Working memory is thought to serve as a buffer for ongoing cognitive operations, even in tasks that have no obvious memory requirements. This conceptualization has been supported by dual-task experiments, in which interference is observed between a primary task involving short-term memory storage and a secondary task that presumably requires the same buffer as the primary task. Little or no interference is typically observed when the secondary task is very simple. Here, we test the hypothesis that even very simple tasks require the working memory buffer, but interference can be minimized by using activity-silent representations to store the information from the primary task. We tested this hypothesis using dual-task paradigm in which a simple discrimination task was interposed in the retention interval of a change detection task. We used contralateral delay activity (CDA) to track the active maintenance of information for the change detection task. We found that the CDA was massively disrupted after the interposed task. Despite this disruption of active maintenance, we found that performance in the change detection task was only slightly impaired, suggesting that activity-silent representations were used to retain the information for the change detection task. A second experiment replicated this result and also showed that automated discriminations could be performed without producing a large CDA disruption. Together, these results suggest that simple but non-automated discrimination tasks require the same processes that underlie active maintenance of information in working memory.

BACKGROUND: Major depression (MD) is a prevalent and disabling condition in Chile, with most cases being treated at the primary care level. In Chilean primary care, the authors have identified key factors associated with more complex presentations of MD and a poorer prognosis, such as a history of childhood trauma, suicidality, and comorbidities. These findings underscore the need for a multidimensional, trauma-informed, and interprofessional approach to the treatment of depression. METHODS: This protocol is a two-arm, single-blinded, cluster RCT to compare the effectiveness of a collaborative multidimensional approach for depression (CMAD) versus usual care to treat MD in primary care clinics in Chile. In total, 394 depressed adults from 18 to 65 years of age in twelve clinics located in Chiles Maule Region will be consented to participate in the study. Patients and care teams from each clinic will be randomized to the intervention or to the control arm.Interprofessional teams in the intervention arm will attend 27 hours of didactic and active learning sessions focused on clinical competences to effectively engage, treat and follow up patients with the factors associated to the complex presentation of MD. Team in the control arm will receive 27 didactic sessions on current clinical guidelines for MD.Patients of both arms will be blindly assessed at baseline, three months, and six months. The primary outcome will be the reduction in depressive symptoms, with secondary outcomes including improvements in anxiety symptoms, interpersonal and social functioning, and treatment adherence. DISCUSSION: This protocol proposes the evaluation of an intervention designed to improve depression symptoms by enhancing the clinical competencies of primary care teams. These competencies are structured around collaborative care and trauma-informed practices. TRIAL REGISTRATION: NCT05016388, registered on 16 August 2021 at ClinicalTrials.gov.

A recently proposed hyperfocusing hypothesis of cognitive dysfunction in schizophrenia proposes that people with schizophrenia (PSZ) tend to concentrate processing resources more narrowly but more intensely than healthy control subjects (HCS). The present study tests a key prediction of this hypothesis, namely, that PSZ will hyperfocus on information presented at the center of gaze. This should lead to greater filtering of peripheral stimuli when the task requires focusing centrally but reduced filtering of central stimuli when the task requires attending broadly in the periphery. These predictions were tested in a double oddball paradigm, in which frequent standard stimuli and rare oddball stimuli were presented at central and peripheral locations while event-related potentials were recorded. Participants were instructed to discriminate between the standard and oddball stimuli at either the central location or at the peripheral locations. PSZ and HCS showed opposite patterns of spatial bias at the level of early sensory processing, as assessed with the P1 component: PSZ exhibited stronger sensory suppression of peripheral stimuli when the task required attending narrowly to the central location, whereas HCS exhibited stronger sensory suppression of central stimuli when the task required attending broadly to the peripheral locations. Moreover, PSZ exhibited a stronger stimulus categorization response than HCS, as assessed with the P3b component, for central stimuli when the task required attending to the peripheral region. These results provide strong evidence of hyperfocusing in PSZ, which may provide a unified mechanistic account of multiple aspects of cognitive dysfunction in schizophrenia.SIGNIFICANCE STATEMENT Schizophrenia clearly involves impaired attention, but attention is complex, and delineating the precise nature of attentional dysfunction in schizophrenia has been difficult. The present study tests a new hyperfocusing hypothesis, which proposes that people with schizophrenia (PSZ) tend to concentrate processing resources more intensely but more narrowly than healthy control subjects (HCS). Using electrophysiological measures of sensory and cognitive processing, we found that PSZ were actually superior to HCS in focusing attention at the point of gaze and filtering out peripheral distractors when the task required a narrow focusing of attention. This finding of superior filtering in PSZ supports the hyperfocusing hypothesis, which may provide the mechanism underlying a broad range of cognitive impairments in schizophrenia.