Changing the intended direction of movement
permalinkSomesthesis and the Neurobiology of the Somatosensory Cortex - 1996-01-01Pellizzer G10.1007/978-3-0348-9016-8
The behavioral and neural correlates of processing of motor directional information are described for two different visuomotor tasks: mental rotation and context-recall. Psychological studies in human subjects suggested that these two tasks may involve different mechanisms processing directional information. Analyses of the activity of single cells and neuronal populations in the motor cortex of behaving monkeys performing in the same tasks provided direct insight into the neural mechanisms involved, and confirmed their different nature.Assessment of Posttraumatic Stress DisorderPosttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern. in World War II Veterans
Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.permalinkPsychological Assessment - 1996-01-01Engdahl B, Eberly RE, Blake JD10.1037/1040-3590.8.4.445
Four Posttraumatic Stress Disorder
scales were compared in a community sample of 330 American former prisoners of war and combat veterans of World War II. The Mississippi Scale for Combat-Related Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
(M-Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
), the Minnesota Multiphasic Personality Inventory-2 Pk Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
scale, and the Impact of Event Scale (IES) all demonstrated moderate relationships with Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
as defined by the Structured Clinical Interview for DSM-III-R. Comparative validities were similar to those observed in Vietnam veteran samples. Confirmatory factor analysis indicated that the 3 scales loaded significantly on 1 factor. The impact of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
criteria changes was examined and found to be minimal. Implications for the use of the M-Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
, Pk, and IES in combat-related Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.PTSD
assessment are discussed.Posttraumatic Stress Disorder (PTSD)
A complex psychiatric syndrome that develops in response to trauma exposure. Individuals with PTSD experience intrusive recollections or reexperiencing of the traumatic event, avoidance of trauma reminders, emotional numbing, and hyperarousal. In addition, PTSD is associated with high rates of concomitant physical and mental health problems, increased health care use, and impairment in social and occupational functioning. Almost 7% of the general population and up to 30% of veterans meet lifetime criteria for PTSD. Indeed, PTSD is one of the most common psychiatric disorders, representing a significant and costly public health concern.The mental and the neural: Psychological and neural studies of mental rotation and memory scanning
System for projection of a three-dimensional, moving virtual target for studies of eye-hand coordination
permalinkJournal of Neuroscience Methods - 1995-11-01Schneider W, Harris TJ, Feldberg IE, Massey JT, Georgopoulos AP, Meyer RA10.1016/0165-0270(95)00068-2
Eye-hand tracking of moving visual objects in three-dimensional (3D) space is common in the behavioral repertoire of primates. However, behavioral and/or neurophysiological studies of this function are lacking mainly because devices do not exist that allow its investigation. We describe a device by which a spot of light can be presented in the immediate extrapersonal space of a subject and can be moved in various trajectories in 3D space. The target is a real image of a circular aperture produced by a system consisting of a light source, aperture, filters, several lenses and fold mirros, and a large concave mirror to focus the final real image. Rapid, computer-controlled movement of the image is obtained by tilting a gimbal-mounted guide mirror (for x and y motion) and by translating a lens (for motion in the z direction). A second configuration of the system allows movement of a 3D image in the 3D...read more
Current issues in directional motor control
Colon cancer: Personality factors predictive of onset and stage of presentation
permalinkJournal of Psychosomatic Research - 1995-11-01Kavan MG, Engdahl B, Kay S10.1016/0022-3999(95)00523-4
This study examined premorbid personality correlates of colon cancer and stage of presentation of colon cancer to health care providers. Sixty-one male veterans who completed the MMPI between 1947 and 1975 and were then diagnosed with colon cancer between 1977 and 1988 were matched with control patients. A 21-factor solution of the MMPI [1] was used to seek potential personality differences between colon cancer cases and their controls in terms of presence of colon cancer and stage of presentation for this disease. A stepwise conditional regression analysis found significant differences between the colon cancer and control groups on the Aggressive Hostility variable (p<0.018). A multivariate analysis of variance conducted across the stages of colon cancer presentation found that patients who presented later on for colon cancer had higher Phobia scores (p<0.05). Religious Fundamentalism who also related to presentation (p<0.05), but in a nonlinear manner. Discussion is related to previous findings regarding...read more
Motor cortical activity in a context-recall task
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Motor cortex and cognitive processing
permalinkThe Cognitive Neurosciences - 1995-01-01Georgopoulos AP
summarizes key observations and concepts concerning the involvement of the motor cortex in [the] motor cognitive processes operating on the direction of movement in space / large populations of neurons in motor cortex are engaged with reaching movements / single cells are directionally broadly tuned, but the neuronal population carries an unambiguous directional signal / the outcome of this population code can be visualized as a vector that points in the direction of the upcoming movement during the reaction time, during an instructed delay period, and during a memorized delay period / moreover, when a mental transformation is required for the generation of a reaching movement in a direction different from a reference direction, the population vector provides a direct insight into the nature of the cognitive process by which the required transformation is achieved (PsycINFO Database Record (c) 2019 APA, all rights reserved)Image and Brain: The Resolution of the Imagery Debate
