Functional MRI and delay discounting in patients infected with hepatitis C

Abstract

Background: Hepatitis C virus infected (HCV+) adults evidence increased rates of psychiatric and cognitive difficulties. This is the first study to use functional magnetic resonance imaging (fMRI) to examine brain activation in untreated HCV+ adults. Objective: To determine whether, relative to non-infected controls (CTLs), HCV+ adults exhibit differences in brain activation during a delay discounting task (DDT), a measure of one’s tendency to choose smaller immediate rewards over larger delayed rewards - one aspect of impulsivity. Methods: 20 adults with HCV and 26 CTLs completed an fMRI protocol during the DDT. Results: Mixed effects regression analyses of Hard versus Easy trials of the DDT showed that, compared with CTLs, the HCV+ group exhibited less activation in the left lateral occipital gyrus, precuneus and superior frontal gyrus. There were also significant interactive effects for Hard – Easy contrasts in the bilateral medial frontal gyrus, left insula, left precuneus, left inferior parietal lobule, and right temporal occipital gyrus; the CTL group evidenced a positive relationship between impulsivity and activation, while the HCV+ group exhibited a negative relationship. Within the HCV+ group, those with high viral load chose immediate rewards more often than those with low viral load, regardless of choice difficulty; those with low viral load chose immediate rewards more often on hard choices relative to easy choices. Conclusions: Results show that HCV+ patients exhibit greater impulsive behavior when presented with difficult choices, and impulsivity is negatively related to activation in regions important for cognitive control. Thus, interventions that decrease impulsive choice may be warranted with some HCV+ patients.

Neuroimaging Findings in Chronic Hepatitis C Virus Infection: Correlation with Neurocognitive and Neuropsychiatric Manifestations

“…Reduced cortical thickness in frontal areas with [26] or without [27] occipital involvement Posterior insula and thalamic atrophy [9] Progressive amygdala and parahippocampal atrophy [9] DAA Reduced frontal cortical volumes [28] DTI Increased MD and reduced FA in global WM [15] more evident in fronto-temporal areas [29] and body of CC [9,24,30] Increased MD in external capsule [4] and fronto-occipital fasciculus [4,9,24] Decreased FA in bilateral middle cerebellar peduncles [24] and superior thalamic radiation [31] Increased FA in the basal ganglia [4] DAA Increased FA in association, commissural and projection tracts [25] Decreased MD in association and projection tract [25] fMRI Altered cortical connectivity possibly due to frontal deficit [32,33] IFN-α Reduced ventral striatum activation [22] and global network efficiency [34] MRS Decreased NAA in anterior [35][36][37] and posterior WM [4,37] Normal [18,35,[37][38][39][40][41][42] or decreased NAA in cortical GM [43] Increased Cho in frontal [35,37,38,43,44] and posterior WM…”

“…fMRI remodeling despite normal gray matter volumes on automated voxel-based whole-brain morphometry suggests that functional impairment actually predates structural alterations [33]. In other cases, HCV infection determines more subtle changes: in HCV-infected subjects faced with an obliged choice, impulsive behavior led to a similar pattern of activation in fronto-parietal areas irrespective of the difficulty of the choice, whereas in healthy controls an increased activation is observed [32].…”