Recently Completed Projects | Overview
Early Childhood Cognitive Stimulation and Successful Transition to Preschool in a Disadvantaged Population in Rural Pakistan *Boston Children’s Hospital/Harvard University & Aga Khan University Eighty-eight million young children worldwide are estimated to drop out of school before completing primary (elementary) school. In Pakistan and many other developing countries, this presents a significant problem for economic growth. The high drop out rate is associated with a range of factors such as poor cognitive stimulation, inadequate nurturing and malnutrition in early life. In this study, we will follow a group of children who received cognitive stimulation and responsive parenting intervention in their first 2 years of life as part of the Pakistan Early Child Development Scale Up (PEDS) Trial. The goal is to evaluate whether these children make a more successful transition from home to preschool at 4 years of age. The PEDS Trial was implemented to determine whether early cognitive stimulation and a responsive parenting intervention, either alone or in combination with a nutrition intervention, could improve development and growth outcomes in the first 2 years of life. The parenting intervention was a local adaptation of the UNICEF and WHO ‘Care for Child Development’ module. Female health workers delivered the interventions through monthly community group meetings, which provided primary caregivers with advice on improved early nutrition and/or child development, and allowed them to practice different play activities that promote cognitive stimulation in young children. This was followed up by a home visit to check how caregivers were implementing intervention advice. We will follow the PEDS Trial cohort during the transition period from home to preschool at 4 years of age in order to identify effects of this intervention on school readiness in disadvantaged children living in rural Sindh, Pakistan. This study will provide evidence on how early cognitive stimulation influences children’s executive functioning skills, brain development, and school readiness as well as family commitment to helping children achieve future potential. A multidisciplinary approach will be used and we will capitalize on the original cluster RCT design by collecting data in order to understand processes at the child, caregiver, and community levels. At the level of the child, we will measure executive functions, school readiness skills, brain development, stress reactivity, health and nutrition status, and child/caregiver interactions. At the level of the primary caregiver, we will measure emotional wellbeing, cognitive abilities, care-giving practices and home environment in order to capture factors that may affect child outcomes. At the community level, we will assess whether participation in the ECD interventions influenced expectations for education of children in the community. We will also assess current preschool and school enrollment rates in the intervention and control communities. By learning more about these factors, we aim to shed light on ways to better support children who need to successfully regulate their behavior and attention in order to adapt to the preschool environment. We also hope to provide valuable evidence to policy makers who have the power to allocate public funding to early childhood interventions.
The purpose of this study is to learn more about how infants process pictures of familiar objects and word sounds during their first 1.5 years of life. In order to investigate how age influences infants’ perceptions, we will measure brain activity as 6-9 month and 12-15 month old infants look at pictures of familiar objects and/or hear familiar words.
Rett Syndrome (RTT) is a genetic disorder caused by a single mutation on the X-chromosome. RTT is characterized by toddlerhood regression of motor and language milestones, as well as onset of stereotypies, breathing abnormalities and gastrointestinal complications. Currently, methods for measuring neural function in girls with Rett Syndrome do not exist, but they are urgently needed so that researchers can learn more about how to treat this neurodevelopmental disorder. One potential pathway toward assessing neural function is through the visual system. We know a great deal about how this system functions in the brain, and can therefore draw conclusions about other neural networks based on how the visual system performs. This has been shown in previous work done in mouse models of RTT, which used assessments of the visual system in order gain information about functional levels in related neural networks. Researchers have also identified a drug that helps RTT mice develop with normal brain functioning. This drug is now being tested in a human clinical trial at Boston Children’s Hospital, and our goal is to build on the mouse model research in order to determine the effects of the drug in human use. We will be using EEG to measure neural function in response to visual stimuli, both before and after treatment. In addition to assessing the effectiveness of this new drug, our goal is to identify a reliable biological marker that can be used for earlier identification and improved assessment of clinical interventions.
