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Brain and Movement: 1. Action and Consciousness of Action: The importance of not being conscious ¥ SG: So when I reach for a glass, I may have an awareness of the glass, but I am not conscious of my reach or my grasp or what my fingers are doing. ¥ MJ: Yes, you are probably conscious of the fact that you want to drink, of the general purpose of the action. By contrast, you will become fully conscious of the action itself if your movement fails, or if the glass is empty.Ê The question we raise is how is it that the visual system can select the proper information (the shape of the glass) and transform it, unknowingly to the subject, into precisely adapted movements.Ê The main purpose of this work is to try to understand what it means to produce actions directed at a visual goal without being aware of that goal. ¥ SG: Such actions would depend on motor representations, which are not yet motor images. ¥ MJ: It is difficult to speak of motor images at this stage, simply because an image, by definition, should be conscious. Yet, some people like Lawrence Parsons now tend to assume that there are two types of motor images.Ê First, there are motor images that we create in our mind as conscious representations of ourselves acting.Ê Those are the overt, conscious, images.Ê But we may also use implicit motor image strategies for producing actions. The argument for assuming that these strategies indeed rely on some sort of motor imagery is slightly indirect: it is based on the fact that the time it takes to mentally make the action is a function of motor contingencies. This point can be illustrated by an experimental example. Imagine that you are instructed to take a glass with marks on it where you are supposed to place your thumb and index finger. If the marks are placed in an appropriate position, the action is very easy, and the time to take the glass is short. If, on the contrary, the marks are placed in an odd position such that you have to rotate your arm in an awkward posture to grasp the glass, the action time increases. In the second part of the experiment, the glass is also presented with marks at different orientations, but, this time, you don't take it.Ê Instead, you are instructed to tell (by pressing different keys) whether the action of grasping the glass would be easy or difficult. The time it takes to give the response is a function of the orientation of the marks, in the same way as for the real action (Frak et al, 2000). The interpretation we gave to this result is that an action has to be simulated before it can be performed. This simulation process is made at a level where the contingencies of the action, like the biomechanics of the arm, are represented. The simulation will take longer in the odd condition than in the easy condition, as if the arm was mentally ÒrotatedÓ in the appropriate posture before the grasping movement is executed, or before the feasibility response is given. This rather complex process is entirely non-conscious. 3. The importance of intentionality ¥ SG: So when a representation is called upon for execution, the target doesn't have to be there.Ê But in the original formulation of the representation, there must be some stimulus, although the stimulus may be an imaginary target, or it may be an intention to do something. I think that your work shows the importance of the intentional level.Ê Specifically, you show that the goal or the intention of my action will really determine the motor specifications of the action.Ê You suggest that goal-directedness is a primary constituent of action (Jeannerod, in press).Ê This means, I think, that the motor system works at the highest pragmatic level of description.Ê In other words, the motor system is not simply a mechanism that organizes itself in terms of what muscles need to be moved, but it organizes itself around intentions.Ê It designs the reaching and grasping differently if the intention is to take a drink from the glass rather than to pick it up and throw it at someone.Ê And it is at that level of pragmatic intention that the system forms the representation.Ê The representation is cast in terms of the intention or the goal.Ê Moreover, this is something real, in the sense that it is not just that there are various levels of description that you could use to describe what is happening -- although there are indeed different levels of description.Ê Rather, the motor system is actually keyed into the intentional level.Ê Is this a good interpretation of what your work shows? ¥ MJ: Yes.Ê What I initially liked in the Arbib's schema theory (e.g., Arbib, 1985) is that there was a representation or schema for every level, from the single finger movement level up to the action level which embedded lower level schemas, and so on and so forth.Ê At the top you had the schema for the whole action, for example, getting something to drink.Ê So, in order to drink you activated schemas to get to the kitchen; then you activated schemas to grasp the glass, to raise it to the mouth, and so on and so forth: for each sub-action you had other sub-sub-actions. That was the organizing idea of going from the higher level down to the lower one, a hierarchical organization. What we want to have in a representation is not only the vocabulary to be assembled for producing the action (this is the static conception of the schema theory). Instead, we need the functional rules for assemblage, including the biomechanical constraints, the spatial reference frame, the initial positions, the forces to apply, etc. All these aspects form the covert part of the representation : they are present in the representation as can be demonstrated in experiments with implicit motor images of the sort that were mentioned earlier (e.g., Frak et al, Parsons et al), but they cannot be accessed consciously. The conscious part of the representation doesn't really have to include all the technicalities of the action, it just specifies the goal. But, interestingly, even though you imagine the action in terms of its goal, in simulating it you also rehearse all the neuronal circuitry. As we said before, if you examine the brain activity during motor imagination, you will find activation of the motor cortex, the cerebellum, etc. Even though the subject is imagining a complex goal, you will observe activation in the executive areas