Original Research ARTICLE
Striatal intrinsic reinforcement signals during recognition memory: relationship to response bias and dysregulation in schizophrenia
- 1 Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
- 2 Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- 3 Philadelphia Veterans Administration Medical Center, Philadelphia, PA, USA
Ventral striatum (VS) is a critical brain region for reinforcement learning and motivation, and VS hypofunction is implicated in psychiatric disorders including schizophrenia. Providing rewards or performance feedback has been shown to activate VS. Intrinsically motivated subjects performing challenging cognitive tasks are likely to engage reinforcement circuitry even in the absence of external feedback or incentives. However, such intrinsic reinforcement responses have received little attention, have not been examined in relation to behavioral performance, and have not been evaluated for impairment in neuropsychiatric disorders such as schizophrenia. Here we used fMRI to examine a challenging “old” vs. “new” visual recognition task in healthy subjects and patients with schizophrenia. Targets were unique fractal stimuli previously presented as salient distractors in a visual oddball task, producing incidental memory encoding. Based on the prediction error theory of reinforcement learning, we hypothesized that correct target recognition would activate VS in controls, and that this activation would be greater in subjects with lower expectation of responding correctly as indexed by a more conservative response bias. We also predicted these effects would be reduced in patients with schizophrenia. Consistent with these predictions, controls activated VS and other reinforcement processing regions during correct recognition, with greater VS activation in those with a more conservative response bias. Patients did not show either effect, with significant group differences suggesting hyporesponsivity in patients to internally generated feedback. These findings highlight the importance of accounting for intrinsic motivation and reward when studying cognitive tasks, and add to growing evidence of reward circuit dysfunction in schizophrenia that may impact cognition and function.
Keywords: memory, reward, intrinsic motivation, ventral striatum, schizophrenia
Citation: Wolf DH, Gerraty RT, Satterthwaite TD, Loughead J, Campellone T, Elliott MA, Turetsky BI, Gur RC and Gur RE (2011) Striatal intrinsic reinforcement signals during recognition memory: relationship to response bias and dysregulation in schizophrenia. Front. Behav. Neurosci. 5:81. doi: 10.3389/fnbeh.2011.00081
Received: 08 August 2011; Paper pending published: 15 October 2011;
Accepted: 30 November 2011; Published online: 16 December 2011.
Edited by:Antonella Gasbarri, University of L’Aquila, Italy
Copyright: © 2011 Wolf, Gerraty, Satterthwaite, Loughead, Campellone, Elliott, Turetsky, Gur and Gur. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
*Correspondence: Daniel H. Wolf, Department of Psychiatry, University of Pennsylvania, 10th Floor Gates Building, 3400 Spruce Street, Philadelphia, PA 19104, USA. e-mail: firstname.lastname@example.org