Andreea O Diaconescu

Andreea O Diaconescu
University of Toronto | U of T · Krembil Centre for Neuroinformatics at CAMH

PhD

About

66
Publications
10,935
Reads
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1,596
Citations
Additional affiliations
July 2013 - present
ETH Zurich
Position
  • PostDoc Position
January 2012 - present
Translational Neuromodeling Unit UZH/ETH Zurich
July 2011 - July 2012
University of Zurich
Position
  • PostDoc Position

Publications

Publications (66)
Article
Full-text available
Background and hypothesis: In a complex world, gathering information and adjusting our beliefs about the world is of paramount importance. The literature suggests that patients with psychotic disorders display a tendency to draw early conclusions based on limited evidence, referred to as the jumping-to-conclusions bias, but few studies have examin...
Preprint
A bstract Connectome-based neural mass modelling is the emerging computational neuroscience paradigm for simulating large-scale network dynamics observed in whole-brain activity measurements such as fMRI, M/EEG, and related techniques. Estimating physiological parameters by fitting these models to empirical data is challenging however, due to large...
Article
Full-text available
Currently, psychiatric practice lacks reliable predictive tools and a sufficiently detailed mechanistic understanding of suicidal thoughts and behaviors (STB) to provide timely and personalized interventions. Developing computational models of STB that integrate across behavioral, cognitive and neural levels of analysis could help better understand...
Article
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Major depressive disorder is a heterogeneous diagnostic category with multiple available treatments. With the goal of optimizing treatment selection, researchers are developing computational models which attempt to predict treatment response based on various pre-treatment measures. In this paper, we review studies which use brain activity data to p...
Article
Full-text available
Rationale Abnormal functioning of the inhibitory gamma-aminobutyric acid (GABA) and excitatory (glutamate) systems is proposed to play a role in the development of schizophrenia spectrum disorder. Although results are mixed, previous 1H-magnetic resonance spectroscopy (MRS) studies in schizophrenia and clinical high-risk samples report these metabo...
Poster
Full-text available
Background Paranoid delusions (PD), defined as unfounded beliefs that others intend to deliberately cause harm, are a frequent and burdensome symptom in early psychosis. About 50% of first-episode psychosis patients (FEP) with PD report well-being lower than 2% of the general population. Despite this urgent clinical need, emergence and consolidatio...
Article
Decoding others’ intentions accurately in order to adapt one's own behavior is pivotal throughout life. In this study, we asked how younger and older adults deal with uncertainty in dynamic social environments. We used an advice-taking paradigm together with Bayesian modelling to characterize effects of aging on learning about others’ time-varying...
Article
Full-text available
The increased democratization of the creation, implementation, and attendance of academic conferences has been a serendipitous benefit of the movement toward virtual meetings. The Coronavirus Disease 2019 (COVID-19) pandemic has accelerated the transition to online conferences and, in parallel, their democratization, by necessity. This manifests no...
Article
Altered hippocampal functioning is proposed to play a critical role in the development of schizophrenia-spectrum disorders. Previous resting state functional Magnetic Resonance Imaging (rs-fMRI) studies report disrupted hippocampal connectivity in patients with psychosis and in individuals with clinical high risk, yet hippocampal connectivity has n...
Article
Full-text available
Psychiatric disorders are ubiquitously characterized by debilitating social impairments. These difficulties are thought to emerge from aberrant social inference. In order to elucidate the underlying computational mechanisms, patients diagnosed with major depressive disorder (N = 29), schizophrenia (N = 31), and borderline personality disorder (N =...
Article
Full-text available
Decision making requires integrating knowledge gathered from personal experiences with advice from others. The neural underpinnings of the process of arbitrating between information sources has not been fully elucidated. In this study, we formalized arbitration as the relative precision of predictions, afforded by each learning system, using hierar...
Article
Full-text available
Decision making requires integrating knowledge gathered from personal experiences with advice from others. The neural underpinnings of the process of arbitrating between information sources has not been fully elucidated. In this study, we formalized arbitration as the relative precision of predictions, afforded by each learning system, using hierar...
