Human Cerebellum Research Articles

Sensorimotor, language, and working memory representation within the human cerebellum.

The cerebellum is involved in a wide range of behaviours. A key organisational principle from animal studies is that somatotopically corresponding sensory input and motor output reside in the same cerebellar cortical areas. However, compelling evidence for a similar arrangement in humans and whether it extends to cognitive functions is lacking. To address this, we applied cerebellar optimised whole‐brain functional MRI in 20 healthy subjects. To assess spatial overlap within the sensorimotor and cognitive domains, we recorded activity to a sensory stimulus (vibrotactile) and a motor task; the Sternberg verbal working memory (VWM) task; and a verb generation paradigm. Consistent with animal data, sensory and motor activity overlapped with a somatotopic arrangement in ipsilateral areas of the anterior and posterior cerebellum. During the maintenance phase of the Sternberg task, a positive linear relationship between VWM load and activity was observed in right Lobule VI, extending into Crus I bilaterally. Articulatory movement gave rise to bilateral activity in medial Lobule VI. A conjunction of two independent language tasks localised activity during verb generation in right Lobule VI‐Crus I, which overlapped with activity during VWM. These results demonstrate spatial compartmentalisation of sensorimotor and cognitive function in the human cerebellum, with each area involved in more than one aspect of a given behaviour, consistent with an integrative function. Sensorimotor localisation was uniform across individuals, but the representation of cognitive tasks was more variable, highlighting the importance of individual scans for mapping higher order functions within the cerebellum.

Using optically pumped magnetometers to measure magnetoencephalographic signals in the human cerebellum.

Key points The application of conventional cryogenic magnetoencephalography (MEG) to the study of cerebellar functions is highly limited because typical cryogenic sensor arrays are far away from the cerebellum and naturalistic movement is not allowed in the recording.A new generation of MEG using optically pumped magnetometers (OPMs) that can be worn on the head during movement has opened up an opportunity to image the cerebellar electrophysiological activity non‐invasively.We use OPMs to record human cerebellar MEG signals elicited by air‐puff stimulation to the eye.We demonstrate robust responses in the cerebellum.OPMs pave the way for studying the neurophysiology of the human cerebellum. We test the feasibility of an optically pumped magnetometer‐based magnetoencephalographic (OP‐MEG) system for the measurement of human cerebellar activity. This is to our knowledge the first study investigating the human cerebellar electrophysiology using optically pumped magnetometers. As a proof of principle, we use an air‐puff stimulus to the eyeball in order to elicit cerebellar activity that is well characterized in non‐human models. In three subjects, we observe an evoked component at approx. 50 ms post‐stimulus, followed by a second component at approx. 85–115 ms post‐stimulus. Source inversion localizes both components in the cerebellum, while control experiments exclude potential sources elsewhere. We also assess the induced oscillations, with time‐frequency decompositions, and identify additional sources in the occipital lobe, a region expected to be active in our paradigm, and in the neck muscles. Neither of these contributes to the stimulus‐evoked responses at 50–115 ms. We conclude that OP‐MEG technology offers a promising way to advance the understanding of the information processing mechanisms in the human cerebellum.

Functional boundaries in the human cerebellum revealed by a multi-domain task battery.

There is compelling evidence that the human cerebellum is engaged in a wide array of motor and cognitive tasks. A fundamental question centers on whether the cerebellum is organized into distinct functional subregions. To address this question, we employed a rich task battery designed to tap into a broad range of cognitive processes. During four functional MRI sessions, participants performed a battery of 26 diverse tasks comprising 47 unique conditions. Using the data from this multi-domain task battery, we derived a comprehensive functional parcellation of the cerebellar cortex and evaluated it by predicting functional boundaries in a novel set of tasks. The new parcellation successfully identified distinct functional subregions, providing significant improvements over existing parcellations derived from task-free data. Lobular boundaries, commonly used to summarize functional data, did not coincide with functional subdivisions. The new parcellation provides a functional atlas to guide future neuroimaging studies.

Cerebellar Function: Multiple Topographic Maps of Visual Space

New evidence from the Human Connectome Project has revealed multiple maps of visual space in human cerebellum. While some features of these maps adhere to the topographic organizational principles shared among the multiple maps in cerebral cortex, some properties appear idiosyncratic.

