Associations between daily mood states and brain gray matter volume, resting-state functional connectivity and task-based activity in healthy adults

Numerous studies have shown differences in the functioning in the areas of the frontal-limbic circuitry between depressed patients and controls. However, current knowledge on frontal-limbic neural substrates of individual differences in mood states in everyday life in healthy individuals is scarce. The present study investigates anatomical, resting-state, and functional neural correlates of daily mood states in healthy individuals. We expected to observe associations between mood and the frontal-limbic circuitry and the default-mode network (DMN). A total of 42 healthy adults (19 men, 23 women; 34 ± 1.2 years) regularly followed for behavior and psychosocial functioning since age of 6, underwent a functional magnetic resonance imaging scan, and completed a daily diary of mood states and related cognitions for 5 consecutive days. Results showed that individuals with smaller left hippocampal gray matter volumes experienced more negative mood and rumination in their daily life. Greater resting-state functional connectivity (rsFC) within the DMN, namely between posterior cingulate cortex (PCC) and medial prefrontal cortex regions as well as between PCC and precuneus, was associated with both greater negative and positive mood states in daily life. These rsFC results could be indicative of the role of the DMN regional functioning in emotional arousal, irrespective of valence. Lastly, greater daily positive mood was associated with greater activation in response to negative emotional stimuli in the precentral gyri, previously linked to emotional interference on cognitive control. Altogether, present findings might reflect neural mechanisms underlying daily affect and cognition among healthy individuals

Serotonin transporter promoter methylation in peripheral cells and neural responses to negative stimuli : a study of adolescent monozygotic twins

Several studies have examined associations between peripheral DNA methylation patterns of the serotonin transporter gene (SLC6A4) promoter and symptoms of depression and anxiety. The SLC6A4 promoter methylation has also been associated with frontal-limbic brain responses to negative stimuli. However, it is unclear how much of this association is confounded by DNA sequence variations. We utilized a monozygotic-twin within-pair discordance design, to test whether DNA methylation at specific CpG sites in the SLC6A4 promoter of peripheral cells is associated with greater frontal-limbic brain responses to negative stimuli (sadness and fear), independently of DNA sequence effects. In total 48 pairs of healthy 15-year-old monozygotic twins from the Quebec Newborn Twin Study, followed regularly since birth, underwent functional magnetic resonance imaging while conducting an emotion-processing task. The SLC6A4 promoter methylation level was assessed in saliva samples using pyrosequencing. Relative to the co-twins with lower SLC6A4 promoter methylation levels, twins with higher peripheral SLC6A4 methylation levels showed greater orbitofrontal cortical (OFC) activity and left amygdala-anterior cingulate cortex (ACC) and left amygdala-right OFC connectivity in response to sadness as well as greater ACC-left amygdala and ACC-left insula connectivity in response to fearful stimuli. By utilising a monozygotic-twin design, we provided evidence that associations between peripheral SLC6A4 promoter methylation and frontal-limbic brain responses to negative stimuli are, in part, independent of DNA sequence variations. Although causality cannot be determined here, SLC6A4 promoter methylation may be one of the mechanisms underlying how environmental factors influence the serotonin system, potentially affecting emotional processing through frontal-limbic areas

Orbitofrontal cortex mediates pain inhibition by monetary reward

Pleasurable stimuli, including reward, inhibit pain, but the level of the neuraxis at which they do so and the cerebral processes involved are unknown. Here, we characterized a brain circuitry mediating pain inhibition by reward. Twenty-four healthy participants underwent functional magnetic resonance imaging while playing a wheel of fortune game with simultaneous thermal pain stimuli and monetary wins or losses. As expected, winning decreased pain perception compared to losing. Inter-individual differences in pain modulation by monetary wins relative to losses correlated with activation in the medial orbitofrontal cortex (mOFC). When pain and reward occured simultaneously, mOFCs functional connectivity changed: the signal time course in the mOFC condition-dependent correlated negatively with the signal time courses in the rostral anterior insula, anterior-dorsal cingulate cortex and primary somatosensory cortex, which might signify momentto-moment down-regulation of these regions by the mOFC. Monetary wins and losses did not change the magnitude of pain-related activation, including in regions that code perceived pain intensity when nociceptive input varies and/or receive direct nociceptive input. Pain inhibition by reward appears to involve brain regions not typically involved in nociceptive intensity coding but likely mediate changes in the significance and/or value of pain

