True memory, false memory, and subjective recollection deficits after focal parietal lobe lesions.
OBJECTIVE
There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Here we assess whether parietal lobe damage affects episodic memory on a different task: the Deese-Roediger-McDermott (DRM) false-memory paradigm.


METHODS
Two patients with bilateral PPC damage and a group of matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures.


RESULTS
The patients exhibited significantly lower levels of false memory to words. One patient showed significantly elevated levels of false memory to pictures. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure.


CONCLUSIONS
PPC damage causes decreased levels of false memories and an abnormal Remember/Know profile. Their false memory rate is similar to the rate exhibited by patients with medial temporal lobe damage. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection.
Drowos
David B
DB
Department of Psychology, Temple University, Philadelphia, PA 19122, USA.
Berryhill
Marian
M
André
Jessica M
JM
Olson
Ingrid R
IR
D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications* / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology; D014705:Verbal Behavior / Q000502:physiology