Recent research suggests that cognitive performance might be altered by the respiratory-synchronized activity generated in the brain. Previous human studies, however, have yielded inconsistent ...results when assessing task performance during distinct respiratory phases (inspiratory phase vs. expiratory phase). We therefore tested whether cognitive performance was regulated based on the timing of breathing components (e.g., expiratory-to-inspiratory (EI) phase transition) during the retrieval process. To determine the role of respiration in performance, the present study employed healthy subjects (n = 18) in a delayed matching-to-sample visual recognition task where a test cue was given in the respiratory phase-locked (Phased) or regularly paced (Non-phased) presentation paradigm. During the Phased session but not during the Non-phased session, the response time (RT) of the task increased by 466 ms (p = 0.003), and accuracy decreased by 21.4% (p = 0.004) when the retrieval process encompassed the EI transition. Breathing-dependent changes were particularly prominent when the EI transition occurred during the middle step of the retrieval process. Meanwhile, changes in the RT and accuracy were not observed when the retrieval process encompassed the inspiratory-to-expiratory phase transition. This is the first time that a certain phase transition in the respiratory cycle has been shown to modulate performance on a time scale of several seconds in a cognitive task. We propose that attenuation of these breathing-dependent cognitive fluctuations might be crucial for the maintenance and stability of successful performance in daily life and sports.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The primary motor cortex (M1) is crucial for motor learning; however, its interaction with other brain areas during motor learning remains unclear. We hypothesized that the fronto-parietal execution ...network (FPN) provides learning-related information critical for the flexible cognitive control that is required for practice. We assessed network-level changes during sequential finger tapping learning under speed pressure by combining magnetic resonance spectroscopy and task and resting-state functional magnetic resonance imaging. There was a motor learning-related increase in preparatory activity in the fronto-parietal regions, including the right M1, overlapping the FPN and sensorimotor network (SMN). Learning-related increases in M1-seeded functional connectivity with the FPN, but not the SMN, were associated with decreased GABA/glutamate ratio in the M1, which were more prominent in the parietal than the frontal region. A decrease in the GABA/glutamate ratio in the right M1 was positively correlated with improvements in task performance (p = 0.042). Our findings indicate that motor learning driven by cognitive control is associated with local variations in the GABA/glutamate ratio in the M1 that reflects remote connectivity with the FPN, representing network-level motor sequence learning formations.
Obtaining a histological fingerprint from the in-vivo brain has been a long-standing target of magnetic resonance imaging (MRI). In particular, non-invasive imaging of iron and myelin, which are ...involved in normal brain functions and are histopathological hallmarks in neurodegenerative diseases, has practical utilities in neuroscience and medicine. Here, we propose a biophysical model that describes the individual contribution of paramagnetic (e.g., iron) and diamagnetic (e.g., myelin) susceptibility sources to the frequency shift and transverse relaxation of MRI signals. Using this model, we develop a method, χ-separation, that generates the voxel-wise distributions of the two sources. The method is validated using computer simulation and phantom experiments, and applied to ex-vivo and in-vivo brains. The results delineate the well-known histological features of iron and myelin in the specimen, healthy volunteers, and multiple sclerosis patients. This new technology may serve as a practical tool for exploring the microstructural information of the brain.
Display omitted
Background
Constipation is frequently observed in patients with chronic kidney disease (CKD). Lactulose is expected to improve the intestinal environment by stimulating bowel movements as a ...disaccharide laxative and prebiotic. We studied the effect of lactulose on renal function in adenine-induced CKD rats and monitored uremic toxins and gut microbiota.
Methods
Wistar/ST male rats (10-week-old) were fed 0.75% adenine-containing diet for 3 weeks to induce CKD. Then, they were divided into three groups and fed as follows: control, normal diet; and 3.0- and 7.5-Lac, 3.0% and 7.5% lactulose-containing diets, respectively, for 4 weeks. Normal diet group was fed normal diet for 7 weeks. The rats were observed for parameters including renal function, uremic toxins, and gut microbiota.