of his brain, corresponding to motor functions which he cannot figure out in his conscious experience of the image. ¥ SG: So the level of intention carries with it all the other levels, as if they were entrained by the intention. ¥ MJ: Right. Neural mechanisms that integrate posture with movement are widespread throughout the central nervous system (CNS), and they are recruited in patterns that are both task- and context-dependent. Scientists from several countries who were born in the 19th century provided essential groundwork for these modern-day concepts. Here, the focus is on three of this group with each selected for a somewhat different reason. Charles Sherrington (1857-1952) had innumerable contributions that were certainly needed in the subsequent study of posture and movement: inhibition as an active coordinative mechanism, the functional anatomy of spinal cord-muscle connectivity, and helping set the stage for modern work on the sensorimotor cortex and the corticospinal tract. Sadly, however, by not championing the work of his trainee and collaborator, Thomas Graham Brown (1882-1965), he delayed progress on two key motor control mechanisms: central programming and pattern generation. Walter Hess (1881-1973), a self-taught experimentalist, is now best known for his work on CNS coordination of autonomic (visceral) and emotional behavior. His contributions to posture and movement, however, were also far-reaching: the coordination of eye movements and integration of goal-directed and ''framework'' (anticipatory set) motor behavior. Nikolai Bernstein (1896-1966), the quintessence of an interdisciplinary, self-taught movement neuroscientist, made far-reaching contributions that were barely recognized by Western workers prior to the 1960s. Today, he is widely praised for showing that the CNS's hierarchy of control mechanisms for posture and movement is organized hand-in-hand with distributed and parallel processing, with all three subject to evolutionary pressures. He also made important observations, like those of several previous workers, on the goal focus of voluntary movements. The contributions of Sherrington, Hess, and Bernstein are enduring. They prompt thought on the philosophical axioms that appear to have driven their research, and the continual need for emphasis on interdisciplinary, comparative, and transnational approaches to advance movement neuroscience. Hippocampal learning of spatial relations of objects in the environment is not dependent upon conscious awareness. Abstract Despite the subjective experience of a continuous and coherent external world, we will argue that the perception and categorisation of visual space is constrained by the spatial resolution of the sensory systems but also and above all, by the pre-reflective representations of the body in action. Recent empirical data in cognitive neurosciences will be presented that suggest that multidimensional categorisation of perceptual space depends on body representations at both an experiential and a functional level. Results will also be resumed that show that representations of the body in action are pre-reflective in nature as only some aspects of the pre-reflective states can be consciously experienced. Finally, a neuro-cognitive model based on the integration of afferent and efferent information will be described, which suggests that action simulation and associated predicted sensory consequences may represent the underlying principle that enables pre-reflective representations of the body for space categorisation and selection for action. Mirror Neurons: Understanding Intentionality of Acts or Learning How to Perform Acts or Both? Embodiment of Knowledge On simulation, mirror neurons, and the conscious-nonconscious distinction.
Male-Female Brain Differences: Google Search: Female brain visuospatial Medical News Today: Main Category: Neurology / Neuroscience Differences in the way men and women perform verbal and visuospatial tasks have been well documented in scientific literature, but findings have been inconsistent as to whether men and women actually use different parts of their brains. This inconsistency has been attributed to many factors, including variability in the tasks used in studies and failure to match study participants on performance equivalency. But a new study published in the journal Brain and Language, which accounted for and corrected these methodological factors, confirmed that men and women do indeed use different parts of their brains when processing both language and visuospatial information. At a time when 37% of boys score below basic levels on standardized academic tests, compared to 15% of girls (National Center for Education Statistics) and the rate of ADHD in boys in twice that of girls (Centers for Disease Control), this study provides a solid benchmark to use in comparing whether underlying sex differences also exist in all children. Such an inquiry can pave the way towards understanding the extent to which sex differences are developmental, sociological and/or hormonal and which differences may become more, or possibly less, distinct with age. The study, led by Dr. Laurie Cutting and research scientist Amy Clements, both of the Kennedy Krieger Institute in Baltimore, used functional magnetic resonance imaging to study thirty adult participants while performing language and visuospatial tasks. Distinct differences were evident between male and female participants. Specifically, females showed more bilateral activation in the inferior frontal gyrus for the language task than males, who were more left lateralized. The opposite pattern of lateralization was found for the visuospatial task, with males showing more bilateral activation in the parietal lobe while processing visuospatial information than females, whose activations were more right lateralized. "What we found most compelling was that male and female participants performed equally on tasks, both in terms of accuracy and timing; they just used different parts of their brains to get the tasks done," said Amy Clements, lead author of the study. "This study forms the basis for understanding early developmental preferences that may differ between boys and girls. Future studies based on these findings may help illuminate more about improved special and mainstream education techniques for males and females." The study's language