Peter Marshall - US grants

A recent focus of psychopathology research has been the identification of factors that promote lowered risk for psychopathology as well as those that enhance vulnerability to affective disorder. Two constructs that have each been associated with lowered risk are relative left frontal electroencephalographic (EEG) asymmetry and a repressive- defensive coping style. The focus of the proposed research is the relation of these constructs to a current major model of hemispheric asymmetry in which affective lateralization of hemispheric function occurs along a dimension of incentive-related approach and punishment- related withdrawal responses. Subjects who report a repressive coping style are predicted to show sustained increased relative left frontal hemispheric activation throughout incentive-related trials of a warned- reaction-time task in which feedback becomes increasingly negative as the task progresses. This would reflect the hypothesized increased motivational sensitivity to incentive in repressors compared to subjects who report a non-repressive coping style, who are not predicted to sustain high levels of relative left frontal activation across such a task. Although the proposed sample will not specifically be drawn from a clinical population, the findings will have implications for the study of affective disorders, especially given the putative roles of left frontal EEG asymmetry and a repressive coping style in conferring lowered risk for the occurrence of depressive episodes.

Throughout our daily lives, we frequently observe other people carrying out various actions. How do we process these actions and come to understand the goals and intentions of the people that we are watching? Historically, the brain systems underlying the perception of an action and the actual carrying out of an action have often been considered to be quite separate, but recent research has suggested substantial overlap. One recent theory suggests that recognizing and understanding an action involves brain systems that would be involved in carrying out the same action--the ?mirror neuron system? (MNS). On that theory, in order to understand someone else's actions, our own brains actually covertly mirror that person's actions. The MNS was originally identified in monkeys, and recent work has suggested that a similar system also exists in humans. However, one key aspect of the MNS that is relatively unexplored is the development of the coupling between the perception and action systems during action observation. With support from the National Science Foundation, Drs. Peter Marshall and Thomas Shipley at Temple University are carrying out a series of studies designed to elucidate the development of the MNS. The studies involve infants, preschoolers and adults participating in different tasks which are designed to assess the overlap between the perception and action systems during action observation. These tasks include the passive viewing of human actions, the recognition of oneself performing an action, and the imitation of novel actions. During some of the tasks, the electroencephalograms (EEG) will be recorded. In combination with analyses of participants' overt behavior during these tasks, it will be determined whether motor areas of the brain are indeed active while infants and children observe human actions. The research will also investigate how this brain activity relates to other behavioral measurements of the coupling between perception and action, and how the patterns of brain activity relate to young children's abilities to understand and copy the actions of others.

The studies involve the active participation of undergraduate and graduate students at all stages of the research process. They have clear potential for being broadcast to professionals and laypeople interested in how children and adults process and understand other people's actions. The result may help us understand pervasive developmental disorders such as autism, which are characterized by deficits in imitation and social cognition and which may involve disruptions in MNS function.

DESCRIPTION (provided by applicant): Infants'Processing of Actions and Goals: A Social Neuroscience Approach. How do we come to understand the actions of other people? What neural systems are associated with understanding others, and how do these systems develop? Addressing these critical questions has far- reaching implications for understanding both typical and atypical human development. Much current interest in this area concerns whether the neural systems involved in infants'own production of actions are also active during the perception of similar actions by others. Debate in this area has centered on the nature and function of this putative shared activation in terms of its role in early action understanding. Until recently, such discussions have largely been speculative, calling for more data, rather than being able to summarize empirical results. Studies from our own and others'laboratories have begun to modify this picture through the application of electroencephalographic (EEG) techniques to the study of intermodal links between perception and production in infants'action processing. Recent work in this area has focused on a particular measure, the desynchronization of the sensor motor mu rhythm during action observation by infants. However, it remains very difficult to say exactly what is being reflected by changes in the mu rhythm while infants are viewing other people's actions. In this proposal we take a highly innovative, integrative approach to this issue by tackling a key question that needs to be addressed in order to move the field forward: What specific aspects of observed actions is the infant mu rhythm response sensitive to? In the proposed work we will make significant inroads into this critical problem by connecting recent findings from neuroscience with the extant literature on infant imitation, leading to a potentially powerful confluence of subfields within developmental science. The proposed work is a step toward building bridges between the emerging infant neuroscience work and the corpus of behavioral evidence showing the flexibility of human imitation. PUBLIC HEALTH RELEVANCE: The proposed research addresses specific questions concerning how human infants process other people's actions, and as such is relevant to understanding how children typically develop an understanding of others. Developing an integrative knowledge base in this area has important implications for the study of both typical and atypical development. As such, knowledge gained through the proposed work may contribute to the study of developmental disorders which are characterized by deficits in social relatedness (e.g., autism).

