Cognitive retrieval impaired in schizophrenia

By Mark Cowen, Senior medwireNews Reporter

Patients with schizophrenia show impairments in the autobiographical memory retrieval brain network, French researchers report.

Cédric Lemogne (Hôpital Européen Georges Pompidou, Paris) and team found that schizophrenia patients and mentally healthy individuals activate similar brain areas during autobiographical memory retrieval.

However, levels of activation in a number of these associated brain regions are significantly reduced in schizophrenia patients compared with mentally healthy individuals.

"Given the role of autobiographical memory in the pursuit of long-term goals and social cognition, this autobiographical memory retrieval impairment may contribute to poor social outcomes associated with schizophrenia," comment the researchers in the British Journal of Psychiatry.

The findings come from a study of 13 medicated men with schizophrenia, aged a mean of 30 years, and 14 age- and education-matched mentally healthy controls.

All of the participants underwent magnetic resonance imaging of the brain while performing an autobiographical memory retrieval task based on cue words chosen for their ability to elicit vivid mental images.

The researchers note that all of the schizophrenia patients were selected for their ability to perform the task and were given specific training.

During the task, patients and controls activated a similar brain network, which included cortical midline structures, the left lateral prefrontal cortex, the left angular gyrus, the medial temporal lobes, the occipital lobe, and the cerebellum.

However, compared with controls, patients with schizophrenia exhibited reduced activation in several of these regions, including two cortical midline structures (the anterior cingulate cortex and precuneus), the left lateral prefrontal cortex, the left medial temporal lobe, the occipital lobe, the right cerebellum, and the left lateral ventral segmental area.

The researchers also found that activation of the caudate nuclei correlated positively with retrieval performance in schizophrenia patients but negatively with retrieval performance in controls.

Lemogne et al write: "Patients with schizophrenia display decreased activation of the cognitive control network during retrieval, possibly due to aberrant functioning of the dorsal striatum."

They add: "Future studies will need to confirm these preliminary results among unmedicated and female patients and translate these results into therapeutic interventions such as cognitive remediation."

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