scholarly journals Optogenetically induced low-frequency correlations impair perception

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Anirvan Nandy ◽  
Jonathan J Nassi ◽  
Monika P Jadi ◽  
John Reynolds
Keyword(s):  
Sensory Processing ◽  
Receptive Fields ◽  
Low Frequency ◽  
Spatial Location ◽  
Covert Attention ◽  
Neuronal Responses ◽  
Substantial Fraction ◽  
Optical Stimulation ◽  
Area V4 ◽  
Stimulation Of

Deployment of covert attention to a spatial location can cause large decreases in low-frequency correlated variability among neurons in macaque area V4 whose receptive-fields lie at the attended location. It has been estimated that this reduction accounts for a substantial fraction of the attention-mediated improvement in sensory processing. These estimates depend on assumptions about how population signals are decoded and the conclusion that correlated variability impairs perception, is purely hypothetical. Here we test this proposal directly by optogenetically inducing low-frequency fluctuations, to see if this interferes with performance in an attention-demanding task. We find that low-frequency optical stimulation of neurons in V4 elevates correlations among pairs of neurons and impairs the animal’s ability to make fine sensory discriminations. Stimulation at higher frequencies does not impair performance, despite comparable modulation of neuronal responses. These results support the hypothesis that attention-dependent reductions in correlated variability contribute to improved perception of attended stimuli.

scholarly journals Optogenetically induced low-frequency correlations impair perception

2018 ◽  
Author(s):  
Anirvan S. Nandy ◽  
Jonathan J. Nassi ◽  
John H. Reynolds
Keyword(s):  
Sensory Processing ◽  
Receptive Fields ◽  
Low Frequency ◽  
Spatial Location ◽  
Covert Attention ◽  
Neuronal Responses ◽  
Substantial Fraction ◽  
Optical Stimulation ◽  
Area V4 ◽  
Stimulation Of

AbstractDeployment of covert attention to a spatial location can cause large decreases in low-frequency correlated variability among neurons in macaque area V4 whose receptive-fields lie at the attended location. It has been estimated that this reduction accounts for a substantial fraction of the attention-mediated improvement in sensory processing. These estimates depend on assumptions about how population signals are decoded and the conclusion that correlated variability impairs perception, is purely hypothetical. Here we test this proposal directly by optogenetically inducing low-frequency fluctuations, to see if this interferes with performance in an attention-demanding task. We find that low‐ frequency optical stimulation of neurons in V4 elevates correlations among pairs of neurons and impairs the animal’s ability to make fine sensory discriminations. Stimulation at higher frequencies does not impair performance, despite comparable modulation of neuronal responses. These results support the hypothesis that attention-dependent reductions in correlated variability contribute to improved perception of attended stimuli.

scholarly journals Attention operates uniformly throughout the classical receptive field and the surround

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Bram-Ernst Verhoef ◽  
John HR Maunsell
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Field Structure ◽  
Neuronal Responses ◽  
Large Variability ◽  
Area V4 ◽  
Classical Receptive Field ◽  
Spatially Varying

Shifting attention among visual stimuli at different locations modulates neuronal responses in heterogeneous ways, depending on where those stimuli lie within the receptive fields of neurons. Yet how attention interacts with the receptive-field structure of cortical neurons remains unclear. We measured neuronal responses in area V4 while monkeys shifted their attention among stimuli placed in different locations within and around neuronal receptive fields. We found that attention interacts uniformly with the spatially-varying excitation and suppression associated with the receptive field. This interaction explained the large variability in attention modulation across neurons, and a non-additive relationship among stimulus selectivity, stimulus-induced suppression and attention modulation that has not been previously described. A spatially-tuned normalization model precisely accounted for all observed attention modulations and for the spatial summation properties of neurons. These results provide a unified account of spatial summation and attention-related modulation across both the classical receptive field and the surround.

Attention to Both Space and Feature Modulates Neuronal Responses in Macaque Area V4

2000 ◽  
Vol 83 (3) ◽  
pp. 1751-1755 ◽  
Author(s):  
Carrie J. McAdams ◽  
John H. R. Maunsell
Keyword(s):  
Rhesus Monkeys ◽  
Cortical Area ◽  
Neuronal Response ◽  
Spatial Location ◽  
Neuronal Responses ◽  
Directed Attention ◽  
Macaque Monkeys ◽  
Area V4 ◽  
Electrophysiological Studies ◽  
Psychological Experiments

Attention is the mechanism with which we select specific aspects of our environment for processing. Psychological experiments have shown that attention can be directed to a spatial location or to a particular object. Electrophysiological studies in trained macaque monkeys have found that attention can strengthen the responses of neurons in cortical area V4. Some of these studies have attributed these effects to spatial attention, whereas others have suggested that feature-directed attention may modulate the neuronal response. Here we report that neuronal correlates for both spatial and feature-directed attention exist in individual neurons in area V4 of behaving rhesus monkeys.

scholarly journals Neural mechanisms mediating responses to abutting gratings: Luminance edgesvs.illusory contours