Caractérisation de la réponse cérébrale à la douleur et ses modulations

Pain is a complex and multidimensional experience that can be modulated by many factors. In order to better understand the respective role and function of the brain regions involved in the processing and the modulation of pain perception, the first part of this thesis focuses on the evaluation with functional magnetic resonance imaging (fMRI) of changes in the brain response to pain through two modulations of pain perception. The first study examines the effect of a negative emotional context on pain perception in order to dissociate the brain areas responding to pain from that related to the emotional context. The second study focuses on the effect of the manipulation of perceived duration of a painful stimulation on the perception of pain. The use of this illusion allows us to change the perceived intensity of pain and to assess the brain areas involved in this type of modulation at given intensity of thermal stimulation. We succeeded to increase or decrease perceived pain intensity and we observed that emotion involves pregenual part of the anterior cingulate cortex, while the illusion of a shortened duration involves an occipito-parietal attentional network. The second part of this thesis focuses on characterizing the time course of the hemodynamic response recorded with fMRI in two important areas processing pain that are the insula and the cingulate cortex. Painful sensation is characterized by a shortened latency of hemodynamic response compared to a non-painful sensation in the anterior insula and the midcingulate cortex, while it is possible to differentiate painful and non-painful sensation by the amplitude of the hemodynamic response in the posterior insula.Dans le but de mieux comprendre le rôle et le fonctionnement des régions cérébrales impliquées dans le traitement et la modulation de la perception douloureuse, la première partie de cette thèse s’intéresse à l’évaluation en IRMf des modifications de la réponse cérébrale à la douleur grâce à deux modulations de la perception douloureuse. La première s’intéresse à l’effet d’un contexte émotionnel négatif sur la perception douloureuse afin de dissocier des aires cérébrales répondant à la douleur, les réponses liées à la composante émotionnelle. La deuxième s’intéresse à l’effet d’une manipulation de l’appréciation de la durée d’une stimulation douloureuse sur la perception de la douleur. L’utilisation d’une illusion permet, pour une intensité de stimulation thermique donnée, de modifier la perception douloureuse et d’évaluer les zones cérébrales impliquées dans ce type de modulation. Nous avons modulé la douleur perçue et pu observer que l’émotion met en jeu la partie prégénuale du cortex cingulaire antérieur, tandis que l’illusion d’une durée raccourcie met en jeu un réseau occipito-pariétal attentionnel. La seconde partie de cette thèse s’intéresse à la caractérisation du décours temporel de la réponse hémodynamique dans deux régions importantes pour le traitement de l’information douloureuse qui sont l’insula et le cortex cingulaire. La douleur est caractérisée par une latence de la réponse plus courte, par rapport à une stimulation non-douloureuse, dans l’insula antérieure et le cortex cingulaire moyen, tandis qu’il est possible de différencier une stimulation douloureuse d’une stimulation non-douloureuse grâce à l’amplitude de la réponse dans l’insula postérieure

