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Age-related changes in the impact of contextual strength on multiple aspects of sentence comprehension.

ABSTRACT: Contextual information influences multiple aspects of language comprehension extended over time. To determine how age-related changes impact normal comprehension, effects of contextual strength were examined with event-related potentials. Increased contextual constraint facilitated semantic processing (reduced N400s). Effects were smaller and delayed for older adults, and sensitivity to contextual information was diminished for weak contexts. Both groups elicited a later left-lateralized frontal negativity associated with reinterpretation of context when multiple interpretations of a sentence were likely. Older adults evidenced the frontal negativity over a wider range of constraint. The change in the use of contextual information across age is attributed to decreased reliance on predictive processing for older adults. Thus, age-related changes in comprehension lead to differential engagement of processing resources over time for older adults.

SUBMITTER: Wlotko EW

PROVIDER: S-EPMC4001119 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Age-related changes in the impact of contextual strength on multiple aspects of sentence comprehension.

Wlotko Edward W EW Federmeier Kara D KD

Psychophysiology 20120403 6

Contextual information influences multiple aspects of language comprehension extended over time. To determine how age-related changes impact normal comprehension, effects of contextual strength were examined with event-related potentials. Increased contextual constraint facilitated semantic processing (reduced N400s). Effects were smaller and delayed for older adults, and sensitivity to contextual information was diminished for weak contexts. Both groups elicited a later left-lateralized frontal ...[more]

PMID: 22469362

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Project description:Changes in dynamic properties of mitochondria are increasingly implicated in neurodegenerative diseases, particularly Parkinson's disease (PD). Static changes in mitochondrial morphology, often under acutely toxic conditions, are commonly utilized as indicators of changes in mitochondrial fission and fusion. However, in neurons, mitochondrial fission and fusion occur in a dynamic system of axonal/dendritic transport, biogenesis and degradation, and thus, likely interact and change over time. We sought to explore this using a chronic neuronal model (nonlethal low-concentration rotenone over several weeks), examining distal neurites, which may give insight into the earliest changes occurring in PD. Using this model, in live primary neurons, we directly quantified mitochondrial fission, fusion, and transport over time and integrated multiple aspects of mitochondrial dynamics, including morphology and growth/mitophagy. We found that rates of mitochondrial fission and fusion change as neurons age. In addition, we found that chronic rotenone exposure initially increased the ratio of fusion to fission, but later, this was reversed. Surprisingly, despite changes in rates of fission and fusion, mitochondrial morphology was minimally affected, demonstrating that morphology can be an inaccurate indicator of fission/fusion changes. In addition, we found evidence of subcellular compartmentalization of compensatory changes, as mitochondrial density increased in distal neurites first, which may be important in PD, where pathology may begin distally. We propose that rotenone-induced early changes such as in mitochondrial fusion are compensatory, accompanied later by detrimental fission. As evidence, in a dopaminergic neuronal model, in which chronic rotenone caused loss of neurites before cell death (like PD pathology), inhibiting fission protected against the neurite loss. This suggests that aberrant mitochondrial dynamics may contribute to the earliest neuropathologic mechanisms in PD. These data also emphasize that mitochondrial fission and fusion do not occur in isolation, and highlight the importance of analysis and integration of multiple mitochondrial dynamic functions in neurons.

Dataset Information

Age-related changes in the impact of contextual strength on multiple aspects of sentence comprehension.

Publications

Age-related changes in the impact of contextual strength on multiple aspects of sentence comprehension.

Similar Datasets

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