Results 1 - 10
of
23
Multiple movement representations in the human brain: an event-related fMRI study
- J. Cogn. Neurosci
, 2002
"... & Neurovascular correlates of response preparation have been investigated in human neuroimaging studies. However, conventional neuroimaging cannot distinguish, within the same trial, between areas involved in response selection and/ or response execution and areas specifically involved in respon ..."
Abstract
-
Cited by 21 (5 self)
- Add to MetaCart
(Show Context)
& Neurovascular correlates of response preparation have been investigated in human neuroimaging studies. However, conventional neuroimaging cannot distinguish, within the same trial, between areas involved in response selection and/ or response execution and areas specifically involved in response preparation. The specific contribution of parietal and frontal areas to motor preparation has been explored in electrophysiological studies in monkey. However, the asso-ciative nature of sensorimotor tasks calls for the additional contributions of other cortical regions. In this article, we have investigated the functional anatomy of movement represen-tations in the context of an associative visuomotor task with instructed delays. Neural correlates of movement representa-tions have been assessed by isolating preparatory activity that
Grasping visual illusions: Consistent data and no dissociation
- Cognitive Neuropsychology
, 2008
"... The finding that the Ebbinghaus/Titchener illusion deceives perception but not grasping is usually seen as strong evidence for Goodale and Milner’s (1992) notion of two parallel visual systems, one being conscious and deceived by the illusion (vision-for-perception) and the other being unconscious a ..."
Abstract
-
Cited by 18 (1 self)
- Add to MetaCart
(Show Context)
The finding that the Ebbinghaus/Titchener illusion deceives perception but not grasping is usually seen as strong evidence for Goodale and Milner’s (1992) notion of two parallel visual systems, one being conscious and deceived by the illusion (vision-for-perception) and the other being unconscious and not deceived (vision-for-action). However, this finding is controversial and led to studies with seemingly contradictory results. We argue that these results are not as contradictory as it might seem. Instead, studies consistently show similar effects of the illusion on grasping. The perceptual effects are strongly dependent on the specific perceptual measure employed. If, however, some methodological precautions are used, then these diverse perceptual results can be reconciled and point to a single internal size esti-mate that is used for perception and for grasping. This suggests that the Ebbinghaus illusion deceives a common representation of object size that is used by perception and action.
Perceiving Virtual Geographical Slant: Action . . .
, 2003
"... Four experiments varied the extent and nature of observer movement in a virtual environment to examine the influence of action on estimates of geographical slant. Previous slant studies demonstrated that people consciously overestimate hill slant but can still accurately guide an action toward the h ..."
Abstract
-
Cited by 15 (2 self)
- Add to MetaCart
(Show Context)
Four experiments varied the extent and nature of observer movement in a virtual environment to examine the influence of action on estimates of geographical slant. Previous slant studies demonstrated that people consciously overestimate hill slant but can still accurately guide an action toward the hill (Proffitt, Bhalla, Gossweiler & Midget, 1995). Related studies (Bhalla & Proffitt, 1999) suggest that one s potential to act may influence perception of slant and that distinct representations may independently inform perceptual and motoric responses. We found that in all conditions, perceptual judgments were overestimated and motoric adjustments were more accurate. The virtual environment allowed manipulation of the effort required to walk up simulated hills. Walking with the effort appropriate to the visual slant led to increased perceptual overestimation of slant compared to active walking with effort appropriate to level ground, while visually guided actions remained accurate.
Target detection and localization in visual search: A dual systems perspective
- Perception & Psychophysics
, 2003
"... The dual visual systems framework (Milner & Goodale, 1995) was used to explore target detection and localization in visual search. Observers searched for a small patch of tilted bars against a dense background of upright bars. Target detection was performed along with two different localization ..."
Abstract
-
Cited by 6 (6 self)
- Add to MetaCart
(Show Context)
The dual visual systems framework (Milner & Goodale, 1995) was used to explore target detection and localization in visual search. Observers searched for a small patch of tilted bars against a dense background of upright bars. Target detection was performed along with two different localization tasks: direct pointing, designed to engage the dorsal stream, and indirect pointing, designed to engage the ventral stream. The results indicated that (1) target detection was influenced more by orientation differences in 3-D space than by 2-D pictorial differences, (2) target localization was more accurate for direct than for indirect pointing, and (3) there were performance costs for indirect localization when it followed target detection, but not for direct localization. This is consistent with direct localization’s having greater dependence on the dorsal visual system than either target detection or indirect localization.
