COGNITIVE NEUROSCIENCE, 2011, 2 (3–4), 135–137
Introduction Cognitive neuroscience of bodily representations: Psychological processes and neural mechanisms Stephen R. Jackson1,2, Laurel J. Buxbaum3, and H. Branch Coslett4 1
School of Psychology, University of Nottingham, Nottingham, UK Department of Brain and Cognitive Engineering, Korea University, Seoul, South Korea 3 Moss Rehabilitation Research Institute, Elkins Park, PA, USA 4 Neurology, Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA 2
The past decade has seen increasing interest within the cognitive neuroscience community in understanding the psychological processes involved in representing the body, and in learning how these processes may be implemented within the brain. This special issue of Cognitive Neuroscience presents six new empirical papers that contribute to this rapidly developing literature, together with two theoretical discussion papers that are accompanied by peer commentaries.
Recent theorizing on the nature of body representations has primarily focused on a small number of partially overlapping themes, several of which are revisited in this special issue of Cognitive Neuroscience. One recurring theme within the body representation literature rests upon the notion that there appear to be multiple mental representations of the body in the brain, and has therefore been concerned with understanding the nature, function, and anatomy of each of these forms of representation. Such representations include classic distinctions, such as that drawn between “body image” and “body schema” (Head & Holmes, 1911/1912), as well as more recent conceptual entities, such as the “extrastriate body” (EBA) and “fusiform body” (FBA) areas, that have arisen as a consequence of the increasing use of functional brain imaging techniques to investigate how the brain represents the body. In this special issue, Downing and Peelen discuss the putative functions of the “extrastriate body” and “fusiform body” areas, particularly the proposal that, based upon the visual appearance of bodies, these areas
code explicit representations of identity, emotion, body movements, or goal-directed actions. They argue that the current evidence is not consistent with the proposal that either region performs either of these higher-level functions, and that the EBA and FBA instead consist of cognitively unelaborated perceptual representations. In their empirical paper, Mohamed and colleagues tackle a related question by investigating, using eventrelated electroencephalography, the effects that attentional load and stimulus inversion manipulations have on the processing of face and body stimuli. They conclude that while some event-related electrical potentials (e.g., N170) may reflect mandatory, categoryspecific, encoding in body- or face-sensitive cortical areas, others (e.g., late occipito-temporal negative components [LNC]) do not. Lesion studies in monkeys (Rushworth, JohansenBerg, & Young, 1998; Rushworth, Nixon, & Passingham, 1997) and in humans (Wolpert, Goodbody, & Husain, 1998), along with recent functional brain imaging studies in humans (Parkinson,
Correspondence should be addressed to: Stephen R. Jackson, School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK. E-mail: [email protected]
© 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business www.psypress.com/cognitiveneuroscience http://dx.doi.org/10.1080/17588928.2011.630723
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Condon, & Jackson, 2010; Pellijeff, Bonilha, Morgan, McKenzie, & Jackson, 2006), suggest that the posterior parietal cortex may play a particularly important role in maintaining an accurate and up-to-date representation of the current postural state of the body (the body schema). Furthermore, it is suggested that this body schema mechanism plays a key role in the mental transformation of bodily representations during mental imagery. In their fascinating paper, Hartmann, Falconer, and Mast investigate whether instructing healthy individuals to imagine themselves as being paralyzed affects their mental transformations of imitable and non-imitable body postures. They report that imagined paralysis selectively impaired mental transformation of imitable body postures but not non-imitable postures. To a large extent, and as illustrated in the papers outlined above, work examining the functions of the EBA and FBA consider situations in which faces, bodies, and their parts are viewed as objects. However, a second important and longstanding theme within the body representation literature has been to understand the psychological processes and neural mechanisms that underlie our subjective sense of body ownership: Particularly the distinction between the bodily “self” and the external “other”, and the processes and mechanisms through which external objects may be temporarily incorporated into the bodily “self” (i.e., the mechanisms of “embodiment”). One particularly important and popular technique that has been widely used to study phenomena associated with embodiment has been variants of the so-called “rubber hand illusion” (RHI), during which, following synchronous tactile stimulation (stroking) of the unseen real hand and the seen rubber hand, the participant comes to perceive the rubber hand as feeling as if it were part of their body. Understanding of this important issue is further elaborated upon by several of the empirical papers contained in the current special issue. Holle and colleagues investigate the necessary and sufficient conditions required to experience the RHI by manipulating factors predicted to strongly influence the process of embodiment: Postural congruence of the rubber limb with the body and the anatomical congruence of the rubber limb. Their results confirm the importance of these factors for establishing a robust RHI. In the first of two papers that appear in this special issue, Preston and Newport examine the related process of “disembodiment” of the limb. Using a novel virtual reality device, these authors investigate how the embodiment of a fake limb is affected by the apparent encroachment onto the fake limb by an apparently solid object. Their results again highlight important limitations in the conditions under which embodiment is likely to occur.
