Regional Hemodynamic Changes Research Articles

Perivascular Adipose Tissue and Uterine Artery Adaptations to Pregnancy.

Pregnancy is characterized by longitudinal maternal, physiological adaptations to support the development of a fetus. One of the cardinal maternal adaptations during a healthy pregnancy is a progressive increase in uterine artery blood flow. This facilitates sufficient blood supply for the development of the placenta and the growing fetus. Regional hemodynamic changes in the uterine circulation, such as a vast reduction in uterine artery resistance, are mainly facilitated by changes in uterine artery reactivity and myogenic tone along with remodeling of the uterine arteries. These regional changes in vascular reactivity have been attributed to pregnancy-induced adaptations of cell-to-cell communication mechanisms, with an emphasis on the interaction between endothelial and vascular smooth muscle cells. Perivascular adipose tissue (PVAT) is considered the fourth layer of the vascular wall and contributes to the regulation of vascular reactivity in most vascular beds and most species. This review focuses on mechanisms of uterine artery reactivity and the role of PVAT in pregnancy-induced maternal vascular adaptations, with an emphasis on the uterine circulation.

Feasibility of using fNIRS to explore motor-related regional haemodynamic signal changes in patients with sensorimotor impairment and healthy controls: A pilot study.

While functional near-infrared spectroscopy (fNIRS) can provide insight into cortical brain activity during motor tasks in healthy and diseased populations, the feasibility of using fNIRS to assess haemoglobin-evoked responses to reanimated upper limb motor function in patients with tetraplegia remains unknown. The primary objective of this pilot study is to determine the feasibility of using fNIRS to assess cortical signal intensity changes during upper limb motor tasks in individuals with surgically restored grip functions. The secondary objectives are: 1) to collect pilot data on individuals with tetraplegia to determine any trends in the cortical signal intensity changes as measured by fNIRS and 2) to compare cortical signal intensity changes in affected individuals versus age-appropriate healthy volunteers. Specifically, patients presented with tetraplegia, a type of paralysis resulting from a cervical spinal cord injury causing loss of movement and sensation in both lower and upper limbs. All patients have their grip functions restored by surgical tendon transfer, a procedure which constitutes a unique, focused stimulus for brain plasticity. fNIRS is used to assess changes in cortical signal intensity during the performance of two motor tasks (isometric elbow and thumb flexion). Six individuals with tetraplegia and six healthy controls participate in the study. A block paradigm is utilized to assess contralateral and ipsilateral haemodynamic responses in the premotor cortex (PMC) and primary motor cortex (M1). We assess the amplitude of the optical signal and spatial features during the paradigms. The accuracy of channel locations is maximized through 3D digitizations of channel locations and co-registering these locations to template atlas brains. A general linear model approach, with short-separation regression, is used to extract haemodynamic response functions at the individual and group levels. Peak oxyhaemoglobin (oxy-Hb) changes in PMC appear to be particularly bilateral in nature in the tetraplegia group during both pinch and elbow trials whereas for controls, a bilateral PMC response is not especially evident. In M1 / primary sensory cortex (S1), the oxy-Hb responses to the pinch task are mainly contralateral in both groups, while for the elbow flexion task, lateralization is not particularly clear. This pilot study shows that the experimental setup is feasible for assessing brain activation using fNIRS during volitional upper limb motor tasks in individuals with surgically restored grip functions. Cortical signal changes in brain regions associated with upper extremity sensorimotor processing appear to be larger and more bilateral in nature in the tetraplegia group than in the control group. The bilateral hemispheric response in the tetraplegia group may reflect a signature of adaptive brain plasticity mechanisms. Larger studies than this one are needed to confirm these findings and draw reliable conclusions.

Precision X-ray diagnosis of osteoporosis in representatives of risk groups for the appearance and development of varicose disease of the lower limbs

Precision X-ray diagnosis of osteoporosis in representatives of risk groups for the appearance and development of varicose disease of the lower limbs

Haemodynamic effects of the flavonoid quercetin in rats revisited.

