Frontal Recruitment During Response Inhibition in Older Adults Replicated With fMRI

Recent research has explored age-related differences in multiple areas of cognitive functioning using fMRI, PET, and SPECT. However, because these studies used different tasks, subjects, and methods, little is known about whether the results of these studies are generalizable or repeatable. The present study replicated a previous study [Psychol. Aging 17 (2002) 56] using the same Go/No-go task with a subset of 11 of the original older adult subjects, and using the same fMRI scanner and imaging methods. A direct comparison was made between these participants at Time 1 and Time 2 for both behavioral and functional data. These participants were also compared to a new young adult group of 11 participants. Although the current young adult group did not perform as well as the original young adult group, the original finding of enhanced left prefrontal activation in older adults relative to younger adults was replicated. Furthermore, when comparing Time 1 to Time 2, older adults exhibited comparable areas of activation, but significantly greater magnitude of activation at Time 1 in a few clusters. The findings indicate that older adults exhibit more bilateral brain activity during this task than young adults, which appears compensatory and is repeatable over time. The magnitude of regional activation, however, may vary with extraneuronal factors such as signal-to-noise ratio or task experience. This study adds to existing research suggesting that bilateral frontal activation is a predominant finding in the aging literature, and not specific to certain tasks in age group comparisons

fMRI of Healthy Older Adults During Stroop Interference

The Stroop interference effect, caused by difficulty inhibiting overlearned word reading, is often more pronounced in older adults. This has been proposed to be due to declines in inhibitory control and frontal lobe functions with aging. Initial neuroimaging studies of inhibitory control show that older adults have enhanced activation in multiple frontal areas, particularly in inferior frontal gyrus, indicative of recruitment to aid with performance of the task. The current study compared 13 younger and 13 older adults, all healthy and well educated, who completed a Stroop test during functional magnetic resonance imaging. Younger adults were more accurate across conditions, and both groups were slower and less accurate during the interference condition. The groups exhibited comparable activation regions, but older adults exhibited greater activation in numerous frontal areas, including the left inferior frontal gyrus. The results support the recruitment construct and suggest, along with previous research, that the inferior frontal gyrus is important for successful inhibition

An Evaluation of Distinct Volumetric and Functional MRI Contributions Toward Understanding Age and Task Performance: A Study in the Basal Ganglia

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\u27s in the bilateral caudate (C) and putamen/globus pallidus (PGp) were studied based upon previous findings of age-related functional MRI differences in basal ganglia for this portion of the task. Structural volumes and functional activation (in percent area under the curve during correct responses) were independently extracted for these ROI\u27s. Results showed that age correlated with ROI volume in bilateral PGp and C, while multiple task performance measures correlated with functional activation in the left PGp. The Go/No-go task measures were also significantly correlated with traditional attention and executive functioning measures. Importantly, fMRI activation and volumes from each ROI were not significantly inter-correlated. These findings suggest that structural and functional MRI make unique contributions to the study of performance changes in aging

Comparability of Functional MRI Response in Young and Old During Inhibition

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 vascular confounds or specific changes in hemodynamic coupling

Gender Specific Disruptions in Emotion Processing in Younger Adults with Depression

Background: One of the principal theories regarding the biological basis of major depressive disorder (MDD) implicates a dysregulation of emotion-processing circuitry. Gender differences in how emotions are processed and relative experience with emotion processing might help to explain some of the disparities in the prevalence of MDD between women and men. This study sought to explore how gender and depression status relate to emotion processing. Methods: This study employed a 2 (MDD status) × 2 (gender) factorial design to explore differences in classifications of posed facial emotional expressions (N=151). Results: For errors, there was an interaction between gender and depression status. Women with MDD made more errors than did nondepressed women and men with MDD, particularly for fearful and sad stimuli (Ps Ps P=.01). Men with MDD, conversely, performed similarly to control men (P=.61). Conclusions: These results provide novel and intriguing evidence that depression in younger adults (years) differentially disrupts emotion processing in women as compared to men. This interaction could be driven by neurobiological and social learning mechanisms, or interactions between them, and may underlie differences in the prevalence of depression in women and men. Depression and Anxiety, 2009. Published 2008 Wiley-Liss, Inc

The Sensitivity and Psychometric Properties of a Brief Computer-Based Cognitive Screening Battery in a Depression Clinic

