The role of early visual cortex (V1/V2) in conscious and unconscious visual perception

Koivisto, Mika; Mäntylä, Teemu; Silvanto, Juha

doi:10.1016/j.neuroimage.2010.02.042

Cited by 83 publications

(96 citation statements)

References 44 publications

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“…Previous TMS studies (Pascual-Leone and Walsh, 2001;Silvanto et al, 2005a,b;Koivisto et al, 2010) have shown that the activity of early visual cortex is necessary for subjective perception of motion after the activity of MT/V5, suggesting a role for recurrent processing along the dorsal stream in motion perception. The present study suggests that recurrent interactions also play a causal role along the ventral stream (the object recognition pathway) contributing to categorization and perception of natural images.…”

Section: Discussionmentioning

confidence: 94%

“…In humans, most of the causal evidence for recurrent processing comes from the dorsal stream; it has been shown that the contribution of early visual areas (V1/V2) is critical for motion perception after the activation of MT/V5 (Pascual-Leone and Walsh, 2001;Silvanto et al, 2005a,b;Koivisto et al, 2010). Causal evidence for the involvement of recurrent processing between early and later areas along the ventral stream is still lacking.…”

Section: Introductionmentioning

confidence: 99%

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Recurrent Processing in V1/V2 Contributes to Categorization of Natural Scenes

Koivisto¹,

Railo²,

Revonsuo³

et al. 2011

J. Neurosci.

101

100

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Humans are able to categorize complex natural scenes very rapidly and effortlessly, which has led to an assumption that such ultra-rapid categorization is driven by feedforward activation of ventral brain areas. However, recent accounts of visual perception stress the role of recurrent interactions that start rapidly after the activation of V1. To study whether or not recurrent processes play a causal role in categorization, we applied fMRI-guided transcranial magnetic stimulation on early visual cortex (V1/V2) and lateral occipital cortex (LO) while the participants categorized natural images as containing animals or not. The results showed that V1/V2 contributed to categorization speed and to subjective perception during a long activity period before and after the contribution of LO had started. This pattern of results suggests that recurrent interactions in visual cortex between areas along the ventral stream and striate cortex play a causal role in categorization and perception of natural scenes.

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Recurrent Processing in V1/V2 Contributes to Categorization of Natural Scenes

Koivisto¹,

Railo²,

Revonsuo³

et al. 2011

J. Neurosci.

101

100

View full text Add to dashboard Cite

show abstract

“…The resulting mean intensity of stimulation during the experiment was 52.5% (SD ϭ 5.3%) of maximum stimulator output. We used jumps of 5% to minimize the time to find the phosphene threshold as in previous studies (Koivisto et al 2010). However, it is important to note that this procedure may have slightly overestimated the phosphene threshold with up to 4%.…”

Section: Methodsmentioning

confidence: 99%

“…To ensure that subjects do not consciously adjust their criteria to compensate for the change in signal variability, ideally, the difference between the conditions of interest should be subtle and mainly focused on increasing variability in one of the conditions. Although transcranial magnetic stimulation (TMS) to the visual cortex is often used to completely "knock out" conscious perception (e.g., Boyer et al 2005;Breitmeyer et al 2004;Kastner et al 1998;Koivisto et al 2010Koivisto et al , 2011Ro et al 2004), some recent studies have shown that low-intensity stimulation can effectively inject noise to the visual system (Ruzzoli et al 2010;Schwarzkopf et al 2011; although, see Harris et al 2008;Ruzzoli et al 2011). In the present study, we applied single-pulse TMS at an intensity below the threshold for the conscious perception of phosphenes.…”