Background and PurposeThe flavonoid quercetin increased the in vitro potency of the α1‐antagonist tamsulosin to reduce phenylephrine‐dependent arterial contractions by 10‐fold. To examine if this supplement–drug interaction luxates hypotensive and orthostatic events in vivo, several set of studies were conducted in spontaneously hypertensive (SHR) and normotensive (Wistar Kyoto [WKY]) rats.Experimental ApproachFirst, in rats pretreated with quercetin or its vehicle, responses to phenylephrine and tamsulosin were examined. Second, tamsulosin‐induced changes in renal, mesenteric, hindquarter and carotid conductance were compared in quercetin‐ and vehicle‐treated rats instrumented with Doppler flow probes. Animals were also placed on a tilt table to record regional haemodynamic changes to orthostatic challenges. Third, adult SHR were instrumented with telemeters to measure 24‐hr patterns of BP. Recordings were made before and during a 5‐week oral treatment of quercetin. Finally, pre‐hypertensive SHR were treated with quercetin from 4 to 8 weeks of age and arterial pressure was measured at 8 and 12 weeks.Key ResultsPretreatment with quercetin did not influence the responses to phenylephrine and tamsulosin, in neither WKY nor SHR. While tamsulosin treatment and tilting lowered BP and increased conductance in all vascular beds, effect size was not influenced by pretreatment with quercetin. Prolonged treatment with quercetin, in either prehypertensive SHR or adult SHR with established hypertension did not lower BP.Conclusions and ImplicationsCumulatively, these data demonstrate that quercetin does not amplify haemodynamic effects of tamsulosin or tilting in vivo in rats and has no effect on BP development in SHR.

Ultrasound vector projectile imaging for detection of altered carotid bifurcation hemodynamics during reductions in cardiac output.

Complex blood flow is commonly observed in the carotid bifurcation, although the factors that regulate these patterns beyond arterial geometry are unknown. The emergence of high-frame-rate ultrasound vector flow imaging allows for noninvasive, time-resolved analysis of complex hemodynamic behavior in humans, and it can potentially help researchers understand which physiological stressors can alter carotid bifurcation hemodynamics in vivo. Here, we seek to pursue the first use of vector projectile imaging (VPI), a dynamic form of vector flow imaging, to analyze the regulation of carotid bifurcation hemodynamics during experimental reductions in cardiac output induced via a physiological stressor called lower body negative pressure (LBNP). Seven healthy adults (age: 27±4yr, 4 men) underwent LBNP at -45mmHg to simulate a postural hemodynamic response in a controlled environment. Using a research-grade, high-frame-rate ultrasound platform, vector flow estimation in each subject's right carotid bifurcation was performed through a multi-angle plane wave imaging (two transmission angles of 10° and -10°) formulation, and VPI cineloops were generated at a frame rate of 750fps. Vector concentration was quantified by the resultant blood velocity vector angles within a region of interest; lower concentration indicated greater flow dispersion. Discrete concentration values during peak and late systole were compared across different segments of the carotid artery bifurcation before, and during, LBNP. Vector projectile imaging revealed that external and internal carotid arteries exhibited regional hemodynamic changes during LBNP, which acted to reduce both the subject's cardiac output (Δ-1.2±0.5L/min, -19%; P<0.01) and peak carotid blood velocity (Δ-6.30±8.27cm/s, -7%; P=0.05). In these carotid artery branches, the vector concentration time trace before and during LBNP were observed to be different. The impact of LBNP on flow complexity in the two carotid artery branches showed variations between subjects. Using VPI, intuitive visualization of complex hemodynamic changes can be obtained in healthy humans subjected to LBNP. This imaging tool has potential for further applications in vascular physiology to identify and quantify complex hemodynamic features in humans during different physiological stressor tests that regulate hemodynamics.

Assessing changes in tissue oxygenation by near-infrared spectroscopy following brachial plexus block for arteriovenous fistula surgery: A prospective observational pilot study.

