Dexamphetamine effects on separate constructs in the rubber hand illusion test

Albrecht, Matthew A.; Martin‐Iverson, Mathew T.; Price, Greg; Lee, Joseph; Iyyalol, Rajan; Waters, Flavie

doi:10.1007/s00213-011-2255-y

Cited by 32 publications

(41 citation statements)

References 104 publications

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“…Using an amphetamine challenge in healthy volunteers as a model of psychoses-related responses in the rubber-hand illusion, our group (44) found that amphetamine appeared to increase the temporal envelope of associability of the rubber-hand visual cues to the feel of the stroking (i.e., had a selective effect of increasing the illusion in the asynchronous condition) in a profile of performance, which was similar to the pattern of performance in the Current group. Together with their functional role of assigning salience to external stimuli (35), dopaminergic pathways may well contribute to confusion, and misattribution, of agency via changes in the normal temporal window for associability such that external cues become a possible source of body input.…”

Section: Discussionmentioning

confidence: 57%

“…Psychometric studies show that illusory sensations over the “other” hand are simultaneously associated with a reduction of the same sensations in the real hand (43). For example, embodiment of the “other” hand is proportionally related to disembodiment of one’s real hand, with the total embodiment of both being equal to one single hand (44, 45). A similar balance also exists with the sense of agency (46).…”

Section: Introductionmentioning

confidence: 99%

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Deficits in Agency in Schizophrenia, and Additional Deficits in Body Image, Body Schema, and Internal Timing, in Passivity Symptoms

et al. 2014

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Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered. Using the projected-hand illusion (a digital video version of the rubber-hand illusion) with synchronous and asynchronous stroking (500 ms delay), and a hand laterality judgment task, we assessed sense of agency, body image, and body schema in 53 people with clinically stable schizophrenia (with a current, past, and no history of passivity symptoms) and 48 healthy controls. The results revealed a stable trait in schizophrenia with no difference between clinical subgroups (sense of agency) and some quantitative (specific) differences depending on the passivity symptom profile (body image and body schema). Specifically, a reduced sense of self-agency was a common feature of all clinical subgroups. However, subgroup comparisons showed that individuals with passivity symptoms (both current and past) had significantly greater deficits on tasks assessing body image and body schema, relative to the other groups. In addition, patients with current passivity symptoms failed to demonstrate the normal reduction in body illusion typically seen with a 500 ms delay in visual feedback (asynchronous condition), suggesting internal timing problems. Altogether, the results underscore self-abnormalities in schizophrenia, provide evidence for both trait abnormalities and state changes specific to passivity symptoms, and point to a role for internal timing deficits as a mechanistic explanation for external cues becoming a possible source of self-body input.

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Section: Discussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Deficits in Agency in Schizophrenia, and Additional Deficits in Body Image, Body Schema, and Internal Timing, in Passivity Symptoms

et al. 2014

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“…The resting-state procedure testing began at 200 min post-dose, shortly after the reference peak dexamphetamine concentration for oral administration of 25 mg [Asghar et al, 2003]. This is also close to the peak time of the autonomic effects of Figure 1 from Albrecht et al, 2011b]. Due to the complex relationships observed between heart rate and EEG [e.g., Lechinger et al, 2015;Dirlich et al, 1998], we report here the heart rate increase in response to amphetamine.…”

Section: Participantsmentioning

confidence: 73%

The effects of dexamphetamine on the resting‐state electroencephalogram and functional connectivity

