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Full-Text Articles in Medicine and Health Sciences
Stressor-Induced Increase In Muscle Fatigability Of Young Men And Women Is Predicted By Strength But Not Voluntary Activation, Manda Keller-Ross, Hugo Pereia, Jaclyn Pruse, Tejin Yoon, Bonnie Schlinder-Delap, Kristy Nielson, Sandra Hunter
Stressor-Induced Increase In Muscle Fatigability Of Young Men And Women Is Predicted By Strength But Not Voluntary Activation, Manda Keller-Ross, Hugo Pereia, Jaclyn Pruse, Tejin Yoon, Bonnie Schlinder-Delap, Kristy Nielson, Sandra Hunter
Kristy Nielson
This study investigated mechanisms for the stressor-induced changes in muscle fatigability in men and women. Participants performed an isometric-fatiguing contraction at 20% maximal voluntary contraction (MVC) until failure with the elbow flexor muscles. Study one (n = 55; 29 women) involved two experimental sessions: 1) a high-stressor session that required a difficult mental-math task before and during a fatiguing contraction and 2) a control session with no mental math. For some participants (n = 28; 14 women), cortical stimulation was used to examine mechanisms that contributed to muscle fatigability during the high-stressor and control sessions. Study two (n = 23; …
Semantic Knowledge For Famous Names In Mild Cognitive Impairment, M Seidenberg, L Guidotti, Kristy Nielson, J Woodard, S Durgerian, Q Zhang, A Gander, M Franczak, P Antuono, S Rao
Semantic Knowledge For Famous Names In Mild Cognitive Impairment, M Seidenberg, L Guidotti, Kristy Nielson, J Woodard, S Durgerian, Q Zhang, A Gander, M Franczak, P Antuono, S Rao
Kristy Nielson
Person identification represents a unique category of semantic knowledge that is commonly impaired in Alzheimer’s disease (AD), but has received relatively little investigation in patients with mild cognitive impairment (MCI). The current study examined the retrieval of semantic knowledge for famous names from three time epochs (recent, remote, and enduring) in two participant groups: 23 amnestic MCI (aMCI) patients and 23 healthy elderly controls. The aMCI group was less accurate and produced less semantic knowledge than controls for famous names. Names from the enduring period were recognized faster than both recent and remote names in both groups, and remote names …
Temporally Graded Activation Of Neocortical Regions In Response To Memories Of Different Ages, J Woodard, M Seidenberg, Kristy Nielson, S Miller, M Franczak, P Antuono, K Douville, S Rao
Temporally Graded Activation Of Neocortical Regions In Response To Memories Of Different Ages, J Woodard, M Seidenberg, Kristy Nielson, S Miller, M Franczak, P Antuono, K Douville, S Rao
Kristy Nielson
The temporally graded memory impairment seen in many neurobehavioral disorders implies different neuroanatomical pathways and/or cognitive mechanisms involved in storage and retrieval of memories of different ages. A dynamic interaction between medial-temporal and neocortical brain regions has been proposed to account for memory’s greater permanence with time. Despite considerable debate concerning its time-dependent role in memory retrieval, medial-temporal lobe activity has been well studied. However, the relative participation of neocortical regions in recent and remote memory retrieval has received much less attention. Using functional magnetic resonance imaging, we demonstrate robust, temporally graded signal differences in posterior cingulate, right middle frontal, …
An Evaluation Of Distinct Volumetric And Functional Mri Contributions Toward Understanding Age And Task Performance: A Study In The Basal Ganglia, S Langenecker, E Briceno, N Hamid, Kristy Nielson
An Evaluation Of Distinct Volumetric And Functional Mri Contributions Toward Understanding Age And Task Performance: A Study In The Basal Ganglia, S Langenecker, E Briceno, N Hamid, Kristy Nielson
Kristy Nielson
Prior work by our group and others has implicated the basal ganglia as important in age-related differences in tasks involving motor response control. The present study used structural and functional MRI approaches to analyze this region of interest (ROI) toward better understanding the contributions of structural and functional MRI measures to understanding age-related and task performance-related cognitive differences. Eleven healthy elders were compared with 11 healthy younger adults while they completed the “go” portion of a complex Go/No-go task. Separate ROI's in the bilateral caudate (C) and putamen/globus pallidus (PGp) were studied based upon previous findings of age-related functional MRI …
Age-Related Functional Recruitment During The Recognition Of Famous Names: An Event-Related Fmri Study, Kristy Nielson, K Douville, M Seidenberg, J Woodard, S Miller, P Antuono, M Franczak, S Rao