Near-infrared spectroscopy (NIRS) can be used to measure tissue oxygen saturation (StO2) in different sites and in a wide range of clinical scenarios. Peripheral regional anaesthesia induces vascular changes causing increased arterial blood flow and venodilatation, but its effect on StO2 is still under debate. This is especially so for patients undergoing arteriovenous fistula surgery, wherein latest data suggest an improved outcome under brachial plexus block (BPB) compared with local anaesthesia, but no data are available. The aim of this study was to investigate changes in StO2 following BPB prior to arteriovenous fistula surgery using NIRS. A prospective observational study. A secondary teaching hospital from August 2016 to March 2017. Fifteen patients undergoing arteriovenous fistula surgery. Ultrasound-guided BPB in 15 patients undergoing arteriovenous fistula surgery. StO2 at baseline and compared with baseline and the contralateral arm following BPB measured using NIRS of the thenar eminence (NIRSth). Baseline values of StO2 assessed by NIRSth were 42.6 ± 7.7% in the arteriovenous fistula arm and 42.7 ± 9.7% in the contralateral arm. There was no significant difference between the two. Five minutes after BPB, there was a significant increase in StO2 of the blocked arm, compared with the control arm expressed as difference of absolute values (7.1 ± 9.7%). At 60 min, an absolute difference of 21.0 ± 13.5% was reached. The absolute increase in StO2 of the blocked arm compared with baseline reached significance after 5 min (8.8 ± 4.6%) and increased up to 23.2 ± 8.2% after 60 min. NIRSth indicates that BPB significantly increases StO2 of the arteriovenous fistula arm in patients undergoing haemodialysis. Clinicaltrials.gov: NCT03044496.

Association of fronto-temporal function with cognitive ability in schizophrenia

Deficits in neuropsychological performance are common in schizophrenia, but their relationship with the fronto-temporal functional abnormalities associated with this condition remains unclear. We explored the relationship between neuropsychological performance as measured using the Brief Assessment of Cognition in Schizophrenia (BACS) and the Social Cognition Screening Questionnaire theory of mind (ToM) subscale and fronto-temporal function in 23 patients with schizophrenia and 23 age- and gender-matched healthy controls (HCs), using 52-channel near-infrared spectroscopy (NIRS). Regional hemodynamic changes were significantly smaller in the schizophrenia group than in the HCs group in the ventro-lateral prefrontal cortex and the anterior part of the temporal cortex (VLPFC/aTC) and dorso-lateral prefrontal cortex and frontopolar cortex (DLPFC/FPC) regions. To dissect the effect of variance in BACS cognitive domains from the relationship between ToM function and fronto-temporal function, we performed additional partial correlation analyses between ToM and NIRS data, using BACS composite score as a control variable. The correlation between ToM and NIRS data remained significant only in the DLPFC/FPC region. This finding is important to models of recovery, as it suggests that intervention programs focusing on enhancing fronto-temporal function may have a greater impact on social and occupational outcomes than traditional rehabilitation programs focusing on neuropsychological performance.

Regional haemodynamic changes after selective block of the four principal nerves in the arm: A double-blind randomised controlled study.

Regional haemodynamic changes after selective block of the four principal nerves in the arm: A double-blind randomised controlled study.

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Spontaneous depolarizations around the core are a consistent feature of focal cerebral ischemia, but the associated regional hemodynamic changes are heterogeneous. We determined how the features of depolarizations relate to subsequent cerebral blood flow (CBF) changes in global forebrain ischemia.Forebrain ischemia was produced in halothane-anesthetized rats (n = 13) by common carotid artery occlusion and hypovolemic hypotension. Mean arterial blood pressure (MABP) was monitored via a femoral catheter. Specific illuminations allowed the capture of image sequences through a cranial window to visualize: changes in membrane potential (voltage-sensitive dye method); CBF (laser speckle contrast imaging); cerebral blood volume (intrinsic optical signal, IOS at 540–550 nm); and hemoglobin deoxygenation (IOS at 620–640 nm).A depolarization occurred (n = 9) when CBF fell below 43.4 ± 5% of control (41 ± 4 mmHg MABP), and propagated with a distinct wave front at a rate of 2.8 mm/min. Depolarizations were either persistent (n = 4), intermediate (n = 3) or short, transient depolarization (n = 2). Persistent and intermediate depolarizations were associated with sustained hypoperfusion (−11.7 ± 5.1%) and transient hypoperfusion (−17.4 ± 5.2, relative to CBF before depolarization). Short, transient depolarizations did not generate clear CBF responses.Depolarizations during incomplete global ischemia occurred at the lower limit of CBF autoregulation, propagated similar to spreading depolarization (SD), and the hemodynamic responses indicated inverse neurovascular coupling. Similar to SDs associated with focal stroke, the propagating event can be persistent or transient.