Albrecht

Roberts

Price

et al. 2015

Human Brain Mapping

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The catecholamines-dopamine and noradrenaline-play important roles in directing and guiding behavior. Disorders of these systems, particularly within the dopamine system, are associated with several severe and chronically disabling psychiatric and neurological disorders. We used the recently published group independent components analysis (ICA) procedure outlined by Chen et al. (2013) to present the first pharmaco-EEG ICA analysis of the resting-state EEG in healthy participants administered 0.45 mg/kg dexamphetamine. Twenty-eight healthy participants between 18 and 41 were recruited. Bayesian nested-domain models that explicitly account for spatial and functional relationships were used to contrast placebo and dexamphetamine on component spectral power and several connectivity metrics. Dexamphetamine led to reductions across delta, theta, and alpha spectral power bands that were predominantly localized to Frontal and Central regions. Beta 1 and beta 2 power were reduced by dexamphetamine at Frontal ICs, while beta 2 and gamma power was enhanced by dexamphetamine in posterior regions, including the parietal, occipital-temporal, and occipital regions. Power-power coupling under dexamphetamine was similar for both states, resembling the eyes open condition under placebo. However, orthogonalized measures of power coupling and phase coupling did not show the same effect of dexamphetamine as power-power coupling. We discuss the alterations of low- and high-frequency EEG power in response to dexamphetamine within the context of disorders of dopamine regulation, in particular schizophrenia, as well as in the context of a recently hypothesized association between low-frequency power and aspects of anhedonia. Hum Brain Mapp 37:570-588, 2016. © 2015 Wiley Periodicals, Inc.

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“…Conversely, D 2 R levels in cortical and striatal areas correlate with positive but not negative symptom scores (Kessler et al, 2009). Nevertheless, some trait-like phenomena can be reproduced by both ketamine and dopaminergic agonists, such as reduced latent inhibition (Young et al, 2005; Razoux et al, 2007), blocking (O’Tuathaigh et al, 2003; Freeman et al, 2013), and the body ownership illusion (Albrecht et al, 2011; Morgan et al, 2011). This is not surprising, as there are complex interactions between glutamatergic, GABAergic, and dopaminergic neurotransmission, within and between the brain stem, striatum, and prefrontal cortex (see Figure 2).…”

Section: The Psychopharmacology Of Precisionmentioning

confidence: 99%

The Computational Anatomy of Psychosis

Adams¹,

Stephan²,

Brown³

et al. 2013

Front. Psychiatry

717

778

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This paper considers psychotic symptoms in terms of false inferences or beliefs. It is based on the notion that the brain is an inference machine that actively constructs hypotheses to explain or predict its sensations. This perspective provides a normative (Bayes-optimal) account of action and perception that emphasizes probabilistic representations; in particular, the confidence or precision of beliefs about the world. We will consider hallucinosis, abnormal eye movements, sensory attenuation deficits, catatonia, and delusions as various expressions of the same core pathology: namely, an aberrant encoding of precision. From a cognitive perspective, this represents a pernicious failure of metacognition (beliefs about beliefs) that can confound perceptual inference. In the embodied setting of active (Bayesian) inference, it can lead to behaviors that are paradoxically more accurate than Bayes-optimal behavior. Crucially, this normative account is accompanied by a neuronally plausible process theory based upon hierarchical predictive coding. In predictive coding, precision is thought to be encoded by the post-synaptic gain of neurons reporting prediction error. This suggests that both pervasive trait abnormalities and florid failures of inference in the psychotic state can be linked to factors controlling post-synaptic gain – such as NMDA receptor function and (dopaminergic) neuromodulation. We illustrate these points using biologically plausible simulations of perceptual synthesis, smooth pursuit eye movements and attribution of agency – that all use the same predictive coding scheme and pathology: namely, a reduction in the precision of prior beliefs, relative to sensory evidence.

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Dexamphetamine effects on separate constructs in the rubber hand illusion test

Abstract: These results show a novel pharmacological manipulation of separate constructs of the RHI. This finding may aid in our understanding of disorders that have overlapping disturbances in both dopamine activity and body representations, particularly schizophrenia.

Cited by 32 publications

References 104 publications

Deficits in Agency in Schizophrenia, and Additional Deficits in Body Image, Body Schema, and Internal Timing, in Passivity Symptoms

Deficits in Agency in Schizophrenia, and Additional Deficits in Body Image, Body Schema, and Internal Timing, in Passivity Symptoms

The effects of dexamphetamine on the resting‐state electroencephalogram and functional connectivity

The Computational Anatomy of Psychosis

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