Introduction According to the dopamine hypothesis functional brain abnormalities and neurochemica... more Introduction According to the dopamine hypothesis functional brain abnormalities and neurochemical alterations may converge to cause psychosis through aberrant salience attribution. Indeed, resting-state functional magnetic resonance imaging (rs-fMRI) has revealed widespread brain disconnectivity across the psychotic spectrum. Objectives To advance the understanding of the dopaminergic involvement in intrinsic functional connectivity (iFC) and its putative relationship to the development of psychotic disorders we aimed to investigate the link between L-Dopa, a dopamine precursor, and its modulation of striatal iFC in subthreshold psychosis, i.e. non-clinical psychosis. Methods We used a randomized, double-blind placebo controlled study design including in our sample 56 healthy, male, right-handed, subjects with no familiar risk factors for psychosis who were assessed with the Schizotypal Personality Questionnaire (SPQ) and underwent 10 minutes of rs-fMRI scanning. All subjects received either 250 mg of Madopar DR®(200 mg L-Dopa plus 50 mg benserazid, dual release form) or a placebo. We analysed resting-state iFC of 6 striatal seeds, known to evoke dopamine related networks. Results The main effect of L-Dopa presented itself (FWE-corrected) as a significant decrease in iFC from the right ventral striatum to the cerebellum and the precuneus cortex, and an increase in iFC to the occipital cortex. Subjects with high SPQ positive symptom sub-scores showed a significant increase of L-Dopa induced connectivity. Conclusion We identified striatal functional connectivity being modulated by augmented dopamine availability, and in support of the dopamine hypothesis, we found that those iFC patterns are associated to high scores of psychotic like experiences.
Recent experimental evidence and theoretical models suggest that an integration of extero-ceptive... more Recent experimental evidence and theoretical models suggest that an integration of extero-ceptive and interoceptive signals underlies several key aspects of the bodily self. While it has been shown that self-attribution of both the hand and the full-body are altered by conflicting extero-exteroceptive (e.g. visuo-tactile) and extero-interoceptive (e.g. visuo-cardiac) information, no study has thus far investigated whether self-attribution of the face might be altered by visuo-cardiac stimulation similarly to visuo-tactile stimulation. In three independent groups of participants we presented ambiguous (i.e. morphed with a stranger's face) self-faces flashing synchronously or asynchronously with the participants' heartbeat. We then measured the subjective percentages of self-face attribution of morphed stimuli. To control for a potential effect of visuo-cardiac synchrony on familiarity, a task assessing the attribution of a familiar face was introduced. Moreover, different durations of visuo-cardiac flashing and different degrees of asynchronicity were used. Based on previous studies showing that synchronous visuo-cardiac stimulation generally increases self-attribution of the full-body and the hand, and that synchronous visuo-tactile stimulation increases self-face attribution, we predicted higher self-face attribution during the synchronous visuo-cardiac flashing of the morphed stimuli. In contrast to this hypothesis, the results showed no difference between synchronous and asynchronous stimulation on self-face attribution in any of the three studies. We thus conclude that visuo-cardiac synchrony does not boost self-attribution of the face as it does that of hand and full-body.
Objective: Xenomelia, that is, the nonacceptance of one’s own limb, is an intriguing but little u... more Objective: Xenomelia, that is, the nonacceptance of one’s own limb, is an intriguing but little understood condition. We sought to further test the most prominent neuroscientific hypothesis that suggests xenomelia results from a breakdown in multisensory integration for the affected body part. Method: A “rubber foot illusion” paradigm was developed and tested in healthy participants and in individuals with a desire for left foot amputation (xenomelia). Behavioral and physiological responses quantified illusory ownership of a fake foot after synchronous and asynchronous stroking of a visible rubber foot and the subject’s own hidden foot. Results: Healthy participants (n 15) showed a rubber foot illusion similar to the well-known rubber hand illusion. Individuals with xenomelia (n 9) experienced the rubber foot illusion in a way comparable to healthy controls. The only difference in the individuals with xenomelia was an increase in the vividness of the illusion for the undesired limb. This vividness of the illusion correlated positively with the strength of amputation desire. Conclusion: These findings might reflect the malleable sense of the body in xenomelia and suggest a weakened representation of the affected body part. These findings may support the use of multisensory stimulation in therapeutic settings
Dr. Diego Pizzagalli Laboratory for Affective Neuroscience Department of Psychology, University o... more Dr. Diego Pizzagalli Laboratory for Affective Neuroscience Department of Psychology, University of Wisconsin 1202 W. Johnson Street, Madison, WI 53706 (USA) Tel. +1 608 263 5072, Fax +1 608 265 2875, E-Mail dpizzag@psyphw.psych.wisc.edu ... ABC Fax + 41 61 306 12 ...