Monitoring Local Regional Hemodynamic Signal Changes during Motor Execution and Motor Imagery Using Near-Infrared Spectroscopy.

The aim of this study was to clarify the topographical localization of motor-related regional hemodynamic signal changes during motor execution (ME) and motor imagery (MI) by using near-infrared spectroscopy (NIRS), as this technique is more clinically expedient than established methods (e.g., fMRI). Twenty right-handed healthy subjects participated in this study. The experimental protocol was a blocked design consisting of 3 cycles of 20 s of task performance and 30 s of rest. The tapping sequence task was performed with their fingers under 4 conditions: ME and MI with the right or left hand. Hemodynamic brain activity was measured with NIRS to monitor changes in oxygenated hemoglobin (oxy-Hb) concentration. Oxy-Hb in the somatosensory motor cortex (SMC) increased significantly only during contralateral ME and showed a significant interaction between task and hand. There was a main effect of hand in the left SMC. Although there were no significant main effects or interactions in the supplemental motor area (SMA) and premotor area (PMA), oxy-Hb increased substantially under all conditions. These results clarified the topographical localization by motor-related regional hemodynamic signal changes during ME and MI by using NIRS.

Left temporal activation associated with depression severity during a verbal fluency task in patients with bipolar disorder: A multichannel near-infrared spectroscopy study

BackgroundNeuroimaging studies using multichannel near-infrared spectroscopy (NIRS) have provided compelling evidence about the dysfunction of the frontotemporal cortices in patients with bipolar disorder (BD). However, it remains unclear whether the dysfunction is associated with mood state or symptom severity. Using NIRS, we aimed to clarify differences in oxygenated hemoglobin (oxy-Hb) activation between depressive and euthymic states as well as regional brain dysfunction in relation to symptom severity in BD. MethodsFifty-five patients with BD, including 30 with bipolar depression (BPD) and 25 with euthymic bipolar disorder (BPE), and 28 healthy controls (HCs) participated in the study. Regional hemodynamic changes during a verbal fluency task (VFT) were monitored using a 52-channel NIRS apparatus. ResultsThe mean oxy-Hb changes induced by VFT were significantly smaller in the BD patients than in the HCs in 18 channels in the frontotemporal regions (false-discovery rate p<0.05, p=0.000–0.011). The BPD group exhibited significantly smaller changes in mean oxy-Hb compared with the BPE group in three channels of the left temporal region (p=0.005–0.014). In the BD patients, significant negative correlations were observed between mean oxy-Hb changes in the left temporal regions and the severity of depression. LimitationsOur sample size was small, making the results susceptible to type II errors. ConclusionsBD patients have persistent hypofunction of the frontotemporal cortical regions. Moreover, the hemodynamic response in the left temporal regions is associated with symptom severity.

Social insecurity in relation to orbitofrontal activity in patients with eating disorders: a near-infrared spectroscopy study.

BackgroundFunctional neuroimaging techniques are widely used to elucidate changes in brain activity, and various questionnaires are used to investigate psychopathological features in patients with eating disorders (ED). It is well known that social skills and interpersonal difficulties are strongly associated with the psychopathology of patients with ED. However, few studies have examined the association between brain activity and social relationships in patients with ED, particularly in patients with extremely low body weight.MethodsIn this study, 22-channel near-infrared spectroscopy was used to quantify regional hemodynamic changes during a letter fluency task (LFT) in 20 female patients with ED with a mean body mass index of 14.0 kg/m2and 31 female controls (CTLs). Symptoms were assessed using the Eating Disorder Inventory-2 and Beck Depression Inventory. We hypothesized that frontal activity in patients with ED would be lower than in CTLs and would show different correlations with psychopathological features compared with CTLs.ResultsThe LFT performance and score on the social insecurity subscale of the Eating Disorder Inventory-2 were significantly higher in the ED group than in the CTL group. The mean change in oxygenated hemoglobin (oxy-Hb) in bilateral frontal regions during the LFT was significantly smaller in the ED group than in the CTL group. Social insecurity score was positively correlated with the concentration of oxy-Hb in the bilateral orbitofrontal cortex in the ED group but not in the CTL group.ConclusionsThese results suggest that activity of the orbitofrontal cortex is associated with social insecurity and disturbed in patients with ED. Therefore, disturbed orbitofrontal cortex activity may underlie the lack of insight and social isolation that is characteristic of patients with ED.