mentioning

confidence: 88%

Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence

Rahnev

Maniscalco

Luber

et al. 2012

Journal of Neurophysiology

120

131

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Rahnev DA, Maniscalco B, Luber B, Lau H, Lisanby SH. Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence. J Neurophysiol 107: 1556 -1563, 2012. First published December 14, 2011 doi:10.1152/jn.00985.2011The relationship between accuracy and confidence in psychophysical tasks traditionally has been assumed to be mainly positive, i.e., the two typically increase or decrease together. However, recent studies have reported examples of exceptions, where confidence and accuracy dissociate from each other. Explanations for such dissociations often involve dual-channel models, in which a cortical channel contributes to both accuracy and confidence, whereas a subcortical channel only contributes to accuracy. Here, we show that a single-channel model derived from signal detection theory (SDT) can also account for such dissociations. We applied transcranial magnetic stimulation (TMS) to the occipital cortex to disrupt the internal representation of a visual stimulus. The results showed that consistent with previous research, occipital TMS decreased accuracy. However, counterintuitively, it also led to an increase in confidence ratings. The data were predicted well by a single-channel SDT model, which posits that occipital TMS increased the variance of the internal stimulus distributions. A formal model comparison analysis that used information theoretic methods confirmed that this model was preferred over single-channel models, in which occipital TMS changed the signal strength or dual-channel models, which assume two different processing routes. Thus our results show that dissociations between accuracy and confidence can, at least in some cases, be accounted for by a single-channel model.

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“…In fact transcranial magnetic stimulation (TMS) studies (22-26) reported that single-pulse TMS applied over primary visual areas produces significant perceptual impairment in two distinct time windows: an early one and a late one, relative to the presentation of a visual stimulus. The perception impairment caused by stimulation during the second (late) time window was interpreted as a consequence of an interference with a top-down reactivation of V1 (27,28). A TMS study by Pascual-Leone and Walsh (29) demonstrated that stimulation of area MT/V5 applied 30 ms before the stimulation of V1 affects the activity of this latter region, making participants perceive still rather than moving phosphenes.…”

mentioning

confidence: 99%

Spatiotemporal dynamics in understanding hand—object interactions

Avanzini

Fabbri-Destro

Campi

et al. 2013

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

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It is generally accepted that visual perception results from the activation of a feed-forward hierarchy of areas, leading to increasingly complex representations. Here we present evidence for a fundamental role of backward projections to the occipitotemporal region for understanding conceptual object properties. The evidence is based on two studies. In the first study, using highdensity EEG, we showed that during the observation of how objects are used there is an early activation of occipital and temporal areas, subsequently reaching the pole of the temporal lobe, and a late reactivation of the visual areas. In the second study, using transcranial magnetic stimulation over the occipital lobe, we showed a clear impairment in the accuracy of recognition of how objects are used during both early activation and, most importantly, late occipital reactivation. These findings represent strong neurophysiological evidence that a top-down mechanism is fundamental for understanding conceptual object properties, and suggest that a similar mechanism might be also present for other higher-order cognitive functions.object use understanding | top-down effect | conceptual knowledge C lassic studies on the neural basis of visual perception showed that neurons located in progressively higher cortical visual areas in the macaque monkey show increasingly complex properties (1-5). On the basis of these findings, it was proposed that neural substrate crucial for visual perception is represented by the higher-order visual areas of the inferior temporal lobe (6-8). Functional MRI (fMRI) data obtained in humans confirmed these findings (9, 10). These data also suggested that the temporal lobe poles are an even higher integration center, where conceptual object properties (e.g., how an object is commonly used) are represented (11-13).Visual information processing has been classically considered to be a feed-forward processing, with perception occurring when the areas at the top of the network become active (6, 14-16). On the other hand, rich anatomical evidence shows that there are massive feedback connections going from higher-order areas back to lower-order areas of the visual ventral stream (17-21). Physiological data also provide evidence for cross-talk between visual areas located at different hierarchical level. In fact transcranial magnetic stimulation (TMS) studies (22-26) reported that single-pulse TMS applied over primary visual areas produces significant perceptual impairment in two distinct time windows: an early one and a late one, relative to the presentation of a visual stimulus. The perception impairment caused by stimulation during the second (late) time window was interpreted as a consequence of an interference with a top-down reactivation of V1 (27,28). A TMS study by Pascual-Leone and Walsh (29) demonstrated that stimulation of area MT/V5 applied 30 ms before the stimulation of V1 affects the activity of this latter region, making participants perceive still rather than moving phosphenes. An analogous cross-talking ef...

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The role of early visual cortex (V1/V2) in conscious and unconscious visual perception

Cited by 83 publications

References 44 publications

Recurrent Processing in V1/V2 Contributes to Categorization of Natural Scenes

Recurrent Processing in V1/V2 Contributes to Categorization of Natural Scenes

Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence

Spatiotemporal dynamics in understanding hand—object interactions

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