This article updates Tune's 1964 review of variables influencing human subjects' attempts... more This article updates Tune's 1964 review of variables influencing human subjects' attempts at generating random sequences of alternatives. It also covers aspects not included in the original review such as randomization behavior by patients with neurological and psychiatric disorders. Relevant work from animal research (spontaneous alternation paradigm) is considered as well. It is conjectured that Tune's explanation of sequential nonrandomness in terms of a limited capacity of short-term memory can no longer be maintained. Rather, interdependence among consecutive choices is considered a consequence of an organism's natural susceptibility to interference. Random generation is thus a complex action which demands complete suppression of any rule-governed behavior. It possibly relies on functions of the frontal lobes but cannot otherwise be "localized" to restricted regions of the brain. Possible developments in the field are briefly discussed, both with respe...
Summary.-20 women (M age= 30.4 yr.) were given the" Mental Dice Task&... more Summary.-20 women (M age= 30.4 yr.) were given the" Mental Dice Task"(randomization of the numbers from 1 to 6) once during the preovulatory and once during the premenstrual phases of their menstrual cycles. In addition, for both test sessions a premenstrual-symptom score was assessed reflecting self-rated severity of cognitive, affective, and somatic complaints during the preovular and the premensuual phases. In comparison to series of real dice throws, the Mental Dice sequences of all the subjects showed a relative lack of ...
The clinical features and natural course of paramedian thalamic stroke is poorly known. The aim o... more The clinical features and natural course of paramedian thalamic stroke is poorly known. The aim of this study was to characterize the evolution of neurological, neuropsychological, and sleep-wake deficits after paramedian thalamic stroke. Forty-six consecutive patients, aged 48.4+/-16.6 years, were studied. Fourteen had bilateral, 16 left-sided, and 16 right-sided lesions. Assessment included neurological examinations, estimation of sleep needs, formal neuropsychological tests (n=27), and polysomnographies (n=31). Functional outcome was followed up over 1 year in 31 patients with the modified Rankin Scale and Barthel index. Oculomotor palsy (76% of patients), mild gait ataxia (67%), deficits of attention (63%), fluency and error control (59%), learning and memory (67%), and behavior (67%) were common in the acute stroke phase. Outcome was excellent with right-sided infarcts but mostly incomplete with bilateral and left-sided lesions. This was mainly related to persistent frontal lobe-related and cognitive deficits found in 100% bilateral and 90% left-sided, but only 33% right-sided strokes. Initially, hypersomnia was present in all patients associated with increased stage 1 sleep, reduced stage 2 sleep, and reduced sleep spindles. Sleep needs improved in patients with bilateral and almost disappeared with unilateral lesions after 1 year. Sleep architecture remained abnormal with the exception of sleep spindles that increased. Whereas neurological deficits and hypersomnia recover to large extent in patients with paramedian thalamic stroke, the frontal lobe-related and cognitive deficits, which are mainly linked with bilateral and left-sided lesions, often persist. As such, stroke outcome is better in right-sided than bilateral or left-sided infarcts.
