Aging and the interaction of sensory cortical function and structure

Abstract

Even the healthiest older adults experience changes in cognitive and sensory function. Studies show that older adults have reduced neural responses to sensory information. However, it is well known that sensory systems do not act in isolation but function cooperatively to either enhance or suppress neural responses to individual environmental stimuli. Very little research has been dedicated to understanding how aging affects the interactions between sensory systems, especially cross-modal deactivations or the ability of one sensory system (e.g., audition) to suppress the neural responses in another sensory system cortex (e.g., vision). Such cross-modal interactions have been implicated in attentional shifts between sensory modalities and could account for increased distractibility in older adults. To assess age-related changes in cross-modal deactivations, functional MRI studies were performed in 61 adults between 18 and 80 years old during simple auditory and visual discrimination tasks. Results within visual cortex confirmed previous findings of decreased responses to visual stimuli for older adults. Age-related changes in the visual cortical response to auditory stimuli were, however, much more complex and suggested an alteration with age in the functional interactions between the senses. Ventral visual cortical regions exhibited cross-modal deactivations in younger but not older adults, whereas more dorsal aspects of visual cortex were suppressed in older but not younger adults. These differences in deactivation also remained after adjusting for age-related reductions in brain volume of sensory cortex. Thus, functional differences in cortical activity between older and younger adults cannot solely be accounted for by differences in gray matter volume.

Age-related neural correlates of cognitive task performance under increased postural load

“…It appears reasonable to assume that the obtained brain activations during the former condition are, at least, partially representative for the latter. Reduced cross-modal deactivations have been detected in older subjects, with respect to visual and auditory processing (Peiffer et al 2009) and a similar age-related increase in multisensory processing has been observed in the context of postural control (Zwergal et al 2012). In view of this evidence for reduced inhibitory interactions between sensory systems, the brain activations we observed are possibly an underestimation of the true activation during standing.…”

Functional Brain Networks Formed Using Cross-Sample Entropy Are Scale Free

“…These subjects were a part of a larger study (Peiffer et al, 2009), and these are the same set of subjects used in our previous network analysis study . All the subjects signed a written informed consent, and the original study was approved by the Institutional Review Board of Wake Forest School of Medicine and conducted in accordance with the Declaration of Helsinki.…”

Lifespan age differences in working memory: A two-component framework

“…Age-related changes at the lowest level of information processing, such as decline in visual cortex activation, indicate age-related reduction in the efficiency of bottom-up processing (Cabeza et al, 2004;Madden et al, 2002Madden et al, , 1997Peiffer et al, 2009). Apart from general reductions, a loss of neural specificity, so-called dedifferentiation, has been observed in ventral visual brain regions (Park et al, 2004; see also Carp et al, 2010Carp et al, , 2011.…”