The planning and control model (PCM) of motorvisual priming: Reconciling motorvisual impairment and facilitation effects
- Psychological Review
, 2012
"... Previous research on dual-tasks has shown that, under some circumstances, actions impair the perception of action-consistent stimuli, whereas, under other conditions, actions facilitate the perception of actionconsistent stimuli. We propose a new model to reconcile these contrasting findings. The pl ..."
Abstract
-
Cited by 6 (0 self)
- Add to MetaCart
(Show Context)
Previous research on dual-tasks has shown that, under some circumstances, actions impair the perception of action-consistent stimuli, whereas, under other conditions, actions facilitate the perception of actionconsistent stimuli. We propose a new model to reconcile these contrasting findings. The planning and control model (PCM) of motorvisual priming proposes that action planning binds categorical representations of action features so that their availability for perceptual processing is inhibited. Thus, the perception of categorically action-consistent stimuli is impaired during action planning. Movement control processes, on the other hand, integrate multi-sensory spatial information about the movement and, therefore, facilitate perceptual processing of spatially movement-consistent stimuli. We show that the PCM is consistent with a wider range of empirical data than previous models on motorvisual priming. Furthermore, the model yields previously untested empirical predictions. We also discuss how the PCM relates to motorvisual research paradigms other than dual-tasks.
Another look at the two visual systems hypothesis: The argument from illusion studies
- Journal of Consciousness Studies
"... The purpose of this paper is to defend what I call the action-oriented coding theory (ACT) of spatially contentful visual experience. Integral to ACT is the view that conscious visual experience and visually guided action make use of a common subject-relative or ‘egocentric ’ frame of ..."
Abstract
-
Cited by 2 (1 self)
- Add to MetaCart
(Show Context)
The purpose of this paper is to defend what I call the action-oriented coding theory (ACT) of spatially contentful visual experience. Integral to ACT is the view that conscious visual experience and visually guided action make use of a common subject-relative or ‘egocentric ’ frame of
StarTrek illusion–general object constancy phenomenon
, 2012
"... We report a new powerful type of contrast and size illusion caused by apparent motion in depth, which we called the StarTrek illusion. We found that an optic flow pattern consistent with objects moving in depth strongly modulates their apparent contrast. Disks that appeared to move away from the ob ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
We report a new powerful type of contrast and size illusion caused by apparent motion in depth, which we called the StarTrek illusion. We found that an optic flow pattern consistent with objects moving in depth strongly modulates their apparent contrast. Disks that appeared to move away from the observer appeared to grow higher in contrast and larger, while their retinal size and contrast remained constant. We explain this illusion of contrast by the term contrast constancy: Normally, objects lose their contrast when viewed from far away, but when this expected loss does not happen, the brain infers that the physical contrast of the object increases as the object moves away. This is perceived as the illusory increase of the object's contrast. The contrast constancy is largely analogous to the well-known size constancy phenomenon. We discovered that the two phenomena are related. By adjusting the size of the disks during the optic flow motion, the illusory contrast increase could be easily canceled or even reversed. On the other hand, the illusory size increase could not be manipulated the same way by contrast modulation. Our results suggest that the brain may use the same scaling factor to account for the size and contrast change with distance and that the estimated object size affects the contrast calculation.
Conscious Vision in Action
"... It is natural to assume that the fine-grained and highly accurate spatial information present in visual experience is often used to guide our bodily actions. Yet this assumption has been chal-lenged by proponents of the Two Visual Systems Hypothesis (TVSH), according to which visuo-motor programming ..."
Abstract
- Add to MetaCart
(Show Context)
It is natural to assume that the fine-grained and highly accurate spatial information present in visual experience is often used to guide our bodily actions. Yet this assumption has been chal-lenged by proponents of the Two Visual Systems Hypothesis (TVSH), according to which visuo-motor programming is the responsibility of a “zombie ” processing stream whose sources of bottom-up spatial information are entirely non-conscious (Clark, 2007, 2009; Goodale & Milner, 1992, 2004a; Milner & Goodale, 1995/2006, 2008). In many formulations of TVSH, the role of conscious vision in action is limited to “recognizing objects, selecting targets for action, and deter-mining what kinds of action, broadly speaking, to perform ” (Clark, 2007, p. 570). Our aim in this study is to show that the available evidence not only fails to support this dichotomous view but actually reveals a significant role for conscious vision in motor programming, especially for actions that require deliberate attention.
Dynamic modulation of illusory and physical target size on separate and coordinated eye and hand movements
"... ..."
(Show Context)
ii Micro-affordances in Visual Mental Imagery and Visual Short-term
, 2002
"... This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the author's prior consent. ..."
Abstract
- Add to MetaCart
(Show Context)
This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the author's prior consent.
