Schizophrenic subjects activate dorsolateral prefrontal cortex during a working memory task, as measured by fMRI

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Previous neuroimaging studies indicate reduced prefrontal cortex activity in schizophrenia patients during working memory tasks.
• This phenomenon is often termed 'hypofrontality'.

Purpose of the Study:

• To investigate dorsolateral prefrontal cortex (DLPFC) activation differences between schizophrenia patients and healthy controls during a working memory (WM) task.
• To explore the relationship between DLPFC activation and task performance in schizophrenia.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to compare DLPFC activation in 12 schizophrenia patients and 10 healthy controls.
• A modified Sternberg Item Recognition Paradigm (SIRP) assessed WM performance under varying cognitive loads.
• Task conditions included high WM load, low WM load, and a non-WM control task.

Main Results:

• Schizophrenia patients performed worse than controls but better than chance on the WM task.
• Patients exhibited greater left DLPFC activation compared to controls, with no significant differences in the right DLPFC or control regions.
• In schizophrenia patients, increased left DLPFC activation correlated with poorer task performance (more errors).

Conclusions:

• The findings challenge previous notions of task-related hypofrontality in schizophrenia.
• Observed performance and activation differences may reflect inefficient neural circuitry and prefrontal dysfunction in schizophrenia's working memory processes.
• Task parameters might influence observed activation patterns, warranting further investigation.