Abnormal medial temporal activity for bound information during working memory maintenance in patients with schizophrenia

Abstract

Alterations of binding in long-term memory in schizophrenia are well established and occur as a result of aberrant activity in the medial temporal lobe (MTL). In working memory (WM), such a deficit is less clear and the pathophysiological bases remain unstudied. Seventeen patients with schizophrenia and 17 matched healthy controls performed a WM binding task while undergoing functional magnetic resonance imaging. Binding was assessed by contrasting two conditions comprising an equal amount of verbal and spatial information (i.e., three letters and three spatial locations), but differing in the absence or presence of a link between them. In healthy controls, MTL activation was observed for encoding and maintenance of bound information but not for its retrieval. Between-group comparisons revealed that patients with schizophrenia showed MTL hypoactivation during the maintenance phase only. In addition, BOLD signals correlated with behavioral performance in controls but not in patients with schizophrenia. Our results confirm the major role that the MTL plays in the pathophysiology of schizophrenia. Short-term and long-term relational memory deficits in schizophrenia may share common cognitive and functional pathological bases. Our results provide additional information about the episodic buffer that represents an integrative interface between WM and long-term memory.

Working memory alpha–beta band oscillatory signatures in adolescents and young adults

“…The functional and neurobiological decomposition of WM into distinct components (see review by Eriksson et al ., ) suggests that WM failures might well result from selective deficits in some components that might not necessarily generalize to the other ones. While this has been already demonstrated clinically, in particular, for encoding and maintenance components (e.g., Johnson et al ., ; Driesen et al ., ; Luck et al ., ), this also sheds considerable doubt as to whether the comparison between correct‐ and incorrect‐recalled trials might actually translate to reflect the contrast between functional vs. dysfunctional encoding, per se .…”

“…This seems to raise the possibility that WM failures might arise from selective deficits in one or a number of these WM subprocesses with the rest remaining relatively intact. The latter has been confirmed in a number of clinical studies that have revealed selective component impairments that do not generalize to the other WM subprocesses (e.g., Johnson et al ., ; Driesen et al ., ; Luck et al ., ). At the experimental level, the multicomponent model of WM functioning can pose significant challenges when one attempts to focus on one or a select number of these components.…”

Patients with schizophrenia show aberrant patterns of basal ganglia activation: Evidence from ALE meta-analysis

“…Analysis completed on only 7 subjects as one outlier per group was removed 1 3 Reward Gradin et al, 2011 1.5 T MRI 15 17 Instrumental reward learning task using fractal pictures and water reward (fluid withdrawal the night before) given on a probabilistic schedule 2 4 Insel et al, 2014 1.5 T MRI 22 0 Reinforcement learning, with conditions for monetary gain, and avoiding monetary loss 8 n/a Schlagenhauf et al, 2014 3 T MRI 24 24 Reversal learning task, two sessions of 100 trials with reward and punishment 0 7 Walter et al, 2009 3 T MRI 16 16 Monetary incentive task, parametric variation of wins 4 3 Gradin et al, 2013 1.5 T MRI 14 18 Pavlovian reward learning task with water reward after fluid withdrawal, using fractal pictures 0 2 Morris et al, 2012 3 T MRI 21 16 Reward prediction error during Pavlovian cue-outcome card game with both expected and unexpected rewards 0 12 Working memory Guse et al, 2013 3 T MRI 25 22 Verbal working memory, 2-back relative to 0-back. Data from controls in two groups of 11 and only include pre-TMS intervention 0 2 Luck et al, 2010 2 T fMRI 16 17 Verbal working memory Sternberg variant with incorrect lures 0 3 Royer et al, 2009 1.5 T MRI 19 12 …”

Verbal working memory‐related neural network communication in schizophrenia

“…Both results suggest compensatory WM network activity in SZ that supports WM processes (evident in variation with load despite general slowing and poorer performance accuracy overall; see also Baenninger et al, ). Accentuated temporal lobe activation in SZ has been reported in relation to visual verbal and visuospatial working memory tasks (Kim et al, ; Luck et al, ; also White, Schmidt et al, ; White, Hongwanishkul, & Schmidt, , for adolescents with early‐onset SZ). Kim and colleagues (2010) observed a similar compensatory network spanning temporal parietal and prefrontal regions in SZ via an fMRI BOLD effect in a modified Sternberg task, as increased activation of the middle temporal gyrus was associated with higher accuracy and faster RT only in SZ.…”