Ryan Stevenson | University of Western Ontario (original) (raw)

Papers by Ryan Stevenson

Journal of autism and developmental disorders, Jan 9, 2016

Atypical sensory perception is one of the most ubiquitous symptoms of autism, including a tendenc... more Atypical sensory perception is one of the most ubiquitous symptoms of autism, including a tendency towards a local-processing bias. We investigated whether local-processing biases were associated with global-processing impairments on a global/local attentional-scope paradigm in conjunction with a composite-face task. Behavioural results were related to individuals' levels of autistic traits, specifically the Attention to Detail subscale of the Autism Quotient, and the Sensory Profile Questionnaire. Individuals showing high rates of Attention to Detail were more susceptible to global attentional-scope manipulations, suggesting that local-processing biases associated with Attention to Detail do not come at the cost of a global-processing deficit, but reflect a difference in default global versus local bias. This relationship operated at the attentional/perceptual level, but not response criterion.

Neurobiology of aging, 2015

Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a ... more Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a rapid growth in the population of older adults. One of the most common complaints with healthy aging is a decreased ability to successfully perceive speech, particularly in noisy environments. In such noisy environments, the presence of visual speech cues (i.e., lip movements) provide striking benefits for speech perception and comprehension, but previous research suggests that older adults gain less from such audiovisual integration than their younger peers. To determine at what processing level these behavioral differences arise in healthy-aging populations, we administered a speech-in-noise task to younger and older adults. We compared the perceptual benefits of having speech information available in both the auditory and visual modalities and examined both phoneme and whole-word recognition across varying levels of signal-to-noise ratio. For whole-word recognition, older adults relat...

Autism research : official journal of the International Society for Autism Research, Jan 24, 2015

A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses o... more A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses on the relationship between multisensory temporal function and the behavioral, perceptual, and cognitive impairments observed in ASD. Atypical sensory processing is becoming increasingly recognized as a core component of autism, with evidence of atypical processing across a number of sensory modalities. These deviations from typical processing underscore the value of interpreting ASD within a multisensory framework. Furthermore, converging evidence illustrates that these differences in audiovisual processing may be specifically related to temporal processing. This review seeks to bridge the connection between temporal processing and audiovisual perception, and to elaborate on emerging data showing differences in audiovisual temporal function in autism. We also discuss the consequence of such changes, the specific impact on the processing of different classes of audiovisual stimuli (e.g. s...

Progress in neurobiology, Jan 6, 2015

Although sensory processing challenges have been noted since the first clinical descriptions of a... more Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what is currently known about sensory processing in ASD, how sensory function fits within contemporary models of ASD, and what is understood about the differences in the underlying neural processing of sensory and social communication observed between individuals with and without ASD. In addition to highlighting the sensory features associated with AS...

Multisensory Research, 2013

The talk will compare and contrast results from animal neurophysiological and human psychophysica... more The talk will compare and contrast results from animal neurophysiological and human psychophysical studies that have focused on characterizing the maturation of temporal factors that are critical determinants in the integration of audiovisual stimuli. In the animal model realm, individual neurons in both cortical and subcortical structures progress through a series of developmental stages. During this maturational progression, neurons first transition from having temporal tuning profiles that are quite narrow to having tuning functions that are very broad. This initial period of broadening is then followed by a more protracted developmental period in which these temporal tuning profiles gradually narrow to achieve adult-like values. In human development, where we have studied children from ages 6-18, a gradual narrowing of multisensory temporal function, specifically in the width of the multisensory temporal binding window, is observed. Our evidence suggests that this window is not fully mature until late adolescence, highlighting a surprisingly long period during which multisensory temporal function is changing. These results will be discussed in the context of their implications for both behavioral and perceptual development.

Brain Topography, 2014

We process information from the world through multiple senses, and the brain must decide what inf... more We process information from the world through multiple senses, and the brain must decide what information belongs together and what information should be segregated. One challenge in studying such multisensory integration is how to quantify the multisensory interactions, a challenge that is amplified by the host of methods that are now used to measure neural, behavioral, and perceptual responses. Many of the measures that have been developed to quantify multisensory integration (and which have been derived from single unit analyses), have been applied to these different measures without much consideration for the nature of the process being studied. Here, we provide a review focused on the means with which experimenters quantify multisensory processes and integration across a range of commonly used experimental methodologies. We emphasize the most commonly employed measures, including single-and multiunit responses, local field potentials, functional magnetic resonance imaging, and electroencephalography, along with behavioral measures of detection, accuracy, and response times. In each section, we will discuss the different metrics commonly used to quantify multisensory interactions, including the rationale for their use, their advantages, and the drawbacks and caveats associated with them. Also discussed are possible alternatives to the most commonly used metrics.

