Family History of Alzheimer's Disease is Associated with Impaired Perceptual Discrimination of Novel Objects.

Early detection may be the key to developing therapies that will combat Alzheimer's disease (AD). It has been consistently demonstrated that one of the main pathologies of AD, tau, is present in the brain decades before a clinical diagnosis. Tau pathology follows a stereotypical route through the medial temporal lobe beginning in the entorhinal and perirhinal cortices.

Eye movements in Alzheimer's disease.

A growing body of literature has investigated changes in eye movements as a result of Alzheimer's disease (AD). When compared to healthy, age-matched controls, patients display a number of remarkable alterations to oculomotor function and viewing behavior. In this article, we review AD-related changes to fundamental eye movements, such as saccades and smooth pursuit motion, in addition to changes to eye movement patterns during more complex tasks like visual search and scene exploration.

The temporal dynamics of visual object priming.

Priming reflects an important means of learning that is mediated by implicit memory. Importantly, priming occurs for previously viewed objects (item-specific priming) and their category relatives (category-wide priming). Two distinct neural mechanisms are known to mediate priming, including the sharpening of a neural object representation and the retrieval of stimulus-response mappings.

Memory-related eye movements challenge behavioral measures of pattern completion and pattern separation.

The hippocampus creates distinct episodes from highly similar events through a process called pattern separation and can retrieve memories from partial or degraded cues through a process called pattern completion. These processes have been studied in humans using tasks where participants must distinguish studied items from perceptually similar lure items. False alarms to lures (incorrectly reporting a perceptually similar item as previously studied) are thought to reflect pattern completion, a retrieval-based process.

Understanding age-related reductions in visual working memory capacity: examining the stages of change detection.

Visual working memory (VWM) capacity is reduced in older adults. Research has shown age-related impairments to VWM encoding, but aging is likely to affect multiple stages of VWM. In the present study, we recorded the event-related potentials (ERPs) of younger and older adults during VWM maintenance and retrieval.

Pattern separation and pattern completion in Alzheimer's disease: evidence of rapid forgetting in amnestic mild cognitive impairment.

Over the past four decades, the characterization of memory loss associated with Alzheimer's disease (AD) has been extensively debated. Recent iterations have focused on disordered encoding versus rapid forgetting. To address this issue, we used a behavioral pattern separation task to assess the ability of the hippocampus to create and maintain distinct and orthogonalized visual memory representations in patients with amnestic mild cognitive impairment (aMCI) and mild AD.

Electrophysiological distinctions between recognition memory with and without awareness.

The influence of implicit memory representations on explicit recognition may help to explain cases of accurate recognition decisions made with high uncertainty. During a recognition task, implicit memory may enhance the fluency of a test item, biasing decision processes to endorse it as "old". This model may help explain recognition-without-identification, a remarkable phenomenon in which participants make highly accurate recognition decisions despite the inability to identify the test item.

Updating objects in visual short-term memory is feature selective.

The purpose of this study was to examine whether the process of updating information in visual short-term memory (VSTM) is object based. We investigated whether modifying the memory of one feature of an object would automatically promote refreshing the memory of all of its other features. The results showed that the facilitative effect of updating was specific to the updated feature of an object and did not spread to its nonupdated features.

Evidence for intact selective attention in Alzheimer's disease patients using a location priming task.

Researchers examining selective attentional mechanisms in patients with Alzheimer's disease (AD) often report impairment in patients' ability to inhibit irrelevant or distracting information. However, in many studies reporting such failures, researchers used tasks that require semantic processing, which a large body of literature documents to be disrupted in AD. The authors of this study used a spatial location-priming task that minimized semantic processing to examine the phenomena of negative priming and facilitative priming in 13 AD patients and 13 healthy older adults.