The current study is part of the Autism Center of Excellence (ACE Network) which includes researchers from Yale University, UCLA, the University of Washington, and Boston Children’s Hospital. The purpose of this study is to identify gender differences in brain structure, function, connectivity, and genetics in children and adolescents with autism spectrum disorders (ASD). Currently, autism spectrum disorders affect more males than females. Research indicates that males are 5 times more likely to be diagnosed with ASD. By learning more about these gender differences, we aim to improve techniques for diagnosis and interventions. In order to thoroughly investigate the questions we are asking, we will be using a variety of methods: neuropsychological testing, EEG, fMRI and a genetics portion. For this study, we will be enrolling three groups of children: children diagnosed with an ASD, siblings of children with an ASD diagnosis, and typically developing children without a brother or sister with an ASD.
Tuberous Sclerosis Complex (TSC) is a genetic disorder caused by mutations in either the TSC1 or TSC2 genes. TSC is characterized by the widespread growth of benign, tumor-like nodules called hamartomas in multiple organ systems, including the brain. It is strongly associated with cognitive impairment, behavioral disturbances, and autism spectrum disorders (ASD), and these neurodevelopmental disorders can cause significant disability from early infancy through adulthood. Cognitive impairment has been reported in 44-80% of individuals with TSC, ranging from learning disabilities to more profound intellectual impairment. We are using behavioral tests as well as measures of the brain’s electrical response to faces to characterize the development of children with and without TSC and evaluate their risk for autism. We will follow infants from age three months through age three, at which time they will be evaluated for autism concerns. We will then determine if any early abnormalities in behavior and face processing can predict autism in these infants.
Complications during labor and delivery can result in the infant getting less oxygen than is needed for normal brain function. Certain areas of the brain, including those that are critical for learning and memory, are particularly hard hit by lack of oxygen and children who have experienced early oxygen deprivation often have damage to these areas of the brain. Many children who have incurred damage to learning and memory systems very early in life have difficulties with remembering information after a delay, navigating through new environments, and recalling everyday events. However, these impairments are often not noticed until the child goes to school. In the current project, we aim to use behavioral memory tasks, measures of brain activity and eye tracking to identify children who may be at risk for later learning problems, much earlier than is currently possible. In addition, we aim to determine whether certain patterns of brain damage are more likely to result in learning and memory problems than others.
In this study, we hypothesize that the adverse fetal events common in the diabetic pregnancy (i.e. iron deficiency, hypoxemia, and hypoglycemia) will have a deleterious and specific effect on the hippocampus. This should result in selective impairments in explicit memory due to the established vulnerability of this structure to these metabolic disturbances. Our results thus far have established a consistent pattern of deficits in recognition memory, from birth through two years of age, as inferred from electrophysiological data (event-related potentials) and behavioral data (Elicited Imitation). The goal of this protocol is to continue to study our cohort of children as they enter the elementary school years. We will do this by conducting detailed electrophysiological (ERPs), metabolic (fMRI), anatomic (MRI), and behavioral (neuropsychologic) studies on our current samples of IDMs and comparison children. Given that approximately 10% of all pregnancies are complicated by maternal diabetes, the current project has important implications for public health.
The ability to perceive and identify emotions in faces is crucial to maintaining successful social interactions, and it is often an area of difficulty for individuals with ASD. Although many researchers have explored behavioral and brain responses to ‘prototypical’ facial expressions (that is, very extreme examples of emotion), much less is known about how we respond to the more subtle expressions that characterize our daily interactions and to what degree that ability changes as we get older. This study is designed to learn more about how the brains of both children and adults respond to expressions of different emotions of varying intensities and whether our behavioral responses to these expressions are consistent with the brain’s response. For example, does our brain detect an emotion in a face even when we don’t think we’ve seen one. Finally, we are curious to learn whether where we look on a face (for instance, at the eyes or the mouth) plays a role in our response to emotional faces. This study will include both typically developing individuals and individuals with an autism spectrum disorder, and we hope that the findings will shed light on the specific areas of strength and difficulty for individuals with ASD. By gaining better insight into the complexities of emotional face processing, we may be able to contribute to a better understanding of the disorder and the design of more effective intervention programs and therapies.