Age-Related Functional Recruitment During The Recognition Of Famous Names: An Event-Related Fmri Study, Kristy Nielson, K Douville, M Seidenberg, J Woodard, S Miller, P Antuono, M Franczak, S Rao
Kristy Nielson
Recent neuroimaging research shows that older adults exhibit recruitment, or increased activation on various cognitive tasks. The current study evaluated whether a similar pattern also occurs in semantic memory by evaluating age-related differences during recognition of Recent (since the 1990s) and Enduring (1950s to present) famous names. Fifteen healthy older and 15 healthy younger adults performed the name recognition task with a high and comparable degree of accuracy, although older adults had slower reaction time in response to Recent famous names. Event-related functional MRI showed extensive networks of activation in the two groups including posterior cingulate, right hippocampus, temporal lobe …
The Effects Of Non-Contingent Extrinsic And Intrinsic Rewards On Memory Consolidation, Kristy Nielson, Ted Bryant
The Effects Of Non-Contingent Extrinsic And Intrinsic Rewards On Memory Consolidation, Kristy Nielson, Ted Bryant
Kristy Nielson
Emotional and arousing treatments given shortly after learning enhance delayed memory retrieval in animal and human studies. Positive affect and reward induced prior to a variety of cognitive tasks enhance performance, but their ability to affect memory consolidation has not been investigated before. Therefore, we investigated the effects of a small, non-contingent, intrinsic or extrinsic reward on delayed memory retrieval. Participants (n = 108) studied and recalled a list of 30 affectively neutral, imageable nouns. Experimental groups were then given either an intrinsic reward (e.g., praise) or an extrinsic reward (e.g., $1). After a one-week delay, participants’ retrieval performance for …
Medial Temporal Lobe Activity For Recognition Of Recent And Remote Famous Names: An Event-Related Fmri Study, K Douville, J Woodard, M Seidenberg, S Miller, C Leveroni, Kristy Nielson, M Franczak, P Antuono, S Rao
Medial Temporal Lobe Activity For Recognition Of Recent And Remote Famous Names: An Event-Related Fmri Study, K Douville, J Woodard, M Seidenberg, S Miller, C Leveroni, Kristy Nielson, M Franczak, P Antuono, S Rao
Kristy Nielson
Previous neuroimaging studies examining recognition of famous faces have identified activation of an extensive bilateral neural network [Gorno Tempini, M. L., Price, C. J., Josephs, O., Vandenberghe, R., Cappa, S. F., Kapur, N. et al. (1998). The neural systems sustaining face and proper-name processing. Brain, 121, 2103–2118], including the medial temporal lobe (MTL) and specifically the hippocampal complex [Haist, F., Bowden, G. J., & Mao, H. (2001). Consolidation of human memory over decades revealed by functional magnetic resonance imaging. Nature Neuroscience, 4, 1139–1145; Leveroni, C. L., Seidenberg, M., Mayer, A. R., Mead, L. A., Binder, J. R., & Rao, S. …
Comparability Of Functional Mri Response In Young And Old During Inhibition, Kristy Nielson, Scott Langenecker, T Ross, H Garavan, S Rao, E Stein
Comparability Of Functional Mri Response In Young And Old During Inhibition, Kristy Nielson, Scott Langenecker, T Ross, H Garavan, S Rao, E Stein
Kristy Nielson
When using fMRI to study age-related cognitive changes, it is important to establish the integrity of the hemodynamic response because, potentially, it can be affected by age and disease. However, there have been few attempts to document such integrity and no attempts using higher cognitive rather than perceptual or motor tasks. We used fMRI with 28 healthy young and older adults on an inhibitory control task. Although older and young adults differed in task performance and activation patterns, they had comparable hemodynamic responses. We conclude that activation during cognitive inhibition, which was predominantly increased in elders, was not due to …
Differences In The Functional Neuroanatomy Of Inhibitory Control Across The Adult Life Span, Kristy Nielson, Scott Langenecker, H Garavan
Differences In The Functional Neuroanatomy Of Inhibitory Control Across The Adult Life Span, Kristy Nielson, Scott Langenecker, H Garavan
Kristy Nielson
Inhibitory control, the ability to suppress irrelevant or interfering stimuli, is a fundamental cognitive function that deteriorates during aging, but little is understood about the bases of decline. Thus, we used event-related functional magnetic resonance imaging (fMRI) to study inhibitory control in healthy adults aged 18 to 78. Activation during successful inhibition occurred predominantly in right prefrontal and parietal regions and was more extensive, bilaterally and prefrontally, in the older groups. Presupplementary motor area was also more active in poorer inhibitory performers. Therefore, older adults activate areas that are comparable to those activated by young adults during inhibition, as well …