Multisensory Research, 2013

The talk will compare and contrast results from animal neurophysiological and human psychophysica... more The talk will compare and contrast results from animal neurophysiological and human psychophysical studies that have focused on characterizing the maturation of temporal factors that are critical determinants in the integration of audiovisual stimuli. In the animal model realm, individual neurons in both cortical and subcortical structures progress through a series of developmental stages. During this maturational progression, neurons first transition from having temporal tuning profiles that are quite narrow to having tuning functions that are very broad. This initial period of broadening is then followed by a more protracted developmental period in which these temporal tuning profiles gradually narrow to achieve adult-like values. In human development, where we have studied children from ages 6-18, a gradual narrowing of multisensory temporal function, specifically in the width of the multisensory temporal binding window, is observed. Our evidence suggests that this window is not fully mature until late adolescence, highlighting a surprisingly long period during which multisensory temporal function is changing. These results will be discussed in the context of their implications for both behavioral and perceptual development.

Frontiers in Neuroscience, 2011

ABSTRACT Although scientists have only recently had the tools available to noninvasively study th... more ABSTRACT Although scientists have only recently had the tools available to noninvasively study the neural mechanisms of multisensory perceptual processes in humans (Calvert et al. 1999), the study of multisensory perception has had a long history in science (James 1890; Molyneux 1688). Before the advent of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and high-density electrical recording, the study of neural mechanisms, using single-unit recording, was restricted to nonhuman animals such as monkeys and cats. These groundbreaking neurophysiological studies established many principles for understanding multisensory processing at the level of single neurons (Meredith and Stein 1983), and continue to improve our understanding of multisensory mechanisms at that level (Stein and Stanford 2008). It is tempting to consider that neuroimaging measurements, like blood oxygenation level–dependent (BOLD) activation measured with fMRI, are directly comparable with findings from single-unit recordings. Although several studies have established clear links between BOLD activation and neural activity (Attwell and Iadecola 2002; Logothetis and Wandell 2004; Thompson et al. 2003), there remains a fundamental difference between BOLD activation and single-unit activity: BOLD activation is measured from the vasculature supplying a heterogeneous population of neurons, whereas single-unit measures are taken from individual neurons (Scannell and Young 1999). The ramifications of this difference are not inconsequential because the principles of multisensory phenomena established using single-unit recording may not apply to population-based neuroimaging data (Calvert et al. 2000). The established principles must be tested theoretically and empirically, and where they fail, they must be replaced with new principles that are specific to the new technique.

Frontiers in Neuroscience, 2011

ABSTRACT Although scientists have only recently had the tools available to noninvasively study th... more ABSTRACT Although scientists have only recently had the tools available to noninvasively study the neural mechanisms of multisensory perceptual processes in humans (Calvert et al. 1999), the study of multisensory perception has had a long history in science (James 1890; Molyneux 1688). Before the advent of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and high-density electrical recording, the study of neural mechanisms, using single-unit recording, was restricted to nonhuman animals such as monkeys and cats. These groundbreaking neurophysiological studies established many principles for understanding multisensory processing at the level of single neurons (Meredith and Stein 1983), and continue to improve our understanding of multisensory mechanisms at that level (Stein and Stanford 2008). It is tempting to consider that neuroimaging measurements, like blood oxygenation level–dependent (BOLD) activation measured with fMRI, are directly comparable with findings from single-unit recordings. Although several studies have established clear links between BOLD activation and neural activity (Attwell and Iadecola 2002; Logothetis and Wandell 2004; Thompson et al. 2003), there remains a fundamental difference between BOLD activation and single-unit activity: BOLD activation is measured from the vasculature supplying a heterogeneous population of neurons, whereas single-unit measures are taken from individual neurons (Scannell and Young 1999). The ramifications of this difference are not inconsequential because the principles of multisensory phenomena established using single-unit recording may not apply to population-based neuroimaging data (Calvert et al. 2000). The established principles must be tested theoretically and empirically, and where they fail, they must be replaced with new principles that are specific to the new technique.