Characterization of cerebral response to pain and its modulations

Dans le but de mieux comprendre le rôle et le fonctionnement des régions cérébrales impliquées dans le traitement et la modulation de la perception douloureuse, la première partie de cette thèse s’intéresse à l’évaluation en IRMf des modifications de la réponse cérébrale à la douleur grâce à deux modulations de la perception douloureuse. La première s’intéresse à l’effet d’un contexte émotionnel négatif sur la perception douloureuse afin de dissocier des aires cérébrales répondant à la douleur, les réponses liées à la composante émotionnelle. La deuxième s’intéresse à l’effet d’une manipulation de l’appréciation de la durée d’une stimulation douloureuse sur la perception de la douleur. L’utilisation d’une illusion permet, pour une intensité de stimulation thermique donnée, de modifier la perception douloureuse et d’évaluer les zones cérébrales impliquées dans ce type de modulation. Nous avons modulé la douleur perçue et pu observer que l’émotion met en jeu la partie prégénuale du cortex cingulaire antérieur, tandis que l’illusion d’une durée raccourcie met en jeu un réseau occipito-pariétal attentionnel. La seconde partie de cette thèse s’intéresse à la caractérisation du décours temporel de la réponse hémodynamique dans deux régions importantes pour le traitement de l’information douloureuse qui sont l’insula et le cortex cingulaire. La douleur est caractérisée par une latence de la réponse plus courte, par rapport à une stimulation non-douloureuse, dans l’insula antérieure et le cortex cingulaire moyen, tandis qu’il est possible de différencier une stimulation douloureuse d’une stimulation non-douloureuse grâce à l’amplitude de la réponse dans l’insula postérieure.Pain is a complex and multidimensional experience that can be modulated by many factors. In order to better understand the respective role and function of the brain regions involved in the processing and the modulation of pain perception, the first part of this thesis focuses on the evaluation with functional magnetic resonance imaging (fMRI) of changes in the brain response to pain through two modulations of pain perception. The first study examines the effect of a negative emotional context on pain perception in order to dissociate the brain areas responding to pain from that related to the emotional context. The second study focuses on the effect of the manipulation of perceived duration of a painful stimulation on the perception of pain. The use of this illusion allows us to change the perceived intensity of pain and to assess the brain areas involved in this type of modulation at given intensity of thermal stimulation. We succeeded to increase or decrease perceived pain intensity and we observed that emotion involves pregenual part of the anterior cingulate cortex, while the illusion of a shortened duration involves an occipito-parietal attentional network. The second part of this thesis focuses on characterizing the time course of the hemodynamic response recorded with fMRI in two important areas processing pain that are the insula and the cingulate cortex. Painful sensation is characterized by a shortened latency of hemodynamic response compared to a non-painful sensation in the anterior insula and the midcingulate cortex, while it is possible to differentiate painful and non-painful sensation by the amplitude of the hemodynamic response in the posterior insula

The 'where' and the 'when' of the BOLD response to pain in the insular cortex. Discussion on amplitudes and latencies.

International audienceThe operculo-insular cortex has been recently pointed out to be the main area of the pain matrix to be involved in the integration of pain intensity. This fMRI study specified the pattern of response to laser stimuli by focusing on this cortical area, by optimizing the temporal sampling and by investigating pain-related differences in the amplitudes and latencies of the BOLD responses. Canonical and temporal derivative hemodynamic response function (HRF) and finite impulse response (FIR) modeling provided consistent results. Amplitude of BOLD response discriminated painful from non-painful conditions in posterior and mid-insular cortices, bilaterally. Pain conditions were characterized by a shortened latency (as compared to non-painful conditions) in the anterior insula. In the functional organization of the insula, these results suggest a double dissociation that can be summarized as the 'where' and the 'when' of the BOLD response to pain. These results suggest that differences in the amplitude of the BOLD activity in the posterior and in the mid-insular cortices as well as shortened latency of the response in the anterior insula deal with discriminative processes related to painful conditions

Histological Underpinnings of Grey Matter Changes in Fibromyalgia Investigated Using Multimodal Brain Imaging

Chronic pain patients present with cortical gray matter alterations, observed with anatomical magnetic resonance (MR) imaging. Reduced regional gray matter volumes are often interpreted to reflect neurodegeneration, but studies investigating the cellular origin of gray matter changes are lacking. We used multimodal imaging to compare 26 postmenopausal women with fibromyalgia with 25 healthy controls (age range: 50-75 years) to test whether regional gray matter volume decreases in chronic pain are associated with compromised neuronal integrity. Regional gray matter decreases were largely explained by T1 relaxation times in gray matter, a surrogate measure of water content, and not to any substantial degree by GABAA receptor concentration, an indirect marker of neuronal integrity measured with [18F] flumazenil PET. In addition, the MR spectroscopy marker of neuronal viability, N-acetylaspartate, did not differ between patients and controls. These findings suggest that decreased gray matter volumes are not explained by compromised neuronal integrity. Alternatively, a decrease in neuronal matter could be compensated for by an upregulation of GABAA receptors. The relation between regional gray matter and T1 relaxation times suggests decreased tissue water content underlying regional gray matter decreases. In contrast, regional gray matter increases were explained by GABAA receptor concentration in addition to T1 relaxation times, indicating perhaps increased neuronal matter or GABAA receptor upregulation and inflammatory edema. By providing information on the histological origins of cerebral gray matter alterations in fibromyalgia, this study advances the understanding of the neurobiology of chronic widespread pain. SIGNIFICANCE STATEMENT Regional gray matter alterations in chronic pain, as detected with voxel-based morphometry of anatomical magnetic resonance images, are commonly interpreted to reflect neurodegeneration, but this assumption has not been tested. We found decreased gray matter in fibromyalgia to be associated with T1 relaxation times, a surrogate marker of water content, but not with GABAA receptor concentration, a surrogate of neuronal integrity. In contrast, regional gray matter increases were partly explained by GABAA receptor concentration, indicating some form of neuronal plasticity. The study emphasizes that voxel-based morphometry is an exploratory measure, demonstrating the need to investigate the histological origin of gray matter alterations for every distinct clinical entity, and advances the understanding of the neurobiology of chronic (widespread) pain

