Publications

Cocaine addiction is associated with increased striatal connectivity and sensitivity to monetary incentives, and decreased connectivity outside the reward system

authors:

  • Vaquero, L.
    • ,
  • Càmara, E.
    • ,
  • Sampedro, F.
    • ,
  • Pérez de los Lobos, J.
    • ,
  • Batlle, F.
    • ,
  • Fábregas, J.M.
    • ,
  • Sales, J.A.
    • ,
  • Cervantes, M.
    • ,
  • Ferrer, X.
    • ,
  • Lazcano, G.
    • ,
  • Rodríguez-Fornells, A.
    • ,
  • Riba, J.
    • (2017)

Abstract

Cocaine addiction has been associated with increased sensitivity of the human reward circuit to drug-related stimuli. However, the capacity of non-drug incentives to engage this network is poorly understood. Here we characterized the functional sensitivity to monetary incentives and the structural integrity of the human reward circuit in abstinent cocaine-dependent (CD) patients and their matched controls. We assessed the BOLD response to monetary gains and losses in 30 CD patients and 30 healthy controls performing a lottery task in an MRI scanner. We measured brain grey matter volume (GMV) using voxel-based morphometry and white matter microstructure using voxel-based fractional anisotropy (FA). Functional data showed that CD patients exhibited higher activation after monetary gains in the ventral striatum (VStr) than controls. Furthermore, we observed an inverted BOLD response pattern in the prefrontal cortex, with highest activity after unexpected high gains and lowest after losses. Patients showed increased GMV in the caudate and the orbitofrontal cortex (OFC), increased white matter FA in the orbito-striatal pathway, but decreased FA in antero-posterior association bundles. Abnormal activation in the prefrontal cortex correlated with GMV and FA increases in the OFC. While functional abnormalities in the VStr were inversely correlated with abstinence duration, structural alterations were not. In conclusion, results suggest abnormal incentive processing in CD patients, with high salience for rewards in subcortical structures but diminished prefrontal control after adverse outcomes. They further suggest that hypertrophy and hyper-connectivity within the reward circuit, to the expense of connectivity outside this network, characterize cocaine addiction.