Mark Wallace

Mark Wallace, Ph.D Laboratory Director

Dean of the Graduate
School

Overview

Development

Plasticity

Receptive Field Organization

Framework for Dyslexia

Multisensory Processes in Autism

Relevant Videos

Current Wallace Lab Projects

 

The neural underpinnings of multisensory behavior

Project Lead: Aaron Nidiffer

Aaron's Figure

My research project is aimed at understanding how multisensory neurons in the superior colliculus contribute to behavior. Non-human primates are trained to report the detection of auditory stimulus via manual response while being presented auditory, visual, and combined audiovisual stimuli. Behavioral responses are simultaneously recorded with neuronal activity so that a direct link between brain activity and behavior can be explored. Additionally, my research seeks to understand how stimulus factors such as intensity and the spatial and temporal relationships between the unisensory components of a multisensory stimulus affect behavior and the neuronal mechanisms responsible for that behavioral change.

 

Multisensory Integration in Clinical Populations

Project Lead: Gabby DiCarlo

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Multisensory integration can be described as the merging and transformation of information from the different senses. Autism spectrum disorders (ASD) are complex neurodevelopmental disorders characterized by impairments in communication and social behavior as well as the presence of repetitive and restrictive behaviors. In addition to the classic domains impacted in autism, sensory abnormalities are also highly prevalent in ASD with the new DSM-V now including sensory disturbances as a criterion for diagnosis. Based on the wealth of evidence highlighting disturbances across multiple sensory systems, there has been increased focus on better characterizing how the integration of information across the different sensory modalities is impacted in autism. My project is focused on psychophysical, behavioral and systems based questions to gain a further understanding of the underlying mechanisms of multisensory processing as it relates to neurodevelopmental disorders such as autism with the ultimate goal of developing more effective remediation tools.

 

Auditory and Tactile Sensory Responsiveness and Links to Autism Symptoms

Project Lead: Lauren Bryant

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Differences in response to sensory input have long been observed in individuals with autism spectrum disorder (ASD) and are now included among the clinical diagnostic criteria for ASD. Atypical sensory responsiveness manifests itself on a continuum spanning hypo-responsive and hyper-responsive patterns of behavior. It is possible that such altered sensory responsiveness is related to the processing and interpretation of sensory signal strength. However, sensory responsiveness to basic sensory stimulus properties like intensity has seldom been studied in a systematic and thorough manner in a neurotypical population. Not only have few studies examined changes in behavioral response patterns across a wide range of stimulus intensities, even fewer have explicitly designed experiments to look at the neural correlates of stimulus intensity coding, particularly under audio-tactile multisensory conditions. My research aims to fill this gap in knowledge of how typical individuals process basic sensory input in order to provide a stronger foundation from which to examine atypical sensory processing and an empirical basis for sensory-based interventions.

 

Audiovisual Processing in Patients with Cochlear Implants

Project Lead: Iliza Butera

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Cochlear implants allow those with profound hearing loss to experience sound, some of them for the first time. However, cochlear implant patients have difficulties with pitch discrimination and sound localization, even using modern implant processors. I’m interested in the mechanisms by which multiple senses are filtered and fused together in the brain, creating what we call spatial and temporal binding. Prior research suggests that perceptual binding may be shaped by experience and can be influenced by subsequent training. My work utilizes lab-based computer games and app-based mobile platforms to understand the development of multisensory integration and cortical plasticity. This research may help shape therapeutic interventions in the clinic as well as future cochlear implant technology.

 

EEG Investigation of Sensory Processing Networks

Project Lead: David Simon

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My research interest is using Electroencephalography (EEG) to explore differences in sensory processing and brain networks in individuals with autism spectrum disorder (ASD).  Sensory dysfunction is a recognized primary component of ASD, but there is still a great deal we do not know about how the neural mechanisms of sensory processing are altered in individuals with ASD and how this leads to behavioral impairment.  Specifically in the multisensory domain, we know that individuals with ASD have a wider temporal window for integration of unisensory components as well as decreased behavioral facilitation in terms of reaction times.  My work centers on using the high temporal resolution of EEG combined with psychophysical approaches to determine how differences in sensory system activity lead to altered perception in individuals with ASD.  Additionally, through application of graph theory approaches of network modelling to EEG data I am investigating how disruptions in overall network properties, such as long range connectivity and modularity, are associated with perception in both ASD and typical development. 

 

Information Integration across Multisensory Systems, Space and Time, and Sensory Awareness.

Project Lead: Jean-Paul Noel

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Project description: I am fundamentally interested in questions regarding neural information processing and integration as it relatesto multisensory systems, space and time, and sensory awareness. Multisensory systems (time): Integration of information across the senses does not happen in an indiscriminate manner, but heavily relies on the environmental and stimuli features. Our group has a long tradition studying the temporal characteristics that give rise to multisensory binding. In this line of research I am studying temporal binding windows across less studied sensory pairings (e.g., cardio-visual; Noel et al., 2015a; 2017a), as a function of sensory history (e.g., Noel et al., 2016a), and in a number of pathological conditions such as Autism (e.g., Noel et al., 2017b) and Epilepsy (e.g., Noel et al., 2017c). Multisensory systems (space): Further, the spatial disparity between sensory cues strongly modulates multisensory integration and interactions. In this line of research I have delineated the multisensory space immediately adjacent one’s body - the peri-personal space (Noel et al., 2014), how distance dictates temporal binding (Noel et al., 2015b), and how it may be anomalous in Autism and Schizophrenia (Noel et al., 2017d). Sensory Awareness: Traditionally, perceptual awareness studies have focused on describing the manner in which visual awareness emerges, however our experience is not limited to vision, but indeed we experience a seamless multisensory world. In this last avenue of research I have proposed that multisensory integration may be leveraged in the study of consciousness (Noel et al., 2015c), and I am currently conducting psychophysical and EEG studies in this regard.

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Past Projects

The Development of Multisensory Processes. Research in this area seeks to better characterize how multisensory circuits mature during early postnatal life. The approaches used for this work range from single neuron electrophysiology to psychophysics and event related potentials (ERPs) in children.

Experiential Plasticity in Developing and Adult Multisensory Circuits. Works seeks to better understand how early sensory experience shapes developing multisensory circuits, and the surprising degree of plasticity that can be enabled in adult representations.

Spatiotemporal Receptive Field Organization and Multisensory Integration. Ongoing research in the lab seeks to describe the complex receptive fields that characterize multisensory neurons in both cortical and subcortical structures, and to describe how this receptive field architecture influences the multisensory processing capabilities of these neurons.

A Multisensory Framework for Developmental Dyslexia. In prior work we have shown that alterations in multisensory temporal processes may be associated with the prevalent reading disability - developmental dyslexia. Current work seeks to extend this finding and better elucidate the affected brain circuits.

Altered Multisensory Processes in Autism Spectrum Disorder. New research in the lab seeks to better characterize sensory and multisensory processing in children with autism spectrum disorder.