Recent studies have shown that drug-induced spatial alteration patterns in resting state functional activity as measured using magnetic resonance imaging (MRI) are associated with the distribution of specific receptor systems targeted by respective compounds. Based on this approach, we introduce a Matlab-based toolbox (JuSpace) allowing for cross-modal correlation of MRI-based measures with positron emission tomography (PET) and single photon emission computed tomography (SPECT) derived estimates covering various receptor systems including dopaminergic, serotonergic, noradrenergic, and GABAergic (gamma-aminobutric acid) neurotransmission. We apply JuSpace to two datasets covering Parkinson's disease patients (PD) on and off levodopa and risperidone-induced changes in rsfMRI and cerebral blood flow (CBF). We correlate rsfMRI derived PD- and levodopa-induced local activity alterations with PET and SPECT maps covering the above neurotransmitter systems. Similarly, we correlate the effects of risperidone on CBF with respective maps. Consistently with the predominant neurodegeneration of dopaminergic and serotonergic system in PD, we find significant spatial associations between rsfMRI activity alterations in PD on and off levodopa and dopaminergic (D2) and serotonergic systems (5-HT1b). Consistently with its mechanism of action, risperidone induced CBF alterations were correlated with key targets of serotonergic and dopaminergic systems. The JuSpace toolbox provides an easy framework for correlation of spatial alteration patterns across different neuroimaging modalities with PET derived receptor maps. Taken together, toolbox allows for cross-modal biologically meaningful evaluation and interpretation of image-derived spatial alteration patterns.### Competing Interest StatementSH is current employee of F.Hoffmann-La Roche. JD is a former employee and currently consultant for F.Hoffmann-La Roche. All authors report no conflicts of interest with respect to the work presented in this study. RL received travel grants and/or conference speaker honoraria within the last three years from Bruker BioSpin MR, Heel, and support from Siemens Healthcare regarding clinical research using PET/MR. He is a shareholder of BM Health GmbH since 2019.

JuSpace: A tool for spatial correlation analyses of magnetic resonance imaging data with positron emission tomography derived neurotransmitter maps