Results
The control group showed significantly higher serum creatinine (sCr) and blood urea nitrogen (BUN) 3 weeks after adenine feeding than at baseline, with a 8.5-fold increase in serum indoxyl sulfate (IS). After switching to 4 weeks of normal diet following adenine feeding, the sCr and BUN in control group remained high with a further increase in serum IS. In addition, tubulointerstitial fibrosis area was increased in control group. On the other hand, 3.0- and 7.5-Lac groups improved sCr and BUN levels, and suppressed tubulointerstitial fibrosis, suggesting preventing of CKD progression by lactulose. Lac groups also lowered level of serum IS and proportions of gut microbiota producing IS precursor.
Conclusion
Lactulose modifies gut microbiota and ameliorates CKD progression by suppressing uremic toxin production.
Reproducibility is one of the most important issues for generalizing the results of clinical research; however, low reproducibility in neuroimaging studies is well known. To overcome this problem, ...the Enhancing Neuroimaging Genetics through Meta‐Analysis (ENIGMA) consortium, an international neuroimaging consortium, established standard protocols for imaging analysis and employs either meta‐ and mega‐analyses of psychiatric disorders with large sample sizes. The Cognitive Genetics Collaborative Research Organization (COCORO) in Japan promotes neurobiological studies in psychiatry and has successfully replicated and extended works of ENIGMA especially for neuroimaging studies. For example, (a) the ENIGMA consortium showed subcortical regional volume alterations in patients with schizophrenia (n = 2,028) compared to controls (n = 2,540) across 15 cohorts using meta‐analysis. COCORO replicated the volumetric changes in patients with schizophrenia (n = 884) compared to controls (n = 1,680) using the ENIGMA imaging analysis protocol and mega‐analysis. Furthermore, a schizophrenia‐specific leftward asymmetry for the pallidum volume was demonstrated; and (b) the ENIGMA consortium identified white matter microstructural alterations in patients with schizophrenia (n = 1,963) compared to controls (n = 2,359) across 29 cohorts. Using the ENIGMA protocol, a study from COCORO showed similar results in patients with schizophrenia (n = 696) compared to controls (n = 1,506) from 12 sites using mega‐analysis. Moreover, the COCORO study found that schizophrenia, bipolar disorder (n = 211) and autism spectrum disorder (n = 126), but not major depressive disorder (n = 398), share similar white matter microstructural alterations, compared to controls. Further replication and harmonization of the ENIGMA consortium and COCORO will contribute to the generalization of their research findings.
The Cognitive Genetics Collaborative Research Organization (COCORO), which is a Japanese consortium established to elucidate psychiatric disorders and brain functions, replicated the results of the ENIGMA consortium, such as subcortical volume abnormalities and white matter microstructural abnormalities in schizophrenia, using the mega‐analysis method. These replication studies strengthened the reliability and generalization of the results of the ENIGMA consortium based on common and different methods in both consortiums. Further replication and harmonization of large consortia will contribute to the generalization of their research findings.
The recent discovery of a circuit of brain regions that is highly active in the absence of overt behavior has led to a quest for revealing the possible function of this so-called default-mode network ...(DMN). A very recent study, finding similarities in awake humans and anesthetized primates, has suggested that DMN activity might not simply reflect ongoing conscious mentation but rather a more general form of network dynamics typical of complex systems. Here, by performing functional MRI in humans, it is shown that a natural, sleep-induced reduction of consciousness is reflected in altered correlation between DMN network components, most notably a reduced involvement of frontal cortex. This suggests that DMN may play an important role in the sustenance of conscious awareness.
•The primary motor cortex (M1) is crucial in sequential finger tapping learning.•We utilized preparatory activity as the measure of activated engram.•The learning included both speed-stressed and ...accuracy stressed modes.•The M1 showed training-related increase in preparatory activity in both modes.•The M1 encodes and retrieves the engram irrespective of training modes' difference.
