OBJECTIVE: Hypofrontality is a common but not invariable finding in schizophrenia. Inconsistencies in the literature may reflect, in part, the fact that abnormal physiological responses in the prefrontal cortex are best identified under conditions that place well-specified functional demands on this region. METHOD: The authors studied eight patients with schizophrenia and eight matched comparison subjects using [(15)O]H2O positron emission tomography and the "N-back" task, which activates the prefrontal cortex as a function of working memory load in normal subjects. RESULTS: Under low-working-memory-load conditions, the accuracy of both groups in the N-back task was equal, but when the memory load increased, the patients' performance deteriorated more than did that of the comparison subjects. The regional cerebral blood flow response to increased working memory load was significantly reduced in the patients' right dorsolateral prefrontal cortex. CONCLUSIONS: These results confirm the importance of using tasks that tap specific cognitive functions, linked to specific neural systems, in studies of brain-behavior relationships in schizophrenia. Hypofrontality is reliably demonstrated in schizophrenia during tasks that engage working memory functions of the prefrontal cortex.
OBJECTIVE: Hypofrontality is a common but not invariable finding in schizophrenia. Inconsistencies in the literature may reflect, in part, the fact that abnormal physiological responses in the prefrontal cortex are best identified under conditions that place well-specified functional demands on this region. METHOD: The authors studied eight patients with schizophrenia and eight matched comparison subjects using [(15)O]H2O positron emission tomography and the "N-back" task, which activates the prefrontal cortex as a function of working memory load in normal subjects. RESULTS: Under low-working-memory-load conditions, the accuracy of both groups in the N-back task was equal, but when the memory load increased, the patients' performance deteriorated more than did that of the comparison subjects. The regional cerebral blood flow response to increased working memory load was significantly reduced in the patients' right dorsolateral prefrontal cortex. CONCLUSIONS: These results confirm the importance of using tasks that tap specific cognitive functions, linked to specific neural systems, in studies of brain-behavior relationships in schizophrenia. Hypofrontality is reliably demonstrated in schizophrenia during tasks that engage working memory functions of the prefrontal cortex.
Authors: Anissa Abi-Dargham; Osama Mawlawi; Ilise Lombardo; Roberto Gil; Diana Martinez; Yiyun Huang; Dah-Ren Hwang; John Keilp; Lisa Kochan; Ronald Van Heertum; Jack M Gorman; Marc Laruelle Journal: J Neurosci Date: 2002-05-01 Impact factor: 6.167
Authors: Britta Hahn; Andrew Hollingworth; Benjamin M Robinson; Samuel T Kaiser; Carly J Leonard; Valerie M Beck; Emily S Kappenman; Steven J Luck; James M Gold Journal: Schizophr Res Date: 2011-11-12 Impact factor: 4.939
Authors: Elisa C Dias; Tammy McGinnis; John F Smiley; John J Foxe; Charles E Schroeder; Daniel C Javitt Journal: Exp Brain Res Date: 2006-04-25 Impact factor: 1.972
Authors: Rajendra A Morey; Seniha Inan; Teresa V Mitchell; Diana O Perkins; Jeffrey A Lieberman; Aysenil Belger Journal: Arch Gen Psychiatry Date: 2005-03