Prefrontal cortex activity during response inhibition associated with excitement symptoms in schizophrenia

Proactive response inhibition abnormalities in the sensorimotor cortex of patients with schizophrenia

“…Behavioural results indicated that the majority of patients and controls successfully inhibited overtmotor responses, with patients exhibiting a nonsignificant tendency for increased false-positive responses during incongruent trials. In contrast to previous studies examining reactive response inhibition, [7][8][9][10][11]19,21 there were no differences between groups within the lateral prefrontal cortex, subcortical regions or inferior parietal cortex. Instead, opposing patterns of activation (patients: positive BOLD; controls: negative BOLD) were observed within the right and left lateral premotor cortex and SMC, with patients also exhibiting decreased connectivity between the anterior and posterior regions of the SMC.…”

“…48 Postmortem studies suggest reduced dendritic GABAergic interneuron projections in the lateral prefrontal cortex of patients with schizophrenia, 49,50 and previous neuroimaging studies have consistently observed BOLD abnormalities in the dorsolateral, ventrolateral and inferior frontal cortices in patients with schizophrenia during inhibitory control. [7][8][9][10][11]19 The null findings observed in the lateral prefrontal cortex in the present study relative to previous studies in patients with schizophrenia therefore likely resulted from differences in task demands. Specifically, the use of a cue (i.e., proactive inhibition) precluded participants from making decisions following stimulus presentation (i.e., reactive inhibition), eliminating the response uncertainty that may trigger inhibitory mechanisms during both go and no-go trials and engaging tonic rather than phasic response inhibition.…”

“…[7][8][9][10] Similar findings emerge during more complex go/no-go tasks. For example, patients with schizophrenia fail to activate a dorsal prefrontal-parietal network while inhibiting responses for negative compared with neutral words.…”

“…Response inhibition, the ability to inhibit planned or ongoing motor actions, represents an important subcomponent of cognitive control. 6 Previous research in patients with schizophrenia used tasks, such as the go/no-go and stop-signal tasks, [7][8][9][10] which require the late-acting inhibition of prepotent motor responses on a trial-by-trial basis following stimulus presentation (hereafter referred to as reactive response inhibition). In contrast, the purposeful and sustained inhibition of motor responses in an anticipatory manner (hereafter referred to as proactive response inhibition) has been infrequently examined in patients with schizophrenia, 11 despite recent suggestions that proactive processes may represent a more sensitive marker of disease.…”

The neural basis of a deficit in abstract thinking in patients with schizophrenia

“…Regarding prefrontal functions in schizophrenia, previous studies have mostly demonstrated hypofrontality, and partly hyperfrontality (Koike et al, 2011;Nishimura et al, 2011;Takizawa et al, 2008). One study demonstrated that while controls show task-related activations in the ventral part of the prefrontal cortex, patients with schizophrenia use the bilateral FPC to compensate and maintain task performance levels as cognitive load changes (Koike et al, 2013).…”