Projects
This page presents a selection of the main projects currently ongoing in the lab.
SubApathy - Multimodal characterization of structural and effective connectivity correlates of subclinical apathy, effort valuation and reward valuation
Apathy is highly prevalent across almost all psychiatric and neurological disorders. Even in otherwise healthy people, there is a large inter-individual variability in apathy, with some individuals exhibiting high apathy scores, though below the clinical threshold, indicative of what is known as subclinical apathy. Despite its significance, the neural underpinnings of individual differences in subclinical apathy and effort-based decision making remain elusive. In this project, we address this gap in healthy human subjects through comprehensive neuropsychological assessments of apathy, depression and anhedonia, as well as computational modeling of behavior in an effort-based decision-making task, enabling quantification of subjective effort and reward valuation in each individual. We combine these behavioral data with a multimodal quantification of brain morphometry using magnetic resonance imaging (MRI), structural connectivity using diffusion-weighted imaging (DWI) and effective connectivity using dual-site transcranial magnetic stimulation (dsTMS).
MotivAction - Role of fronto-striato-motor circuits in effort-based decision-making
Past research on effort-based decision-making and apathy has mostly focused on a key fronto-striatal network, involving the supplementary motor area, the dorsal anterior cingulate cortex the orbitofrontal cortex and the ventral striatum. Further, a few studies have highlighted a role of the motor cortex in effort-based decisions. Surprisingly, these two groups of studies have neglected potential interactions between the fronto-striatal and motor structures. In this project, we propose leveraging recent technological advances in effective connectivity quantification and modulation to establish an integrative framework questioning the role of recurrent circuits between the fronto-striatal network and the motor cortex. The project involves testing the hypothesis that (1) the fronto-striatal network continuously modulates motor cortex activity during decision-making, depending on the efforts and rewards at stake and that (2) an alteration of effective connectivity within fronto-striato-motor circuits would contribute to apathy in Parkinson’s disease patients.
ShizApathy- Neurocomputational basis of apathy in schizophrenia
Current research on apathy faces three significant challenges. First, there is a need to transition from an isolationist approach focused on atrophy of specific brain structures to a connectionist framework to better characterize the network-level alterations at the basis of apathy. Second, we need to develop computational biomarkers of effort and reward valuation that provide objective and specific insights into the potential causes of apathy in various disorders. Lastly, and relatedly, there is a lack of effective therapeutic approaches to enhance engagement in effort and alleviate apathy, as many treatments do not target the specific network-level and neuro-computational alterations mentioned above, resulting in mixed clinical outcomes. Importantly, these three challenges are especially prominent in schizophrenia, where apathy significantly exceeds the impairments caused by any other negative symptom. SchizApathy is a PhD project that aims to address these three challenges in Schizophrenia. It is conducted by Sanchari Sengupta in tight collaboration with Dr. Franziska Knolle in Munich.
ThetaOnOrbit - Causal role of orbitofrontal theta oscillations in effort-based decision-making
The orbitofrontal cortex (OFC) is known to play a pivotal role in deciding to engage in effortful actions to reach rewarding goals – i.e., effort-based decision-making. Specifically, recent studies have highlighted the critical role of OFC theta oscillations in reward processing. Yet, whether OFC theta oscillations play a causal role in effort-based decision-making has been overlooked. This project involves a randomized, double-blind, sham-controlled brain stimulation protocol to address this issue. We combine computational modelling of behavior in an effort-based decision-making with concurrent high-definition transcranial alternating current stimulation (HD-tACS) of the OFC. EEG and e-field modelling are also exploited to quantify the effect of HD-tACS on cortical tissues.
DeepStimSim – Simulating the electric field induced within deep brain structures through non-invasive stimulation
Brain electrical stimulation allows the modulation of neuron activity in specific brain areas through an electric field applied via electrodes placed on the surface of the skull. This technique has been widely used to stimulate cortical structures, located at the surface of the brain. The project aims to explore the impact of different electrode montages on the stimulation of deep brain structures.