Abnormal neural filtering of irrelevant visual information in depression

Abstract

The pathophysiology of major depressive disorder (MDD) includes both affective and cognitive dysfunctions. We aimed to clarify how regions regulating affective processing interact with those involved in attention, and how such interaction impacts perceptual processing within sensory cortices. Based on previous work showing that top-down influences from attention can determine the processing of external inputs within early sensory cortices, we tested with functional magnetic resonance imaging (fMRI) whether MDD alters attentional ("top-down") effects on the neural filtering of irrelevant, nonemotional visual stimuli. The present fMRI study was conducted in 14 nonmedicated patients with a first episode of unipolar MDD and 14 matched controls. During scanning, subjects performed two tasks imposing two different levels of attentional load at fixation (easy or difficult), while irrelevant colored stimuli were presented in the periphery. Analyses of fMRI data revealed that MDD patients show (1) an abnormal filtering of irrelevant information in visual cortex, (2) an altered functional connectivity between frontoparietal networks and visual cortices, and (3) a hyperactivity in subgenual cingulate/ medial orbitofrontal cortex that was modulated by attentional load. These results demonstrate that biological abnormalities contribute to the cognitive deficits seen in major depression, and clarify how neural networks implicated in mood regulation influence executive control and perceptual processes. These findings not only improve our understanding of the pathophysiological mechanisms underlying cognitive dysfunctions in MDD, but also shed new light on the interaction between cognition and mood regulation.

State-dependent and trait-related gray matter changes in nonrefractory depression

“…It is known that biased attention to negative information is an important symptom in depression [38], whereas the FPN is involved in cognitive control function and has been shown to be impaired in depression [38]. The gray matter alterations in the FPN and dorsal ATN, in agreement with the results of the previous functional MRI studies to some extent [38,39], might contribute toward some cognitive impairments in depression, including selective attention, working memory, and executive functions [40][41][42]. The current study showed that the antidepressant treatment normalized some parts of the two networks, implying some improvements in cognitive functions in the clinically recovered patients.…”

Alterations in neural systems mediating cognitive flexibility and inhibition in mood disorders

“…Taken all together, these findings suggest that sgACC, known to be central in the pathophysiology of depression, is intimately associated with automatic self-processing mechanisms that involve implicit emotion regulation and interoceptive signals, and shows a distinctive pattern of dysfunctional modulation by task demands in mood disorder patients. This is consistent with other findings that this region shows deactivation in attentional tasks only with much higher cognitive load in depressed patients as compared with healthy individuals [Desseilles et al, 2009]. More generally, this interpretation also accords with a recent theory of altered interoceptive state in MDD and anxiety, postulating the existence of noisily amplified selfreferential interoceptive belief states that may contribute to negative processing biases in these patients [Paulus and Stein, 2010].…”

Impact of lingual gyrus volume on antidepressant response and neurocognitive functions in Major Depressive Disorder: A voxel-based morphometry study

“…The lingual gyrus was not commonly identified in previous volumetric studies on MDD. However, functional imaging studies have revealed abnormal activation in the lingual gyrus and altered visual network including the lingual gyrus in depressed patients compared to healthy controls (Desseilles et al, 2009;Veer et al, 2010;Laurent and Ablow., 2012;Zeng et al, 2012). Especially, Keedwell et al (2009) demonstrated the activity change of the lingual gyrus and primary visual cortex after an open label antidepressant treatments.…”

“…In visual attention control, the activity of lingual gyrus is mediated by a top-down attention control system which includes the frontoparietal network (Hopfinger et al, 2000). Desseilles et al (2009) demonstrated the interaction between mood regulation and cognition in MDD patients focusing on visual information processing. They found an abnormal filtering of irrelevant information in visual cortices as well as altered functional connectivity between frontoparietal network and visual cortices.…”

“…Furthermore, Smith et al (2013) demonstrated an increase in volume of the DLPFC in depressed patients, after 12 weeks of antidepressant treatment. Emerging findings from Positron Emission Tomography (PET) and functional magnetic resonance imaging (fMRI) studies suggest activity changes in ACC (Mayberg et al, 1999;Gotlib et al, 2005), ventral striatum (Fu et al, 2004), visual cortices (Davidson et al, 2003;Fu et al, 2004;Desseilles et al, 2009;Veer et al, 2010;Zeng et al, 2012), and amygdala (Sheline et al, 2001;Davidson et al, 2003;Fu et al, 2007;Victor et al, 2010;Arnone et al, 2012b) during and after antidepressant treatment. These findings suggest that antidepressant treatment can bring about structural and functional brain changes in brain areas of the limbic-cortical network in relation to clinical improvement.…”