title: Self-initiated encoding facilitates object working memory in schizophrenia: implications for the etiology of working memory deficit.
abstract: BACKGROUND
  Working memory (WM) deficit is present in a majority of patients with schizophrenia but it is unclear which components of WM are impaired. Past studies suggest that encoding may be compromised. One important determinant of encoding is the deployment of selective attention to the target stimulus. In addition, attention and encoding are modulated by motivational factors. In this study, we investigated the effects of self-initiated encoding (i.e., voluntary attention) on WM.
  
  
  METHODS
  19 patients with schizophrenia and 19 matched control subjects participated in visual WM and control tasks. Encoding was manipulated by asking subjects to select from two face targets and memorize 1) one of the two identical faces (Non-preference condition), 2) one that is marked (Non-choice condition), and 3) one they prefer (Preference condition). WM accuracy for both location (spatial) and identity (object) was measured.
  
  
  RESULTS
  Overall, patients with schizophrenia were less accurate and slower than the control subjects but the deficit was greater for object WM. However, patients were more accurate in object WM when they selected a preferred face as their target during encoding (preference condition) compared with the other two conditions. This effect was not significant for spatial WM.
  
  
  CONCLUSIONS
  These results suggest that voluntary, self-initiated attention may facilitate object encoding especially if the selection of the target involves affective choice, and that attention may play different roles in encoding 'what' versus 'where' in WM. Since encoding affects all forms of memory, these results may have a more general implication for memory.
authors.affiliation: Department of Psychology, Vanderbilt University, 111 21st Ave South, TN 37240, USA.
authors.forename: Jejoong
authors.initials: J
authors.lastname: Kim
authors.forename: Sohee
authors.initials: S
authors.lastname: Park
authors.forename: Yong-Wook
authors.initials: YW
authors.lastname: Shin
authors.forename: Kyung
authors.initials: K
authors.lastname: Jin Lee
authors.forename: Jun Soo
authors.initials: JS
authors.lastname: Kwon
mesh_terms: D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy*; D009483:Neuropsychological Tests; D011930:Reaction Time; D012559:Schizophrenia / Q000150:complications*; D020377:Self Efficacy; D012932:Social Facilitation