Neuropsychiatry, neuropsychology, and behavioral neurology
Our aim was to investigate the influence of optokinetically induced rotatory self-motion sensatio... more Our aim was to investigate the influence of optokinetically induced rotatory self-motion sensation (circular vection [CV]) on asymmetries in real and representational space in normal subjects. Vestibular and optokinetic stimulation (particularly when accompanied by rightward CV) can reduce left-sided hemineglect in patients. Twenty healthy right-handed men were administered a line bisection (LB) task and a stimulus-response compatibility task monitoring mental representation of space (the RULER task). The RULER task required speeded unimanual decisions ("smaller than 6?" vs. "larger than 6?") to foveally presented numbers between 1 and 11. Both tasks were performed in a baseline condition (no stimulation) and with full-field optokinetic stimulation to induce CV to either side. The bisection marks of both hands were shifted significantly to the left during leftward CV, introducing a pseudoneglect for the left and right hands. Rightward CV did not influence LB. In the RULER task, we found a stimulus-response compatibility, namely, faster right-hand responses to large numbers (i.e., 7-11) and faster left-hand responses to small numbers (i.e., 1-5). Although optokinetic stimulation did not significantly affect subjects' representation of space, the overall pattern of observed deviations was strikingly similar to that obtained in LB. Optokinetic stimulation affects healthy subjects' exploration and, to a lesser extent, their representation of space. In contrast to previous studies in neglect patients and healthy subjects, we found that leftward CV rather than rightward CV induced a leftward deviation of the subjective midpoint. This discrepancy is most likely a consequence of the exclusively peripheral visual field stimulation in our experiment. We suggest that the leftward deviation during rightward CV described in former studies may be due to the cuing effect of the leftward moving dots in the central visual field. In the absence of these central cues, the direction of CV seems to be the main determining factor for observed hemispatial effects.
This paper consists of two parts. In the first, we discuss the neuropsychological correlates of b... more This paper consists of two parts. In the first, we discuss the neuropsychological correlates of belief in a 'paranormal' or magical causation of coincidences. In particular, we review experimental evidence demonstrating that believers in ESP and kindred forms of paranormal phenomena differ from disbelievers with respect to indices of sequential response production and semantic-associative processing. Not only do believers judge
Background / Purpose: The empirical investigation of human moral behavior is increasingly based o... more Background / Purpose: The empirical investigation of human moral behavior is increasingly based on studies that include patients with rare lesions in specific regions of the frontal lobe. This poses two questions from the perspectives of neuroethics and medical ethics: what is the role of such findings for our understanding of human morality? And how should we deal with such patients in research and clinical practice? Main conclusion: We indicate two underestimated problems: first, the recent studies using frontal patients in moral research promote a neurodeterminism in human morality that is, however, not sufficiently supported by the current state of knowledge. Secondly, we find a shift in research away from clinical issues towards basic research on human morality.
Objective: Late outcome after mitral valve repair was examined to define preoperative predictors ... more Objective: Late outcome after mitral valve repair was examined to define preoperative predictors of recurrent atrial fibrillation late after successful mitral valve reconstruction. Methods: One hundred and eighty-nine patients, 112 with preoperative sinus rhythm and 72 with preoperative chronic or intermittent atrial fibrillation, were followed for 12.2±10 years after valve repair. Clinic, hemodynamic end echocardiographic data were entered into Cox-regression and Kaplan–Meyer analysis to assess predictors for recurrent atrial fibrillation late after successful mitral valve repair. Results: Univariate and multivariate predictors for recurrent atrial fibrillation late after successful mitral valve reconstruction were preoperative atrial fibrillation (P=0.0001), preoperative antiarrhythmic drug treatment (P=0.005), heart rate (P=0.01), left ventricular ejection fraction (P=0.01) and increased left ventricular posterior wall thickness (P=0.05). Patients>57.5 years with a mean pulmon...
Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers w... more Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.