Right temporal activation differs between melancholia and nonmelancholic depression: A multichannel near-infrared spectroscopy study

The aim of this study was to determine whether melancholia differs from nonmelancholic depression in frontotemporal functioning by means of multichannel near-infrared spectroscopy. We recruited 32 major depressive disorder (MDD) patients with melancholic features (MDD-MF), 28 MDD patients with nonmelancholic features (MDD-NMF), and 24 healthy controls. Regional hemodynamic changes induced by a verbal fluency task (VFT) were monitored, and their correlations with depressive symptoms were examined. In comparison with the controls, significant differences were observed in mean oxygenated hemoglobin (oxy-Hb) changes induced by VFT in patients with MDD-MF in 25 channels (p = 0.000–0.047) and in those with MDD-NMF in 12 channels (p = 0.000–0.023). Moreover, patients with MDD-MF had significantly smaller mean oxy-Hb changes than those with MDD-NMF in 8 channels of the right temporal region (p = 0.001–0.048). No significant correlations were observed between mean oxy-Hb changes and the Hamilton rating scale for depression (HAMD) 17 total score in both groups of patients with MDD. On examining each item of HAMD17, psychomotor retardation in patients with MDD-MF showed a significant positive correlation with mean oxy-Hb changes in the right temporal region (ch43; ρ = 0.55; p = 0.001), whereas that in patients with MDD-NMF showed a significant negative correlation with mean oxy-Hb changes in the frontal and left temporal regions in 3 channels (ρ = −0.60 to −0.53; p = 0.000–0.004). In conclusion, our results indicate that melancholia is qualitatively distinct from nonmelancholic depression both clinically and biologically.

Sex Differences in Peripheral Augmentation Index and Arterial Reservoir Pressure during Upper Limb Postural Shifts

We examined the peripheral hemodynamic response to passive arm postural changes in young men and women. Radial artery pulse waveforms were captured using applanation tonometry in 20 men (age 27 ± 2 yrs, BMI 25 ± 1 kg/m2) and 20 women (age 27 ± 2 yrs, BMI 23±1 kg/m2). Arm position was maintained at either heart level or supported 14 cm above/below heart level in a randomized fashion. Systolic augmentation index (sAIx) and diastolic augmentation index (dAIx) were used as estimates of pressure from wave reflections arriving in systole and diastole, respectively. A novel reservoir-wave separation technique was used to obtain arterial reservoir pressure (pressure generated by arterial capacitance). Women showed a significant reduction in radial diastolic pressure-time integral (DPTI) (P&lt;0.05) and reservoir pressure (P&lt;0.05), with no change in peripheral sAIx (P&gt;0.05) or dAIx (P&gt;0.05) when moving the arm from below to above heart level. Conversely, men showed an attenuated change in radial DPTI (P&gt;0.05) concomitant with significant increases in reservoir pressure (P&lt;0.05), sAIx (P&lt;0.05), and dAIx (P&lt;0.05). Gravity-mediated changes in regional hemodynamics produced by passive arm postural shifts are sex specific. Men demonstrate less change in regional diastolic pressure concomitant with increased augmentation index and arterial reservoir pressure.

Ischemia-induced depolarizations and associated hemodynamic responses in incomplete global forebrain ischemia in rats