Vermal Length and Transcerebellar Diameter in Gestational Age Estimation: A Guide to Forensic Expert

Abstract Background Transcerebellar diameter is one of the reliable, constant predicting parameters to assess the gestational age and fetal growth. Other than this, measurements of vermis, mostly the vermal length (height), have also been mentioned by authors to assess gestational age. Establishing a correlation between parameters and advancing gestation would be helpful in estimating the gestational age of fetus. Aims and Objectives To establish a correlation of vermal length and transcerebellar diameter with gestational age. Materials and Methods An observational and descriptive study conducted on 60 formalin-fixed human cerebellums. Fetuses with gross congenital/neurological abnormality were excluded. Fetuses were grouped into four groups—group 1 (13–17 weeks), group 2 (18–22 weeks), group 3 (23–27 weeks), and group 4 (28–32 weeks of gestation). Vermal length and transcerebellar diameter were measured with help of Vernier calipers. The data obtained were analyzed using statistical software SPSS version 20.0 and one-way analysis of variance. Observation A linear increase in vermal length parameters and transcerebellar diameter were seen with increasing gestational age. Regression analysis was done and regression equation was derived for each parameter. Conclusion Such correlations would help in fetal age determination in the field of forensic studies.

A connectivity-based parcellation improved functional representation of the human cerebellum

The cerebellum is traditionally well known for its role in motor learning and coordination. Recently, it is recognized that the function of the cerebellum is highly diverse and extends to non-motor domains, such as working memory, emotion and language. The diversity of the cerebellum can be appreciated by examining its extensive connectivity to the cerebral regions selective for both motor and cognitive functions. Importantly, the pattern of cerebro-cerebellar connectivity is specific and distinct to different cerebellar subregions. Therefore, to understand the cerebellum and the various functions it involves, it is essential to identify and differentiate its subdivisions. However, most studies are still referring the cerebellum as one brain structure or by its gross anatomical subdivisions, which does not necessarily reflect the functional mapping of the cerebellum. We here employed a data-driven method to generate a functional connectivity-based parcellation of the cerebellum. Our results demonstrated that functional connectivity-based atlas is superior to existing atlases in regards to cluster homogeneity, accuracy of functional connectivity representation and individual identification. Furthermore, our functional atlas improves statistical results of task fMRI analyses, as compared to the standard voxel-based approach and existing atlases. Our detailed functional parcellation provides a valuable tool for elucidating the functional diversity and connectivity of the cerebellum as well as its network relationships with the whole brain.

Mapping the structural connectivity between the periaqueductal gray and the cerebellum in humans

The periaqueductal gray is a mesencephalic structure involved in modulation of responses to stressful stimuli. Structural connections between the periaqueductal gray and the cerebellum have been described in animals and in a few diffusion tensor imaging studies. Nevertheless, these periaqueductal gray–cerebellum connectivity patterns have yet to be fully investigated in humans. The objective of this study was to qualitatively and quantitatively characterize such pathways using high-resolution, multi-shell data of 100 healthy subjects from the open-access Human Connectome Project repository combined with constrained spherical deconvolution probabilistic tractography. Our analysis revealed robust connectivity density profiles between the periaqueductal gray and cerebellar nuclei, especially with the fastigial nucleus, followed by the interposed and dentate nuclei. High-connectivity densities have been observed between vermal (Vermis IX, Vermis VIIIa, Vermis VIIIb, Vermis VI, Vermis X) and hemispheric cerebellar regions (Lobule IX). Our in vivo study provides for the first time insights on the organization of periaqueductal gray–cerebellar pathways thus opening new perspectives on cognitive, visceral and motor responses to threatening stimuli in humans.

Functional Differentiation of Visual Attention Processing Within Human Cerebellum

Functional Differentiation of Visual Attention Processing Within Human Cerebellum

Cerebellar repetitive transcranial magnetic stimulation restores pharyngeal brain activity and swallowing behaviour after disruption by a cortical virtual lesion.

