The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Gregor R Szycik - One of the best experts on this subject based on the ideXlab platform.
-
reduced audio Visual Integration in synaesthetes indicated by the double flash illusion
Brain Research, 2012Co-Authors: Janina Neufeld, Christopher Sinke, Markus Zedler, Hinderk M Emrich, Gregor R SzycikAbstract:Abstract It has been suggested that synaesthesia is the result of a hyper-sensitive multimodal binding-mechanism. To address the question whether multi-modal Integration is altered in synaesthetes in general, grapheme-colour and auditory–Visual synaesthetes were studied using the double-flash illusion. This illusion is induced by a single light flash presented together with multiple beep sounds, which is then perceived as multiple flashes. By varying the separation of auditory and Visual stimuli, the hypothesis of a widened temporal window of audio–Visual Integration in synaesthetes was tested. As hypothesised, the results show differences between synaesthetes and controls concerning multisensory Integration, but surprisingly other than expected synaesthetes perceive a reduced number of illusions and have a smaller time-window of audio–Visual Integration compared to controls. This indicates that they do not have a hyper-sensitive binding mechanism. On the contrary, synaesthetes seem to integrate even less than controls between vision and audition.
-
Reduced audio–Visual Integration in synaesthetes indicated by the double-flash illusion
Brain research, 2012Co-Authors: Janina Neufeld, Christopher Sinke, Markus Zedler, Hinderk M Emrich, Gregor R SzycikAbstract:Abstract It has been suggested that synaesthesia is the result of a hyper-sensitive multimodal binding-mechanism. To address the question whether multi-modal Integration is altered in synaesthetes in general, grapheme-colour and auditory–Visual synaesthetes were studied using the double-flash illusion. This illusion is induced by a single light flash presented together with multiple beep sounds, which is then perceived as multiple flashes. By varying the separation of auditory and Visual stimuli, the hypothesis of a widened temporal window of audio–Visual Integration in synaesthetes was tested. As hypothesised, the results show differences between synaesthetes and controls concerning multisensory Integration, but surprisingly other than expected synaesthetes perceive a reduced number of illusions and have a smaller time-window of audio–Visual Integration compared to controls. This indicates that they do not have a hyper-sensitive binding mechanism. On the contrary, synaesthetes seem to integrate even less than controls between vision and audition.
Rainer Guski - One of the best experts on this subject based on the ideXlab platform.
-
Spatio-temporal constraints for auditory--Visual Integration.
Behavioural Brain Research, 2001Co-Authors: Jörg Lewald, Walter H. Ehrenstein, Rainer GuskiAbstract:The perceptual coherence of auditory and Visual information is achieved by integrative brain processes. Specialized single neurons with spatial and temporal interactions of auditory and Visual stimuli have been demonstrated by several neurophysiological studies. The present, psychophysical, study investigates possible perceptual correlates of these neuronal features. Subjects had to indicate the point of subjective spatial alignment (PSSA) for a horizontally moving Visual stimulus that crossed the position of a stationary sound source. Auditory and Visual stimuli consisted of periodic pulses that were systematically varied in their phase relationship or repetition rate. PSSAs obtained for continuous Visual stimuli served as a reference. When sound and light pulses were coincident in phase at a repetition rate of 2 Hz, PSSAs were shifted by ∼3° in a direction opposite to the movement of the Visual stimulus (with respect to the reference condition). This shift markedly decreased when the temporal disparity exceeded ∼100 ms and disappeared near phase opposition (250 ms disparity). With 4 Hz repetition rate (temporal disparity ≤125 ms), there was no significant effect of phase relationship on PSSAs, but still an approximately constant shift with respect to the reference value. Variation of the repetition rate resulted in almost constant shifts in PSSA of ∼3° between 1 and 4 Hz and a linear decrease (slope 0.27°/Hz) with higher repetition rates. These results suggest a spatio-temporal ‘window’ for auditory–Visual Integration, that extends over ∼100 ms and ∼3°: when auditory and Visual stimuli are within this window, they are always perceived as spatially coincident. These psychophysical findings may be related to properties of bimodal neurons such as have been demonstrated by neurophysiological recordings in midbrain and cortex.