Article
While persecutory delusions (PDs) have been linked to fallacies of reasoning and social inference, computational characterizations of delusional tendencies are rare. Here, we examined 151 individuals from the general population on opposite ends of the PD spectrum (Paranoia Checklist [PCL]). Participants made trial-wise predictions in a probabilisti...
Preprint
One potentially positive result of the movement towards virtual academic meetings, accelerated by the COVID-19 pandemic, is increased democratization of the creation, implementation, and attendance of academic conferences. Here we describe an early ``proof of principle" of this democratizing power via our experience organizing the Canadian Computat...
Article
The auditory mismatch negativity (MMN) is significantly reduced in schizophrenia. Notably, a similar MMN reduction can be achieved with NMDA receptor (NMDAR) antagonists. Both phenomena have been interpreted as reflecting an impairment of predictive coding or, more generally, the "Bayesian brain" notion that the brain continuously updates a hierarc...
Article
Full-text available
Background Persecutory delusions (PD) are a prominent symptom in first episode psychosis and psychosis patients. PD have been linked to abnormalities in probabilistic reasoning and social inference (e.g., attribution styles). Predictive Coding theories of delusion formation suggest that rigid delusional beliefs could be formalized as precise (i.e....
Article
Full-text available
Computational models of social learning and decision-making provide mechanistic tools to investigate the neural mechanisms that are involved in understanding other people. While most studies employ explicit instructions to learn from social cues, everyday life is characterized by the spontaneous use of such signals (e.g. the gaze of others) to infe...
Article
Full-text available
Current theories of psychosis highlight the role of abnormal learning signals, i.e., prediction errors (PEs) and uncertainty, in the formation of delusional beliefs. We employed computational analyses of behaviour and functional magnetic resonance imaging (fMRI) to examine whether such abnormalities are evident in clinical high risk (CHR) individua...
Chapter
Neuroimaging methods have greatly contributed to our understanding of structural and functional brain changes in schizophrenia. This chapter reviews seminal studies that started the field, as well as more recent neuroimaging research, including discovery-oriented and theory-driven approaches. The chapter structures the latter literature according t...
Article
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The remarkable expedience of human learning is thought to be underpinned by meta-learning, whereby slow accumulative learning processes are rapidly adjusted to the current learning environment. To date, the neurobiological implementation of meta-learning remains unclear. A burgeoning literature argues for an important role for the catecholamines do...
Preprint
Full-text available
Decision making often requires integrating self-gathered information with information acquired from observing others. Depending on the situation, it may be beneficial to rely more on one than the other source, taking into account that either information may be imprecise or deceiving. The process by which one source is selected over the other based...
Article
Full-text available
Decision making often requires integrating self-gathered information with information acquired from observing others. Depending on the situation, it may be beneficial to rely more on one than the other source, taking into account that either information may be imprecise or deceiving. The process by which one source is selected over the other based...
Preprint
Full-text available
Background: Current theories of psychosis highlight the role of abnormal learning signals, i.e., prediction errors (PEs) and uncertainty, in the formation of delusional beliefs. We employed computational analyses of behaviour and functional magnetic resonance imaging (fMRI) to examine whether such abnormalities are evident in at-risk mental state (...
Article
Full-text available
Background The autistic spectrum is characterized by profound impairments of social interaction. The exact subpersonal processes, however, which underlie the observable lack of social reciprocity, are still a matter of substantial controversy. Recently, it has been suggested that the autistic spectrum might be characterized by alterations of the br...
Article
Full-text available
It has been suspected that abnormalities in social inference (e.g., learning others' intentions) play a key role in the formation of persecutory delusions (PD). In this study, we examined the association between subclinical PD and social inference, testing the prediction that proneness to PD is related to altered social inference and beliefs about...
Poster
Full-text available
While persecutory delusions (PD) have been linked to fallacies of reasoning (1-4) and social inference (5-7), computational characterisations of delusional tendencies are rare. In this study, we examined individuals from the general population on opposite ends of the PD spectrum (Paranoia Checklist, PCL, 7) employing hierarchical Bayesian models of...