task consisted of participants viewing two 4-letter pronounceable nonsense word strings, one above the other. Participants were instructed to push a button with their right index finger if the words rhymed, and their left index finger if they did not rhyme. The visuospatial task involved displaying a fan of eleven lines, with nine lines in blue and two in yellow. Above the fan was a pair of yellow lines oriented in either the same or different positions as the two yellow lines highlighted in the fan. Participants pushed a button with their right index finger if all the yellow lines were aligned or pushed a button with their left hand finger if the lines were not aligned. In order to ensure performance equivalency, all participants were right handed, had English as their first language, finished at least some college coursework and completed tasks with an average of 90% accuracy. " Only by understanding what constitutes normal brain development can we increase our capabilities for treating pediatric learning disorders," said Dr. Goldstein, M.D., President and CEO of the Kennedy Krieger Institute. "Through our many research projects at Kennedy Krieger, our experts are unlocking the mysteries of the brain and translating those findings into better outcomes for children and their families." "We know that there are frequent and significant gender differences in intellectual developmental disabilities," said Ljubisa Vitkovic, Ph.D., of the Mental Retardation and Developmental Disabilities Branch of the National Institute of Child Health and Human Development, NIH. "Knowledge of gender differences in normally functioning brains is essential for understanding what may go wrong during development." Cautionary Tales: Not going overboard on what gender "differences" might mean -- "The author consistently confuses neural structure (brain) with psychological function (mind, mental performance, emotions, behavior). This is a huge error. The author is extraordinarily fond of citing functional gender differences. She'll talk about differences in verbal output, memory, eye contact, thoughts about sex, emotions, divorce initiation, aggression, chilhood behaviors, etc. She'll say these functional effects are in the brain, repeatedly. Good scientific thinking doesn't confuse these things. Part of the work is to measure sex differences in the brain (e.g., anatomy, physiology, chemistry). A completely separate part of the work is to measure psychological variables (e.g., behaviors, cognitions, emotions, perceptions). The third, most essential part, is to discover true correlations between structure and function. Many of the most egregious and elementary errors of cognitive neuroscience occur when researchers attempt to localize psychological functions inside brain regions or chemicals. All good neuroscientists understand this, but it is a tricky issue. One of my mentors, Davida Teller, spent years contemplating the issues surrounding "linking" hypotheses, while many great neuroscientists have struggled with this third part (Robert Efron, Steve Kosslyn, Georg von Bekesy, Gustav Fechner, and on and on and on). The author's disregard for this elementary issue is an obvious felony in my book." From a review of The Female Brain, Louann Brizendine (Broadway, 2006), by David H Peterzell, PhD, San Diego. Brain Hemispheric Dominance / Assymetry / Laterality: Anatomically, the central nervous system looks remarkably symmetrical--from the relatively simple structures of the spinal cord to the extensively convoluted folds of the cerebral hemispheres. At the functional level, however, there are striking differences between the left and right hemispheres. Although popular writings attribute language abilities to the left hemisphere and spatial abilities to the right, differences in hemispheric function appear to be more subtle. According to Ivry and Robertson, asymmetries over a wide range of perceptual tasks reflect a difference in strength rather than kind, with both hemispheres contributing to the performance of complex tasks, whether linguistic or spatial. Cerebral Dominance books at Amazon.com Neural Plasticity: Vision Neuroscience: Visual Development (Perspectives in Vision Research), Nigel W. Daw (Springer, 1995) Visual Perception, Steven H. Schwartz (McGraw-Hill Medical, 2004) Principal optometry school text. More than one third of the human brain is devoted to the processes of seeing - vision is after all the main way in which we gather information about the world. But human vision is a dynamic process during which the eyes continually sample the environment. Where most books on vision consider it as a passive activity, this book is unique in focusing on vision as an 'active' process. It goes beyond most accounts of vision where the focus is on seeing, to provide an integrated account of seeing AND looking. The book starts by pointing out the weaknesses in our traditional approaches to vision and the reason we need this new approach. It then gives a thorough description of basic details of the visual and oculomotor systems necessary to understand active vision. The book goes on to show how this approach can give a new perspective on visual attention, and how the approach has progressed in the areas of visual orienting, reading, visual search, scene perception and neuropsychology. Finally, the book summarises progress by showing how this approach sheds new light on the old problem of how we maintain perception of a stable visual world. Written by two leading vision scientists, this book will be valuable for vision researchers and psychology students, from undergraduate level upwards. This collection of papers by leading researchers in vision science deals with the role of color in spatial vision and the emergent spatio-chromatic properties within visual scenes. Several fascinating phenomena are studied through psychophysical experiments and explained in terms of neural and computational models. Topics include: prior adaptation to blurry images, chromatic induction, the influence of color contrast on shape perception, Fechner-Benham subjective color, a novel filling-in effect Ð dynamic texture spreading, the watercolor illusion, and new illusions based on chromatic variations of the luminance profile across the boundaries. This book reviews the current state of color vision research as seen from different disciplines of color