The primary motor cortex (M1) is crucial in motor learning. Whether the M1 encodes the motor engram for sequential finger tapping formed by an emphasis on speed is still inconclusive. The active states of engrams are hard to discriminate from the motor execution per se. As preparatory activity reflects the upcoming movement parameters, we hypothesized that the retrieval of motor engrams generated by different learning modes is reflected as a learning-related increase in the preparatory activity of the M1. To test this hypothesis, we evaluated the preparatory activity during the learning of sequential finger-tapping with the non-dominant left hand using a 7T functional MRI. Participants alternated between performing a tapping sequence as quickly as possible (maximum mode) or at a constant speed of 2 Hz paced by a sequence-specifying visual cue (constant mode). We found a training-related increase in preparatory activity in the network covering the bilateral anterior intraparietal sulcus and inferior parietal lobule extending to the right M1 during the maximum mode and the right M1 during the constant mode. These findings indicate that the M1, as the last effector of the motor output, integrates the motor engram distributed through the networks despite training mode differences.
Background
The aim of this study was to reveal the short-term and long-term outcomes of single-incision laparoscopic colorectal resection (SILC) compared with multi-incision laparoscopic colorectal ...resection (MILC) for colorectal cancer using propensity score matching analysis.
Methods
The study group included 235 patients who underwent SILC and 730 patients who underwent MILC for colorectal cancer between April 2009 and September 2014. The propensity score matching for age, gender, body mass index, tumor location (right-sided colon/sigmoid colon/upper rectum), lymph node dissection (D1/D2/D3), pathologic T (≤T3) stage and TNM (0–I/II/III) stage produced 107 matched pairs. The exclusion criteria for SILC were as follows: (1) tumors located at the transverse, descending colon or lower rectum, (2) stage IV tumors, synchronous or previous malignancies, (3) locally advanced tumors >T4, (4) acute obstructions or previous major abdominal surgery and (5) obese patients: BMI > 30.
Results
No significant differences were observed in operating time, bleeding volumes, starting time of liquid diet and length of hospital stay between the SILC and MILC groups. However, the SILC group showed less analgesic requirements (1.1 vs. 1.9 times;
p
= 0.0006) and shorter length of incision (2.7 vs. 4.3 cm;
p
= 0.0000) compared to MILC group. The overall rate of postoperative complications was similar in both groups (2.8 vs. 3.7 %,
p
= 0.70). The 5-year overall survival rate of SILC and MILC was 100 and 95 % (
p
= 0.125) and 5-year disease-free survival rates in stages 0–III were 97 and 94 % (
p
= 0.189), 100 and 92 % in stage II and 90 and 85 % in stage III, respectively.
Conclusions
This study suggests that SILC for colorectal cancer is a safe and feasible option with better cosmetic results and less pain in strictly selected patients. SILC can also produce good oncological results with similar postoperative outcomes to MILC.
•Healthy volunteer subjects (N = 583) underwent a diffusion tensor imaging scan.•The fractional anisotropy of the superior longitudinal fasciculus was evaluated.•The Perceptual Organization Index was ...correlated the fractional anisotropy.•The Working Memory Index was correlated the fractional anisotropy.•Results contribute to neuromodulation in the treatment of neurological disorders.
The superior longitudinal fasciculus (SLF) is a white matter structure that has long bidirectional projections among the prefrontal, temporal, occipital, and parietal cortices and extends over a wide area in a human brain. Recently, anatomical details of the SLF have been clarified using a diffusion tensor imaging (DTI) template of subjects from the Human Connectome Project. However, the neurobehavioral functions of the SLF have not been fully elucidated. It is speculated that the SLF contributes to a broad cognitive domain including visuospatial nonverbal cognitive ability and verbal memory ability because of its anatomical location; however, previous findings in imaging studies are inconsistent. Showing the contribution of the SLF to cognitive function may be important for improving our understanding of the functional role of white matter structures in the human brain. This study aimed to identify the relationship between DTI indices of the SLF and the Verbal Comprehension, Perceptual Organization, Working Memory and Processing Speed Indices of the Wechsler Adult Intelligence Scale-Third Edition using regression analysis, accounting for the effects of age, sex and scanner type in 583 healthy volunteers. We showed significant correlations between the fractional anisotropy of the left SLF and the Perceptual Organization Index (β = 0.21, p = 4.5×10–4) and Working Memory Index (β = 0.19, p = 4.0×10–4). These findings may have implications for the rehabilitation of cognitive function in patients with neurological disorders.
PDF