Mitempfindung is the referral of a tactile sensation to a location far away from the stimulation ... more Mitempfindung is the referral of a tactile sensation to a location far away from the stimulation site. This brief note reports a 40% incidence of Mitempfindung in a sample of 20 digit-color synaesthetes which contrasts with a 10% incidence in two control groups of non-synaesthetes. Phenomenological similarities between Mitempfindung and synaesthesia are discussed, and we propose that an erratic neural
Introduction According to the dopamine hypothesis functional brain abnormalities and neurochemica... more Introduction According to the dopamine hypothesis functional brain abnormalities and neurochemical alterations may converge to cause psychosis through aberrant salience attribution. Indeed, resting-state functional magnetic resonance imaging (rs-fMRI) has revealed widespread brain disconnectivity across the psychotic spectrum. Objectives To advance the understanding of the dopaminergic involvement in intrinsic functional connectivity (iFC) and its putative relationship to the development of psychotic disorders we aimed to investigate the link between L-Dopa, a dopamine precursor, and its modulation of striatal iFC in subthreshold psychosis, i.e. non-clinical psychosis. Methods We used a randomized, double-blind placebo controlled study design including in our sample 56 healthy, male, right-handed, subjects with no familiar risk factors for psychosis who were assessed with the Schizotypal Personality Questionnaire (SPQ) and underwent 10 minutes of rs-fMRI scanning. All subjects received either 250 mg of Madopar DR®(200 mg L-Dopa plus 50 mg benserazid, dual release form) or a placebo. We analysed resting-state iFC of 6 striatal seeds, known to evoke dopamine related networks. Results The main effect of L-Dopa presented itself (FWE-corrected) as a significant decrease in iFC from the right ventral striatum to the cerebellum and the precuneus cortex, and an increase in iFC to the occipital cortex. Subjects with high SPQ positive symptom sub-scores showed a significant increase of L-Dopa induced connectivity. Conclusion We identified striatal functional connectivity being modulated by augmented dopamine availability, and in support of the dopamine hypothesis, we found that those iFC patterns are associated to high scores of psychotic like experiences.
Recent experimental evidence and theoretical models suggest that an integration of extero-ceptive... more Recent experimental evidence and theoretical models suggest that an integration of extero-ceptive and interoceptive signals underlies several key aspects of the bodily self. While it has been shown that self-attribution of both the hand and the full-body are altered by conflicting extero-exteroceptive (e.g. visuo-tactile) and extero-interoceptive (e.g. visuo-cardiac) information, no study has thus far investigated whether self-attribution of the face might be altered by visuo-cardiac stimulation similarly to visuo-tactile stimulation. In three independent groups of participants we presented ambiguous (i.e. morphed with a stranger's face) self-faces flashing synchronously or asynchronously with the participants' heartbeat. We then measured the subjective percentages of self-face attribution of morphed stimuli. To control for a potential effect of visuo-cardiac synchrony on familiarity, a task assessing the attribution of a familiar face was introduced. Moreover, different durations of visuo-cardiac flashing and different degrees of asynchronicity were used. Based on previous studies showing that synchronous visuo-cardiac stimulation generally increases self-attribution of the full-body and the hand, and that synchronous visuo-tactile stimulation increases self-face attribution, we predicted higher self-face attribution during the synchronous visuo-cardiac flashing of the morphed stimuli. In contrast to this hypothesis, the results showed no difference between synchronous and asynchronous stimulation on self-face attribution in any of the three studies. We thus conclude that visuo-cardiac synchrony does not boost self-attribution of the face as it does that of hand and full-body.
Objective: Xenomelia, that is, the nonacceptance of one’s own limb, is an intriguing but little u... more Objective: Xenomelia, that is, the nonacceptance of one’s own limb, is an intriguing but little understood condition. We sought to further test the most prominent neuroscientific hypothesis that suggests xenomelia results from a breakdown in multisensory integration for the affected body part. Method: A “rubber foot illusion” paradigm was developed and tested in healthy participants and in individuals with a desire for left foot amputation (xenomelia). Behavioral and physiological responses quantified illusory ownership of a fake foot after synchronous and asynchronous stroking of a visible rubber foot and the subject’s own hidden foot. Results: Healthy participants (n 15) showed a rubber foot illusion similar to the well-known rubber hand illusion. Individuals with xenomelia (n 9) experienced the rubber foot illusion in a way comparable to healthy controls. The only difference in the individuals with xenomelia was an increase in the vividness of the illusion for the undesired limb. This vividness of the illusion correlated positively with the strength of amputation desire. Conclusion: These findings might reflect the malleable sense of the body in xenomelia and suggest a weakened representation of the affected body part. These findings may support the use of multisensory stimulation in therapeutic settings
Dr. Diego Pizzagalli Laboratory for Affective Neuroscience Department of Psychology, University o... more Dr. Diego Pizzagalli Laboratory for Affective Neuroscience Department of Psychology, University of Wisconsin 1202 W. Johnson Street, Madison, WI 53706 (USA) Tel. +1 608 263 5072, Fax +1 608 265 2875, E-Mail dpizzag@psyphw.psych.wisc.edu ... ABC Fax + 41 61 306 12 ...
