Do we have independent visual streams for perception and action?

Schenk, Thomas; McIntosh, Robert D.

doi:10.1080/17588920903388950

Cited by 243 publications

(182 citation statements)

References 124 publications

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“…Yet apraxic patients have shown appropriate memory-driven reach and grasp movements believed to be reliant on the integration of ventral and dorsal processes (Ietswaart, Carey, Della Sala, & Dijkhuizen, 2001). However, the reliance of memory-driven reach and grasp movements on cross-talk between the two visual pathways has since been questioned; the dorsal stream is believed to play a dominant role in both immediate and delayed action, whilst the role of the ventral stream increases with extended delay of movement onset (Schenk & McIntosh, 2010). Appropriate memory-driven grasping in these patients could therefore be attributable to sufficient information remaining present in the dorsal stream.…”

Section: * Discussionmentioning

confidence: 99%

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

et al. 2016

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This study evaluated whether apraxia can be understood as due to impaired motor representations or motor imagery necessary for appropriate object-use, imitation, and pantomime. The causal role of the left inferior parietal lobe (IPL), which is heavily implicated in apraxia, is also evaluated. These processes are appraised in light of the proposed ventro-dorsal sub-stream of the classic two visual pathway model, where perceptual information from the ventral stream and the dorsal action stream are integrated and essential for object manipulation. Using a task assessing object-use perception, stroke patients with apraxia demonstrated a selective deficit during perceptual decisions reliant on the integration of visible and known object properties to select the appropriate grasp for object-use. This deficit increased with apraxia severity. A dissociation was evident in these patients showing intact non-motoric perceptual decisions regarding the functional semantic relationship between two objects in the absence of the actor (e.g. how a hammer hits a nail). Converging evidence was found using a modified version of the same task in a neuromodulation study that directly targeted the left IPL in healthy participants using transcranial direct current stimulation (tDCS). Application of inhibitory stimulation over the left IPL reduced performance during perceptual decisions regarding object manipulation whilst performance was unaffected during functional semantic decisions. Excitatory stimulation of the left IPL did not affect performance in either task. Combined, these results suggest that the left inferior parietal lobe is critical for motor imagery, and that apraxia may be caused by an inability to use internal motor representations of object manipulation. These results are discussed in terms of motoric and non-motoric perceptual processes and the proposal of an additional ventro-dorsal sub-stream within the dorsal and ventral visual pathways model

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Section: * Discussionmentioning

confidence: 99%

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

et al. 2016

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“…Thus, there have been a number of demonstrations of the involvement of 21 Delay in spatial priming the dorsal stream in delayed action (for a review see Ref. [9]) which suggests that the visual information used for action-guidance, presumably egocentric in nature, is not as transient as was originally claimed. Furthermore, while the differential effects of visual illusions on delayed and immediate motor performance have been taken as evidence that the ventral stream is being used after a delay, it has also been found that the availability of visual feedback may instead explain the differences between immediate and delayed performance [25].…”

Section: Discussionmentioning

confidence: 99%

“…As such it is argued that visuomotor performance depends on the use of egocentric representations [8]; [9]; [10] ; [11]. This current study assesses the claim that egocentric coding leads to very short-lived representations and that these representations are less persistent than those used in allocentric coding.…”

Section: Introductionmentioning

confidence: 98%

Comparing the effect of temporal delay on the availability of egocentric and allocentric information in visual search

Ball

Birch

Lane

et al. 2017

Behavioural Brain Research

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(2017) 'Comparing the e ect of temporal delay on the availability of egocentric and allocentric information in visual search. ', Behavioural brain research., Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractFrames of reference play a central role in perceiving an object's location and reaching to pick that object up. It is thought that the ventral stream, believed to subserve vision for perception, utilises allocentric coding, while the dorsal stream, argued to be responsible for vision for action, primarily uses an egocentric reference frame. We have previously shown that egocentric representations can survive a delay; however, it is possible that in comparison to allocentric information, egocentric information decays more rapidly. Here we directly compare the effect of delay on the availability of egocentric and allocentric representations.We used spatial priming in visual search and repeated the location of the target relative to either a landmark in the search array (allocentric condition) or the observer's body (egocentric condition). Three inter-trial intervals created minimum delays between two consecutive trials of 2, 4, or 8 seconds. In both conditions, search times to primed locations were faster than search times to un-primed locations. In the egocentric condition the effects were driven by a reduction in search times when egocentric information was repeated, an effect that was observed at all three delays. In the allocentric condition while search times did not change when the allocentric information was repeated, search times to un-primed target locations became slower. We conclude that egocentric representations are not as transient as previously thought but instead this information is still available, and can influence behaviour, after lengthy periods of delay. We also discuss the possible origins of the differences between allocentric and egocentric priming effects.

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“…This suggests that the ventral stream is not just critical for allocentric (Schenk 2006) but also for egocentric coding. On the basis of these assumptions we could explain why persistent egocentric representations are found in healthy participants, and this set of Egocentric representations are most often thought of with regard to motor tasks (Westwood et al 2001;Witt et al 2008;Schenk and McIntosh 2010). Therefore, how is using a perceptual task here to investigate the temporal persistence of egocentric information relevant to the real time visuomotor hypothesis?…”

Section: Discussionmentioning

confidence: 99%

Spatial priming in visual search: memory for body-centred information

et al. 2011

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Publisher's copyright statement:The original publication is available at www.springerlink.com Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractSpatial priming allows memory for target locations to be evaluated, whereby when a target appears in the same location across trials participants become more efficient at locating it and consequently their search times decrease. Previously, we reported priming effects when the location of a target was repeated with respect to the participant's body but not when it was repeated relative to their eye position; therefore, suggesting that body-centred information is available after a delay of at least a few seconds (Ball, Smith, Ellison, & Schenk, 2010). However, we were unable to rule out the possibility that stable allocentric cues within the room may have contributed to the priming effects that we observed. In this current study we introduced a condition where, despite participants moving to a new location between trials, their position relative to the target was maintained. This movement disrupted any potential room-based cues about the target location. While we replicated our previous finding of priming when the location of the target was repeated relative to the viewer when no movement was required, we also found robust priming effects when participants moved to a new location in between trials. Thus, we provide clear evidence that in our spatial priming task the location of the target was being coded in a body-centred reference frame and that this information is available after a delay.

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Do we have independent visual streams for perception and action?

Cited by 243 publications

References 124 publications

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

Comparing the effect of temporal delay on the availability of egocentric and allocentric information in visual search

Spatial priming in visual search: memory for body-centred information

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