Eighty-eight million young children worldwide are estimated to drop out of school before completing primary (elementary) school. In Pakistan and many other developing countries, this presents a significant problem for economic growth. The high drop out rate is associated with a range of factors such as poor cognitive stimulation, inadequate nurturing and malnutrition in early life. In this study, we will follow a group of children who received cognitive stimulation and responsive parenting intervention in their first 2 years of life as part of the Pakistan Early Child Development Scale Up (PEDS) Trial. The goal is to evaluate whether these children make a more successful transition from home to preschool at 4 years of age. The PEDS Trial was implemented to determine whether early cognitive stimulation and a responsive parenting intervention, either alone or in combination with a nutrition intervention, could improve development and growth outcomes in the first 2 years of life. The parenting intervention was a local adaptation of the UNICEF and WHO ‘Care for Child Development’ module. Female health workers delivered the interventions through monthly community group meetings, which provided primary caregivers with advice on improved early nutrition and/or child development and allowed them to practice different play activities that promote cognitive stimulation in young children. This was followed up by a home visit to check how caregivers were implementing intervention advice. We will follow the PEDS Trial cohort during the transition period from home to preschool at 4 years of age in order to identify effects of this intervention on school readiness in disadvantaged children living in rural Sindh, Pakistan. This study will provide evidence on how early cognitive stimulation influences children’s executive functioning skills, brain development, and school readiness as well as family commitment to helping children achieve future potential. A multidisciplinary approach will be used and we will capitalize on the original cluster RCT design by collecting data in order to understand processes at the child, caregiver, and community levels. At the level of the child, we will measure executive functions, school readiness skills, brain development, stress reactivity, health and nutrition status, and child/caregiver interactions. At the level of the primary caregiver, we will measure emotional wellbeing, cognitive abilities, care-giving practices and home environment in order to capture factors that may affect child outcomes. At the community level, we will assess whether participation in the ECD interventions influenced expectations for education of children in the community. We will also assess current preschool and school enrollment rates in the intervention and control communities. By learning more about these factors, we aim to shed light on ways to better support children who need to successfully regulate their behavior and attention in order to adapt to the preschool environment. We also hope to provide valuable evidence to policy makers who have the power to allocate public funding to early childhood interventions.
The primary goal of this study is to examine how experience contributes to the development and neural bases of face processing. The overarching hypothesis is that experience with faces recruits specific neural circuits that become specialized for processing faces. We are exploring a specific model of how experience influences the development of face processing, also known as perceptual narrowing. A series of studies is outlined in a larger NIMH-funded project that examines how the timing, amount, and duration of different types of experience influence the development and neural bases of face processing. This study aims to further our understanding as to how the ability to recognize faces of different ages is influenced by experience viewing such faces. The premise underlying this study, as well as the larger project, is that the perceptual window through which faces are viewed is broadly tuned at birth, and narrows with experience. This study is employing both electrophysiological (event-related potentials) and behavioral (eye-tracking) measures. We are testing 6-month-old infants, 3- & 4-year-old children, and adults. Children and adults with varying degrees of experience viewing newborn faces are specifically being sought for participation: children with and without younger siblings, adults who have extensive experience viewing newborn faces (nurses working in a newborn nursery, daycare providers, and parents with a children under one year of age), as well as adults without in-depth experience viewing infant faces. We will be testing the hypothesis that the ability to recognize newborn and adult faces is modulated by the amount of experience one has accumulated with these types of faces.
When infants are born they have a very wide perceptual window through which they are able to process all different kinds of stimuli. As they grow and develop, their brains begin to tune in to those objects in the world that are most functionally significant. In other words, they become better at processing the kinds of objects, such as faces, that are most common in their environment. This process is known as perceptual narrowing. Over the course of the first year, infants quickly develop a specific set of brain networks to help them interpret faces, which are a special class of object and carry important social cues like identity and emotion. As part of this process, infants are already beginning to “specialize” in the kinds of faces they see most often. In fact, previous research has demonstrated that adults are “face experts” who are most adept at recognizing and remembering faces of their own race, gender, age, and species. In the current study, we will examine infants’ discrimination of male and of female faces while taking into consideration the infants' experiential history with faces of different sexes. We specifically aim to recruit participants who have varying degrees of experience with male and female caretakers. An in-depth questionnaire, administered at the beginning of the session, will help us to establish an approximate male to female “care giving ratio” for each child. Using our Tobii Eye Tracking system, we will be able to track each participant’s eye movements as they are presented with photographs of male and female faces in a simple discrimination task. In a separate task, we will record the infant’s brain activity (or EEG) as he or she looks at a series of male and female faces. In this part of the session, repeated stimuli will help us to determine how differential experience with either males or females can affect an infant’s ability to recognize and remember the two different categories of faces. The results of this study will not only further our understanding of the typical development of facial recognition strategies but will also provide an important baseline against which we can measure the behavior and looking patterns of children who show differences in facial recognition, such as children diagnosed with Autism Spectrum Disorders.