Zopf, Harris, and Williams report the results of an investigation into the role that body ownership cues have in our ability to detect and to discriminate somatosensory stimuli. Their findings indicate that body ownership cues induce reliable differences in our perception of somatosensory stimulation. In their second paper in this issue, Newport and Preston ask an intriguing question, namely, What happens to the real limb during the embodiment of a fake limb? While this question has been raised before in the context of RHI experiments, it is difficult to address this issue satisfactorily in standard RHI experiments because, as Newport and Preston correctly point out, typical RHI studies invariably induce a strong spatial mismatch between the viewed (fake) limb and the unseen (but proprioceptively sensed) real limb. In a clever experiment, Newport and Preston overcome this limitation using a novel VR device, and demonstrate that, in circumstances in which visual-proprioceptive mismatch is minimal, increased perceived “ownership” of a fake limb is accompanied by increased disembodiment of the individual’s real limb. A further major theme in the body representation literature is concerned with the awareness of bodily sensations and their relationship to human action. This issue is re-visited in the discussion paper by Jackson and colleagues, which focuses on the functional anatomy of the bodily sensations that we experience as urges for action. Jackson and colleagues discuss the defining characteristics of urges, with particular reference to pathological cases, such as the urgeto-tic in Tourette syndrome, and review evidence in support of the proposal that there is considerable overlap between the functional anatomy of urges associated with everyday behaviors such as swallowing, yawning, and micturition, and those urges associated with the generation of tics in Tourette syndrome. This collection of empirical and theoretical discussion papers and their commentaries provides a timely review of the current state-of-the-art in several of the most important topic areas of the body representation field.
REFERENCES Head, H., & Holmes, G. (1911/1912). Sensory disturbances from cerebral lesion. Brain, 34, 102–254. Parkinson, A., Condon, L., & Jackson, S. R. (2010). Parietal cortex coding of limb posture: In search of the body schema. Neuropsychologia, 48, 3228–3234. Pellijeff, A., Bonilha, L., Morgan, P. S., McKenzie, K., & Jackson, S. R. (2006). Parietal updating of limb posture: An event-related fMRI study. Neuropsychologia, 44, 2685–2690.
INTRODUCTION
Rushworth, M. F. S., Johansen-Berg, H., & Young, S. A. (1998). Parietal cortex and spatial-postural transformation during arm movements. Journal of Neurophysiology, 79, 478–482. Rushworth, M. F. S., Nixon, P. D., & Passingham, R. E. (1997). Parietal cortex and movement 1. Movement
137
selection and reaching. Experimental Brain Research, 117, 292–310. Wolpert, D. M., Goodbody, S. J., & Husain, M. (1998). Maintaining internal representations: The role of the human superior parietal lobe. Nature Neuroscience, 1, 529–533.
