Altered resting state attentional networks in diabetic neuropathic pain

Abstract

Chronic pain can be considered as a highly salient stimulus that continuously taxes the attentional and salience processing networks, thus interfering with cognitive abilities and, more specifically, consuming attentional resources. The aim of the paper was to explore whether and how diabetic neuropathic pain (NP) affects attentional networks. We sought to achieve this by investigating resting state functional connectivity (rsFC) in diabetic NP patients and comparing it with that of matched healthy controls. NP patients showed a widespread reduction of connectivity in both the dorsal and ventral attentional networks, as well as in the dorsal anterior cingulated cortex (ACC), typically implicated in salience processing. We also found a generalized reduction of the length of functional connections in the NP group: in all the examined networks, the Euclidian distance between connected voxels was significantly shorter in patients vs. controls. In sum, our work showed that in diabetic NP pain a parieto-fronto-cingulate network controlling attention to external stimuli is impaired. In line with previous studies, we conclude that chronic pain can disrupt the synchrony of a common pool of brain areas, involved in self monitoring, pain processing and salience detection. 2 INTRODUCTIONThe nervous system is continuously bombarded by internal and extrapersonal stimuli. The priority is to identify the most relevant among these myriad of inputs. This capacity requires a system that can integrate highly processed sensory data with visceral, autonomic, and hedonic markers [1]. Pain is inherently salient, and it demands attention and cognitive resources, as it has to be evaluated in intensity and in other qualities. Thus, attention to a salient input such as pain can be viewed as the focusing of resources on a specific stimulus. While a growing number of studies have examined the relationships between attention and pain, and their neural correlates, few studies have addressed the issue of how pain engages and modifies attention. Indeed, the majority of studies to date have focused on the effects of attention on pain, while the effects of pain on attention are practically unexplored. Lesion and neuroimaging studies employing non-painful stimuli have related attentional control to a network composed of parietal, frontal, and cingulate cortical regions [2]. Some studies have found similar patterns of cortical activation for both voluntary and involuntary attentional control mechanisms [3]. Similarly to other attentional tasks, pain engages a common group of brain regions that includes the posterior parietal, prefrontal, and anterior cingulate cortices [4]. Sharing common cognitive resources and neural correlates, pain and attention systems are likely to interact. Indeed, it has been demonstrated that experimental pain can decrease cognitive performance and task-related activity [5,6]. However, the interaction between pain and other functional networks has only recently started to be considered [7,8]. We believe a promising ...

HIV Distal Neuropathic Pain Is Associated with Smaller Ventral Posterior Cingulate Cortex

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