Does extensive motor learning trigger local sleep?

After prolonged learning we all have experienced a reduction of alertness, resulting in errors that we would normally not make. Despite this being a common situation in everyday life, the reasons for this phenomenon are unclear. A possible explanation is that the regions of the brain which are involved in the learning, go off-line trying to partially recover. This event is defined as local sleep and it has been detected in animals and sleep-deprived humans performing learning tasks. Local sleep is a sleep-like electrophysiological activity occurring locally, while the rest of the brain is fully awake, and producing performance deterioration. However, since all the studies included both lack of sleep and learning, it is uncertain whether such phenomenon is related to sleep deprivation or if it is the consequence of prolonged learning. Further, local sleep has not been related to electrophysiological changes occurring during the task. This thesis aimed to assess, for the first time in well rested subjects, whether local sleep and performance decline occur because of prolonged learning. Specifically, the goal was to discriminate between sustained practice and learning, as to determine whether learning is required to cause local sleep. Also, a 90-minute nap was evaluated to establish whether sleep is necessary to counterbalance neuronal fatigue and performance decrease. The starting hypothesis was that local sleep is a plasticity-related phenomenon affecting performance and requiring learning to be triggered. Consequently, sleep would be a prerequisite to counterbalance performance and electrophysiological changes. High-Density EEG and behavioral data of 78 healthy young subjects were collected during and after two learning tasks performed for three hours: a visual sequence learning task, and a visuo-motor rotation task, randomly selected. Afterward, subjects were divided in two groups: those who slept for one hour and a half and those who remained awake and quietly rested for the same amount of time before being tested for electrophysiological and behavioral changes. Moreover, to discriminate between the effects of prolonged learning and practice, 11 additional subjects performed a control condition consisting in planar upper limb reaching movements instead of the above-mentioned learning tasks. In detail, the power spectrum of the EEG activity during the task and at rest with eyes opened was divided into five ranges to determine frequency changes of the EEG activity: delta 1 to 4 Hz; theta 4 to 8 Hz; alpha 8 to 13 Hz, beta 13 to 25 Hz, gamma 25 to 55 Hz. Additionally, movement-related beta activity of 35 young subjects was analyzed to find a relationship between task related oscillations and performance indices, as the modulatory activity during practice may reflect plasticity-related phenomena that can describe the occurrence of local sleep. Finally, 13 young subjects were compared to a dataset of 13 older participants who performed planar upper limb reaching movements to determine whether beta oscillations were affected by age. Specifically, beta activity was assessed during reaching movements in different brain regions, in terms of topography, magnitude, and peak frequency. Results demonstrated that sustained learning produced electrophysiological changes both at rest and during the task. In fact, resting state was characterized by a progressive slowing of the EEG activity over areas overlapping with those engaged during the task. Precisely, we detected task-related activity mainly in the high-frequency ranges (gamma and beta right temporo-parietal activity for the visual sequence learning task; alpha and beta activity over a fontal and left parietal areas for the visuo-motor rotation); the same areas were characterized by a progressive increase of the low frequency EEG activity at rest ranging from alpha, beta after one hour of practice, to theta after three one-hour blocks. The control task did not trigger such EEG slowing, as reaching movements without learning did only left an alpha, beta trace in the resting state over a cluster reflecting the motor area contralateral to the movement. Further, continuous learning triggered performance deteriorations only in tests sharing the same neural substrate of the previously performed task. In other words, the visuo-motor learning task only affected performance in a motor test consisting in random reaching movements; conversely, visual sequence learning altered performance on a visual working memory test, but did not influence reaching movements. Also, the control condition did not affect performance in any of the two exercises. Performance decline, learning ability and local sleep were partially renormalized by a 90-minute nap but not by an equivalent period of wake. As such, the global EEG activity, computed as the mean power of all the electrodes, was not affected by either 90 minutes of sleep or quiet wake. However, the regions characterized by low frequency at rest benefited from the sleep period, as the low frequencies content partially decreased after the nap but not after quiet wake. Task related beta activity during motor practice presented similar magnitude and timing patterns in different brain areas, with a progressive increase with practice, in both young and older subjects, despite the older subjects performing slower, less accurate movements. Intriguingly, the motor areas showed a post movement beta synchronization having a peak between 15 and 18 Hz, as opposed to a frontal area that has it between 23 and 29 Hz. Finally, results did not reveal any direct relationship between EEG beta oscillations and performance indices. Altogether, these results indicate that local sleep and performance decrease can be triggered by prolonged learning in well rested subjects; furthermore, some amount of sleep can partially renormalize learning ability, EEG activity and performance. Also, differences in the brainnoscillations during motor activity can express separate processes underlying motor planning, execution and skills acquisition. The present study adds some important knowledge in the field of local sleep; in fact, it suggests that such phenomenon is triggered by sustained learning rather than sleep deprivation, thus being a plasticity-related phenomenon. Finally, the role of sleep on counterbalancing local sleep has been proved, despite additional studies are required to establish whether a full night of sleep rather than a specific amount of time is needed to fully restore learning ability and electrophysiological activity. In conclusion, the present findings are of importance in all the fields where sustained learning is required, such as rehabilitative programs, sport and military trainings, and must be taken into account when plasticity plays a fundamental role in the acquisition of new skills