Copyright of Cognitive Neuroscience is the property of Psychology Press (UK) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Introduction Cognitive neuroscience of bodily representations: Psychological processes and neural mechanisms Stephen R. Jackson1,2, Laurel J. Buxbaum3, and H. Branch Coslett4 1
School of Psychology, University of Nottingham, Nottingham, UK Department of Brain and Cognitive Engineering, Korea University, Seoul, South Korea 3 Moss Rehabilitation Research Institute, Elkins Park, PA, USA 4 Neurology, Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA 2
The past decade has seen increasing interest within the cognitive neuroscience community in understanding the psychological processes involved in representing the body, and in learning how these processes may be implemented within the brain. This special issue of Cognitive Neuroscience presents six new empirical papers that contribute to this rapidly developing literature, together with two theoretical discussion papers that are accompanied by peer commentaries.
Recent theorizing on the nature of body representations has primarily focused on a small number of partially overlapping themes, several of which are revisited in this special issue of Cognitive Neuroscience. One recurring theme within the body representation literature rests upon the notion that there appear to be multiple mental representations of the body in the brain, and has therefore been concerned with understanding the nature, function, and anatomy of each of these forms of representation. Such representations include classic distinctions, such as that drawn between “body image” and “body schema” (Head & Holmes, 1911/1912), as well as more recent conceptual entities, such as the “extrastriate body” (EBA) and “fusiform body” (FBA) areas, that have arisen as a consequence of the increasing use of functional brain imaging techniques to investigate how the brain represents the body. In this special issue, Downing and Peelen discuss the putative functions of the “extrastriate body” and “fusiform body” areas, particularly the proposal that, based upon the visual appearance of bodies, these areas
code explicit representations of identity, emotion, body movements, or goal-directed actions. They argue that the current evidence is not consistent with the proposal that either region performs either of these higher-level functions, and that the EBA and FBA instead consist of cognitively unelaborated perceptual representations. In their empirical paper, Mohamed and colleagues tackle a related question by investigating, using eventrelated electroencephalography, the effects that attentional load and stimulus inversion manipulations have on the processing of face and body stimuli. They conclude that while some event-related electrical potentials (e.g., N170) may reflect mandatory, categoryspecific, encoding in body- or face-sensitive cortical areas, others (e.g., late occipito-temporal negative components [LNC]) do not. Lesion studies in monkeys (Rushworth, JohansenBerg, & Young, 1998; Rushworth, Nixon, & Passingham, 1997) and in humans (Wolpert, Goodbody, & Husain, 1998), along with recent functional brain imaging studies in humans (Parkinson,
Correspondence should be addressed to: Stephen R. Jackson, School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK. E-mail: [email protected]
© 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business www.psypress.com/cognitiveneuroscience http://dx.doi.org/10.1080/17588928.2011.630723
136
BUXBAUM, BRANCH COSLETT, JACKSON
Condon, & Jackson, 2010; Pellijeff, Bonilha, Morgan, McKenzie, & Jackson, 2006), suggest that the posterior parietal cortex may play a particularly important role in maintaining an accurate and up-to-date representation of the current postural state of the body (the body schema). Furthermore, it is suggested that this body schema mechanism plays a key role in the mental transformation of bodily representations during mental imagery. In their fascinating paper, Hartmann, Falconer, and Mast investigate whether instructing healthy individuals to imagine themselves as being paralyzed affects their mental transformations of imitable and non-imitable body postures. They report that imagined paralysis selectively impaired mental transformation of imitable body postures but not non-imitable postures. To a large extent, and as illustrated in the papers outlined above, work examining the functions of the EBA and FBA consider situations in which faces, bodies, and their parts are viewed as objects. However, a second important and longstanding theme within the body representation literature has been to understand the psychological processes and neural mechanisms that underlie our subjective sense of body ownership: Particularly the distinction between the bodily “self” and the external “other”, and the processes and mechanisms through which external objects may be temporarily incorporated into the bodily “self” (i.e., the mechanisms of “embodiment”). One particularly important and popular technique that has been widely used to study phenomena associated with embodiment has been variants of the so-called “rubber hand illusion” (RHI), during which, following synchronous tactile stimulation (stroking) of the unseen real hand and the seen rubber hand, the participant comes to perceive the rubber hand as feeling as if it were part of their body. Understanding of this important issue is further elaborated upon by several of the empirical papers contained in the current special issue. Holle and colleagues investigate the necessary and sufficient conditions required to experience the RHI by manipulating factors predicted to strongly influence the process of embodiment: Postural congruence of the rubber limb with the body and the anatomical congruence of the rubber limb. Their results confirm the importance of these factors for establishing a robust RHI. In the first of two papers that appear in this special issue, Preston and Newport examine the related process of “disembodiment” of the limb. Using a novel virtual reality device, these authors investigate how the embodiment of a fake limb is affected by the apparent encroachment onto the fake limb by an apparently solid object. Their results again highlight important limitations in the conditions under which embodiment is likely to occur.