Frontiers in Psychology, 2014

Survey of Anesthesiology, 2013

Background: Anesthesiology requires performing visually oriented procedures while monitoring audi... more Background: Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient's vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. Methods: The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists' abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise.

Multisensory Research, 2013

Multisensory Research, 2013

Anesthesia & Analgesia, 2014

A n anesthesia provider must critically manage patients in the operating room and respond to any ... more A n anesthesia provider must critically manage patients in the operating room and respond to any physiologic aberration in an environment that contains a large amount of sensory information. Relevant information must be appropriately assimilated and irrelevant information filtered. 1 Attention to the pulse oximeter, a vital piece of monitoring equipment, needs to be particularly acute during induction and emergence, the period when attention is heavily directed toward the patient and when errors are most likely to occur. Dividing attention and triaging clinical events and tasks are imperative to the anesthesiologist, and these challenges are amplified under circumstances in which the physician's attentional resources are at or beyond capacity. 4 The consequences of divided attention have been the subject of a significant amount of psychological, neuroscience, and human factors research, including applied studies asking how such abilities might be improved. 4-10 Indeed, training in which subjects make use of combined visual and auditory (i.e., multisensory) cues has been shown to be able to improve sensory performance and perception. 10-12 The ability to integrate information across multiple senses leads to improvements in detection, 13,14 accuracy, 15,16 and response times. We assessed whether perceptual training would improve the ability of resident anesthesiologists to detect frequency changes used to report oxygen saturation.

Neuropsychologia, 2014

Behavior, perception and cognition are strongly shaped by the synthesis of information across the... more Behavior, perception and cognition are strongly shaped by the synthesis of information across the different sensory modalities. Such multisensory integration often results in performance and perceptual benefits that reflect the additional information conferred by having cues from multiple senses providing redundant or complementary information. The spatial and temporal relationships of these cues provide powerful statistical information about how these cues should be integrated or "bound" in order to create a unified perceptual representation. Much recent work has examined the temporal factors that are integral in multisensory processing, with many focused on the construct of the multisensory temporal binding windowthe epoch of time within which stimuli from different modalities is likely to be integrated and perceptually bound. Emerging evidence suggests that this temporal window is altered in a series of neurodevelopmental disorders, including autism, dyslexia and schizophrenia. In addition to their role in sensory processing, these deficits in multisensory temporal function may play an important role in the perceptual and cognitive weaknesses that characterize these clinical disorders. Within this context, focus on improving the acuity of multisensory temporal function may have important implications for the amelioration of the "higher-order" deficits that serve as the defining features of these disorders.

Journal of Experimental Psychology: Human Perception and Performance, 2012

Human multisensory systems are known to bind inputs from the different sensory modalities into a ... more Human multisensory systems are known to bind inputs from the different sensory modalities into a unified percept, a process that leads to measurable behavioral benefits. This integrative process can be observed through multisensory illusions, including the McGurk effect and the sound-induced flash illusion, both of which demonstrate the ability of one sensory modality to modulate perception in a second modality. Such multisensory integration is highly dependent upon the temporal relationship of the different sensory inputs, with perceptual binding occurring within a limited range of asynchronies known as the temporal binding window (TBW). Previous studies have shown that this window is highly variable across individuals, but it is unclear how these variations in the TBW relate to an individual's ability to integrate multisensory cues. Here we provide evidence linking individual differences in multisensory temporal processes to differences in the individual's audiovisual integration of illusory stimuli. Our data provide strong evidence that the temporal processing of multiple sensory signals and the merging of multiple signals into a single, unified perception, are highly related. Specifically, the width of right side of an individuals' TBW, where the auditory stimulus follows the visual, is significantly correlated with the strength of illusory percepts, as indexed via both an increase in the strength of binding synchronous sensory signals and in an improvement in correctly dissociating asynchronous signals. These findings are discussed in terms of their possible neurobiological basis, relevance to the development of sensory integration, and possible importance for clinical conditions in which there is growing evidence that multisensory integration is compromised.