Evaluation of MMP‑2, MMP‑9, TIMP‑1, TIMP‑2, NGAL and MMP‑9/NGAL complex in urine and sera from patients with bladder cancer

The identification of biomarkers in urine or serum samples from patients with bladder cancer is urgently required for the development of non-invasive methods for the diagnosis of bladder carcinoma and to facilitate follow-up surveillance, to combat the high progression and recurrence rates of this type of cancer. The current study measured the content of matrix metalloproteinase (MMP)-2 and -9, as well as tissue inhibitor of metalloproteinase (TIMP)-1 and -2 in the urine and sera of 41 patients with bladder cancer by ELISA. The association between levels of MMP-2 and -9 and TIMP-1 and -2, and tumor grade and stage were investigated to verify whether these molecules are involved in tumor differentiation. Statistical analysis of the data revealed that urinary TIMP-1 levels were significantly higher in the high grade group compared with those of the low grade samples (P=0.022). The results also revealed a significantly differing distribution of TIMP-1 expression between Ta and T1 stage specimens (P=0.040). The corresponding area under the curves (AUCs) were 0.72, with a sensitivity of 0.70 and specificity of 0.75. In addition, neutrophil gelatinase-associated lipocalin (NGAL) and MMP-9/NGAL complex levels in the sera were measured. All molecules evaluated were detected in the sera of the patients studied. In particular, tumors staged as non-muscle invasive (Ta and T1), demonstrated significantly higher NGAL levels compared with those of muscle invasive (>T1) bladder cancer (32.8 ng/ml vs. 16.2 ng/ml; P=0.029). The discriminatory ability of NGAL expression was confirmed by receiver operating characteristic curve analysis that revealed an AUC of 0.75, a sensitivity of 0.88 and a specificity of 0.67. These data indicated that urinary TIMP-1 and serum NGAL may be useful non-invasive biomarkers to provide clinical information for bladder cancer disease management. Multicenter, prospective studies are required to confirm these preliminary results

Long term effects of mesoglycan on brachial arterial stiffness and MMP-9/TIMP-1 system in patients with metabolic syndrome

Objectives: The aim of this study was to evaluate the chronic effects of mesoglycan on the vascular remodeling in patients with metabolic syndrome (Mets). Background: MetS is defined by a clustering of vascular risk factors that require both pharmacologic and non-pharmacologic interventions, including body weight reductions and physical activity. The correction of vascular remodeling associated with MetS has lately received increasing interest. Methods: Thirty consecutive ambulatory patients affected by MetS were 2:1 randomized in a doubleblind fashion to receive mesoglycan or placebo, respectively. At the beginning and after 90 days of oral treatment we appraised the effects of mesoglycan (50 mg per os bid) or placebo on vascular remodeling, as assessed by the measurement of arterial wall elastic properties. Moreover, the matrix metalloproteinase’s (MMPs) type 9 and tissue inhibitor of metalloproteinase (TIMP) type 1 were analyzed by enzyme-linked immune sorbent assay (ELISA) and gelatin substrate zymography at the beginning of the study and after 90 days of treatment. Results: After 90 days of treatment, a marked improvement of arterial distensibility and compliance was detected in Mesoglycan group, with associated significant reduction of arterial stiffness, and a significant reduction of serum levels of MMP-9 and TIMP-1 and significant reduction of enzyme activity of MMPs. Conclusions: This small, preliminary study shows that mesoglycan exerts relevant effects on vascular remodeling after three-month treatment, in patients affected by metabolic syndrome

Vibrational Spectroscopies and Chemometry for Nondestructive Identification and Differentiation of Painting Binders

A comprehensive dataset of vibrational spectra of different natural organic binding media is presented and discussed. The binding media were applied on a glass substrate and analyzed after three months of natural ageing. The combination of Raman and FT-NIR spectroscopies allows for an improved identification of these materials as Raman technique is more informative about the skeletal vibrations, while FT-NIR spectroscopy is more sensitive to the substituents and polar groups. The experimental results are initially discussed in the framework of current spectral assignment. Then, multivariate analysis (PCA) is applied leading to differentiation among the samples. The two major principal components allow for a complete separation of the different classes of organic materials. Further differentiation within the same class is possible thanks to the secondary components. The loadings obtained from PCA are discussed on the basis of the spectral assignment leading to clear understanding of the physical basis of this differentiation process

