TY  - JOUR
A1  - Mayer, Jutta
A1  - Stäblein, Michael
A1  - Oertel-Knöchel, Viola
A1  - Fiebach, Christian
T1  - Functional dissociation of confident and not-confident errors in the spatial delayed response task demonstrates impairments in working memory encoding and maintenance in Schizophrenia
T2  - Frontiers in psychiatry
N2  - Even though extensively investigated, the nature of working memory (WM) deficits in patients with schizophrenia (PSZ) is not yet fully understood. In particular, the contribution of different WM sub-processes to the severe WM deficit observed in PSZ is a matter of debate. So far, most research has focused on impaired WM maintenance. By analyzing different types of errors in a spatial delayed response task (DRT), we have recently demonstrated that incorrect yet confident responses (which we labeled as false memory errors) rather than incorrect/not-confident responses reflect failures of WM encoding, which was also impaired in PSZ. In the present study, we provide further evidence for a functional dissociation between confident and not-confident errors by manipulating the demands on WM maintenance, i.e., the length over which information has to be maintained in WM. Furthermore, we investigate whether these functionally distinguishable WM processes are impaired in PSZ. Twenty-four PSZ and 24 demographically matched healthy controls (HC) performed a spatial DRT in which the length of the delay period was varied between 1, 2, 4, and 6 s. In each trial, participants also rated their level of response confidence. Across both groups, longer delays led to increased rates of incorrect/not-confident responses, while incorrect/confident responses were not affected by delay length. This functional dissociation provides additional support for our proposal that false memory errors (i.e., confident errors) reflect problems at the level of WM encoding, while not-confident errors reflect failures of WM maintenance. Schizophrenic patients showed increased numbers of both confident and not-confident errors, suggesting that both sub-processes of WM—encoding and maintenance—are impaired in schizophrenia. Combined with the delay length-dependent functional dissociation, we propose that these impairments in schizophrenic patients are functionally distinguishable.
KW  - schizophrenia
KW  - working memory
KW  - encoding
KW  - maintenance
KW  - false memory
KW  - spatial
Y1  - 2018
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/39826
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-398263
SN  - 1664-0640
N1  - Copyright © 2018 Mayer, Stäblein, Oertel-Knöchel and Fiebach. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
VL  - 9
IS  - Art. 202
SP  - 1
EP  - 11
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  -