Journal of Autism and Developmental Disorders, 2013

This study examined unisensory and multisensory speech perception in 8-17 year old children with ... more This study examined unisensory and multisensory speech perception in 8-17 year old children with autism spectrum disorders (ASD) and typically developing controls matched on chronological age, sex, and IQ. Consonant-vowel syllables were presented in visual only, auditory only, matched audiovisual, and mismatched audiovisual (''McGurk'') conditions. Participants with ASD displayed deficits in visual only and matched audiovisual speech perception. Additionally, children with ASD reported a visual influence on heard speech in response to mismatched audiovisual syllables over a wider window of time relative to controls. Correlational analyses revealed associations between multisensory speech perception, communicative characteristics, and responses to sensory stimuli in ASD. Results suggest atypical speech perception is linked to broader behavioral characteristics of ASD.

Frontiers in Psychology, 2014

Experimental Brain Research, 2013

larger and more symmetrical than that seen using simple and complex non-speech stimuli. These eff... more larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes.

Experimental Brain Research, 2013

The importance of multisensory integration for human behavior and perception is well documented, ... more The importance of multisensory integration for human behavior and perception is well documented, as is the impact that temporal synchrony has on driving such integration. Thus, the more temporally coincident two sensory inputs from different modalities are, the more likely they will be perceptually bound. This temporal integration process is captured by the construct of the temporal binding window -the range of temporal offsets within which an individual is able to perceptually bind inputs across sensory modalities. Recent work has shown that this window is malleable, and can be narrowed via a multisensory perceptual feedback training process. In the current study, we seek to extend this by examining the malleability of the multisensory temporal binding window through changes in unisensory experience. Specifically, we measured the ability of visual perceptual feedback training to induce changes in the multisensory temporal binding window. Visual perceptual training with feedback successfully improved temporal visual processing and more importantly, this visual training increased the temporal precision across modalities, which manifested as a narrowing of the multisensory temporal binding window. These results are the first to establish the ability of unisensory temporal training to modulate multisensory temporal processes, findings that can provide mechanistic insights into multisensory integration and which may have a host of practical applications.

Journal of autism and developmental disorders, Jan 9, 2016

Atypical sensory perception is one of the most ubiquitous symptoms of autism, including a tendenc... more Atypical sensory perception is one of the most ubiquitous symptoms of autism, including a tendency towards a local-processing bias. We investigated whether local-processing biases were associated with global-processing impairments on a global/local attentional-scope paradigm in conjunction with a composite-face task. Behavioural results were related to individuals' levels of autistic traits, specifically the Attention to Detail subscale of the Autism Quotient, and the Sensory Profile Questionnaire. Individuals showing high rates of Attention to Detail were more susceptible to global attentional-scope manipulations, suggesting that local-processing biases associated with Attention to Detail do not come at the cost of a global-processing deficit, but reflect a difference in default global versus local bias. This relationship operated at the attentional/perceptual level, but not response criterion.

Neurobiology of aging, 2015

Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a ... more Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a rapid growth in the population of older adults. One of the most common complaints with healthy aging is a decreased ability to successfully perceive speech, particularly in noisy environments. In such noisy environments, the presence of visual speech cues (i.e., lip movements) provide striking benefits for speech perception and comprehension, but previous research suggests that older adults gain less from such audiovisual integration than their younger peers. To determine at what processing level these behavioral differences arise in healthy-aging populations, we administered a speech-in-noise task to younger and older adults. We compared the perceptual benefits of having speech information available in both the auditory and visual modalities and examined both phoneme and whole-word recognition across varying levels of signal-to-noise ratio. For whole-word recognition, older adults relat...

Autism research : official journal of the International Society for Autism Research, Jan 24, 2015

A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses o... more A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses on the relationship between multisensory temporal function and the behavioral, perceptual, and cognitive impairments observed in ASD. Atypical sensory processing is becoming increasingly recognized as a core component of autism, with evidence of atypical processing across a number of sensory modalities. These deviations from typical processing underscore the value of interpreting ASD within a multisensory framework. Furthermore, converging evidence illustrates that these differences in audiovisual processing may be specifically related to temporal processing. This review seeks to bridge the connection between temporal processing and audiovisual perception, and to elaborate on emerging data showing differences in audiovisual temporal function in autism. We also discuss the consequence of such changes, the specific impact on the processing of different classes of audiovisual stimuli (e.g. s...