Key points Despite evidence that the human cerebellum has an important role in swallowing neurophysiology, the effects of cerebellar stimulation on swallowing in the disrupted brain have not been explored.In this study, for the first time, the application of cerebellar neurostimulation is characterized in a human model of disrupted swallowing (using a cortical virtual lesion).It is demonstrated that cerebellar stimulation can reverse the suppressed activity in the cortical swallowing system and restore swallowing function in a challenging behavioural task, suggesting the findings may have important therapeutic implications. Repetitive transcranial magnetic stimulation (rTMS) can alter neuronal activity within the brain with therapeutic potential. Low frequency stimulation to the ‘dominant’ cortical swallowing projection induces a ‘virtual‐lesion’ transiently suppressing cortical excitability and disrupting swallowing behaviour. Here, we compared the ability of ipsi‐lesional, contra‐lesional and sham cerebellar rTMS to reverse the effects of a ‘virtual‐lesion’ in health. Two groups of healthy participants (n = 15/group) were intubated with pharyngeal catheters. Baseline pharyngeal motor evoked potentials (PMEPs) and swallowing performance (reaction task) were measured. Participants received 10 min of 1 Hz rTMS to the pharyngeal motor cortex which elicited the largest PMEPs to suppress cortical activity and disrupt swallowing behaviour. Over six visits, participants were randomized to receive 250 pulses of 10 Hz cerebellar rTMS to the ipsi‐lesional side, contra‐lesional side or sham while assessing PMEP amplitude or swallowing performance for an hour afterwards. Compared to sham, active cerebellar rTMS, whether administered ipsi‐lesionally (P = 0.011) or contra‐lesionally (P = 0.005), reversed the inhibitory effects of the cortical ‘virtual‐lesion’ on PMEPs and swallowing accuracy (ipsi‐lesional, P < 0.001, contra‐lesional, P < 0.001). Cerebellar rTMS was able to reverse the disruptive effects of a ‘virtual lesion’. These findings provide evidence for developing cerebellar rTMS into a treatment for post‐stroke dysphagia.

Emerging connections between cerebellar development, behaviour and complex brain disorders.

The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the cerebellum iscritical for motor behaviour, it is not surprising that most neurodevelopmental disorders share motor deficits as a common sequela. However, evidence gathered since the late 1980s suggests that the cerebellum is involved in motor and non-motor function, including cognition and emotion. More recently, evidence indicates that major neurodevelopmental disorders such as intellectual disability, autism spectrum disorder, attention-deficit hyperactivity disorder and Down syndrome have potential links to abnormal cerebellar development. Out of recent findings from clinical and preclinical studies, the concept of the 'cerebellar connectome' has emerged that can be used as a framework to link the role of cerebellar development to human behaviour, disease states and the design of better therapeutic strategies.

Isolation and Characterization of Cerebellum-Derived Stem Cells in Poststroke Human Brain.

There is compelling evidence that the mature central nervous system (CNS) harbors stem cell populations outside conventional neurogenic regions. We previously demonstrated that brain pericytes (PCs) in both mouse and human exhibit multipotency to differentiate into various neural lineages following cerebral ischemia. PCs are found throughout the CNS, including cerebellum, but it remains unclear whether cerebellar PCs also form ischemia-induced multipotent stem cells (iSCs). In this study, we demonstrate that putative iSCs can be isolated from poststroke human cerebellum (cerebellar iSCs [cl-iSCs]). These cl-iSCs exhibited multipotency and differentiated into electrophysiologically active neurons. Neurogenic potential was also confirmed in single-cell suspensions. DNA microarray analysis revealed highly similar gene expression patterns between PCs and cl-iSCs, suggesting PC origin. Global gene expression comparison with cerebral iSCs revealed general similarity, but cl-iSCs differentially expressed certain cerebellum-specific genes. Thus, putative iSCs are present in poststroke cerebellum and possess region-specific traits, suggesting potential capacity to regenerate functional cerebellar neurons following ischemic stroke.