science such as neurobiology, neuroethology, molecular genetics, medicine, psychology, color metrics and measurement, philosophy, and art. The book is an introductory text for graduate students as well as for experts who would like an overview of the state of the art in related areas of color vision research. Vision is not an end in itself. Instead, it has evolved to assure survival in a dynamic environment. Vision -- as well as the other senses -- evolved from the necessity to act in this environment. Therefore, perceptual processes and action planning are much more interlocked than evident at first sight. This special issue examines the basic processes of space perception and how these processes interact with action planning and motor control. The tasks under consideration range from the simple localization of a single object to the coordination of a series of events in natural scenes. The contributions were written by various experts in the field, ranging from experimental psychologists, neurophysiologists to computational modellers and philosophers. Each contribution introduces new concepts and ideas that explain how visual space is being established and represented. The overarching question is whether vision and action are based on a single spatial map or on different, interacting spatial representations. Brain and Space: The Geometries of Visual Space (Paperback) by Mark Wagner (Lawrence Erlbaum Assocs., 2006) When most people think of space, they think of physical
space. However, visual space concerns space as consciously
experienced, and it is studied through subjective measures,
such as asking people to use numbers to estimate perceived
distances, areas, angles, or volumes. This book explores
the mismatch between perception and physical reality,
and describes the many factors that influence the perception
of space including the meaning assigned to geometric
concepts like distance, the judgment methods used to
report the experience, the presence or absence of cues
to depth, and the orientation of a stimulus with respect
to point of view. The main theme of the text is that
no single geometry describes visual space, but that
the geometry of visual space depends upon the stimulus
conditions and mental shifts in the subjective meaning
of size and distance. In addition, The Geometries of
Visual Space: Brain-Based Education: Educating the Human Brain, Michael I. Posner & Mary K. Rothbart (American Psychological Ass'n, 2006) Educating the Human Brain, the product of a quarter century of research, provides an empirical account of the early development of attention and self-regulation in infants and young children. It examines the brain areas involved in regulatory networks, their connectivity, and how their development is influenced by genes and experience. Relying on the latest techniques in cognition and temperament measurement, neuroimaging, and molecular genetics, the book integrates research on neural networks common to all humans with studies of individual differences. This is a detailed introduction to the major theories that lie behind children's learning styles. The book examines how to develop learning situations and how to plan and create the best opportunities for effective and lasting learning. Brain and Emotion: Decision making is an area of profound importance to a wide range of specialities - for psychologists, economists, lawyers, clinicians, managers, and of course philosophers. Only relatively recently, though, have we begun to really understand how decision making processes are implemented in the brain, and how they might interact with our emotions. 'Emotion and Reason' presents a groundbreaking new approach to understanding decision making processes and their neural bases. The book presents a sweeping survey of the science of decision making. It examines the brain mechanisms involved in making decisions, and controversially proposes that many of our perceptual actions are essentially decision making processes. Whether looking, listening, hearing, or moving, we choose to attend to certain stimuli, at the expense of others. In some psychiatric disorders the inability to respond selectively to certain stimuli can be harmful - such pathologies of decision making are additionally considered. Berthoz also considers how many decision making processes involve an internal dialogue with our other self, and how this dialogue with our "doppelganger" might be represented in the brain. He considers the important implications that a neuroscience of decision making can have for the judiciary - how we apportion blame and responsibility; for economics - with discussion of the growing field of neuroeconomics; and for theories of management. Lastly he examines decision making and creativity - if perception relies in part on decision making processes, how might this alter our view of the artistic process. Written by a neuroscientist of international fame and accessible for both scientists and non-scientists, this book is the most exhaustive examination of the science of decision making yet. Brain and Time: Understanding temporal integration by the brain is expected to be among the premier topics to unite systems, cellular, computational, and cognitive neuroscience over the next decade. The phenomenon has been studied in humans and animals, yet until now, there has been no publication to successfully bring together the latest information gathered from this exciting area of research. For the first time, Functional and Neural Mechanisms of Interval Timing synthesizes the current knowledge of both animal behavior and human cognition as related to both technical and theoretical approaches in the study of duration discrimination. Chapters written by the foremost experts in the field integrate the fields of time quantum and psychophysics, rhythmic performance and synchronization, as well as attentional effort and cognitive strategies through the linkage of time as information in brain and behavior. This cutting-edge scientific work promotes a concerted view of timing and time perception for those on both sides of the behavior-biology divide. With Functional and Neural Mechanisms of Interval Timing neuroscientists, ethologists, and psychologists will gain the necessary background to understand the psychophysics and neurobiology of this crucial behavior. |
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