Progress in neurobiology, Jan 6, 2015

Although sensory processing challenges have been noted since the first clinical descriptions of a... more Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what is currently known about sensory processing in ASD, how sensory function fits within contemporary models of ASD, and what is understood about the differences in the underlying neural processing of sensory and social communication observed between individuals with and without ASD. In addition to highlighting the sensory features associated with AS...

Multisensory Research, 2013

The talk will compare and contrast results from animal neurophysiological and human psychophysica... more The talk will compare and contrast results from animal neurophysiological and human psychophysical studies that have focused on characterizing the maturation of temporal factors that are critical determinants in the integration of audiovisual stimuli. In the animal model realm, individual neurons in both cortical and subcortical structures progress through a series of developmental stages. During this maturational progression, neurons first transition from having temporal tuning profiles that are quite narrow to having tuning functions that are very broad. This initial period of broadening is then followed by a more protracted developmental period in which these temporal tuning profiles gradually narrow to achieve adult-like values. In human development, where we have studied children from ages 6-18, a gradual narrowing of multisensory temporal function, specifically in the width of the multisensory temporal binding window, is observed. Our evidence suggests that this window is not fully mature until late adolescence, highlighting a surprisingly long period during which multisensory temporal function is changing. These results will be discussed in the context of their implications for both behavioral and perceptual development.

Brain Topography, 2014

We process information from the world through multiple senses, and the brain must decide what inf... more We process information from the world through multiple senses, and the brain must decide what information belongs together and what information should be segregated. One challenge in studying such multisensory integration is how to quantify the multisensory interactions, a challenge that is amplified by the host of methods that are now used to measure neural, behavioral, and perceptual responses. Many of the measures that have been developed to quantify multisensory integration (and which have been derived from single unit analyses), have been applied to these different measures without much consideration for the nature of the process being studied. Here, we provide a review focused on the means with which experimenters quantify multisensory processes and integration across a range of commonly used experimental methodologies. We emphasize the most commonly employed measures, including single-and multiunit responses, local field potentials, functional magnetic resonance imaging, and electroencephalography, along with behavioral measures of detection, accuracy, and response times. In each section, we will discuss the different metrics commonly used to quantify multisensory interactions, including the rationale for their use, their advantages, and the drawbacks and caveats associated with them. Also discussed are possible alternatives to the most commonly used metrics.

Multisensory Research, 2013

The talk will compare and contrast results from animal neurophysiological and human psychophysica... more The talk will compare and contrast results from animal neurophysiological and human psychophysical studies that have focused on characterizing the maturation of temporal factors that are critical determinants in the integration of audiovisual stimuli. In the animal model realm, individual neurons in both cortical and subcortical structures progress through a series of developmental stages. During this maturational progression, neurons first transition from having temporal tuning profiles that are quite narrow to having tuning functions that are very broad. This initial period of broadening is then followed by a more protracted developmental period in which these temporal tuning profiles gradually narrow to achieve adult-like values. In human development, where we have studied children from ages 6-18, a gradual narrowing of multisensory temporal function, specifically in the width of the multisensory temporal binding window, is observed. Our evidence suggests that this window is not fully mature until late adolescence, highlighting a surprisingly long period during which multisensory temporal function is changing. These results will be discussed in the context of their implications for both behavioral and perceptual development.