2006 ◽  
Vol 23 (2) ◽  
pp. 181-199 ◽  
Author(s):  
YUNING SONG ◽  
CURTIS L. BAKER
Keyword(s):  
Spatial Scales ◽  
Receptive Fields ◽  
Low Frequency ◽  
Neuronal Responses ◽  
Motion Direction ◽  
Frequency Responses ◽  
Energy Mechanism ◽  
Nonlinear Responses ◽  
Spatial Frequencies ◽  
Visual Mechanism

The discontinuities of phase-shifted abutting line gratings give rise to perception of an “illusory contour” (IC) along the line terminations. Neuronal responses to such ICs have been interpreted as evidence for a specialized visual mechanism, since such responses cannot be predicted from conventional linear receptive fields. However, when the spatial scale of the component gratings (carriers) is large compared to the neuron's luminance passband, these IC responses might be evoked simply by the luminance edges at the line terminations. Thus by presenting abutting gratings at a series of carrier spatial scales to cat A18 neurons, we were able to distinguish genuine nonlinear responses from those due to luminance edges. Around half of the neurons (both simple and complex types) showed a bimodal response pattern to abutting gratings: one peak at a low carrier spatial frequency range that overlapped with the luminance passband, and a second distinct peak at much higher frequencies beyond the neuron's grating resolution. For those bimodally responding neurons, the low-frequency responses were sensitive to carrier phase, but the high-frequency responses were phase-invariant. Thus the responses at low carrier spatial frequencies could be understoodviaa linear model, while the higher frequency responses represented genuine nonlinear IC processing. IC responsive neurons also demonstrated somewhat lower spatial preference to the periodic contours (envelopes) compared to gratings, but the optimal orientation and motion direction for both were quite similar. The nonlinear responses to ICs could be explained by the same energy mechanism underlying responses to second-order stimuli such as contrast-modulated gratings. Similar neuronal preferences for ICs and for gratings may contribute to the form-cue invariant perception of moving contours.

scholarly journals Attention selectively gates afferent signal transmission to area V4

2015 ◽  
Author(s):  
Iris Grothe ◽  
David Rotermund ◽  
Simon D. Neitzel ◽  
Sunita Mandon ◽  
Udo A. Ernst ◽  
...  
Keyword(s):  
Selective Attention ◽  
Cortical Neurons ◽  
Signal Transmission ◽  
Receptive Fields ◽  
Low Frequency ◽  
Area V4 ◽  
Gating Mechanism ◽  
V4 Neurons ◽  
Visual Cortical ◽  
Signal Routing

Selective attention causes visual cortical neurons to act as if only one of multiple stimuli are within their receptive fields. This suggests that attention employs a, yet unknown, neuronal gating mechanism for transmitting only the information that is relevant for the current behavioral context. We introduce an experimental paradigm to causally investigate this putative gating and the mechanism underlying selective attention by determining the signal availability of two time-varying stimuli in local field potentials of V4 neurons. We find transmission of the low frequency (<20Hz) components only from the attended visual input signal and that the higher frequencies from both stimuli are attenuated. A minimal model implementing routing by synchrony replicates the attentional gating effect and explains the spectral transfer characteristics of the signals. It supports the proposal that selective gamma-band synchrony subserves signal routing in cortex and further substantiates our experimental finding that attention selectively gates signals already at the level of afferent synaptic input.

scholarly journals Deep Brain Stimulation of the Posterior Insula in Chronic Pain: A Theoretical Framework

2021 ◽  
Vol 11 (5) ◽  
pp. 639
Author(s):  
David Bergeron ◽  
Sami Obaid ◽  
Marie-Pierre Fournier-Gosselin ◽  
Alain Bouthillier ◽  
Dang Khoa Nguyen
Keyword(s):  
Chronic Pain ◽  
Electrical Stimulation ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
High Frequency ◽  
Brain Lesion ◽  
Low Frequency ◽  
Posterior Insula ◽  
Deep Brain ◽  
Stimulation Of

Introduction: To date, clinical trials of deep brain stimulation (DBS) for refractory chronic pain have yielded unsatisfying results. Recent evidence suggests that the posterior insula may represent a promising DBS target for this indication. Methods: We present a narrative review highlighting the theoretical basis of posterior insula DBS in patients with chronic pain. Results: Neuroanatomical studies identified the posterior insula as an important cortical relay center for pain and interoception. Intracranial neuronal recordings showed that the earliest response to painful laser stimulation occurs in the posterior insula. The posterior insula is one of the only regions in the brain whose low-frequency electrical stimulation can elicit painful sensations. Most chronic pain syndromes, such as fibromyalgia, had abnormal functional connectivity of the posterior insula on functional imaging. Finally, preliminary results indicated that high-frequency electrical stimulation of the posterior insula can acutely increase pain thresholds. Conclusion: In light of the converging evidence from neuroanatomical, brain lesion, neuroimaging, and intracranial recording and stimulation as well as non-invasive stimulation studies, it appears that the insula is a critical hub for central integration and processing of painful stimuli, whose high-frequency electrical stimulation has the potential to relieve patients from the sensory and affective burden of chronic pain.

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