scholarly journals Prism adaptation does not alter configural processing of faces

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 215 ◽  
Author(s):  
Janet H. Bultitude ◽  
Paul E. Downing ◽  
Robert D. Rafal
Keyword(s):  
Spatial Attention ◽  
Brain Lesion ◽  
Dorsal Stream ◽  
Visual Image ◽  
Prism Adaptation ◽  
Therapeutic Effects ◽  
Sensorimotor Training ◽  
Composite Face ◽  
Face Task ◽  
Healthy Participants

Patients with hemispatial neglect (‘neglect’) following a brain lesion show difficulty responding or orienting to objects and events on the left side of space. Substantial evidence supports the use of a sensorimotor training technique called prism adaptation as a treatment for neglect. Reaching for visual targets viewed through prismatic lenses that induce a rightward shift in the visual image results in a leftward recalibration of reaching movements that is accompanied by a reduction of symptoms in patients with neglect. The understanding of prism adaptation has also been advanced through studies of healthy participants, in whom adaptation to leftward prismatic shifts results in temporary neglect-like performance. Interestingly, prism adaptation can also alter aspects of non-lateralised spatial attention. We previously demonstrated that prism adaptation alters the extent to which neglect patients and healthy participants process local features versus global configurations of visual stimuli. Since deficits in non-lateralised spatial attention are thought to contribute to the severity of neglect symptoms, it is possible that the effect of prism adaptation on these deficits contributes to its efficacy. This study examines the pervasiveness of the effects of prism adaptation on perception by examining the effect of prism adaptation on configural face processing using a composite face task. The composite face task is a persuasive demonstration of the automatic global-level processing of faces: the top and bottom halves of two familiar faces form a seemingly new, unknown face when viewed together. Participants identified the top or bottom halves of composite faces before and after prism adaptation. Sensorimotor adaptation was confirmed by significant pointing aftereffect, however there was no significant change in the extent to which the irrelevant face half interfered with processing. The results support the proposal that the therapeutic effects of prism adaptation are limited to dorsal stream processing.

scholarly journals Prism adaptation does not alter object-based attention in healthy participants

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 232 ◽  
Author(s):  
Janet H. Bultitude ◽  
Alexandra List ◽  
Anne M. Aimola Davies
Keyword(s):  
Visual Image ◽  
Prism Adaptation ◽  
Hemispatial Neglect ◽  
Clinical Tests ◽  
After Effects ◽  
Object Based ◽  
Improved Performance ◽  
The Right ◽  
The Brain ◽  
Healthy Participants

Hemispatial neglect (‘neglect’) is a disabling condition that can follow damage to the right side of the brain, in which patients show difficulty in responding to or orienting towards objects and events that occur on the left side of space. Symptoms of neglect can manifest in both space- and object-based frames of reference. Although patients can show a combination of these two forms of neglect, they are considered separable and have distinct neurological bases. In recent years considerable evidence has emerged to demonstrate that spatial symptoms of neglect can be reduced by an intervention called prism adaptation. Patients point towards objects viewed through prismatic lenses that shift the visual image to the right. Approximately five minutes of repeated pointing results in a leftward recalibration of pointing and improved performance on standard clinical tests for neglect. The understanding of prism adaptation has also been advanced through studies of healthy participants, in whom adaptation to leftward prismatic shifts results in temporary neglect-like performance. Here we examined the effect of prism adaptation on the performance of healthy participants who completed a computerised test of space- and object-based attention. Participants underwent adaptation to leftward- or rightward-shifting prisms, or performed neutral pointing according to a between-groups design. Significant pointing after-effects were found for both prism groups, indicating successful adaptation. In addition, the results of the computerised test revealed larger reaction-time costs associated with shifts of attention between two objects compared to shifts of attention within the same object, replicating previous work. However there were no differences in the performance of the three groups, indicating that prism adaptation did not influence space- or object-based attention for this task. When combined with existing literature, the results are consistent with the proposal that prism adaptation may only perturb cognitive functions for which normal baseline performance is already biased.

scholarly journals Holistic face processing is influenced by non-conscious visual information

2021 ◽  
Author(s):  
Haiyang Jin ◽  
Matt Oxner ◽  
Paul Michael Corballis ◽  
William Hayward
Keyword(s):  
Face Perception ◽  
Face Processing ◽  
Visual Information ◽  
Irrelevant Information ◽  
Composite Effect ◽  
Continuous Flash Suppression ◽  
Facial Information ◽  
Holistic Face Processing ◽  
Composite Face ◽  
Face Task

Holistic face processing has been widely implicated in conscious face perception. Yet, little is known about whether holistic face processing occurs when faces are processed unconsciously. The present study used the composite face task and continuous flash suppression (CFS) to inspect whether the processing of target facial information (the top half of a face) is influenced by irrelevant information (the bottom half) that is presented unconsciously. Results of multiple experiments showed that the composite effect was observed in both the monocular and CFS conditions, providing the first evidence that the processing of top facial halves is influenced by the aligned bottom halves no matter whether they are presented consciously or unconsciously. However, much of the composite effect for faces without masking was disrupted when bottom facial parts were rendered with CFS. These results suggest that holistic face processing can occur unconsciously, but also highlight the significance of holistic processing of consciously presented faces.