This article updates Tune's 1964 review of variables influencing human subjects' attempts... more This article updates Tune's 1964 review of variables influencing human subjects' attempts at generating random sequences of alternatives. It also covers aspects not included in the original review such as randomization behavior by patients with neurological and psychiatric disorders. Relevant work from animal research (spontaneous alternation paradigm) is considered as well. It is conjectured that Tune's explanation of sequential nonrandomness in terms of a limited capacity of short-term memory can no longer be maintained. Rather, interdependence among consecutive choices is considered a consequence of an organism's natural susceptibility to interference. Random generation is thus a complex action which demands complete suppression of any rule-governed behavior. It possibly relies on functions of the frontal lobes but cannot otherwise be "localized" to restricted regions of the brain. Possible developments in the field are briefly discussed, both with respe...
Summary.-20 women (M age= 30.4 yr.) were given the" Mental Dice Task&... more Summary.-20 women (M age= 30.4 yr.) were given the" Mental Dice Task"(randomization of the numbers from 1 to 6) once during the preovulatory and once during the premenstrual phases of their menstrual cycles. In addition, for both test sessions a premenstrual-symptom score was assessed reflecting self-rated severity of cognitive, affective, and somatic complaints during the preovular and the premensuual phases. In comparison to series of real dice throws, the Mental Dice sequences of all the subjects showed a relative lack of ...
The clinical features and natural course of paramedian thalamic stroke is poorly known. The aim o... more The clinical features and natural course of paramedian thalamic stroke is poorly known. The aim of this study was to characterize the evolution of neurological, neuropsychological, and sleep-wake deficits after paramedian thalamic stroke. Forty-six consecutive patients, aged 48.4+/-16.6 years, were studied. Fourteen had bilateral, 16 left-sided, and 16 right-sided lesions. Assessment included neurological examinations, estimation of sleep needs, formal neuropsychological tests (n=27), and polysomnographies (n=31). Functional outcome was followed up over 1 year in 31 patients with the modified Rankin Scale and Barthel index. Oculomotor palsy (76% of patients), mild gait ataxia (67%), deficits of attention (63%), fluency and error control (59%), learning and memory (67%), and behavior (67%) were common in the acute stroke phase. Outcome was excellent with right-sided infarcts but mostly incomplete with bilateral and left-sided lesions. This was mainly related to persistent frontal lobe-related and cognitive deficits found in 100% bilateral and 90% left-sided, but only 33% right-sided strokes. Initially, hypersomnia was present in all patients associated with increased stage 1 sleep, reduced stage 2 sleep, and reduced sleep spindles. Sleep needs improved in patients with bilateral and almost disappeared with unilateral lesions after 1 year. Sleep architecture remained abnormal with the exception of sleep spindles that increased. Whereas neurological deficits and hypersomnia recover to large extent in patients with paramedian thalamic stroke, the frontal lobe-related and cognitive deficits, which are mainly linked with bilateral and left-sided lesions, often persist. As such, stroke outcome is better in right-sided than bilateral or left-sided infarcts.