permalinkScience - 1995-01-01Georgopoulos AP
Kosslyn's Image and Brain is a tour de force in the analysis of visual perception and imagery, looked upon from all possible perspectives. It is an examination of work done during the past 15 years on visual imagery by a variety of methods, from chronometric measurements to computer models to functional brain imaging, bringing a systematic approach to bear on this multitude of data to delineate the issues of brain mechanisms underlying visual perception and imagery. The scheme adopted posits a number of systems and subsystems (for example for edge detection and for encoding motion relations) that process specific kinds of information and that together make for an apparently seamless operation of visual perception and imagery. This analytical approach is open-ended, in the sense that more processing stations can be adduced if need or evidence for them arises; it is flexible, so that rearrangements in processing order are allowed for; and...read more
Population activity in the control of movement
permalinkInternational Review of Neurobiology - 1994-12-23Georgopoulos AP
This review summarizes key observations and concepts concerning the role of neuronal populations in specification and control of the direction of movement and isometric force. Large populations of neurons in the motor cortex are engaged with reaching movements. This engagement is fairly early, starting approximately 60 msec following target onset. Single cells are directionally broadly tuned, but the neuronal population carries an unambiguous directional signal. The outcome of this population code can be visualized as a vector that points in the direction of the upcoming movement during the reaction time, during an instructed delay period, and during a memorized delay period. Moreover, when a mental transformation is required for the generation of a reaching movement in a different direction from a reference direction, the population vector provides a direct insight into the nature of the cognitive process by which the required transformation is achieved.Behavioral neurophysiology of the motor cortex
permalinkJournal of Laboratory and Clinical Medicine - 1994-12-01Georgopoulos AP
The study of the motor cortex in behaving monkeys during the past 20 years has provided important information on the brain mechanisms underlying motor control. With respect to reaching movements in space, several aspects of motor cortical function concerning the specification of the direction of movement have now been elucidated and are reviewed in this article. The activity of single cells in the motor cortex is broadly tuned with respect to the direction of reaching, so that the discharge rate is highest with movements in a preferred direction and decreases progressively with movements made in directions more and more away from the preferred one. Thus the neural command for the direction of reaching can be regarded as an ensemble of cell vectors, with each vector pointing in the cell's preferred direction and having a length proportional to the change in cell activity. The outcome of this population code can be visualized...read more
Movement Parameters and Neural Activity in Motor Cortex and Area 5
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Overlapping neural networks for multiple motor engrams
permalinkProceedings of the National Academy of Sciences - 1994-08-30Lukashin A, Wilcox GL, Georgopoulos AP10.1073/pnas.91.18.8651
The hypothesis was tested that learned movement trajectories of different shapes can be stored in, and generated by, largely overlapping neural networks. Indeed, it was possible to train a massively interconnected neural network to generate different shapes of internally stored, dynamically evolving movement trajectories using a general-purpose core part, common to all networks, and a special-purpose part, specific for a particular trajectory. The weights of connections between the core units do not carry any information about trajectories. The core network alone could generate externally instructed trajectories but not internally stored ones, for which both the core and the trajectory-specific part were needed. All information about the movements is stored in the weights of connections between the core part and the specialized units and between the specialized units themselves. Due to these connections the core part reveals specific dynamical behavior for a particular trajectory and, as the result, discriminates different tasks. The...read more
New concepts in generation of movement
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Directional operations in the motor cortex modeled by a neural network of spiking neurons
Measuring Synaptic Interactions
Representations of movement and representations in movement
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A Neural Network for Coding of Trajectories by Time Series of Neuronal Population Vectors
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Mechanisms of Eye-Hand Coordination
permalinkDefense Technical Information Center - 1993-11-29Georgopoulos AP
We studied the capacities of human subjects to localize tactile stimuli in 3D space. For that purpose, five subjects (3 women and 2 men) were asked to make a pointing movement to a visual stimulus in otherwise complete darkness. At some random time before, during or after this initial movement, a tactile probe was presented to the tip of the subject's index finger. The probe (1-mm diameter, 0.75-mm extent, 5-ms duration) was applied by a lightweight (80 g) tactile stimulator worn on the subject's hand. To complete the task, the subject was required to point to the 3D spatial location at which the probe was applied. Hand position was monitored (200 Hz) by a video-based motion analysis system. In each subject, probes presented just before or during the initial movement were systematically mislocalized in the direction of that movement so that subjects perceived the probe to be at the location occupied...read more
A dynamical neural network model for motor cortical activity during movement: population coding of movement trajectories
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