(Micro)Saccades, corollary activity and cortical oscillations

Melloni, Lucía; Schwiedrzik, Caspar M.; Rodríguez, Eugenio; Singer, Wolf

doi:10.1016/j.tics.2009.03.007

Cited by 93 publications

(103 citation statements)

References 66 publications

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“…Phase resetting, is only one of several possible mechanisms by which visual input could facilitate auditory processing. First, it is not excluded that eye movements (that were only partly monitored in this experiment) could phase-reset auditory activity thereby structuring and facilitating the auditory response (Chandrasekaran et al, 2009;Melloni et al, 2009). Second, our results do not prove that input from motionsensitive cortex is modulatory rather than of feedforward nature.…”

Section: Discussioncontrasting

confidence: 61%

Dual Neural Routing of Visual Facilitation in Speech Processing

Arnal

Morillon²,

Kell³

et al. 2009

J. Neurosci.

222

270

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Viewing our interlocutor facilitates speech perception, unlike for instance when we telephone. Several neural routes and mechanisms could account for this phenomenon. Using magnetoencephalography, we show that when seeing the interlocutor, latencies of auditory responses (M100) are the shorter the more predictable speech is from visual input, whether the auditory signal was congruent or not. Incongruence of auditory and visual input affected auditory responses ϳ20 ms after latency shortening was detected, indicating that initial content-dependent auditory facilitation by vision is followed by a feedback signal that reflects the error between expected and received auditory input (prediction error). We then used functional magnetic resonance imaging and confirmed that distinct routes of visual information to auditory processing underlie these two functional mechanisms. Functional connectivity between visual motion and auditory areas depended on the degree of visual predictability, whereas connectivity between the superior temporal sulcus and both auditory and visual motion areas was driven by audiovisual (AV) incongruence. These results establish two distinct mechanisms by which the brain uses potentially predictive visual information to improve auditory perception. A fast direct corticocortical pathway conveys visual motion parameters to auditory cortex, and a slower and indirect feedback pathway signals the error between visual prediction and auditory input.

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Section: Discussioncontrasting

confidence: 61%

Dual Neural Routing of Visual Facilitation in Speech Processing

Arnal

Morillon²,

Kell³

et al. 2009

J. Neurosci.

222

270

View full text Add to dashboard Cite

show abstract

“…For example, these same recordings revealed that STS neurons are phase-locked to saccadic eye movements, and that the LFP shows a supra-additive phase concentration when the eye movements occur coincident with image onset (19). Thus, the phase coding in gamma that was not locked to stimulus onset could still be locked to the saccadic command signals, consistent with saccade-related synchronization in other visual areas (37)(38)(39)(40)(41)(42). This is just one example of a specialized type of intrinsic activity that interacts with stimulus-driven responses.…”

Section: Discussionmentioning

confidence: 71%

Category-selective phase coding in the superior temporal sulcus

Turesson

Logothetis

Hoffman

2012

Proc. Natl. Acad. Sci. U.S.A.