Spontaneous depolarizations around the core are a consistent feature of focal cerebral ischemia, but the associated regional hemodynamic changes are heterogeneous. We determined how the features of depolarizations relate to subsequent cerebral blood flow (CBF) changes in global forebrain ischemia.Forebrain ischemia was produced in halothane-anesthetized rats (n=13) by common carotid artery occlusion and hypovolemic hypotension. Mean arterial blood pressure (MABP) was monitored via a femoral catheter. Specific illuminations allowed the capture of image sequences through a cranial window to visualize: changes in membrane potential (voltage-sensitive dye method); CBF (laser speckle contrast imaging); cerebral blood volume (intrinsic optical signal, IOS at 540–550nm); and hemoglobin deoxygenation (IOS at 620–640nm).A depolarization occurred (n=9) when CBF fell below 43.4±5% of control (41±4mmHg MABP), and propagated with a distinct wave front at a rate of 2.8mm/min. Depolarizations were either persistent (n=4), intermediate (n=3) or short, transient depolarization (n=2). Persistent and intermediate depolarizations were associated with sustained hypoperfusion (−11.7±5.1%) and transient hypoperfusion (−17.4±5.2, relative to CBF before depolarization). Short, transient depolarizations did not generate clear CBF responses.Depolarizations during incomplete global ischemia occurred at the lower limit of CBF autoregulation, propagated similar to spreading depolarization (SD), and the hemodynamic responses indicated inverse neurovascular coupling. Similar to SDs associated with focal stroke, the propagating event can be persistent or transient.

Respiratory, metabolic and cardiac functions are altered by disinhibition of subregions of the medial prefrontal cortex

The prefrontal cortex (PFC) is referred to as the visceral motor cortex; however, little is known about whether this region influences respiratory or metabolic outflows. The aim of this study was to describe simultaneous changes in respiratory, metabolic and cardiovascular functions evoked by disinhibition of the medial PFC (mPFC) and adjacent lateral septal nucleus (LSN). In urethane-anaesthetized rats, bicuculline methiodide was microinjected (2 mm; GABA-A receptor antagonist) into 90 sites in the mPFC at 0.72-4.00 mm from bregma. Phrenic nerve amplitude and frequency, arterial pressure, heart rate, splanchnic and lumbar sympathetic nerve activities (SNA), expired CO2, and core and brown adipose tissue temperatures were measured. Novel findings included disturbances to respiratory rhythm evoked from all subregions of the mPFC. Injections into the cingulate cortex evoked reductions in central respiratory function exclusively, whereas in ventral sites, particularly the infralimbic region, increases in respiratory drive and frequency, and metabolic and cardiac outflows were evoked. Disinhibition of sites in surrounding regions revealed that the LSN could evoke cardiovascular changes accompanied by distinct oscillations in SNA, as well as increases in respiratory amplitude. We show that activation of neurons within the mPFC and LSN influence respiratory, metabolic and cardiac outflows in a site-dependent manner. This study has implications with respect to the altered PFC neuronal activity seen in stress-related and mental health disorders, and suggests how basic physiological systems may be affected.

Association between cognitive insight and prefrontal function during a cognitive task in schizophrenia: A multichannel near-infrared spectroscopy study

Insight has been studied mostly from a clinical perspective. Recently, the focus of this research field shifted to cognitive insight or the ability to monitor and correct the erroneous convictions of individuals. In this study, we investigated the relationship between cognitive insight and prefrontal function during a cognitive task in 30 patients with clinically stable schizophrenia and 30 age- and gender-matched healthy controls. We measured the changes in hemoglobin concentration in the prefrontal and temporal cortical regions during a verbal fluency task (VFT) by using 52-channel near-infrared spectroscopy (NIRS). Cognitive insight was measured using the Beck Cognitive Insight Scale (BCIS). Regional hemodynamic changes were significantly smaller in the schizophrenia group than in the control group in prefrontal and temporal regions, and significant positive relationship was observed between the score of the BCIS self-reflectiveness subscale and right ventrolateral prefrontal and right temporal functions during the VFT. These results suggest that the right ventrolateral prefrontal and temporal cortical regions are associated with cognitive insight in clinically stable patients with schizophrenia and that NIRS is an efficient medical tool for monitoring these characteristics.

Resting state low-frequency fluctuations in prefrontal cortex reflect degrees of harm avoidance and novelty seeking: an exploratory NIRS study