scholarly journals Measuring Gaze and Arrow Cuing Effects With a Short Test Adapted to Brain Damaged Patients With Unilateral Spatial Neglect: A Preliminary Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Rindra Narison ◽  
Marie de Montalembert ◽  
Andrew Bayliss ◽  
Laurence Conty
Keyword(s):  
Older Patients ◽  
Brain Lesion ◽  
Brain Lesions ◽  
Spatial Neglect ◽  
Short Version ◽  
Unilateral Spatial Neglect ◽  
Right Brain ◽  
Short Test ◽  
Preliminary Study ◽  
Healthy Participants

People with left unilateral spatial neglect (USN) following a right brain lesion show difficulty in orienting their attention toward stimuli presented on the left. However, cuing the stimuli with gaze direction or a pointing arrow can help some of them to compensate for this difficulty. In order to build a tool that helps to identify these patients, we needed a short version of the paradigm classically used to test gaze and arow cuing effects in healthy adults, adapted to the capacities of patients with severe attention deficit. Here, we tested the robustness of the cuing effects measured by such a short version in 48 young adult healthy participants, 46 older healthy participants, 10 patients with left USN following a right brain lesion (USN+), and 10 patients with right brain lesions but no USN (USN–). We observed gaze and arrow cuing effects in all populations, independently of age and presence or absence of a right brain lesion. In the neglect field, the USN+ group showed event greater cuing effect than older healthy participants and the USN– group. We showed that gaze and arrow cuing effects are powerful enough to be detected in a very short test adapted to the capacities of older patients with severe attention deficits, which increases their applicability in rehabilitation settings. We further concluded that our test is a suitable basis to develop a tool that will help neuropsychologists to identify USN patients who respond to gaze and/or arrow cuing in their neglect field.

scholarly journals Long lasting reduction of postural asymmetry by prism adaptation after right brain lesion without neglect

2015 ◽  
Vol 58 ◽  
pp. e109
Author(s):  
A. Hugues ◽  
J. Di Marco ◽  
M. Lunven ◽  
S. Jacquin-Courtois ◽  
Y. Rossetti ◽  
...  
Keyword(s):  
Brain Lesion ◽  
Prism Adaptation ◽  
Postural Asymmetry ◽  
Right Brain

scholarly journals Shape effects on reflexive spatial attention are driven by the dorsal stream

2012 ◽  
Vol 55 ◽  
pp. 32-40 ◽  
Author(s):  
Stuart D. Red ◽  
Saumil S. Patel ◽  
Anne B. Sereno
Keyword(s):  
Spatial Attention ◽  
Dorsal Stream ◽  
Shape Effects

scholarly journals Influence of Perceptual Discriminability and Spatial Distance on Holistic Processing of Faces

2021 ◽  
Vol 12 ◽  
Author(s):  
Chao-Chih Wang ◽  
Gary C.-W. Shyi ◽  
Peter Kuan-Hao Cheng
Keyword(s):  
Face Recognition ◽  
Face Perception ◽  
Spatial Perception ◽  
Holistic Processing ◽  
Spatial Distance ◽  
Perceptual Discrimination ◽  
The Face ◽  
Underlying Mechanisms ◽  
Composite Face ◽  
Face Task

Background: Holistic processing is defined as the perceptual integration of facial features, and plays an important role in face recognition. While researchers recognize the crucial role played by holistic processing in face perception, a complete delineation of the underlying mechanisms is impending. Very few studies have examined the effects of perceptual discrimination and spatial perception on holistic processing. Hence, the present study aimed to examine the influence of perceptual discrimination and spatial perception on face recognition.Methods: We conducted two experiments by manipulating the perceptual discriminability of the target (the top-half faces) and non-target face (the bottom-half faces) parts in the composite-face task and examined how perceptual discriminability may affect holistic processing of faces.Results: The results of Experiment 1 illustrated that holistic processing was modulated by the perceptual discriminability of the face. Furthermore, differential patterns of perceptual discriminability with the target and non-target parts suggested that different mechanisms may be responsible for the influence of target and non-target parts on face perception. The results of Experiment 2 illustrated that holistic processing was modulated by spatial distance between two faces, implicating that feature-by-feature strategy might decrease the magnitude of holistic processing.Conclusion: The results of the present study suggest that holistic processing may lead to augmented perception effect exaggerating the differences between the two faces and may also be affected by the feature-by-feature strategy.

scholarly journals Unchanged EEG correlates of covert visual spatial attention after prism adaptation in healthy subjects

2018 ◽  
Author(s):  
Marjolein van der Waal ◽  
Inez Wijnands ◽  
Jason Farquhar
Keyword(s):  
Spatial Attention ◽  
Healthy Subjects ◽  
Prism Adaptation ◽  
Attention Task ◽  
Visual Spatial Attention ◽  
Visual Spatial ◽  
Brain Signals ◽  
Before And After ◽  
Behavioural Performance ◽  
P3 Component

