Kirk R. Daffner

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The authors examined false recognition of semantic associates in patients with probable Alzheimer's disease (AD), older adults, and young adults using a paradigm that provided rates of false recognition after single and multiple exposures to word lists. Using corrected false recognition scores to control for unrelated false alarms, the authors found that(More)
The physiological basis for the striking decrease of attention to novel events following frontal lobe injury is poorly understood. In this study, event-related potentials (ERPs) were recorded from patients with frontal lobe damage and matched subjects, who controlled the duration of viewing of background, novel and target stimuli. Frontal lobe patients did(More)
This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple(More)
Decline in episodic memory is a common feature of healthy aging. Event-related potential (ERP) studies in young adults have consistently reported several modulations thought to index memory retrieval processes, but relatively limited work has explored the impact of aging on them. Further, work with functional imaging has demonstrated differential neural(More)
Despite the important role that attending to novel events plays in human behavior, there is limited information about the neuroanatomical underpinnings of this vital activity. This study investigated the relative contributions of the frontal and posterior parietal lobes to the differential processing of novel and target stimuli under an experimental(More)
This study took advantage of the subsecond temporal resolution of ERPs to investigate mechanisms underlying age- and performance-related differences in working memory. Young and old subjects participated in a verbal n-back task with three levels of difficulty. Each group was divided into high and low performers based on accuracy under the 2-back condition.(More)
This study examined the relationship between orienting responses to novel events and subsequent exploratory behavior. The N2-P3 electrophysiologic component of the orienting response was found to be larger for novel than repetitive background stimuli. Across subjects, the amplitude of this N2-P3 response in frontal regions strongly predicted the(More)
Previous research has shown that patients with Alzheimer's disease show increasing levels of false recognition across five repeated study-test trials of semantic associates. The present study tested the hypotheses that (i) the increasing false recognition was partly due to the frontal lobe dysfunction of patients with Alzheimer's disease, and (ii) a failure(More)
Brain potentials associated with true and false recognition were recorded using a paradigm consisting of categorized color photographs. Two ERP components were identified. A parietal component was most positive for both true and false recognition, less positive for rejection of lures, and least positive for rejection of novel items. A later frontal(More)
Within the framework of the dual process model of recognition memory, prior work with event-related potentials (ERPs) has suggested that an early component, the FN400, is a correlate of familiarity while a later component, the Late Positive Complex (LPC), is a correlate of recollection. However, other work has questioned the validity of these correlations,(More)