Zopf, Harris, and Williams report the results of an investigation into the role that body ownership cues have in our ability to detect and to discriminate somatosensory stimuli. Their findings indicate that body ownership cues induce reliable differences in our perception of somatosensory stimulation. In their second paper in this issue, Newport and Preston ask an intriguing question, namely, What happens to the real limb during the embodiment of a fake limb? While this question has been raised before in the context of RHI experiments, it is difficult to address this issue satisfactorily in standard RHI experiments because, as Newport and Preston correctly point out, typical RHI studies invariably induce a strong spatial mismatch between the viewed (fake) limb and the unseen (but proprioceptively sensed) real limb. In a clever experiment, Newport and Preston overcome this limitation using a novel VR device, and demonstrate that, in circumstances in which visual-proprioceptive mismatch is minimal, increased perceived “ownership” of a fake limb is accompanied by increased disembodiment of the individual’s real limb. A further major theme in the body representation literature is concerned with the awareness of bodily sensations and their relationship to human action. This issue is re-visited in the discussion paper by Jackson and colleagues, which focuses on the functional anatomy of the bodily sensations that we experience as urges for action. Jackson and colleagues discuss the defining characteristics of urges, with particular reference to pathological cases, such as the urgeto-tic in Tourette syndrome, and review evidence in support of the proposal that there is considerable overlap between the functional anatomy of urges associated with everyday behaviors such as swallowing, yawning, and micturition, and those urges associated with the generation of tics in Tourette syndrome. This collection of empirical and theoretical discussion papers and their commentaries provides a timely review of the current state-of-the-art in several of the most important topic areas of the body representation field.
REFERENCES Head, H., & Holmes, G. (1911/1912). Sensory disturbances from cerebral lesion. Brain, 34, 102–254. Parkinson, A., Condon, L., & Jackson, S. R. (2010). Parietal cortex coding of limb posture: In search of the body schema. Neuropsychologia, 48, 3228–3234. Pellijeff, A., Bonilha, L., Morgan, P. S., McKenzie, K., & Jackson, S. R. (2006). Parietal updating of limb posture: An event-related fMRI study. Neuropsychologia, 44, 2685–2690.
INTRODUCTION
Rushworth, M. F. S., Johansen-Berg, H., & Young, S. A. (1998). Parietal cortex and spatial-postural transformation during arm movements. Journal of Neurophysiology, 79, 478–482. Rushworth, M. F. S., Nixon, P. D., & Passingham, R. E. (1997). Parietal cortex and movement 1. Movement
137
selection and reaching. Experimental Brain Research, 117, 292–310. Wolpert, D. M., Goodbody, S. J., & Husain, M. (1998). Maintaining internal representations: The role of the human superior parietal lobe. Nature Neuroscience, 1, 529–533.
Copyright of Cognitive Neuroscience is the property of Psychology Press (UK) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