Frontiers in Neuroscience, 2011

ABSTRACT Although scientists have only recently had the tools available to noninvasively study th... more ABSTRACT Although scientists have only recently had the tools available to noninvasively study the neural mechanisms of multisensory perceptual processes in humans (Calvert et al. 1999), the study of multisensory perception has had a long history in science (James 1890; Molyneux 1688). Before the advent of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and high-density electrical recording, the study of neural mechanisms, using single-unit recording, was restricted to nonhuman animals such as monkeys and cats. These groundbreaking neurophysiological studies established many principles for understanding multisensory processing at the level of single neurons (Meredith and Stein 1983), and continue to improve our understanding of multisensory mechanisms at that level (Stein and Stanford 2008). It is tempting to consider that neuroimaging measurements, like blood oxygenation level–dependent (BOLD) activation measured with fMRI, are directly comparable with findings from single-unit recordings. Although several studies have established clear links between BOLD activation and neural activity (Attwell and Iadecola 2002; Logothetis and Wandell 2004; Thompson et al. 2003), there remains a fundamental difference between BOLD activation and single-unit activity: BOLD activation is measured from the vasculature supplying a heterogeneous population of neurons, whereas single-unit measures are taken from individual neurons (Scannell and Young 1999). The ramifications of this difference are not inconsequential because the principles of multisensory phenomena established using single-unit recording may not apply to population-based neuroimaging data (Calvert et al. 2000). The established principles must be tested theoretically and empirically, and where they fail, they must be replaced with new principles that are specific to the new technique.

Frontiers in Neuroscience, 2011

ABSTRACT Although scientists have only recently had the tools available to noninvasively study th... more ABSTRACT Although scientists have only recently had the tools available to noninvasively study the neural mechanisms of multisensory perceptual processes in humans (Calvert et al. 1999), the study of multisensory perception has had a long history in science (James 1890; Molyneux 1688). Before the advent of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and high-density electrical recording, the study of neural mechanisms, using single-unit recording, was restricted to nonhuman animals such as monkeys and cats. These groundbreaking neurophysiological studies established many principles for understanding multisensory processing at the level of single neurons (Meredith and Stein 1983), and continue to improve our understanding of multisensory mechanisms at that level (Stein and Stanford 2008). It is tempting to consider that neuroimaging measurements, like blood oxygenation level–dependent (BOLD) activation measured with fMRI, are directly comparable with findings from single-unit recordings. Although several studies have established clear links between BOLD activation and neural activity (Attwell and Iadecola 2002; Logothetis and Wandell 2004; Thompson et al. 2003), there remains a fundamental difference between BOLD activation and single-unit activity: BOLD activation is measured from the vasculature supplying a heterogeneous population of neurons, whereas single-unit measures are taken from individual neurons (Scannell and Young 1999). The ramifications of this difference are not inconsequential because the principles of multisensory phenomena established using single-unit recording may not apply to population-based neuroimaging data (Calvert et al. 2000). The established principles must be tested theoretically and empirically, and where they fail, they must be replaced with new principles that are specific to the new technique.

Frontiers in Psychology, 2014

Survey of Anesthesiology, 2013

Background: Anesthesiology requires performing visually oriented procedures while monitoring audi... more Background: Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient's vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. Methods: The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists' abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise.

Multisensory Research, 2013

Multisensory Research, 2013

Anesthesia & Analgesia, 2014

A n anesthesia provider must critically manage patients in the operating room and respond to any ... more A n anesthesia provider must critically manage patients in the operating room and respond to any physiologic aberration in an environment that contains a large amount of sensory information. Relevant information must be appropriately assimilated and irrelevant information filtered. 1 Attention to the pulse oximeter, a vital piece of monitoring equipment, needs to be particularly acute during induction and emergence, the period when attention is heavily directed toward the patient and when errors are most likely to occur. Dividing attention and triaging clinical events and tasks are imperative to the anesthesiologist, and these challenges are amplified under circumstances in which the physician's attentional resources are at or beyond capacity. 4 The consequences of divided attention have been the subject of a significant amount of psychological, neuroscience, and human factors research, including applied studies asking how such abilities might be improved. 4-10 Indeed, training in which subjects make use of combined visual and auditory (i.e., multisensory) cues has been shown to be able to improve sensory performance and perception. 10-12 The ability to integrate information across multiple senses leads to improvements in detection, 13,14 accuracy, 15,16 and response times. We assessed whether perceptual training would improve the ability of resident anesthesiologists to detect frequency changes used to report oxygen saturation.