Behavioural effects of prism adaptation in healthy subjects and neglect patients suggest a link between prism adaptation and spatial attention. A recent study found an effect of prism adaptation on several EEG correlates of spatial attention, but for two other correlates (the P3 component of the oddball ERP and alpha lateralization), the relationship remained unclear. In the current experiment, 10 healthy subjects performed a visual spatial attention task which was optimized for eliciting these two brain signals. This task was performed before and after adaptation to prism glasses with a leftward optical deviation. While prism adaptation induced a rightward bias on a pointing task, there was no effect of adaptation on behavioural performance on the spatial attention task. Moreover, the P3 component of the ERP and alpha lateralization were not influenced by prism adaptation. Together, these results show that some EEG correlates of visual spatial attention remain unchanged after prism adaptation, a finding which has its implications for current models of the neurocognitive mechanisms behind prism adaptation.

scholarly journals Prism adaptation speeds reach initiation in the direction of the prism after-effect.

2021 ◽  
Author(s):  
Christopher Lee Striemer ◽  
Carley Borza
Keyword(s):  
Sensory Input ◽  
Right Hemisphere ◽  
Prism Adaptation ◽  
Spatial Neglect ◽  
Egocentric Reference Frame ◽  
After Effect ◽  
The Right ◽  
Reach Planning ◽  
Direction Opposite ◽  
Healthy Participants

Damage to the temporal-parietal cortex in the right hemisphere often leads to spatial neglect – a disorder in which patients are unable to attend to sensory input from their contralesional (left) side. Neglect has been associated with both attentional and premotor deficits. That is, in addition to having difficulty with attending to the left side, patients are often slower to initiate leftward vs. rightward movements (i.e., directional hypokinesia). Previous research has indicated that a brief period of adaptation to rightward shifting prisms can reduce symptoms of neglect by adjusting the patient’s movements leftward, towards the neglected field. Although prism adaptation has been shown to reduce spatial attention deficits in patients with neglect, very little work has examined the effects of prisms on premotor symptoms. In the current study, we examined this in healthy individuals using leftward shifting prisms to induce a rightward shift in the egocentric reference frame, similar to neglect patients prior to prism adaptation. Specifically, we examined the speed with which healthy participants initiated leftward and rightward reaches (without visual feedback) prior to and following adaptation to either 17° leftward (n=16) or 17° rightward (n=15) shifting prisms. Our results indicated that, following adaptation, participants were significantly faster to initiate reaches towards targets located in the direction opposite the prism shift. That is, participants were faster to initiate reaches to right targets following leftward prism adaptation, and were faster to initiate reaches to left targets following rightward prism adaptation. Overall these results are consistent with the idea that prism adaptation can influence the speed with which a reach can be planned toward a target in the direction opposite the prism shift, possibly through altering activity in neural circuits involved in reach planning.

scholarly journals BRBN-T validation: adaptation of the Selective Reminding Test and Word List Generation

2015 ◽  
Vol 73 (10) ◽  
pp. 867-872 ◽  
Author(s):  
Mariana Rigueiro Neves ◽  
Ana Margarida Passos ◽  
Aristides Ferreira ◽  
Cláudia Sousa ◽  
Andreia Sá ◽  
...  
Keyword(s):  
Neuropsychological Tests ◽  
Cognitive Rehabilitation ◽  
Item Analysis ◽  
Classical Test Theory ◽  
Word List ◽  
Test Theory ◽  
Therapeutic Effects ◽  
Selective Reminding ◽  
Selective Reminding Test ◽  
Healthy Participants

Objective This study aims to present the Selective Reminding Test(SRT) and Word List Generation (WLG) adaptation to the Portuguese population, within the validation of the Brief Repeatable Battery of Neuropsychological Tests (BRBN-T)for multiple sclerosis (MS) patients.Method 66 healthy participants (54.5% female) recruited from the community volunteered to participate in this study.Results A combination of procedures from Classical Test Theory (CTT) and Item Response Theory (ITR) were applied to item analysis and selection. For each SRT list, 12 words were selected and 3 letters were chosen for WLG to constitute the final versions of these tests for the Portuguese population.Conclusion The combination of CTT and ITR maximized the decision making process in the adaptation of the SRT and WLG to a different culture and language (Portuguese). The relevance of this study lies on the production of reliable standardized neuropsychological tests, so that they can be used to facilitate a more rigorous monitoring of the evolution of MS, as well as any therapeutic effects and cognitive rehabilitation.

scholarly journals Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
Laure Christophe ◽  
Eric Chabanat ◽  
Ludovic Delporte ◽  
Patrice Revol ◽  
Pierre Volckmann ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Reference Frames ◽  
Pain Syndrome ◽  
Body Representation ◽  
Prism Adaptation ◽  
Spatial Neglect ◽  
Therapeutic Effects ◽  
Egocentric Reference Frame ◽  
Motor Neglect

Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations.

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