Neuropsychiatry, neuropsychology, and behavioral neurology
Our aim was to investigate the influence of optokinetically induced rotatory self-motion sensatio... more Our aim was to investigate the influence of optokinetically induced rotatory self-motion sensation (circular vection [CV]) on asymmetries in real and representational space in normal subjects. Vestibular and optokinetic stimulation (particularly when accompanied by rightward CV) can reduce left-sided hemineglect in patients. Twenty healthy right-handed men were administered a line bisection (LB) task and a stimulus-response compatibility task monitoring mental representation of space (the RULER task). The RULER task required speeded unimanual decisions ("smaller than 6?" vs. "larger than 6?") to foveally presented numbers between 1 and 11. Both tasks were performed in a baseline condition (no stimulation) and with full-field optokinetic stimulation to induce CV to either side. The bisection marks of both hands were shifted significantly to the left during leftward CV, introducing a pseudoneglect for the left and right hands. Rightward CV did not influence LB. In the RULER task, we found a stimulus-response compatibility, namely, faster right-hand responses to large numbers (i.e., 7-11) and faster left-hand responses to small numbers (i.e., 1-5). Although optokinetic stimulation did not significantly affect subjects' representation of space, the overall pattern of observed deviations was strikingly similar to that obtained in LB. Optokinetic stimulation affects healthy subjects' exploration and, to a lesser extent, their representation of space. In contrast to previous studies in neglect patients and healthy subjects, we found that leftward CV rather than rightward CV induced a leftward deviation of the subjective midpoint. This discrepancy is most likely a consequence of the exclusively peripheral visual field stimulation in our experiment. We suggest that the leftward deviation during rightward CV described in former studies may be due to the cuing effect of the leftward moving dots in the central visual field. In the absence of these central cues, the direction of CV seems to be the main determining factor for observed hemispatial effects.
This paper consists of two parts. In the first, we discuss the neuropsychological correlates of b... more This paper consists of two parts. In the first, we discuss the neuropsychological correlates of belief in a 'paranormal' or magical causation of coincidences. In particular, we review experimental evidence demonstrating that believers in ESP and kindred forms of paranormal phenomena differ from disbelievers with respect to indices of sequential response production and semantic-associative processing. Not only do believers judge
Background / Purpose: The empirical investigation of human moral behavior is increasingly based o... more Background / Purpose: The empirical investigation of human moral behavior is increasingly based on studies that include patients with rare lesions in specific regions of the frontal lobe. This poses two questions from the perspectives of neuroethics and medical ethics: what is the role of such findings for our understanding of human morality? And how should we deal with such patients in research and clinical practice? Main conclusion: We indicate two underestimated problems: first, the recent studies using frontal patients in moral research promote a neurodeterminism in human morality that is, however, not sufficiently supported by the current state of knowledge. Secondly, we find a shift in research away from clinical issues towards basic research on human morality.
Objective: Late outcome after mitral valve repair was examined to define preoperative predictors ... more Objective: Late outcome after mitral valve repair was examined to define preoperative predictors of recurrent atrial fibrillation late after successful mitral valve reconstruction. Methods: One hundred and eighty-nine patients, 112 with preoperative sinus rhythm and 72 with preoperative chronic or intermittent atrial fibrillation, were followed for 12.2±10 years after valve repair. Clinic, hemodynamic end echocardiographic data were entered into Cox-regression and Kaplan–Meyer analysis to assess predictors for recurrent atrial fibrillation late after successful mitral valve repair. Results: Univariate and multivariate predictors for recurrent atrial fibrillation late after successful mitral valve reconstruction were preoperative atrial fibrillation (P=0.0001), preoperative antiarrhythmic drug treatment (P=0.005), heart rate (P=0.01), left ventricular ejection fraction (P=0.01) and increased left ventricular posterior wall thickness (P=0.05). Patients>57.5 years with a mean pulmon...
Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers w... more Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.