Article
Full-text available
Identifying robust markers for predicting the onset of psychosis has been a key challenge for early detection research. Persecutory delusions are core symptoms of psychosis, and social cognition is particularly impaired in first-episode psychosis patients and individuals at risk for developing psychosis. Here, we propose new avenues for translation...
Preprint
Decoding others’ intentions accurately in order to adapt one’s own behavior remains pivotal throughout life. Yet, it is a process that is imbued with uncertainty since others’ intentions are not directly observable and may change over time. In this study, we asked the question of how younger and older adults deal with uncertainty in dynamic social...
Preprint
It has long been suspected that abnormalities in social inference (e.g., learning others’ intentions) play a key role in the formation of persecutory delusions (PD). In this study, we examined the association between subclinical PD and social inference, testing the prediction that proneness to PD is related to altered social inference and beliefs a...
Preprint
Full-text available
The auditory mismatch negativity (MMN) is significantly reduced in schizophrenia. Notably, a similar MMN reduction can be achieved with NMDA receptor (NMDAR) antagonists. Both phenomena have been interpreted as reflecting an impairment of predictive coding or, more generally, the “Bayesian brain” notion that the brain continuously updates a hierarc...
Article
Full-text available
Background Persecutory delusions (PD) constitute core symptoms in psychosis that may emerge from aberrant learning and inference about others’ intentions. Computational assays that use generative models of electrophysiological data to probe this learning process and its underlying neuronal mechanisms, in particular the effects of dopamine (DA) on s...
Poster
Full-text available
Background A central theme of contemporary neuroscience is the notion that the brain embodies a generative model of its sensory inputs to infer on the underlying environmental causes, and that it uses hierarchical prediction errors (PEs) to continuously update this model. In two pharmacological EEG studies, we investigate trial-wise hierarchical PE...
Article
Full-text available
Background It has long been suspected that abnormalities in social inference (e.g., about the intentions of others) play a key role for persecutory delusions. In this study, we examined the association between subclinical persecutory delusions (PD) and social inference, testing the prediction that proneness to PD is related to altered social infere...
Poster
Full-text available
Experimental investigation of social inference in sublinical persecutory delusion with a neurobiologically implemented probabilistic advice taking paradigm.
Article
Full-text available
Hierarchies feature prominently in anatomical accounts of cortical organisation. An open question is which computational (algorithmic) processes are implemented by these hierarchies. One renowned hypothesis is that cortical hierarchies implement a model of the world's causal structure and serve to infer environmental states from sensory inputs. Thi...
Article
Full-text available
Social learning is fundamental to human interactions, yet its computational and physiological mechanisms are not well understood. One prominent open question concerns the role of neuromodulatory transmitters. We combined fMRI, computational modelling, and genetics to address this question in two separate samples (N=35, N=47). Participants played a...
Article
This work investigates the role of magnetic field fluctuations as a confound in fMRI. In standard fMRI experiments with single-shot EPI acquisition at 3 Tesla the uniform and gradient components of the magnetic field were recorded with NMR field sensors. By principal component analysis it is found that differences of field evolution between the EPI...
Article
Full-text available
Background: Physiological noise is one of the major confounds for fMRI. A common class of correction METHODS: model noise from peripheral measures, such as ECGs or pneumatic belts. However, physiological noise correction has not emerged as a standard preprocessing step for fMRI data yet due to: (1) the varying data quality of physiological recordi...
Article
This scientific commentary refers to 'Estimating changing contexts in schizophrenia', by Kaplan et al. (doi:10.1093/brain/aww095).
Article
Full-text available
Autism is characterized by impairments of social interaction. The underlying subpersonal processes, however, are still a matter of controversy. Recently, it has been suggested that the autistic spectrum might be characterized by alterations of the brain’s inference on the causes of socially relevant signals. However, it is unclear at what level of...
Article
Functional neuroimaging has made fundamental contributions to our understanding of brain function. It remains challenging, however, to translate these advances into diagnostic tools for psychiatry. Promising new avenues for translation are provided by computational modeling of neuroimaging data. This article reviews contemporary frameworks for comp...