At present, there is poor accuracy in assessing cognitive and vegetative symptoms in depression using clinician or self-rated measures, suggesting the need for development of standardized tasks to assess these functions. The current study assessed the psychometric properties and diagnostic specificity of a brief neuropsychological screening battery designed to assess core signs of depression; psychomotor retardation, attention and executive functioning difficulties, and impaired emotion perception within an outpatient psychiatry setting. Three hundred eighty-four patients with mood disorders and 77 healthy volunteers participated. A large percentage of patients met diagnostic criteria for Major Depressive Disorder alone (49%) or with another comorbid psychiatric disorder (24%). A brief, 25-min battery of computer-based tests was administered to control participants and patients measuring the constructs of inhibitory control, attention, visual perception, and both executive and visual processing speed. The patient groups performed significantly worse than the control group regardless of diagnosis on visual perception and attention accuracy and processing speed factors. Surprisingly, the anxiety disorder group performed better than several other psychiatric disorder groups in inhibitory control accuracy. Developing valid and reliable measures of cognitive signs in mood disorders creates excellent opportunities for tracking cognitive status prior to initiation of treatment, and allows for reliable retest following treatment

The double burden of age and disease on cognition and quality of life in bipolar disorder

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108337/1/gps4084.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108337/2/gps4084-sup-0002-TableS1.pd

The neuroanatomy of inhibitory control in healthy aging: Evidence from event-related fMRI

Working memory is an important cognitive function for selecting, maintaining, and manipulating relevant information and thoughts. Inhibitory control, or the ability to suppress irrelevant or interfering stimuli, is a crucial component of working memory. Impaired inhibitory control has been proposed to account for decreased efficiency in cognitive processing for older adults, particularly in working memory tasks. Previous imaging studies with older adults, although limited in number and scope, suggest that activation in older adults is more bilateral and more diffuse compared to younger adults. Three theories have been proposed to account for activation differences between younger and older adults: Recruitment, Reorganization, and Sigmoid Function. Thus, event-related fMRI was used with a response inhibition task to test these three theories and to expand on previous findings on inhibition in aging by examining successful and unsuccessful inhibition trials. Both younger and older adults were expected to exhibit primarily right prefrontal and parietal activation during inhibition, based on some preliminary studies. In addition, because older adults have exhibited greater activation compared to younger adults during successful inhibition in the left inferior frontal gyrus, left inferior parietal lobule and bilateral dorsomedial thalamic nuclei, similar findings were expected in the current study. There were eleven young adults and thirteen healthy older adults as participants in the current study. Contrary to expectations, older adults were not impaired in inhibitory performance when compared to younger adults, likely due to poorer than expected performance by younger adults. Cerebral activation during successful inhibition was predominantly in bilateral prefrontal and right parietal regions for older adults, but not in left parietal or bilateral thalamic areas. Unexpectedly, activation in younger adults was of greater relative magnitude compared to older adults in bilateral prefrontal areas, including the anterior cingulate. In addition, the bilateral frontal activation for younger adults was evident at the easiest level of the task. The present results best support the Recruitment theory. Finally, older adults exhibited greater activation for unsuccessful inhibition in several limbic, visual, and motor association areas, while younger adults did not, supporting the utility of using event-related fMRI in separating behavioral events within imaging studies

Event-Related fMRI of Inhibitory Control Reveals Lateralized Prefrontal Activation Differences between Healthy Young and Older Adults

Damage to the ventromedial prefrontal cortex (VM) frequently impairs decision making. This association is also supported by functional imaging studies. It has been proposed that normal aging may be accompanied by disproportionate changes in frontal lobe structure and function. We studied 80 normal adults, aged 26 to 85 years, using a gambling task sensitive to decision-making impairments and frontal lobe dysfunction. Nearly all younger participants (37/40) performed advantageously (i.e., developed risk aversion over trials); however, a number of older participants (14/40) failed to develop risk aversion and made disadvantageous decisions in a manner reminiscent of VM patients. The results lend support to the notion that there can be differential aging of the frontal lobes and may explain why some older adults show vulnerability to advertising fraud

A Task to Manipulate Attentional Load, Set-Shifting, and Inhibitory Control: Convergent validity and test–retest reliability of the Parametric Go/No-Go Test

Traditional neuropsychological measures of executive functioning are difficult to employ in functional imaging and clinical trial contexts and have tremendous practice effects. They also have poor sensitivity and specificity, while test–retest reliability is often not assessed in computer-based tests. The present study evaluates some psychometric properties of a new Parametric Go/No-Go (PGNG) Task. The PGNG consists of three levels of difficulty assessing attention, set-shifting, and processing speed, with the two more difficult levels assessing inhibitory control. A total of 63 healthy control participants were recruited at two sites to evaluate the psychometric properties of the PGNG. The PGNG was found to have solid parametric characteristics and strong test–retest reliability. Modest convergent validity was also demonstrated with other executive-functioning tests. Learning effects were significantly less than those for the Trail Making Test. The present results provide solid initial support for the validity and reliability of the PGNG