Expression of executive dysfunctions is marked by substantial heterogeneity in people living with HIV infection (PLWH) and attributed to neuropathological degradation of frontostriatal circuitry with age and disease.
Physiological Responses to Acute Psychosocial Stress in Women with Menopausal Insomnia
Insomnia disorder is a common sleep disorder and frequently emerges in the context of menopause, being associated with menopause-specific factors such as hot flashes and other psychosocial variables.
Compromised Frontocerebellar Circuitry Contributes to Nonplanning Impulsivity in Recovering Alcoholics
We tested the hypothesis that alcoholic patients would demonstrate compromised dorsal anterior cingulate cortex (dACC) -cerebellar functional connectivity when adjusting their strategies to accommodate uncertain conditions and would recruit compensatory brain regions to overcome ineffective response patterns.
Interhemispheric Functional Connectivity Change Is Linked to Callosal Fiber Integrity Change over a 1-Year Follow-up in Chronic Alcoholics
We tested whether microstructural fiber changes relate to resting-state functional connectivity changes in alcoholics who have maintained sobriety during a one-year interval, and whether these changes are beyond those potentially exhibited by controls.
Brain Connectivity Changes over Time in Alcoholism
SRI Authors: Adolf Pfefferbaum, Tilman Schulte
Synchrony of Anterior Cingulate Cortex and Insular-Striatal Activation Predicts Ambiguity Aversion in Individuals with Low Impulsivity
Personal attitude toward ambiguity contributes to individual differences in decision making in uncertain situations. Operationally, these attitudes reflect the various coping strategies elected to overcome the limited information. A key brain region involved in cognitive control for performance adjustments is the dorsal anterior cingulate cortex (dACC). To test how dACC functional network connectivity would be modulated by uncertainty and differ between individuals, 24 healthy participants underwent functional MRI in 3 sequential runs: 1 resting-state and 2 decision-making task runs. Individuals with lower nonplanning impulsiveness made greater use of a Pass option and avoided uncertain ambiguous situations. Seed-based functional connectivity analysis during the task runs revealed that stronger activation synchrony between the left dACC and the right anterior insula correlated with greater use of a Pass response option. During the resting-state, stronger resting-state functional connectivity between the left dACC and the ventral striatum predicted the adoption of Pass as a behavioral strategy and correlated with stronger task-activated synchrony between the dACC and the right anterior insula. Our findings indicate that that the synchrony between the dACC and insula-striatal circuitry was greater in individuals with low compared with high nonplanning impulsiveness and contributed to adopting Pass as a useful behavioral strategy.
Fiber Tract-Driven Topographical Mapping (FTTM) Reveals Microstructural Relevance for Interhemispheric Visuomotor Function in the Aging Brain
We present a novel approach – DTI-based fiber tract-driven topographical mapping (FTTM) – to map and measure the influence of age on the integrity of interhemispheric fibers and challenge their selective functions with measures of interhemispheric integration of lateralized information. This approach enabled identification of spatially specific topographical maps of scalar diffusion measures and their relation to measures of visuomotor performance. Relative to younger adults, older adults showed lower fiber integrity indices in anterior than posterior callosal fibers. FTTM analysis identified a dissociation in the microstructural-function associates between age groups: in younger adults, genu fiber integrity correlated with interhemispheric transfer time, whereas in older adults, body fiber integrity was correlated with interhemispheric transfer time with topographical specificity along left-lateralized callosal fiber trajectories. Neural co-activation from redundant targets was evidenced by fMRI-derived bilateral extrastriate cortex activation in both groups, and a group difference emerged for a pontine activation cluster that was differently modulated by response hand in older than younger adults. Bilateral processing advantages in older but not younger adults further correlated with fiber integrity in transverse pontine fibers that branch into the right cerebellar cortex, thereby supporting a role for the pons in interhemispheric facilitation. In conclusion, in the face of compromised anterior callosal fibers, older adults appear to use alternative pathways to accomplish visuomotor interhemispheric information transfer and integration for lateralized processing. This shift from youthful associations may indicate recruitment of compensatory mechanisms involving medial corpus callosum fibers and subcortical pathways.