Article
Full-text available
Inferring on others' (potentially time-varying) intentions is a fundamental problem during many social transactions. To investigate the underlying mechanisms, we applied computational modeling to behavioral data from an economic game in which 16 pairs of volunteers (randomly assigned to "player'' or "adviser'' roles) interacted. The player performe...
Preprint
Full-text available
Introduction: The brain maintains and continuously updates a generative model of its environment 1. Recent evidence suggests that this process generates the mismatch negativity (MMN) 2-an event related potential elicited by the violation of a learned regularity 3. In addition to the MMN, a second component of the EEG signal, the P300 complex (P3b),...
Article
Full-text available
Recent theoretical and empirical work has focused on the variability of network dynamics in maturation. Such variability seems to reflect the spontaneous formation and dissolution of different functional networks. We sought to extend these observations into healthy aging. Two different data sets, one EEG (total n = 48, ages 18-72) and one magnetoen...
Article
Full-text available
This paper presents a model-based investigation of mechanisms underlying the reduction of mismatch negativity (MMN) amplitudes under the NMDA-receptor antagonist ketamine. We applied dynamic causal modeling and Bayesian model selection to data from a recent ketamine study of the roving MMN paradigm, using a cross-over, double-blind, placebo-control...
Article
Full-text available
Background The importance of developing unique, neural circuitry–based treatments for the cognitive and neuropsychiatric symptoms of Alzheimer disease (AD) was the impetus for a phase I study of deep brain stimulation (DBS) in patients with AD that targeted the fornix. Objective To test the hypotheses that DBS would increase cerebral glucose metabo...
Article
Variability in the affective and cognitive symptom response to antidepressant treatment has been observed in geriatric depression. The underlying neural circuitry is poorly understood. This study evaluated the cerebral glucose metabolic effects of citalopram treatment and applied multivariate, functional connectivity analyses to identify brain netw...
Article
Full-text available
Perceptual objects often comprise a visual and auditory signature that arrives simultaneously through distinct sensory channels, and cross-modal features are linked by virtue of being attributed to a specific object. Continued exposure to cross-modal events sets up expectations about what a given object most likely "sounds" like, and vice versa, th...
Article
Full-text available
It has recently been suggested that schizophrenia involves dysfunction in brain connectivity at a neural level, and a dysfunction in reward processing at a behavioral level. The purpose of the present study was to link these two levels of analyses by examining effective connectivity patterns between brain regions mediating reward learning in patien...
Article
Full-text available
The present study examined the modality specificity and spatio-temporal dynamics of "what" and "where" preparatory processes in anticipation of auditory and visual targets using ERPs and a cue-target paradigm. Participants were presented with an auditory (Experiment 1) or a visual (Experiment 2) cue that signaled them to attend to the identity or l...
Article
Full-text available
The present study examined the modality specificity and spatio-temporal dynamics of "what" and "where" preparatory processes in anticipation of auditory and visual targets using ERPs and a cue-target paradigm. Participants were presented with an auditory (Experiment 1) or a visual (Experiment 2) cue that signaled them to attend to the identity or l...
Article
The aim of the present paper is to assess the effects of altered dopamine (DA) transmission on the functional connectivity among brain regions mediating aversive conditioning in humans. To this aim, we analyzed a previous published data set from a double-blind design combined with functional magnetic resonance imaging (fMRI) recordings in which hea...
Article
The present study examined the modality specificity and spatio-temporal dynamics of “what” and “where” preparatory processes in anticipation of auditory and visual targets using ERPs and a cue–target paradigm. Participants were presented with an auditory (Experiment 1) or a visual (Experiment 2) cue that signaled them to attend to the identity or l...
Article
We used event-related potentials (ERPs) in a crossmodal stimulus-response compatibility paradigm to identify modality-independent aspects of rule processing and cued response facilitation. Participants responded to a lateralized target with the ipsilateral (compatible) or contralateral (incompatible) hand. Cue-target modality and cue-target order w...
Article
The effects of learning on the geometry of face space were investigated by measuring thresholds for discrimination and recognition of synthetic faces. This was based on a novel experimental technique that permitted measurement of psychometric functions for face recognition. Two major results were obtained. First, thresholds for face recognition wer...