During the first years of life as infants are learning to crawl and walk, they build an increasingly sophisticated understanding of the space around them. Previous studies suggest that there are two distinct strategies to learning spatial representations and that these strategies emerge at different times during development. The first is an egocentric spatial memory (memory for locations is coded in relation to the body) that has been observed as early as a few months old. The second is an allocentric spatial memory (memory for locations is coded in relation to the surrounding environment) that emerges around preschool age. In this project, we aim to study the development of these two memory abilities and understand the specific neural circuits underlying them throughout early childhood. Given the impact of several neurodevelopmental disorders, such as autism, schizophrenia and Down syndrome, on the behavioral and neural components of memory, it is of particular interest to understand the development of memory and the neural circuits underlying it.
Previous studies have shown that, between 5 and 7 months of age, developmental changes take place in babies’ ability to recognize and respond to facial expressions of emotion. At 7 months, babies prefer to look at faces that express emotions, such as fear, whereas 5-month-olds do not yet show this preference. The purpose of the current study is to investigate where and how this developmental shift occurs in the brain. We hypothesize that during this period of development certain areas of the brain reach functional maturation, specifically a network that includes emotion-related neural systems like the amygdala, as well as visual and attention-related systems. As a result, by 7 months babies begin to show this preference for faces that show an expression of emotion. The ability to perceive and identify emotions in faces is crucial to maintaining successful social interactions. By learning more about how these brain systems develop, we aim to gain insight into typical patterns of emotional and social development. In gaining a better understanding of these typical patterns we also hope to shed light on how and why these patterns often differ in individuals with certain disorders, including anxiety and autism spectrum disorders. We also hope that our work will be useful for future studies examining individual differences in emotion processing.
*University of Minnesota, Twin Cites- Center for Neurobehavioral Development *Center for Human Growth and Development, University of Michigan *Wayne State University, Detroit MI *Boston Children's Hospital- Division of Developmental Medicine, Laboratories of Cognitive Neuroscience This multi-site program-project is examining the developmental effects of early iron deficiency in human infants, monkeys, and rodents, as well as the long-term consequences of iron deprivation in monkeys and rodents. While Dr. Georgieff continues to study the effects of iron deficiency in rodents, Dr. Nelson and Ms. Westerlund are working with the infant study site that is based at Wayne State University in Detroit, MI. Infants are identified at 9-months of age as iron deficient with anemia, iron deficient without anemia, or nonanemic controls. The assessment at 9-months include visual evoked potentials, visual acuity, spatial working memory, motor development, spontaneous motor activity, and recognition memory (visual paired comparison and ERPs). All infants are treated with a daily dose of iron for 3 months. There is then a re-evaluation of brain and behavior measures at 12-months. This study will help determine whether iron deficiency with or without anemia alters specific central nervous system functions, as well as help identify alterations that respond to iron therapy and ones that do not.