Pattern of Cerebellar Atrophy in Friedreich’s Ataxia—Using the SUIT Template

Whole-brain voxel-based morphometry (VBM) studies revealed patterns of patchy atrophy within the cerebellum of Friedreich's ataxia patients, missing clear clinico-anatomic correlations. Studies so far are lacking an appropriate registration to the infratentorial space. To circumvent these limitations, we applied a high-resolution atlas template of the human cerebellum and brainstem (SUIT template) to characterize regional cerebellar atrophy in Friedreich's ataxia (FRDA) on 3-T MRI data. We used a spatially unbiased voxel-based morphometry approach together with T2-based manual segmentation, T2 histogram analysis, and atlas generation of the dentate nuclei in a representative cohort of 18 FRDA patients and matched healthy controls. We demonstrate that the cerebellar volume in FRDA is generally not significantly different from healthy controls but mild lobular atrophy develops beyond normal aging. The medial parts of lobule VI, housing the somatotopic representation of tongue and lips, are the major site of this lobular atrophy, which possibly reflects speech impairment. Extended white matter affection correlates with disease severity across and beyond the cerebellar inflow and outflow tracts. The dentate nucleus, as a major site of cerebellar degeneration, shows a mean volume loss of about 30%. Remarkably, not the atrophy but the T2 signal decrease of the dentate nuclei highly correlates with disease duration and severity.

Cerebellum and cognition: Does the rodent cerebellum participate in cognitive functions?

There is a widespread, nearly complete consensus that the human and non-human primate cerebellum is engaged in non-motor, cognitive functions. This body of research has implicated the lateral portions of lobule VII (Crus I and Crus II) and the ventrolateral dentate nucleus. With rodents, however, it is not so clear. We review here approximately 40 years of experiments using a variety of cerebellar manipulations in rats and mice and measuring the effects on executive functions (working memory, inhibition, and cognitive flexibility), spatial navigation, discrimination learning, and goal-directed and stimulus-driven instrumental conditioning. Our conclusion is that there is a solid body of support for engagement of the rodent cerebellum in tests of cognitive flexibility and spatial navigation, and some support for engagement in working memory and certain types of discrimination learning. Future directions will involve determining the relevant cellular mechanisms, cerebellar regions, and precise cognitive functions of the rodent cerebellum.

Abstract TP143: Potential of Cerebellum-derived Stem Cells in Human Brain to Regenerate Functional Neurons Following Ischemic Stroke

Introduction: Despite the availability of effective reperfusion therapies, only a few prove beneficial to the patients after stroke, owing to their limited time window. We had earlier demonstrated that adult brain pericytes develop stemness following ischemia, and these ischemia-induced multipotent stem cells (iSCs) can self-propagate and differentiate into mature neural cells, including neurons (Nakagomi et al. Eur J Neurosci. 2009, Stem Cells. 2009, 2015). More recently, we have shown putative iSCs to be present within post-stroke human cerebral tissues (Tatebayashi K et al. Stem Cells Dev 2017). The current study aimed to establish iSCs from cerebellar infarction of two patients and examine their characteristics. Methods: We isolated iSCs from post-stroke human cerebellum, examined their characteristics by Polymerase chain reaction and immunocytochemistry, and compared their traits with those of others by microarray and flow cytometry analyses. Furthermore, we investigated the cerebellar-iSCs (cl-iSCs) for multi-potency and differentiation into functional neurons. Electrophysiological properties were analyzed using multi-electrode arrays. Results: The isolated cl-iSCs exhibited multi-potency and differentiated into electrophysiologically active neurons (Fig. A). Neurogenic potential was confirmed in single-cell suspensions (Fig. B.C). Highly similar gene expression patterns were observed between pericytes and iSCs (Fig. D), and a strong lineage resemblance between cl-iSCs and cerebral ischemia-induced multi-potent stem cells (cr-iSCs) was revealed, although cl-iSCs differentially expressed certain cerebellum-specific genes. Conclusions: Putative iSCs are present in post-stroke cerebellum and possess region-specific traits, suggesting their potential to regenerate functional neurons following an ischemic stroke.

Evidence that inflammation promotes estradiol synthesis in human cerebellum during early childhood