PREP1 DEFICIENCY AFFECTS OLFACTORY SYSTEM INTEGRITY BY IMPAIRING TRKB-MEDIATED NEUROTROPHIC SIGNALLING

Prep1 is a transcription factor belonging to the TALE proteins, which plays an important role in the embryonic development of the hindbrain. However, as reported on web-based atlas, morphological data revealed that Prep1 expression is kept also in adult mouse brain and, in particular, within the olfactory bulb (OB), even though its function is still unknown. In order to investigate the role of Prep1 in olfactory nuclei I used a prep1 hypomorphic mouse (prep1i/+), which express about 55-57% of protein. Brain morphological analysis revealed that prep1i/+ mice feature a significant reduction of OB area, a reduced number of periglomerular interneurons and an increased number of mitral cells within the main olfactory bulb, compared to WT mice. prep1i/+ mice OB cytochrome C oxidase staining showed also a reduced neuronal metabolism within the glomerular layer. Consistently, olfactory perception test highlighted that hypomorphic mice display a low ability to distinguish odor scents, accompanied to a significant locomotor hypoactivity. Molecular analysis, indeed, revealed that prep1i/+ mouse olfactory nuclei express reduced levels of TrkB, the downstream receptor of BDNF, the main neurotrophic factor involved in olfactory plasticity and functions. In parallel, also a decreased activation of molecular mediators involved in TrkB-mediated neurotrophic signalling (Akt, ERK) was observed. Congruously, mouse neuronal cells (N2A) overexpressing Prep1 showed increased cell growth, viability and metabolism, with high levels of TrkB expression and Akt/ERK phosphorylation, compared to control cells. Thus, our data suggest that Prep1 deficiency alters olfactory system morpho-functional integrity by affecting TrkB expression and signalling pathway, giving a rationale to further investigate Prep1 as potential marker in olfactory dysfunctions associated to impaired responsiveness to BDNF signalling

Transcription Pattern of Neurotrophic Factors and Their Receptors in Adult Zebrafish Spinal Cord

In vertebrates, neurotrophins and their receptors play a fundamental role in the central and peripheral nervous systems. Several studies reported that each neurotrophin/receptor signalling pathway can perform various functions during axon development, neuronal growth, and plasticity. Previous investigations in some fish species have identified neurotrophins and their receptors in the spinal cord under physiological conditions and after injuries, highlighting their potential role during regeneration. In our study, for the first time, we used an excellent animal model, the zebrafish (Danio rerio), to compare the mRNA localization patterns of neurotrophins and receptors in the spinal cord. We quantified the levels of mRNA using qPCR, and identified the transcription pattern of each neurotrophin/receptor pathway via in situ hybridization. Our data show that ngf/trka are the most transcribed members in the adult zebrafish spinal cord

Virtual and Augmented Reality in Basic and Advanced Life Support Training

The use of augmented reality (AR) and virtual reality (VR) for life support training is increasing. These technologies provide an immersive experience that supports learning in a safe and controlled environment. This review focuses on the use of AR and VR for emergency care training for health care providers, medical students, and nonprofessionals. In particular, we analyzed (1) serious games, nonimmersive games, both single-player and multiplayer; (2) VR tools ranging from semi-immersive to immersive virtual and mixed reality; and (3) AR applications. All the toolkits have been investigated in terms of application goals (training, assessment, or both), simulated procedures, and skills. The main goal of this work is to summarize and organize the findings of studies coming from multiple research areas in order to make them accessible to all the professionals involved in medical simulation. The analysis of the state-of-the-art technologies reveals that tools and studies related to the multiplayer experience, haptic feedback, and evaluation of user’s manual skills in the foregoing health care-related environments are still limited and require further investigation. Also, there is an additional need to conduct studies aimed at assessing whether AR/VR-based systems are superior or, at the minimum, comparable to traditional training methods

Analysis of clasp2 Transcription Pattern in Male Germ Cells during Spermatogenesis: A Comparative Study in Zebrafish (Danio rerio) and Guppy (Poecilia reticulata)

Cytoplasmic linker-associated protein-2 (CLASP2) is a member of the CLIP-associating proteins (CLASPs) family involved in the structure and function of microtubules and Golgi apparatus. Several studies performed using different mammalian and non-mammalian model organisms reported that CLASP2 controls microtubule dynamics and the organization of microtubule networks. In Drosophila and mice, an important role of CLASP2 during the development of germ cell lines has been uncovered. However, no study has clearly defined its role during fish germ cell differentiation. In the present study, we used two excellent aquatic animal models among teleost fish: zebrafish (Danio rerio) and guppy (Poecilia reticulata). Using qPCR, we found that the clasp2 transcript level is significantly high in the testis of both fish. Then, by in situ hybridization, we localized the clasp2 transcript in the spermatozoa of zebrafish and the spermatozeugmata of guppy. Our data suggest a potential role for this gene in the last stage of spermiogenesis in fis

Dissipative control over the toehold-mediated DNA strand displacement reaction

Here we show a general approach to achieve dissipative control over toehold-mediated strand-displacement, the most widely employed reaction in the field of DNA nanotechnology. The approach relies on rationally re-engineering the classic strand displacement reaction such that the high-energy invader strand (fuel) is converted into a low-energy waste product through an energy-dissipating reaction allowing the spontaneous return to the original state over time. We show that such dissipative control over the toehold-mediated strand displacement process is reversible (up to 10 cycles), highly controllable and enables unique temporal activation of DNA systems. We show here two possible applications of this strategy: the transient labelling of DNA structures and the additional temporal control of cascade reactions