Previous research with infants has shown that 6-month-olds are capable of discriminating between both human faces and monkey faces. In other words, if you show a 6-month-old two monkey or two human faces side by side, she will be able to tell them apart. However, by the age of 9 months, infants lose the ability to discriminate between the monkey (other-species) faces. This phenomenon, broadly known as perceptual narrowing, is the focus of the current study. We know that as babies develop, they begin to specialize in interpreting the faces that they see most often in their surroundings, while losing the ability to interpret the types of faces that they see less often, such as monkey faces. This developmental trajectory is the underlying hypothesis for why adults are much better are processing faces of their own race, gender, and species. By using a Tobii eye-tracking system to record scanning and fixation patterns, we hope to gain insight as to why and exactly how younger infants are able to tell the difference between two monkey faces, and older infants are not. If 6-month olds employ more rudimentary looking patterns, while 9-month olds use more sophisticated, adult-like face scanning patterns, this will be reflected in the eye-tracking data. The results of this study will not only further our understanding of the typical development of facial recognition strategies, but will also provide an important baseline against which we can measure the behavior and looking patterns of children who show differences in facial recognition, such as children diagnosed with Autism Spectrum Disorders. How can we tell if infants are discriminating between two faces? Infants consistently show a novelty preference, which means that they will look longer at something that is new, rather than something they have seen before. To test whether or not infants can discriminate between two faces, we familiarize them with a single face and then present them with that same face next to a new one of the same type (monkey or human). We can infer that infants who look longer at the new picture are not only remembering the first face, but they are successfully discriminating between the two (one is new and exciting, the other is old and boring). Conversely, if they look equally at the old and the new face, we can infer that they cannot discriminate between the two.
The ability to process and remember faces is critical to social interactions. Research with adults suggests, however, that not all faces are created equal in perception and memory. For example, adults are better at processing same-race, same-gender, and same-age faces than they are at processing other-race, other-gender, and other-age faces. This effect is known as "own-group bias." When do children begin to show own-group biases, and what is the role of experience in their development? In this study, we are interested in whether and how infants categorize faces according to visual information about race and ethnicity, as well as what role experience and environment might play in the development of such social category perception. In the study, infants see pictures of White and African-American faces, and we measure their brain activity while they watch these pictures. The way in which infants respond to these faces is of particular interest to researchers, as babies have yet to experience the many social influences that affect the race-based perceptions and biases of children and adults.
Phase 2 is a double-blinded, placebo-controlled cross-over study designed to test the efficacy of IGF-1 for treatment of Rett syndrome. The Nelson Lab uses both EEG and a cognitive developmental assessment to evaluate changes in cortical function across treatment. For the EEG, we do this by evaluating two well characterized systems in the brain (the auditory system and the visual system). We use traditional ERP paradigms as well as steady-state presentation of auditory and visual stimuli and power spectra analysis to assess cortical function of V1 and auditory cortex. In addition, the Nelson Lab has adapted the Mullen Scales of Early Learning for use with children with Rett syndrome.
Previous studies on the development of emotional face processing have shown that by 7 months of age, infants have the ability to categorize (i.e., to recognize the same expressions posed by different models to a common class) at least happy and surprised expressions, while the recognition of negative emotions (e.g., fear and anger) seems to be less developed. However, by the same age, infants show an attentional preference for fearful over happy faces. This is shown in looking time and electrophysiological measures. Such attentional preference could be considered to reflect a rudimentary understanding of the social meaning of fearful faces in 7-month-olds. In the present study we will examine this hypothesis in more detail. We will track infants' eye movements while they are presented with a task designed to assess disengagement of visual attention from different facial expressions. This study will be important in highlighting the co-development of emotional and attentional processes and in further determining whether infants as young as 7 months of age are able to recognize the social meaning conveyed by fearful faces.
The ability to remember things and reason through everyday problems is critical to living successfully as an adult. Research suggests that these abilities have a long developmental trajectory over the course of childhood and into adolescence. This long trajectory of development is different than other abilities which are solidified when children are relatively young, like vision. Because of this long trajectory we believe that these abilities might be much more impacted by the experiences a child has and their reactions to these experiences. What parts of a child’s experiences or reactions might result in differences in their ability to plan, organize, and remember things? Could their reaction to mildly stressful experiences be part of what affects their brain development? In this study, we are interested the effects of stress on the development of planning and memory abilities in children and the associated brain areas. In the study, children first have their heart rate measured while they count backwards from a high number, an experience which raises their heart rate slightly, a measure of the child’s sensitivity to stress (session 1). Next, they look at some pictures of people and houses which they try to remember while we record their brain waves (session 2). In addition, during this session we have them and their parent/guardian do some puzzles and vocabulary games. Finally we invite them to come to CHB Waltham where they get an MRI of their brain while playing more memory and planning games. The way in which children perform these tasks is of particular interest to researchers, as children’s brains are still in the process of developing and changing. Using these tasks we can tell if a child’s sensitivity to stress is related to their brain function when they are doing memory and planning games. A child’s performance on memory and planning games predicts success in school and may be related to health in adulthood. By learning how stress sensitivity is related to these brain functions we can find ways to insure that all children have the kind of environment in which they can flourish.