Is Rep 529 real-time PCR suitable for diagnosis of toxoplasmosis in patients infected with non-type II strains in Northern America?

International audienc

Associations Between Daily Mood States and Brain Gray Matter Volume, Resting-State Functional Connectivity and Task-Based Activity in Healthy Adults

Numerous studies have shown differences in the functioning in the areas of the frontal-limbic circuitry between depressed patients and controls. However, current knowledge on frontal-limbic neural substrates of individual differences in mood states in everyday life in healthy individuals is scarce. The present study investigates anatomical, resting-state, and functional neural correlates of daily mood states in healthy individuals. We expected to observe associations between mood and the frontal-limbic circuitry and the default-mode network (DMN). A total of 42 healthy adults (19 men, 23 women; 34 ± 1.2 years) regularly followed for behavior and psychosocial functioning since age of 6, underwent a functional magnetic resonance imaging scan, and completed a daily diary of mood states and related cognitions for 5 consecutive days. Results showed that individuals with smaller left hippocampal gray matter volumes experienced more negative mood and rumination in their daily life. Greater resting-state functional connectivity (rsFC) within the DMN, namely between posterior cingulate cortex (PCC) and medial prefrontal cortex regions as well as between PCC and precuneus, was associated with both greater negative and positive mood states in daily life. These rsFC results could be indicative of the role of the DMN regional functioning in emotional arousal, irrespective of valence. Lastly, greater daily positive mood was associated with greater activation in response to negative emotional stimuli in the precentral gyri, previously linked to emotional interference on cognitive control. Altogether, present findings might reflect neural mechanisms underlying daily affect and cognition among healthy individuals

Data‐driven beamforming technique to attenuate ballistocardiogram artefacts in electroencephalography–functional magnetic resonance imaging without detecting cardiac pulses in electrocardiography recordings

International audienceSimultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a very promising non-invasive neuroimaging technique. However, EEG data obtained from the simultaneous EEG-fMRI are strongly influenced by MRI-related artefacts, namely gradient artefacts (GA) and ballistocardiogram (BCG) artefacts. When compared to the GA correction, the BCG correction is more challenging to remove due to its inherent variabilities and dynamic changes over time. The standard BCG correction (i.e., average artefact subtraction [AAS]), require detecting cardiac pulses from simultaneous electrocardiography (ECG) recording. However, ECG signals are also distorted and will become problematic for detecting reliable cardiac peaks. In this study, we focused on a beamforming spatial filtering technique to attenuate all unwanted source activities outside of the brain. Specifically, we applied the beamforming technique to attenuate the BCG artefact in EEG-fMRI, and also to recover meaningful task-based neural signals during an attentional network task (ANT) which required participants to identify visual cues and respond accurately. We analysed EEG-fMRI data in 20 healthy participants during the ANT, and compared four different BCG corrections (non-BCG corrected, AAS BCG corrected, beamforming + AAS BCG corrected, beamforming BCG corrected). We demonstrated that the beamforming approach did not only significantly reduce the BCG artefacts, but also significantly recovered the expected task-based brain activity when compared to the standard AAS correction. This data-driven beamforming technique appears promising especially for longer data acquisition of sleep and resting EEG-fMRI. Our findings extend previous work regarding the recovery of meaningful EEG signals by an optimized suppression of MRI-related artefacts