From the moment of birth, humans begin to form social relationships with others. These relationships, of course, become increasingly more complex across infancy, childhood, and beyond, but the abilities that support this development likely have their foundations in early infancy. The focus of this research project is on one such ability, infants' recognition that there is a correspondence between their own bodies and those of others (such as recognizing one's own hand as the same body part with the same function as one's parents' hands). This recognition of bodily correspondences requires that infants have a basic sense of the structure of their own bodies despite not being able to see them from the outside. This research investigates how infants' brains are organized to recognize and organize information about their own bodies, how this changes over development, and how it might influence their ability to recognize bodily correspondences with others.

This award supports studies in which electroencephalographic (EEG) methods will be used to study the properties of somatotopic body maps in the first weeks and months of life. Specifically, mu rhythm desynchronization and event-related-potential (ERP) responses in one-month-old infants will be measured in response to tactile stimulation of the hands, feet, and lips, with the spatial pattern of these responses being used to chart body maps in the developing human brain. The investigators anticipate that the magnitude and patterning of these brain responses may be modified when the infant is attending to the movements of other people during the periods of tactile stimulation. This will inform how body maps in the infant brain may be part of an early process relating self and other at a bodily level.

A great deal of research with adults has documented the presence of body maps in the human brain. These neural maps have an organized spatial layout. Neighboring parts of the body are connected in an orderly fashion to areas of the brain that process touch and movement. Body maps are important for many aspect of everyday life including the sense of one's own body and controlling our movements. Body maps also likely play an important role in learning from others, through allowing us to register similarities between ourselves and other people. Despite the importance of body maps, very little is currently understood about how they develop in the early months and years of life. The research supported by this award would provide significant new information on the development of body maps and their relation to early learning. The award supports a collaborative, cross-disciplinary network of investigators who will combine expertise in developmental psychology and infant learning, brain science, cognitive science, computer modelling, and robotics. The proposed network will also support the development and training of junior investigators through specific activities designed to expose them to the benefits of an interdisciplinary approach.

Advances in methods for safely measuring the brain activity of human infants are allowing new questions to be asked concerning the role of body maps in early learning. The proposed research involves using magnetoencephalography (MEG) to non-invasively measure responses of the infant brain to tactile stimulation of different parts of the body (e.g., hands vs. feet), and to relate these responses to aspects of infant learning. Another set of studies involving electroencephalography (EEG) will examine how body maps facilitate early imitation and learning from others. Insights from these studies will inform (and be informed by) a further strain of research using computer modelling that takes bodily factors into account in designing robotic systems that can learn from people. The research questions will also provide insight into the control of brain-computer interfaces that can assist disabled individuals in learning to control artificial limbs and other external devices.

? DESCRIPTION (provided by applicant): The proposed work addresses a clear gap in the literature on the early development of neural body maps, and as such will provide novel insights into a fundamental psychological task accomplished by the human infant: The recognition of similarities and differences between self and others. While this capacity is the bedrock of human social cognition, little is known about the neural processes involved in the early registration of correspondences between self and other. Recent work has suggested that studies employing the infant electroencephalogram (EEG) can shed light on the mechanisms that establish and support this prelinguistic mapping at the level of bodily actions. In particular, studies of the sensorimotor mu rhythm in the infant EEG, when taken together with developmental theory and extant behavioral data, are proving to be useful in illuminating the origins of imitative learning and interpersonal connections. In prior EEG work we showed the first evidence for the somatotopic organization of brain responses while 14-month-olds observed an adult's actions. These EEG findings are compatible with findings concerning body part specificity in behavioral imitation by younger infants, although various constraints have precluded the appearance of relevant neuroscience data from human infants in the first weeks and months of life. In the proposed studies we will expand on recent pilot work that has suggested a novel direction for assessing related EEG responses at younger ages. We propose two studies, one with 6-month-old infants and another with 1-month-old infants. In both studies we will analyze event-related EEG responses to discrete tactile stimuli delivered to the infant's hands and feet. In the study of 6-month-olds we will primarily examine whether the topography of the mu rhythm responses to the tactile stimuli is modulated by the infants' visual attention to a corresponding body part of a adult experimenter. In the study of 1-month-olds we will test for somatotopy of evoked responses to tactile stimulation of infants' hands and feet. As a further exploratory goal, in the second study, we will also examine the response to stimulation of the lower lip. The proposed work promises to open up exciting possibilities for studying developmental aspects of body maps, particularly their relation to social engagement processes, and the development of nascent interpersonal body representations in the first weeks and months of life.