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Object perception and categorization can occur so rapidly that behavioral responses precede or co-occur with the firing rate changes in the object-selective neocortex. Phase coding could, in principle, support rapid representation of object categories, whereby the first spikes evoked by a stimulus would appear at different phases of an oscillation, depending on the object category. To determine whether object-selective regions of the neo-cortex demonstrate phase coding, we presented images of faces and objects to two monkeys while recording local field potentials (LFP) and single unit activity from object-selective regions in the upper bank superior temporal sulcus. Single units showed preferred phases of firing that depended on stimulus category, emerging with the initiation of spiking responses after stimulus onset. Differences in phase of firing were seen below 20 Hz and in the gamma and high-gamma frequency ranges. For all but the <20-Hz cluster, phase differences remained category-specific even when controlling for stimulus-locked activity, revealing that phase-specific firing is not a simple consequence of category-specific differences in the evoked responses of the LFP. In addition, we tested for firing rate-to-phase conversion. Category-specific differences in firing rates accounted for 30-40% of the explained variance in phase occurring at lower frequencies (<20 Hz) during the initial response, but was limited (<20% of the explained variance) in the 30-to 60-Hz frequency range, suggesting that gamma phase-of-firing effects reflect more than evoked LFP and firing rate responses. The present results are consistent with theoretical models of rapid object processing and extend previous observations of phase coding to include object-selective neocortex.category coding | primate | visual perception A rtificial systems have yet to replicate the speed and accuracy of our ability to categorize objects. One challenge has been to understand how the visual system accomplishes such a task, when the speed of recognition (<200 ms) is estimated to accommodate approximately one spike per neuron in a feed-forward "sweep" through the visual system (1-4). Prima facie, such a fast reaction time seems incompatible with the typical ratecoding scheme used to describe neural discrimination of object categories. Given these considerations, the fastest and smallest temporal window for decoding in face/object-selective cells in inferior temporal cortex (IT) would be ∼100-150 ms after stimulus onset. In contrast, rate-based decoding is typically based on windows of 50-500 ms (5, 6), positioned 100 ms after stimulus onset (7,8). Considering that downstream movement planning is still needed, this suggests that some categorization behaviors are occurring during the neural responses thought to underlie them. As a consequence of this temporal bottleneck, several alternative schemes have emerged to accommodate rapid coding in face-and object-selective cells.One of these alternative schemes is phase coding, or phase-offiring coding, invol...

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“…Neural modulation by attention Schroeder and Lakatos, 2009) and saccadic eye movements (Rajkai et al, 2008;Melloni et al, 2009;Schroeder et al, 2010) is seen in early sensory areas as an increase is the consistency of LFP phase over trials. In light of these results, we examined whether LFP phase in uSTS would show an increase in consistency across trials (i.e., phase concentration) when locked to fixation onset.…”

Section: Phase Concentration Following Fixation Onsetmentioning

confidence: 99%

“…In this way, saccades have been posited to provide a reset or preparatory signal to the visual system (Melloni et al, 2009;Schroeder et al, 2010), acting as a tabula rasa for representation of local (high spatial frequency) image patches (Gutkin et al, 2001;Kupper et al, 2005) and removing contamination of the neural responses to preceding visual stimuli. Although this is an attractive framework for interpreting the effect of SEMs on early visual areas (but see Gawne and Woods, 2003;MacEvoy et al, 2008), it is unlikely that object recognition operates on such context-free (or history-free) representations of retinal images.…”

Section: Active Vision and Object Recognition In Natural Imagesmentioning

confidence: 99%

Saccades during Object Viewing Modulate Oscillatory Phase in the Superior Temporal Sulcus

et al. 2011

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Saccadic eye movements (SEMs) are the primary means of gating visual information in primates and strongly influence visual perception. The active exploration of the visual environment ("active vision") via SEMs produces suppression during saccades and enhancement afterward (i.e., during fixation) in occipital visual areas. In lateral temporal lobe visual areas, the influence, if any, of eye movements is less well understood, despite the necessity of these areas for forming coherent percepts of objects. The upper bank of the superior temporal sulcus (uSTS) is one such area whose sensitivity to SEMs is unknown. We therefore examined how saccades modulate local field potentials (LFPs) in the uSTS of macaque monkeys while they viewed face and nonface object stimuli. LFP phase concentration increased following fixation onset in the alpha (8 -14 Hz), beta (14 -30 Hz), and gamma (30 -60 Hz) bands and was distinct from the image-evoked response.

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(Micro)Saccades, corollary activity and cortical oscillations

Cited by 93 publications

References 66 publications

Dual Neural Routing of Visual Facilitation in Speech Processing

Dual Neural Routing of Visual Facilitation in Speech Processing

Category-selective phase coding in the superior temporal sulcus

Saccades during Object Viewing Modulate Oscillatory Phase in the Superior Temporal Sulcus

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