Discovering and characterizing critical and sensitive periods in brain development is essential for unraveling the myriad variables that impact disease risk. In previous work, we identified a critical period in cerebellar development in the rat that depends upon an intrinsic gene expression program and links increased prostaglandin production to local estradiol synthesis by stimulating Cyp19a, the estradiol synthetic enzyme, aromatase. This intrinsic critical period is sensitive to disruption by either inflammation or administration of cyclooxygenase (COX) inhibitors, ultimately impacting Purkinje cell dendritic growth. In a first step towards determining if a similar sensitive period exists in humans, the same gene expression profile was characterized in post-mortem cerebellar tissue of 58 children aged 0 to 9 years. Subjects were categorized as experiencing inflammation or not at the time of death. In individuals experiencing inflammation and over 1 year of age, there was a significant increase in the messenger RNA (mRNA) of the COX-1 and COX-2 enzymes and this strongly correlated with mRNA levels of aromatase. A step-wise linear model accounted for 94% of the variance in aromatase mRNA levels by co-variance with the COX enzymes, prostaglandin E2 synthase and other inflammatory mediators (Toll-like receptor 4), and Purkinje cell markers (calbindin, estrogen receptor 2). The influence of inflammation on these measures was not seen in subjects younger than 1 year. These data suggest a sensitive period to inflammation in the human cerebellum begins at about 1 year of age and may provide insight into sources of vulnerability of very young children to either inflammation or drugs designed to treat it.

Transcranial direct current stimulation of the human cerebellum during associative learning

Transcranial direct current stimulation of the human cerebellum during associative learning

A Stainless Protocol for High Quality RNA Isolation from Laser Capture Microdissected Purkinje Cells in the Human Post-Mortem Cerebellum

A Stainless Protocol for High Quality RNA Isolation from Laser Capture Microdissected Purkinje Cells in the Human Post-Mortem Cerebellum

A Stainless Protocol for High Quality RNA Isolation from Laser Capture Microdissected Purkinje Cells in the Human Post-Mortem Cerebellum.

Laser capture microdissection (LCM) is an advantageous tool that allows for the collection of cytologically and/or phenotypically relevant cells or regions from heterogenous tissues. Captured product can be used in a variety of molecular methods for protein, DNA or RNA isolation. However, preservation of RNA from postmortem human brain tissue is especially challenging. Standard visualization techniques for LCM require histologic or immunohistochemical staining procedures that can further degrade RNA. Therefore, we designed a stainless protocol for visualization in LCM with the intended purpose of preserving RNA integrity in post-mortem human brain tissue. The Purkinje cell of the cerebellum is a good candidate for stainless visualization, due to its size and characteristic location. The cerebellar cortex has distinct layers that differ in cell density, making them a good archetype to identify under high magnification microscopy. Purkinje cells are large neurons situated between the granule cell layer, which is a densely cellular network of small neurons, and the molecular layer, which is sparse in cell bodies. Because of this architecture, the use of stainless visualization is feasible. Other organ or cell systems that mimic this phenotype would also be suitable. The stainless protocol is designed to fix fresh-frozen tissue with ethanol and remove lipids with xylene for improved morphological visualization under high magnification light microscopy. This protocol does not account for other fixation methods and is specifically designed for fresh-frozen tissue samples captured using an ultraviolet (UV)-LCM system. Here, we present a full protocol for sectioning and fixing fresh frozen post-mortem human cerebellar tissue and purification of RNA from Purkinje cells isolated by UV-LCM, while preserving RNA quality for subsequent RNA-sequencing. In our hands, this protocol produces exceptional levels of cellular visualization without the need for staining reagents and yields RNA with high RNA integrity numbers (≥8) as needed for transcriptional profiling experiments.

Mechanical measurement of the human cerebellum under compressive loading

The cerebellum is responsible for controlling the posture and walking stability of the body. The cerebellum can subject to the traumatic injuries following by complicated clinical problems, i.e., the cerebellar pathologies. Application of the computational models can be helpful to figure out the injury mechanisms of the cerebellum, however, there is a lack of knowledge on the mechanical properties of the cerebellum under compressive loading. Therefore, this study aimed to perform an experimental study to measure the mechanical properties of 17 male individuals’ cerebellum under the series of compressive loadings. The resulted stress-strain data of the cerebellum revealed the elastic modulus and maximum/failure stress of 13.48 ± 2.65 (Mean ± SD) and 19.65 ± 3.89 kPa, respectively. The findings of this study have implications not only for understanding the mechanical properties of the human cerebellum tissue under the compressive loading, but also for providing a raw data for the doctors and biomechanical experts as the mechanical threshold of the cerebellum as well as computational modelling of the traumatic brain injuries.

