Impaired perception of mnemonic oldness, but not mnemonic newness, after parietal lobe damage

• Published in: Neuropsychologia 2014-04, Vol.56, p.409-417
• Main Authors: Hower, Kylie H., Wixted, John, Berryhill, Marian E., Olson, Ingrid R.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; Adult and adolescent clinical studies; Biological and medical sciences; Brain Injuries - complications; Brain Injuries - pathology; Brain Mapping; Female; Humans; Male; Medical sciences; Memory Disorders - etiology; Memory, Episodic; Mental Recall - physiology; Metamemory; Middle Aged; Neuropsychological Tests; Organic mental disorders. Neuropsychology; Parietal Lobe - pathology; Parietal lobe damage; Perceptual Disorders - etiology; Photic Stimulation; Psycholinguistics; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Receiver operating characteristic; Recognition memory; ROC Curve
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2014.02.014

In studies of episodic memory retrieval, recognition paradigms are known to elicit robust activations in the inferior parietal lobe. However, damage to this region does not produce severe deficits in episodic memory performance as indexed by typical accuracy measures. Rather, because problems with memory confidence are frequently reported, the observed deficits may be best described as “metamemory” or subjective memory deficits. Here, we further investigated the inferior parietal lobe’s role in recognition memory as well as metamemory. We tested the hypothesis that the inferior parietal lobe gauges the perceived oldness of items, given several neuroimaging findings suggesting that a portion of the left inferior parietal lobe is sensitive to perceived oldness. We tested two patients with bilateral parietal lobe lesions and matched controls on an old/new recognition task. From these data we constructed receiver operating characteristic (ROC) curves by fitting the data with the unequal-variance signal-detection (UVSD) model. The results revealed no memory impairment in terms of patients’ accuracy. However, patients exhibited lower hit rates and false alarms rates at high confidence levels. Further, patients and controls differed in how they set decision criteria for making recognition responses. Patients’ decision criteria for “old” responses were shifted in a conservative fashion such that they were unwilling to endorse recognized target items with high levels of confidence. These findings provide constraints on models of inferior parietal lobe contributions to episodic memory retrieval. •We tested two patients with bilateral parietal lobe lesions and matched controls.•We used an old/new recognition task and constructed ROC curves.•Results revealed no memory impairment in terms of patients׳ accuracy.•Patients exhibited lower hit and false alarm rates at high confidence levels.•Patients and controls differed in how they set decision criteria for responding.