention on visual information communication. We found that attentional modulation of visual information communication was not static, but dynamic over the time course of trials.

scholarly journals Shape Processing Area LO and Illusory Contours

Perception ◽  
10.1068/p6388 ◽  
2009 ◽  
Vol 38 (8) ◽  
pp. 1260-1263 ◽  
Author(s):  
Lee H de-Wit ◽  
Robert W Kentridge ◽  
A David Milner
Keyword(s):  
Visual Cortex ◽  
Functional Mri ◽  
Primary Visual Cortex ◽  
Visual Illusions ◽  
Visual Area ◽  
Illusory Contours ◽  
Feedback Effects ◽  
Shape Representations ◽  
Shape Processing

Recent functional MRI has demonstrated that illusory contours can activate the primary visual cortex. Our investigation sought to demonstrate whether this correlation reflects computations performed in the primary visual cortex or feedback effects from shape processing area LO. We explored this in a patient who has a bilateral lesion to LO, but a functionally spared V1. Our data indicate that illusory contours are unable to influence behaviour without visual area LO. Whilst we would not claim that our data provide evidence for the ‘cognitive’ nature of illusory contours, they certainly suggest that illusory contours are dependent upon the computations involved in extracting shape representations in LO. Our data highlight the importance of neuropsychological research in interpreting the role of feedforward and feedback effects in the generation of visual illusions.

scholarly journals Separable codes for read-out of mouse primary visual cortex across attentional states

2019 ◽  
Author(s):  
Ashley M. Wilson ◽  
Jeffrey M. Beck ◽  
Lindsey L. Glickfeld
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Activity Patterns ◽  
Specific Effect ◽  
Sensory Cortex ◽  
Evoked Responses ◽  
Attentional Modulation ◽  
Population Activity ◽  
V1 Neurons ◽  
Encode Task

AbstractAttentional modulation of neuronal activity in sensory cortex could alter perception by enhancing the local representation of attended stimuli or its behavioral read-out downstream. We tested these hypotheses using a task in which mice are cued on interleaved trials to attend visual or auditory targets. Neurons in primary visual cortex (V1) that encode task stimuli have larger visually-evoked responses when attention is directed toward vision. To determine whether the attention-dependent changes in V1 reflect changes in representation or read-out, we decoded task stimuli and choices from population activity. Surprisingly, both visual and auditory choices can be decoded from V1, but decoding takes advantage of unique activity patterns across modalities. Furthermore, decoding of choices, but not stimuli, is impaired when attention is directed toward the opposite modality. The specific effect on choice suggests behavioral improvements with attention are largely due to targeted read-out of the most informative V1 neurons.

scholarly journals Remapping of attentional modulation across eye movements in primary visual cortex of the monkey

2010 ◽  
Vol 1 (3) ◽  
pp. 220-220
Author(s):  
P. Khayat ◽  
H. Spekreijse ◽  
P. R. Roelfsema
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Primary Visual Cortex ◽  
Attentional Modulation

Lateral Inhibition Organizes Beta Attentional Modulation in the Primary Visual Cortex

2019 ◽  
Vol 29 (03) ◽  
pp. 1850047
Author(s):  
Elżbieta Gajewska-Dendek ◽  
Andrzej Wróbel ◽  
Marek Bekisz ◽  
Piotr Suffczynski
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Large Scale ◽  
Cross Correlation ◽  
Spatial Organization ◽  
Visual Stimulation ◽  
Attentional Modulation ◽  
Attentional Processing ◽  
Sensory Inputs ◽  
Inhibitory Interactions

We have previously shown that during top-down attentional modulation (stimulus expectation) correlations of the beta signals across the primary visual cortex were uniform, while during bottom-up attentional processing (visual stimulation) their values were heterogeneous. These different patterns of attentional beta modulation may be caused by feed-forward lateral inhibitory interactions in the visual cortex, activated solely during stimulus processing. To test this hypothesis, we developed a large-scale computational model of the cortical network. We first identified the parameter range needed to support beta rhythm generation, and next, simulated the different activity states corresponding to experimental paradigms. The model matched our experimental data in terms of spatial organization of beta correlations during different attentional states and provided a computational confirmation of the hypothesis that the paradigm-specific beta activation spatial maps depend on the lateral inhibitory mechanism. The model also generated testable predictions that cross-correlation values depend on the distance between the activated columns and on their spatial position with respect to the location of the sensory inputs from the thalamus.

scholarly journals Effects of phase regression on high-resolution functional MRI of the primary visual cortex

NeuroImage ◽  
2021 ◽  
Vol 227 ◽  
pp. 117631
Author(s):  
Olivia W Stanley ◽  
Alan B Kuurstra ◽  
L Martyn Klassen ◽  
Ravi S Menon ◽  
Joseph S Gati
Keyword(s):  
Visual Cortex ◽  
High Resolution ◽  
Functional Mri ◽  
Primary Visual Cortex
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