Harm avoidance (HA) and novelty seeking (NS) are temperament dimensions defined by Temperament and Character Inventory (TCI), respectively, reflecting a heritable bias for intense response to aversive stimuli or for excitement in response to novel stimuli. High HA is regarded as a risk factor for major depressive disorder and anxiety disorder. In contrast, higher NS is linked to increased risk for substance abuse and pathological gambling disorder. A growing body of evidence suggests that patients with these disorders show abnormality in the power of slow oscillations of resting-state brain activity. It is particularly interesting that previous studies have demonstrated that resting state activities in medial prefrontal cortex (MPFC) are associated with HA or NS scores, although the relation between the power of resting state slow oscillations and these temperament dimensions remains poorly elucidated. This preliminary study investigated the biological bases of these temperament traits by particularly addressing the resting state low-frequency fluctuations in MPFC. Regional hemodynamic changes in channels covering MPFC during 5-min resting states were measured from 22 healthy participants using near-infrared spectroscopy (NIRS). These data were used for correlation analyses. Results show that the power of slow oscillations during resting state around the dorsal part of MPFC is negatively correlated with the HA score. In contrast, NS was positively correlated with the power of resting state slow oscillations around the ventral part of MPFC. These results suggest that the powers of slow oscillation at rest in dorsal or ventral MPFC, respectively, reflect the degrees of HA and NS. This exploratory study therefore uncovers novel neural bases of HA and NS. We discuss a neural mechanism underlying aversion-related and reward-related processing based on results obtained from this study.

The Degree of Early Life Stress Predicts Decreased Medial Prefrontal Activations and the Shift from Internally to Externally Guided Decision Making: An Exploratory NIRS Study during Resting State and Self-Oriented Task

Early life stress (ELS), an important risk factor for psychopathology in mental disorders, is associated neuronally with decreased functional connectivity within the default mode network (DMN) in the resting state. Moreover, it is linked with greater deactivation in DMN during a working memory task. Although DMN shows large amplitudes of very low-frequency oscillations (VLFO) and strong involvement during self-oriented tasks, these features’ relation to ELS remains unclear. Therefore, our preliminary study investigated the relationship between ELS and the degree of frontal activations during a resting state and self-oriented task using near-infrared spectroscopy (NIRS). From 22 healthy participants, regional hemodynamic changes in 43 front-temporal channels were recorded during 5 min resting states, and execution of a self-oriented task (color-preference judgment) and a control task (color-similarity judgment). Using a child abuse and trauma scale, ELS was quantified. We observed that ELS showed a negative correlation with medial prefrontal cortex (MPFC) activation during both resting state and color-preference judgment. In contrast, no significant correlation was found between ELS and MPFC activation during color-similarity judgment. Additionally, we observed that ELS and the MPFC activation during color-preference judgment were associated behaviorally with the rate of similar color choice in preference judgment, which suggests that, for participants with higher ELS, decisions in the color-preference judgment were based on an external criterion (color similarity) rather than an internal criterion (subjective preference). Taken together, our neuronal and behavioral findings show that high ELS is related to lower MPFC activation during both rest and self-oriented tasks. This is behaviorally manifest in an abnormal shift from internally to externally guided decision making, even under circumstances where internal guidance is required.

The relationship between the prefrontal activation during a verbal fluency task and stress-coping style in major depressive disorder: A near-infrared spectroscopy study

This study aimed to identify coping styles used by patients with major depressive disorder (MDD) in comparison with those used by healthy controls, and to explore their association with prefrontal hemodynamic response related to a cognitive task. Regional hemodynamic changes were monitored during a verbal fluency task (VFT) using a 52-channel near-infrared spectroscopy (NIRS) apparatus in 26 MDD patients in depressive state and 30 matched healthy controls, and their correlation with coping styles assessed by Coping Inventory for Stressful Situations (CISS) were examined. We found the Emotion-oriented coping style was significantly higher, whereas the Task-oriented coping and Avoidance-oriented coping style were lower in the MDD group compared with controls. Emotion-oriented coping style positively correlated with subjective assessment of depression severity. Regional hemodynamic changes were significantly smaller in the MDD group than in the control group in prefrontal and temporal regions, and positively correlated with Task-oriented coping (adaptive coping) in the bilateral ventrolateral and dorsolateral prefrontal cortex, and the midline fronto-polar and bilateral orbitofrontal cortex regions. These findings suggest coping styles may be considered an important source of knowledge for patients who struggle with the illness and for mental health professionals who work with MDD patients, and that hemodynamic response in the ventrolateral and dorsolateral prefrontal cortex, midline fronto-polar, and orbitofrontal cortex regions during a VFT may reflect the adaptive coping (Task-oriented coping) style in MDD patients in depressive state.