Mitempfindung is the referral of a tactile sensation to a location far away from the stimulation ... more Mitempfindung is the referral of a tactile sensation to a location far away from the stimulation site. This brief note reports a 40% incidence of Mitempfindung in a sample of 20 digit-color synaesthetes which contrasts with a 10% incidence in two control groups of non-synaesthetes. Phenomenological similarities between Mitempfindung and synaesthesia are discussed, and we propose that an erratic neural
Introduction: At the centenary of research on anosognosia, the time seems ripe to supplement work... more Introduction: At the centenary of research on anosognosia, the time seems ripe to supplement work in anosognosic patients with empirical studies on nosognosia in healthy participants. To this end, we adopted a signal detection framework to investigate the lateralized recognition of illness words e an operational measure of nosognosia e in healthy participants. As posi- tively biased reports about one's current health status (anosognosia) and future health status (unrealistic optimism) have both been associated with deficient right hemispheric func- tioning, and conversely with undisturbed left hemispheric functioning, we hypothesised that more optimistic participants would adopt a more conservative response criterion, and/ or display less sensitivity, when identifying illnesses in our nosognosia task; especially harmful illnesses presented to the left hemisphere via the right visual field. Material and methods: Thirty-two healthy right-handed men estimated their own relative risk of contracting a series of illnesses in the future, and then completed a novel computer task assessing their recognition of illness names presented to the left or right visual field. To check that effects were specific to the recognition of illness (rather than reflecting recognition of lexical items per se), we also administered a standard lateralized lexical decision task. Results: Highly optimistic participants tended to be more conservative in detecting ill- nesses, especially harmful illnesses presented to the right visual field. Contrary to expec- tation, they were also more sensitive to illness names in this half-field. Conclusions: We suggest that, in evolutionary terms, unrealistic optimism may be an adaptive trait that combines a high perceptual sensitivity to threat with a high threshold for acknowledging its presence. The signal detection approach to nosognosia developed here may open up new avenues for the understanding of anosognosia in neurological patients.
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Papers by peter brugger
condition. We sought to further test the most prominent neuroscientific hypothesis that suggests
xenomelia results from a breakdown in multisensory integration for the affected body part. Method: A
“rubber foot illusion” paradigm was developed and tested in healthy participants and in individuals with
a desire for left foot amputation (xenomelia). Behavioral and physiological responses quantified illusory
ownership of a fake foot after synchronous and asynchronous stroking of a visible rubber foot and the
subject’s own hidden foot. Results: Healthy participants (n 15) showed a rubber foot illusion similar
to the well-known rubber hand illusion. Individuals with xenomelia (n 9) experienced the rubber foot
illusion in a way comparable to healthy controls. The only difference in the individuals with xenomelia
was an increase in the vividness of the illusion for the undesired limb. This vividness of the illusion
correlated positively with the strength of amputation desire. Conclusion: These findings might reflect the
malleable sense of the body in xenomelia and suggest a weakened representation of the affected body
part. These findings may support the use of multisensory stimulation in therapeutic settings
condition. We sought to further test the most prominent neuroscientific hypothesis that suggests
xenomelia results from a breakdown in multisensory integration for the affected body part. Method: A
“rubber foot illusion” paradigm was developed and tested in healthy participants and in individuals with
a desire for left foot amputation (xenomelia). Behavioral and physiological responses quantified illusory
ownership of a fake foot after synchronous and asynchronous stroking of a visible rubber foot and the
subject’s own hidden foot. Results: Healthy participants (n 15) showed a rubber foot illusion similar
to the well-known rubber hand illusion. Individuals with xenomelia (n 9) experienced the rubber foot
illusion in a way comparable to healthy controls. The only difference in the individuals with xenomelia
was an increase in the vividness of the illusion for the undesired limb. This vividness of the illusion
correlated positively with the strength of amputation desire. Conclusion: These findings might reflect the
malleable sense of the body in xenomelia and suggest a weakened representation of the affected body
part. These findings may support the use of multisensory stimulation in therapeutic settings
Material and methods: Thirty-two healthy right-handed men estimated their own relative risk of contracting a series of illnesses in the future, and then completed a novel computer task assessing their recognition of illness names presented to the left or right visual field. To check that effects were specific to the recognition of illness (rather than reflecting recognition of lexical items per se), we also administered a standard lateralized lexical decision task.
Results: Highly optimistic participants tended to be more conservative in detecting ill- nesses, especially harmful illnesses presented to the right visual field. Contrary to expec- tation, they were also more sensitive to illness names in this half-field.
Conclusions: We suggest that, in evolutionary terms, unrealistic optimism may be an adaptive trait that combines a high perceptual sensitivity to threat with a high threshold for acknowledging its presence. The signal detection approach to nosognosia developed here may open up new avenues for the understanding of anosognosia in neurological patients.