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Research Mentor Name

Vaibhav A. Diwadkar

Research Mentor Email Address


Institution / Department

Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine

Document Type

Research Abstract

Research Type


Level of Research


Type of Post-Bachelor Degree

Medical Doctorate


Schizophrenia (SCZ) is characterized by both cognitive and reward impairments. A recent study suggests that SCZ is associated with a loss of synchrony between learning and reward circuits (Robison et al., 2019) and higher levels of dis-organization of functional brain networks may underpin failures in learning that characterize SCZ (Hütt et al., 2014). Therefore, here we examined inter-group (HC ≠ SCZ) 4th order differences in statistical regularity across a connectome of cognition and reward brain circuits. The analyses were conducted on fMRI time series data from a previous learning paradigm (Stanley et al., 2017) with periods of Encoding and Retrieval. 75 participants (46 SCZ, 18 Age 50) consented for fMRI. Time Series were extracted from eight bilateral a priori nodes (across learning and reward sub-networks). 2nd order undirectional functional connectivity was characterized across all nodal pairs during Encoding, Retrieval, and their subsequent rest periods. From this, a 4th order cross-correlation matrix was produced within each group and condition. Significant 4th order differences were projected to chords in the 4th order connectomic rings for Encoding and Retrieval (Figure 1). Two effects are evident: 1) SCZ are characterized by a massive loss of 4th order synchrony during both Encoding and Retrieval and 2) Retrieval evokes a greater loss in 4th order statistical synchrony than does Encoding. These results appear to validate the idea the SCZ is characterized by a loss of synergy between cognition and reward circuits, and that this loss of synergy is evident at higher order scales.


Behavior and Behavior Mechanisms | Medicine and Health Sciences | Psychiatry and Psychology


Hasan S, Huq M, Chowdury A, Thakkar K, Robison AJ, Stanley JA, Diwadkar VA (In Submission). Learning without contingencies: Dysfunctional interactions between Learning and Reward circuits in schizophrenia. Schizophrenia Research.

Robison, A.J., Thakkar, K., Diwadkar, V.A., (2019), ‘Cognition and Reward Circuits in Schizophrenia: Synergistic, not Separate’, Biological Psychiatry, 21 Sep 2019.

Hutt, M.T., Kaiser, M., Hilgetag, C.C., (2014), ‘Perspective: network-guided pattern formation of neural dynamics’, Philos Trans R Soc Lond B Biol Sci vol 369, 1653.