The ability to process emotional information in faces and voices is critical to everyday social interactions. Children with autism have difficulties understanding the emotions of others, and research has shown that they also have atypical brain responses to faces posed in emotional expressions, which may contribute to their difficulties in social interaction. In this study, we are interested in learning more about how children with autism process emotional information in faces and voices, and how they use that information to develop expectations about what information might come next.
Despite the wide-ranging and prolonged interest in face recognition abilities and ample evidence that faces constitute a "special" class of stimuli, it is still unclear as to why or how face processing becomes specialized. Empirical evidence has indicated that face processing abilities in adults are impaired when stimuli are inverted, which has lead some researchers to posit that extensive experience with upright faces leads to this specialization of function. Additionally, previous research by de Haan and colleagues (2002) has suggested that specialization of cortical face processing circuits develops gradually over the first year of life, possibly due to increasing experience with faces. The purpose of this study is to examine how extensive experience with a specific face influences the development of the neural activity underlying face recognition during the first six months of life, in hopes of determining whether face recognition is an acquired expert system derived via experience-dependent or experience-expectant mechanisms. Specifically, we record six-month-old human infants' event related potentials (ERPs) while they view pictures of their mother's face, in both upright and inverted orientations, from 64 locations on the scalp using an EGI system. Additionally, another group of six-month-old infants view pictures of their father's face and a male stranger's face. Preliminary results provide support for the argument that specialization of face processing is influenced by experience.
Infants' looking behavior has long been used as an index of their memory. Preferential looking tasks, such as the visual paired-comparison (VPC) procedure, typically involve a familiarization phase in which the infant is shown a pair of identical stimuli until a fixed amount of looking time is accumulated. Following a delay, infants are shown another pair of pictures; this time one is the same as the familiarization stimulus and one is new. Visual behavior is recorded and memory is typically inferred if the infant exhibits a novelty preference, that is, spends more than 50% of the test phase fixating the novel stimulus. Although infants most commonly exhibit novelty preferences when tested on preferential looking paradigms, sometimes the similarity between objects that we choose to be novel vs familiar influences infants' visual preferences. In this study, we aim to understand the effect of stimulus discrepancy on VPC performance. To do this, we measure both visual behavior and ERPs in response to familiar, discrepant and novel stimuli. This project is unique because it aims to look at the relation between electrophysiological and behavioral indices of memory.
Face recognition is an extremely difficult task that adults usually manage to perform almost effortlessly. However, adults generally find faces that belong to "out-group" categories harder to tell apart than faces that belong to the "in-group." When talking about racial and ethnic categories, this is often referred to as the "other-race effect." In this study, we are interested in understanding what visual information makes a face look like it belongs to one race or another, and also studying how the brain responds to these visual cues. During the experiment, participants will watch Caucasian and African faces while we measure their brain activity. We use computer-generated faces to study how face shape and face pigmentation contribute to making a face look like an "other-race" face. In particular, some of the faces have had their skin tone changed so that they still have their original shape, but look like they belong to the opposite category. Measuring brain responses in this study helps us understand the difference between recognizing the faces we are "experts" at and faces that we see less often. By combining this information with the results of our infant study on the same subject, we hope to illuminate the full trajectory of this developmental process.
The ability to process emotional information in faces and voices is critical to everyday social interactions. Children with autism have difficulties understanding the emotions of others, and research has shown that they also have atypical brain responses to faces posed in emotional expressions, which may contribute to their difficulties in social interaction. In this study, we are interested in learning more about how children with autism process emotional information in faces and voices, and how they use that information to develop expectations about what information might come next.