-
Spatio-temporal constraints for auditory--Visual Integration.
Behavioural brain research, 2001Co-Authors: Jörg Lewald, Walter H. Ehrenstein, Rainer GuskiAbstract:The perceptual coherence of auditory and Visual information is achieved by integrative brain processes. Specialized single neurons with spatial and temporal interactions of auditory and Visual stimuli have been demonstrated by several neurophysiological studies. The present, psychophysical, study investigates possible perceptual correlates of these neuronal features. Subjects had to indicate the point of subjective spatial alignment (PSSA) for a horizontally moving Visual stimulus that crossed the position of a stationary sound source. Auditory and Visual stimuli consisted of periodic pulses that were systematically varied in their phase relationship or repetition rate. PSSAs obtained for continuous Visual stimuli served as a reference. When sound and light pulses were coincident in phase at a repetition rate of 2 Hz, PSSAs were shifted by approximately 3 degrees in a direction opposite to the movement of the Visual stimulus (with respect to the reference condition). This shift markedly decreased when the temporal disparity exceeded approximately 100 ms and disappeared near phase opposition (250 ms disparity). With 4 Hz repetition rate (temporal disparity < or =125 ms), there was no significant effect of phase relationship on PSSAs, but still an approximately constant shift with respect to the reference value. Variation of the repetition rate resulted in almost constant shifts in PSSA of approximately 3 degrees between 1 and 4 Hz and a linear decrease (slope 0.27 degrees /Hz) with higher repetition rates. These results suggest a spatio-temporal 'window' for auditory-Visual Integration, that extends over approximately 100 ms and approximately 3 degrees : when auditory and Visual stimuli are within this window, they are always perceived as spatially coincident. These psychophysical findings may be related to properties of bimodal neurons such as have been demonstrated by neurophysiological recordings in midbrain and cortex.
Janina Neufeld - One of the best experts on this subject based on the ideXlab platform.
-
reduced audio Visual Integration in synaesthetes indicated by the double flash illusion
Brain Research, 2012Co-Authors: Janina Neufeld, Christopher Sinke, Markus Zedler, Hinderk M Emrich, Gregor R SzycikAbstract:Abstract It has been suggested that synaesthesia is the result of a hyper-sensitive multimodal binding-mechanism. To address the question whether multi-modal Integration is altered in synaesthetes in general, grapheme-colour and auditory–Visual synaesthetes were studied using the double-flash illusion. This illusion is induced by a single light flash presented together with multiple beep sounds, which is then perceived as multiple flashes. By varying the separation of auditory and Visual stimuli, the hypothesis of a widened temporal window of audio–Visual Integration in synaesthetes was tested. As hypothesised, the results show differences between synaesthetes and controls concerning multisensory Integration, but surprisingly other than expected synaesthetes perceive a reduced number of illusions and have a smaller time-window of audio–Visual Integration compared to controls. This indicates that they do not have a hyper-sensitive binding mechanism. On the contrary, synaesthetes seem to integrate even less than controls between vision and audition.
-
Reduced audio–Visual Integration in synaesthetes indicated by the double-flash illusion
Brain research, 2012Co-Authors: Janina Neufeld, Christopher Sinke, Markus Zedler, Hinderk M Emrich, Gregor R SzycikAbstract:Abstract It has been suggested that synaesthesia is the result of a hyper-sensitive multimodal binding-mechanism. To address the question whether multi-modal Integration is altered in synaesthetes in general, grapheme-colour and auditory–Visual synaesthetes were studied using the double-flash illusion. This illusion is induced by a single light flash presented together with multiple beep sounds, which is then perceived as multiple flashes. By varying the separation of auditory and Visual stimuli, the hypothesis of a widened temporal window of audio–Visual Integration in synaesthetes was tested. As hypothesised, the results show differences between synaesthetes and controls concerning multisensory Integration, but surprisingly other than expected synaesthetes perceive a reduced number of illusions and have a smaller time-window of audio–Visual Integration compared to controls. This indicates that they do not have a hyper-sensitive binding mechanism. On the contrary, synaesthetes seem to integrate even less than controls between vision and audition.
