A biased competition account of attention and memory in Alzheimer's disease

Abstract

The common view of Alzheimer's disease (AD) is that of an age-related memory disorder, i.e. declarative memory deficits are the first signs of the disease and associated with progressive brain changes in the medial temporal lobes and the default mode network. However, two findings challenge this view. First, new model-based tools of attention research have revealed that impaired selective attention accompanies memory deficits from early pre-dementia AD stages on. Second, very early distributed lesions of lateral parietal networks may cause these attention deficits by disrupting brain mechanisms underlying attentional biased competition. We suggest that memory and attention impairments might indicate disturbances of a common underlying neurocognitive mechanism. We propose a unifying account of impaired neural interactions within and across brain networks involved in attention and memory inspired by the biased competition principle. We specify this account at two levels of analysis: at the computational level, the selective competition of representations during both perception and memory is biased by AD-induced lesions; at the large-scale brain level, integration within and across intrinsic brain networks, which overlap in parietal and temporal lobes, is disrupted. This account integrates a large amount of previously unrelated findings of changed behaviour and brain networks and favours a brain mechanism-centred view on AD.

Using the virtual reality device Oculus Rift for neuropsychological assessment of visual processing capabilities

“…This flexible action control depends on how fast visual objects can be processed5678. Therefore, deficiencies in visual processing speed are one source of the declined everyday functioning in neurological and psychiatric disorders and in aging910111213. Reliable assessment of visual processing speed is a prerequisite for accurate diagnosis and, hence, for adequate treatment of all clinical conditions of impaired visual processing speed.…”

Functional degeneration in dorsal and ventral attention systems in amnestic mild cognitive impairment and Alzheimer’s disease: An fMRI study

“…11.050 0304-3940/© 2014 Elsevier Ireland Ltd. All rights reserved. mechanism with memory deficits in early stage of AD [7,14]. Even, poor initial performances of attention and executive function were better predictors than test of memory on discriminating aMCI and normal aging [18,21].…”

Attentional selection in visual perception, memory and action: a quest for cross-domain integration

“…Because parameters related to temporal expectancy turn out to be simple (linear) functions of the model's internal parameters, the article naturally extends the scope of TVA to relevant experimental parameters in the temporal domain. Finke et al [73] apply TVA to disentangle attention and memory processes impaired in Alzheimer's disease (AD) from another. They find that competitive attentional selection is impaired very early in AD and based on these data suggest that initial phases of AD should be understood as 'attentional weighing deficit' rather than a deficit in memory per se.…”