Disease modeling of Angelman syndrome using hiPSC-derived cerebellar organoids

Event Abstract Back to Event Disease modeling of Angelman syndrome using hiPSC-derived cerebellar organoids Carina Maranga1, 2, Teresa P. Da Silva1, 2, Sandra Vaz2, Simão T. Da Rocha2, Tiago G. Fernandes1, Evguenia P. Bekman1, 2 and Joaquim S. Cabral1* 1 Institute for Biotechnology and Bioengineering, Portugal 2 Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, Portugal Angelman syndrome (AS) is an incurable neurodevelopmental disorder characterized by ataxia, intellectual disability, speech impairment, seizures, autism behavior and happy demeanor. Based on murine AS mouse models, several neuronal types of the central nervous system are functionally affected, including Purkinje and granule cells within the cerebellum. However, the contribution of the cerebellum to the pathophysiology of AS remains enigmatic and has only been functionally explored in mouse models. AS is caused by a loss of the maternal UBE3A allele on 15q11- q13 chromosomal region. Previous work in our lab showed that neurons generated from AS-derived iPSCs maintain their imprinting status of parental UBE3A locus undergoing neuron-specific silencing upon maturation, validating the use of iPSC-derived neurons for in vitro modeling of AS. In this work, AS patients-derived induced pluripotent stem cell (iPSC) lines are used to generate 3D cerebellar organoids recapitulating the development of human cerebellum, with the aim of understanding the involvement of the cerebellum in the pathophysiology of the disease. We are using an optimized protocol developed in our group that allows to achieve functional in vitro maturation of all major cerebellar neuronal types such as Purkinje cells, Golgi cells, granule cells and non-Golgi-type interneurons. A comparison of cerebellar neurons obtained from three different AS-derived iPSC lines with those of two control (healthy) iPSC lines revealed that the generation of all GABAergic neuronal types is severely reduced in all AS conditions, with an excessive production of rhombic lip (glutamatergic) derivatives. AS-derived cerebellar aggregates have reduced size, showing a decrease in cerebellar ventricular markers KIRREL2, OLIG2 and CORL2 together with a decrease in PAX6 and PAX2 RNA levels. Ongoing experiments are focused on functional analysis of AS-derived neurons, as well as on the thorough evaluation of different neuronal types generated in these cultures, with quantitative assessment of proliferation and apoptosis during in vitro cerebellar differentiation of AS- derived and healthy iPSCs. Acknowledgements This work was supported by Fundação para a Ciência e a Tecnologia, Portugal (UID/BIO/04565/2013 and PD/BD/135505/2018 to C.M.; SFRH/BPD/81627/2011 to S.H.V.); LISBOA-01-0145-FEDER-007391/007317/029298, and PAC-PRECISE-LISBOA-01-0145- FEDER-016394, projects cofunded by FEDER through POR Lisboa 2020 - Programa Operacional Regional de Lisboa PORTUGAL 2020, and Fundação para a Ciência e a Tecnologia Keywords: Angelman Syndrome, HiPSCs, Organoids, Cerebellum, Ataxia Conference: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019), Lisboa, Portugal, 30 May - 1 Jun, 2019. Presentation Type: Pitch communication + Poster presentation Topic: Rare Disorders Citation: Maranga C, Da Silva TP, Vaz S, Da Rocha ST, Fernandes TG, Bekman EP and Cabral JS (2019). Disease modeling of Angelman syndrome using hiPSC-derived cerebellar organoids. Front. Cell. Neurosci. Conference Abstract: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019). doi: 10.3389/conf.fncel.2019.01.00041 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Prof. Joaquim S Cabral, Institute for Biotechnology and Bioengineering, Lisbon, Portugal, joaquim.cabral@ist.utl.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Carina Maranga Teresa P Da Silva Sandra Vaz Simão T Da Rocha Tiago G Fernandes Evguenia P Bekman Joaquim S Cabral Google Carina Maranga Teresa P Da Silva Sandra Vaz Simão T Da Rocha Tiago G Fernandes Evguenia P Bekman Joaquim S Cabral Google Scholar Carina Maranga Teresa P Da Silva Sandra Vaz Simão T Da Rocha Tiago G Fernandes Evguenia P Bekman Joaquim S Cabral PubMed Carina Maranga Teresa P Da Silva Sandra Vaz Simão T Da Rocha Tiago G Fernandes Evguenia P Bekman Joaquim S Cabral Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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