Damage to the prefrontal cortex impairs familiarity but not recollection memory

Authors:

• Mariam Aly

• Andrew P. Yonelinas

• Mark M. Kishiyama

• Robert T. Knight

Date: 2011

PubMed: 21827792

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Abstract:

Frontal lobe lesions impair recognition memory but it is unclear whether the deficits arise from impaired recollection, impaired familiarity, or both. In the current study, recognition memory for verbal materials was examined in patients with damage to the left or right lateral prefrontal cortex. Words were incidentally encoded under semantic or phonological orienting conditions, and recognition memory was tested using a 6-point confidence procedure. Receiver operating characteristics (ROCs) were examined in order to measure the contributions of recollection and familiarity to recognition memory. In both encoding conditions, lateral prefrontal cortex damage led to a deficit in familiarity but not recollection. Similar deficits were observed in left and right hemisphere patients. The results indicate that the lateral prefrontal cortex plays a critical role in the monitoring or decision processes required for accurate familiarity-based recognition responses.

Faces are special but not too special: spared face recognition in amnesia is based on familiarity

Authors:

• Mariam Aly

• Robert T. Knight

• Andrew P. Yonelinas

Date: 2010

DOI: 10.1016/j.neuropsychologia.2010.09.005

PubMed: 20833190

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Abstract:

Most current theories of human memory are material-general in the sense that they assume that the medial temporal lobe (MTL) is important for retrieving the details of prior events, regardless of the specific type of materials. Recent studies of amnesia have challenged the material-general assumption by suggesting that the MTL may be necessary for remembering words, but is not involved in remembering faces. We examined recognition memory for faces and words in a group of amnesic patients, which included hypoxic patients and patients with extensive left or right MTL lesions. Recognition confidence judgments were used to plot receiver operating characteristics (ROCs) in order to more fully quantify recognition performance and to estimate the contributions of recollection and familiarity. Consistent with the extant literature, an analysis of overall recognition accuracy showed that the patients were impaired at word memory but had spared face memory. However, the ROC analysis indicated that the patients were generally impaired at high confidence recognition responses for faces and words, and they exhibited significant recollection impairments for both types of materials. Familiarity for faces was preserved in all patients, but extensive left MTL damage impaired familiarity for words. These results show that face recognition may appear to be spared because performance tends to rely heavily on familiarity, a process that is relatively well preserved in amnesia. In addition, the findings challenge material-general theories of memory, and suggest that both material and process are important determinants of memory performance in amnesia.