Jörg Lewald - One of the best experts on this subject based on the ideXlab platform.
-
Spatio-temporal constraints for auditory--Visual Integration.
Behavioural Brain Research, 2001Co-Authors: Jörg Lewald, Walter H. Ehrenstein, Rainer GuskiAbstract:The perceptual coherence of auditory and Visual information is achieved by integrative brain processes. Specialized single neurons with spatial and temporal interactions of auditory and Visual stimuli have been demonstrated by several neurophysiological studies. The present, psychophysical, study investigates possible perceptual correlates of these neuronal features. Subjects had to indicate the point of subjective spatial alignment (PSSA) for a horizontally moving Visual stimulus that crossed the position of a stationary sound source. Auditory and Visual stimuli consisted of periodic pulses that were systematically varied in their phase relationship or repetition rate. PSSAs obtained for continuous Visual stimuli served as a reference. When sound and light pulses were coincident in phase at a repetition rate of 2 Hz, PSSAs were shifted by ∼3° in a direction opposite to the movement of the Visual stimulus (with respect to the reference condition). This shift markedly decreased when the temporal disparity exceeded ∼100 ms and disappeared near phase opposition (250 ms disparity). With 4 Hz repetition rate (temporal disparity ≤125 ms), there was no significant effect of phase relationship on PSSAs, but still an approximately constant shift with respect to the reference value. Variation of the repetition rate resulted in almost constant shifts in PSSA of ∼3° between 1 and 4 Hz and a linear decrease (slope 0.27°/Hz) with higher repetition rates. These results suggest a spatio-temporal ‘window’ for auditory–Visual Integration, that extends over ∼100 ms and ∼3°: when auditory and Visual stimuli are within this window, they are always perceived as spatially coincident. These psychophysical findings may be related to properties of bimodal neurons such as have been demonstrated by neurophysiological recordings in midbrain and cortex.
-
Spatio-temporal constraints for auditory--Visual Integration.
Behavioural brain research, 2001Co-Authors: Jörg Lewald, Walter H. Ehrenstein, Rainer GuskiAbstract:The perceptual coherence of auditory and Visual information is achieved by integrative brain processes. Specialized single neurons with spatial and temporal interactions of auditory and Visual stimuli have been demonstrated by several neurophysiological studies. The present, psychophysical, study investigates possible perceptual correlates of these neuronal features. Subjects had to indicate the point of subjective spatial alignment (PSSA) for a horizontally moving Visual stimulus that crossed the position of a stationary sound source. Auditory and Visual stimuli consisted of periodic pulses that were systematically varied in their phase relationship or repetition rate. PSSAs obtained for continuous Visual stimuli served as a reference. When sound and light pulses were coincident in phase at a repetition rate of 2 Hz, PSSAs were shifted by approximately 3 degrees in a direction opposite to the movement of the Visual stimulus (with respect to the reference condition). This shift markedly decreased when the temporal disparity exceeded approximately 100 ms and disappeared near phase opposition (250 ms disparity). With 4 Hz repetition rate (temporal disparity < or =125 ms), there was no significant effect of phase relationship on PSSAs, but still an approximately constant shift with respect to the reference value. Variation of the repetition rate resulted in almost constant shifts in PSSA of approximately 3 degrees between 1 and 4 Hz and a linear decrease (slope 0.27 degrees /Hz) with higher repetition rates. These results suggest a spatio-temporal 'window' for auditory-Visual Integration, that extends over approximately 100 ms and approximately 3 degrees : when auditory and Visual stimuli are within this window, they are always perceived as spatially coincident. These psychophysical findings may be related to properties of bimodal neurons such as have been demonstrated by neurophysiological recordings in midbrain and cortex.
