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Start Over Author "Skimminge A" Journal neurobiology of aging
3 results on '"Skimminge A"'

1. Healthy aging attenuates task-related specialization in the human medial temporal lobe

Author

Ramsøy, Thomas Z, Liptrot, Matthew G, Skimminge, Arnold, Lund, Torben E, Sidaros, Karam, Christensen, Mark Schram, Baaré, William, Paulson, Olaf B, Jernigan, Terry L, and Siebner, Hartwig R

Subjects
Biological Psychology, Psychology, Applied and Developmental Psychology, Neurosciences, Clinical Research, Aging, Aetiology, 1.1 Normal biological development and functioning, 2.1 Biological and endogenous factors, 1.2 Psychological and socioeconomic processes, Underpinning research, Neurological, Mental health, Adult, Age Factors, Aged, Aged, 80 and over, Brain Mapping, Cognition, Cohort Studies, Denmark, Female, Functional Laterality, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Middle Aged, Neuropsychological Tests, Photic Stimulation, Recognition, Psychology, Specialization, Temporal Lobe, Time Factors, Young Adult, Episodic memory, Encoding, Recognition, Neural specificity, Working memory, Clinical Sciences, Neurology & Neurosurgery, Biological psychology
Abstract

Recent research on aging has established important links between the neurobiology of normal aging and age-related decline in episodic memory, yet the exact nature of this relationship is still unknown. Functional neuroimaging of regions such as the medial temporal lobe (MTL) have produced conflicting findings. Using functional magnetic resonance imaging (fMRI), we have recently shown that young healthy individuals show a stronger activation of the MTL during encoding of objects as compared with encoding of positions. Using the same encoding task, the present study addressed the question whether this greater MTL activation during encoding of objects varies with age. Fifty-four healthy individuals aged between 18 and 81 years underwent functional magnetic resonance imaging while they encoded and subsequently made new-old judgments on objects and positions. Region of interest (ROI) analysis of task related changes in the blood oxygen level-dependent (BOLD) signal was performed in native space after correction for gender effects and individual differences in cerebral blood flow. The hippocampus, amygdala, and parahippocampal, perirhinal, entorhinal, and temporopolar cortices of right and left hemisphere were defined as ROIs. Aging had an adverse effect on memory performance that was similar for memorizing objects or positions. In left and right MTL, relatively greater activation for object stimuli was attenuated in older individuals. Age-related attenuation in content specificity was most prominent in the recognition stage. During recognition, the larger response to objects gradually decreased with age in all ROIs apart from left temporopolar and entorhinal cortex. An age-related attenuation was also present during encoding, but only in right parahippocampus and amygdala. Our results suggest that memory-related processing in the MTL becomes gradually less sensitive to content during normal aging.

Published
2012

3. Hearts and minds: linking vascular rigidity and aerobic fitness with cognitive aging

Author

Said Mekary, Muriel Lefort, Michèle Desjardins, Claudine J. Gauthier, Cécile Madjar, Frédérique Frouin, Laurence Desjardins-Crépeau, Richard D. Hoge, Arnold Skimminge, Frédéric Lesage, Louis Bherer, Pernille Iversen, and Ellen Garde

Subjects
Adult, Male, medicine.medical_specialty, Aging, Physical exercise, Cohort Studies, Cognition, Vascular Stiffness, medicine.artery, Internal medicine, medicine, Aerobic exercise, Humans, Pulse wave velocity, Exercise, Aorta, Aged, General Neuroscience, VO2 max, Cardiorespiratory fitness, Middle Aged, Executive functions, Elasticity, Physical Fitness, Physical therapy, Cardiology, Neurology (clinical), Geriatrics and Gerontology, Psychology, Developmental Biology, Stroop effect
Abstract

Human aging is accompanied by both vascular and cognitive changes. Although arteries throughout the body are known to become stiffer with age, this vessel hardening is believed to start at the level of the aorta and progress to other organs, including the brain. Progression of this vascular impairment may contribute to cognitive changes that arise with a similar time course during aging. Conversely, it has been proposed that regular exercise plays a protective role, attenuating the impact of age on vascular and metabolic physiology. Here, the impact of vascular degradation in the absence of disease was investigated within 2 groups of healthy younger and older adults. Age-related changes in executive function, elasticity of the aortic arch, cardiorespiratory fitness, and cerebrovascular reactivity were quantified, as well as the association between these parameters within the older group. In the cohort studied, older adults exhibited a decline in executive functions, measured as a slower performance in a modified Stroop task (1247.90 � 204.50 vs. 898.20 � 211.10 ms on the inhibition and/or switching component, respectively) than younger adults. Older participants also showed higher aortic pulse wave velocity (8.98 � 3.56 vs. 3.95 � 0.82 m/s, respectively) and lower VO 2 max (29.04 � 6.92 vs. 42.32 � 7.31 mL O2/kg/min, respectively) than younger adults. Within the older group, faster performance of the modified Stroop task was associated with preserved aortic elasticity (lower aortic pulse wave velocity; p ¼ 0.046) and higher cardiorespiratory fitness (VO2 max; p ¼ 0.036). Furthermore, VO2 max was found to be negatively associated with blood oxygenation level dependent cerebrovascular reactivity to CO2 in frontal regions involved in the task (p ¼ 0.038) but positively associated with cerebrovascular reactivity in periventricular watershed regions and within the postcentral gyrus. Overall, the results of this study support the hypothesis that cognitive status in aging is linked to vascular health, and that preservation of vessel elasticity may be one of the key mechanisms by which physical exercise helps to alleviate cognitive aging.

Published
2014

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