In early infancy, babies are able to recognize faces from a wide range of categories including faces of different species, genders, and races. As they grow older, however, infants begin to show what is known as an "other-race effect." This means that faces belonging to ethnic groups that babies see less often become harder to tell apart. In this study, we are interested in determining how infants' use their experience with different kinds of faces to determine what to look for when recognizing, and possibly categorizing, a face. During the experiment, infants watch Caucasian and African faces while we measure their brain activity. We use computer-generated faces to study how face shape and face pigmentation contribute to making a face look like an "other-race" face. Face perception is a critical piece of social development. From a very early age, infants build categories of faces, but we don't yet know whether they define these categories according to face shape, pigmentation, or other measures. By measuring the brain responses of infants in this study, we hope to determine how these factors contribute to this aspect of visual learning.
Young infants' memories are very context specific. As infants grow older, however, their dependence on contextual cues for retrieval diminishes and they are able to exhibit retention even when tested in a new environment (Hayne, 2004). Although well documented behaviorally, very little is known about how brain development is related to infants' ability to use their memories flexibly. This study will investigate how changes in brain response contribute to age-related changes in memory flexibility during the first year of life. Infants will be tested using a deferred imitation paradigm developed by Hayne and colleagues (Barr, Dowden, & Hayne, 1996; Hayne Boniface, & Barr, 2000.) During the first session, infants will be shown a series of actions that can be performed using an animal hand puppet. Twenty-four hours later, infants will be tested using both ERPs and the traditional imitation test. At testing, infants will be randomly assigned to either the context-change group or the context-same group. For infants in the context-same condition, testing will occur in the same laboratory room in which the demonstration phase occurred. For infants in the context-change condition, testing will occur in a different laboratory room. Previous research using this deferred imitation task has shown that while 12-month-old infants will imitate the actions even when they are tested in a new context, 6-month-old infants will only imitate if they are tested in the same context in which the demonstration occurred (Hayne, Boniface, & Barr, 2000). In this study, we aim to investigate the neural basis of this age-related change in memory flexibility by looking at how ERP components that are sensitive to novelty and familiarity are affected by changes in context in 6- and 12-month-old infants.
Several recent studies have demonstrated that infants show different behavioral and brain responses when viewing their mother's face as compared to viewing a stranger's face (Barrera & Maurer, 1981; de Haan & Nelson, 1999). However, the reason for why this occurs is still unknown. Potentially, these differences are caused by the emotional salience attributed to Mom compared to a stranger, through infants' extensive interactions with her. In contrast, these differences in behavior and brain activity could be due to the relative familiarity of Mom compared to a stranger - most infants see Mom's face far more often than any other face. In order to distinguish between these two possibilities, infants are divided into two groups. Parents of the "experience" group are given a realistic 3D model of a woman's face to keep in their homes starting when their babies are 2 months old. The 3D models have neutral facial expressions and do not move, so that emotional salience is likely not attributed to them. After 1 month of experience with the 3D models, the infants are brought in to our lab and event-related potentials (ERPs) are recorded while they view pictures of the familiar face and an unfamiliar face. Parents of the "no-experience" group bring their infants into our lab after they are already 3 months old and are familiarized to one of the 3D models for a short period of time. We then record ERPs while they view pictures of the familiar face and an unfamiliar face, similar to the "experience" group. The overall goal of this study is to determine how these different kinds of experiences affect infants' processing of familiar and unfamiliar faces. Therefore, we will examine how ERP components that are sensitive to novelty and familiarity differ across the two groups of infants.
