Cognitive modes underlying attentional control impairments in schizophrenia: an fMRI study

Among the cognitive impairments characteristic of schizophrenia, deficits in cognitive control are particularly prominent. In the current functional magnetic resonance imaging (fMRI) study, we examined the spatial patterns and task-induced blood-oxygenation-level-dependent (BOLD) changes associated with attentional control deficits in participants with schizophrenia relative to neurotypical participants. We employed a cognitive paradigm that required participants to alternated between three judgment tasks (i.e., identifying colours, parity, or letter case), while being presented with stimuli comprised of one (univalent), two (bivalent), or three (trivalent) dimension(s). Three cognitive modes were detected: (1) Multiple Demand (MD), (2) Language (LAN), and (3) Default mode B (DM-B). Participants with schizophrenia showed impaired task performance, muted but sustained activations of the MD mode, hypo-activations of the LAN mode, and hyper-deactivations of the DM-B mode relative to neurotypical participants. Thus, attentional control impairments in individuals with schizophrenia are likely due to disrupted activity of the MD, LAN, and DM-B modes. Additionally, in participants with schizophrenia, the sustained activation of the MD mode in the Trivalent condition was associated with higher scores on positive symptoms (hallucinations and delusions), while the reduced activation of the LAN mode in the Trivalent condition and the pronounced deactivation of the DM-B mode in the Univalent condition were associated with higher scores on negative symptoms (i.e., poverty of speech and flattened affect). Our findings highlight the contributions of fMRI to individualized medicine due to symptom-specific effects, and identifying potential targets for neuromodulation techniques that aim to restore BOLD activity and improve cognitive function in schizophrenia.