Neuropsychologia, 2014

Behavior, perception and cognition are strongly shaped by the synthesis of information across the... more Behavior, perception and cognition are strongly shaped by the synthesis of information across the different sensory modalities. Such multisensory integration often results in performance and perceptual benefits that reflect the additional information conferred by having cues from multiple senses providing redundant or complementary information. The spatial and temporal relationships of these cues provide powerful statistical information about how these cues should be integrated or "bound" in order to create a unified perceptual representation. Much recent work has examined the temporal factors that are integral in multisensory processing, with many focused on the construct of the multisensory temporal binding windowthe epoch of time within which stimuli from different modalities is likely to be integrated and perceptually bound. Emerging evidence suggests that this temporal window is altered in a series of neurodevelopmental disorders, including autism, dyslexia and schizophrenia. In addition to their role in sensory processing, these deficits in multisensory temporal function may play an important role in the perceptual and cognitive weaknesses that characterize these clinical disorders. Within this context, focus on improving the acuity of multisensory temporal function may have important implications for the amelioration of the "higher-order" deficits that serve as the defining features of these disorders.

Journal of Experimental Psychology: Human Perception and Performance, 2012

Human multisensory systems are known to bind inputs from the different sensory modalities into a ... more Human multisensory systems are known to bind inputs from the different sensory modalities into a unified percept, a process that leads to measurable behavioral benefits. This integrative process can be observed through multisensory illusions, including the McGurk effect and the sound-induced flash illusion, both of which demonstrate the ability of one sensory modality to modulate perception in a second modality. Such multisensory integration is highly dependent upon the temporal relationship of the different sensory inputs, with perceptual binding occurring within a limited range of asynchronies known as the temporal binding window (TBW). Previous studies have shown that this window is highly variable across individuals, but it is unclear how these variations in the TBW relate to an individual's ability to integrate multisensory cues. Here we provide evidence linking individual differences in multisensory temporal processes to differences in the individual's audiovisual integration of illusory stimuli. Our data provide strong evidence that the temporal processing of multiple sensory signals and the merging of multiple signals into a single, unified perception, are highly related. Specifically, the width of right side of an individuals' TBW, where the auditory stimulus follows the visual, is significantly correlated with the strength of illusory percepts, as indexed via both an increase in the strength of binding synchronous sensory signals and in an improvement in correctly dissociating asynchronous signals. These findings are discussed in terms of their possible neurobiological basis, relevance to the development of sensory integration, and possible importance for clinical conditions in which there is growing evidence that multisensory integration is compromised.

Journal of Autism and Developmental Disorders, 2013

This study examined unisensory and multisensory speech perception in 8-17 year old children with ... more This study examined unisensory and multisensory speech perception in 8-17 year old children with autism spectrum disorders (ASD) and typically developing controls matched on chronological age, sex, and IQ. Consonant-vowel syllables were presented in visual only, auditory only, matched audiovisual, and mismatched audiovisual (''McGurk'') conditions. Participants with ASD displayed deficits in visual only and matched audiovisual speech perception. Additionally, children with ASD reported a visual influence on heard speech in response to mismatched audiovisual syllables over a wider window of time relative to controls. Correlational analyses revealed associations between multisensory speech perception, communicative characteristics, and responses to sensory stimuli in ASD. Results suggest atypical speech perception is linked to broader behavioral characteristics of ASD.

Frontiers in Psychology, 2014

Experimental Brain Research, 2013

larger and more symmetrical than that seen using simple and complex non-speech stimuli. These eff... more larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes.

Experimental Brain Research, 2013

The importance of multisensory integration for human behavior and perception is well documented, ... more The importance of multisensory integration for human behavior and perception is well documented, as is the impact that temporal synchrony has on driving such integration. Thus, the more temporally coincident two sensory inputs from different modalities are, the more likely they will be perceptually bound. This temporal integration process is captured by the construct of the temporal binding window -the range of temporal offsets within which an individual is able to perceptually bind inputs across sensory modalities. Recent work has shown that this window is malleable, and can be narrowed via a multisensory perceptual feedback training process. In the current study, we seek to extend this by examining the malleability of the multisensory temporal binding window through changes in unisensory experience. Specifically, we measured the ability of visual perceptual feedback training to induce changes in the multisensory temporal binding window. Visual perceptual training with feedback successfully improved temporal visual processing and more importantly, this visual training increased the temporal precision across modalities, which manifested as a narrowing of the multisensory temporal binding window. These results are the first to establish the ability of unisensory temporal training to modulate multisensory temporal processes, findings that can provide mechanistic insights into multisensory integration and which may have a host of practical applications.