*Boston Children's Hospital- Division of Developmental Medicine, Laboratories of Cognitive Neuroscience *Universiti degli Studi di Milano - Bicocca, Italy A number of behavioral studies have shown that newborns' visual attention is spontaneously attracted toward face-like visual configurations, raising the possibility that an experience-independent mechanism dedicated to face processing exists at birth. Recent studies question this conclusion, suggesting that the apparent preference for faces over non-faces in newborns reflects non-specific basic visual preferences rather than content-determined preferences. For example, Turati et al. (2002) recently demonstrated that one of the general structural properties that is crucial in determining newborns' face preference is the presence of an up-down asymmetry in the distribution of the elements within the shape, with a higher density of elements appearing in the upper visual field. This evidence suggests that the face processing specificity, assumed in the adult perceptual and neural system, may be induced by an experience-expectant developmental process (Nelson, 2001), through which circuits in the developing cortical pathways involved in visual recognition gradually become specialized for face processing. Our hypothesis is that selectivity for the specific geometry of the face may be learned during the first 2 or 3 months of life arising from the non-specific attentional bias toward patterns with more features in the upper versus lower half. In the current study we predicted that selectivity for the specific geometry of the face may emerge during the first 3 months of life as a product of perceptual narrowing resulting from experiential input, leading to the construction of the first broadly defined face category segregating faces from other visual objects which may share with faces one or more visual properties. In the current investigation we examined whether there is electrophysiological differentiation at 3 months between face and non-face stimuli. Event-related-potentials (ERPs) were recorded from 62 scalp electrodes in three separate experiments: 1) while infants viewed pictures of faces and scrambled faces which were matched to the natural face for the number of elements appearing in the upper part of the configuration, 2) while infants viewed pictures of faces and geometric patterns in which all characteristics common to faces were removed, except the top-heavy property, and 3) while infants viewed pictures of faces, as well as toys that shared no specific properties with faces. ERP results from Experiment 1 showed evidence of differentiation between the face and scrambled stimuli, but only for the N700 component. No differentiation was found for earlier components that are thought to reflect the adult-like structural encoding stage of face processing in infants (N290 and P400). Results from Experiment 2 also revealed no differentiation between faces and top-heavy geometric stimuli for early ERP components (N290, P400). Experiment 3 revealed differentiation between faces and toys for the P400. All categories of non-face stimuli were differentiated from faces at later attentional components. These findings suggest that the top-heavy property still plays a role in triggering brain responses to faces at 3 months, but by this time faces have been salient enough to recruit differential attentional responses. This may reflect the high degree of familiarity and/or the social value faces have gained over the infants' first 3 months of life. Implications of this work: There are a number of childhood disorders that result in facial processing deficits. This project was designed to more closely examine aspects that drive infants' basic visual preferences for faces early in life. By better understanding how a specific face template develops during the first 2-3 months of life, we may be better able to identify infants at risk for developing difficulties with facial processing. Early identification of such individuals would allow us to develop more effective and time-sensitive interventions.
Avoidance of social interactions is one of the characteristic features of autism spectrum disorders (ASDs). The goal of this research study is to see if children with autism find social stimuli (for example, faces showing different emotions) as aversive. This study is going to look at the possibility that people with autism may view these types of pictures/interactions as aversive, rather than finding them unimportant or uninteresting. This may mean that people with autism avoid social interactions as a means of reducing anxiety. The nature of social avoidance is thought to be the result of finding social interactions aversive, particularly with unfamiliar individuals. In this protocol, we will use eye tracking equipment that records looking time data and eye-gaze data as well as pupil size as a response to seeing pictures. We will use this data together with scalp EEG and electrophysiologic measures to look at the response to seeing pictures of different faces/emotions in children with and without autism.
Children with autism often have repetitive movements and other motor difficulties that may reflect dysfunction of a particular part of the brain, known as the striatum. The striatum is responsible for pattern-based learning (also called implicit learning or implicit memory), reward-processing, and control of movements. It is also the target of medications like Risperidone, which is used to treat irritability and aggression in children with autism. Why some children respond so well to Risperidone and others do not may reflect differences in brain circuits. Our study proposes to study striatal function, and to characterize repetitive movements, motor function, and pattern-based learning in young children with autism. Pattern-based learning will be investigated through a serial reaction time task using eye tracking and high density EEG. We hypothesize that we will be able to define a subgroup of children with striatal dysfunction and that their motor impairments may predict specific cognitive deficits. Our study represents an attempt to define a more uniform subgroup within the autism spectrum. Only in doing so will we be able to create targeted, brain-based treatments for children affect by this disorder.