T Lee Ryan - One of the best experts on this subject based on the ideXlab platform.
-
Visual Integration of objects and scenes increases recollection-based responding despite differential MTL recruitment in young and older adults.
Hippocampus, 2018Co-Authors: Molly Memel, T Lee RyanAbstract:Unitization, the process of encoding previously independent units as one coherent representation, improves associative memory in both young and older adults, or in some cases, differentially benefits older adults. Unitization of verbal associative pairs may reduce reliance on the hippocampus (HC) for successful encoding and recognition by shifting to familiarity-based processing mediated by perirhinal cortex (PRC). However, this shift was not observed in a recent study of Visual associative memory, with equivalent activation in HC and PRC during encoding of Visually integrated (unitized) and nonintegrated object and scene pairs. Furthermore, behavioral findings from this study suggested an increase in recollection rather than familiarity during recognition of Visually integrated pairs. The present study extends our previous work by focusing on the influence of Visual Integration on fMRI activation during associative recognition, rather than encoding and these patterns between young and older adults. In contrast to our findings from encoding, Visual Integration reduced HC and PRC activation during retrieval of object and scene associative pairs across both age groups. However, Visual Integration increased the correlation between bilateral HC and left parahippocampal (PHC) activation and behavioral performance among older adults, consistent with an increased reliance on recollection. In contrast, Visual Integration reduced the correlation between HC activation and behavioral performance in young adults, more consistent with findings from the verbal unitization literature. Taken together, these results suggest that associative memory for Visually integrated pairs may involve differential recruitment of medial temporal regions in young and older adults.
-
Visual Integration enhances associative memory equally for young and older adults without reducing hippocampal encoding activation.
Neuropsychologia, 2017Co-Authors: Molly Memel, T Lee RyanAbstract:The ability to remember associations between previously unrelated pieces of information is often impaired in older adults (Naveh-Benjamin, 2000). Unitization, the process of creating a perceptually or semantically integrated representation that includes both items in an associative pair, attenuates age-related associative deficits (Bastin et al., 2013; Ahmad et al., 2015; Zheng et al., 2015). Compared to non-unitized pairs, unitized pairs may rely less on hippocampally-mediated binding associated with recollection, and more on familiarity-based processes mediated by perirhinal cortex (PRC) and parahippocampal cortex (PHC). While unitization of verbal materials improves associative memory in older adults, less is known about the impact of Visual Integration. The present study determined whether Visual Integration improves associative memory in older adults by minimizing the need for hippocampal (HC) recruitment and shifting encoding to non-hippocampal medial temporal structures, such as the PRC and PHC. Young and older adults were presented with a series of objects paired with naturalistic scenes while undergoing fMRI scanning, and were later given an associative memory test. Visual Integration was varied by presenting the object either next to the scene (Separated condition) or Visually integrated within the scene (Combined condition). Visual Integration improved associative memory among young and older adults to a similar degree by increasing the hit rate for intact pairs, but without increasing false alarms for recombined pairs, suggesting enhanced recollection rather than increased reliance on familiarity. Also contrary to expectations, Visual Integration resulted in increased hippocampal activation in both age groups, along with increases in PRC and PHC activation. Activation in all three MTL regions predicted discrimination performance during the Separated condition in young adults, while only a marginal relationship between PRC activation and performance was observed during the Combined condition. Older adults showed less overall activation in MTL regions compared to young adults, and associative memory performance was most strongly predicted by prefrontal, rather than MTL, activation. We suggest that Visual Integration benefits both young and older adults similarly, and provides a special case of unitization that may be mediated by recollective, rather than familiarity-based encoding processes.
