scholarly journals Blood Lactate is an Important Energy Source for the Human Brain

2009 ◽  
Vol 29 (6) ◽  
pp. 1121-1129 ◽  
Author(s):  
Gerrit van Hall ◽  
Morten Stømstad ◽  
Peter Rasmussen ◽  
Øle Jans ◽  
Morten Zaar ◽  
...  
Keyword(s):  
Energy Source ◽  
Human Brain ◽  
Arterial Lactate ◽  
Oxidation Rates ◽  
Lactate Uptake ◽  
Lactate Utilization ◽  
Lactate Infusion ◽  
The Brain ◽  
Brain Energy

Lactate is a potential energy source for the brain. The aim of this study was to establish whether systemic lactate is a brain energy source. We measured in vivo cerebral lactate kinetics and oxidation rates in 6 healthy individuals at rest with and without 90 mins of intravenous lactate infusion (36 μmol per kg bw per min), and during 30mins of cycling exercise at 75% of maximal oxygen uptake while the lactate infusion continued to establish arterial lactate concentrations of 0.89 ± 0.08, 3.9 ± 0.3, and 6.9 ± 1.3 mmol/L, respectively. At rest, cerebral lactate utilization changed from a net lactate release of 0.06 ± 0.01 to an uptake of 0.16 ± 0.07 mmol/min during lactate infusion, with a concomitant decrease in the net glucose uptake. During exercise, the net cerebral lactate uptake was further increased to 0.28 ± 0.16 mmol/min. Most 13C-label from cerebral [1-13C]lactate uptake was released as 13CO2 with 100% ± 24%, 86% ± 15%, and 87% ± 30% at rest with and without lactate infusion and during exercise, respectively. The contribution of systemic lactate to cerebral energy expenditure was 8% ± 2%, 19% ± 4%, and 27% ± 4% for the respective conditions. In conclusion, systemic lactate is taken up and oxidized by the human brain and is an important substrate for the brain both under basal and hyperlactatemic conditions.

A Three-Component-System Hypothesis of Psychosis

1989 ◽  
Vol 155 (S5) ◽  
pp. 37-39 ◽  
Author(s):  
Hinderk M. Emrich
Keyword(s):  
Human Brain ◽  
Causative Factor ◽  
Microscopic Level ◽  
Point Of View ◽  
Component System ◽  
Pathogenetic Factor ◽  
Pet Scans ◽  
The Brain ◽  
Different Levels

Hypotheses as to the pathogenesis of schizophrenia can be discussed at different levels of a possible manifestation of the causative factor: the macroscopic-morphological, the microscopic-morphological, and the molecular. Some abnormalities have been observed on all of them: e.g. increased ventricular-brain ratios in CT, hypofrontality in SPECT and in glucographic PET-scans, and other macromorphological abnormalities (for reviews cf. Bogerts 1984; Mundt, 1986; Bogerts et al, 1987), gliosis on a microscopic level (Stevens, 1982), and an increased dopamine-binding in in vivo receptor studies (PET as well as in post-mortem studies; Cazzullo, 1988). However, the diversity and variability of these findings point to the view that rather than there being a single distinct pathogenetic factor responsible for the pathogenesis of schizophrenic psychoses, a constitutional disposition exists, which can be described as a functional dysequilibrium within the human brain. From this point of view, schizophrenia would not appear as an inherited disorder of metabolism, but as a weakness of a neurobiological ‘system’, i.e. as an interactional disorder of a complex of networks, in which the interaction between different substructures is labile in such a way that under special conditions (e.g. ‘stress’), a decompensation (functional breakdown) results. In this sense, ‘vulnerability’ to schizophrenia may be interpreted as a consequence of a constitutional deficiency of the brain which results in an inability to stabilise, under specially challenging conditions, the interaction between different substructures of the human brain. Before this ‘functional dysequilibrium-hypothesis’ (which is a special form of a constitutional structural deficiency-hypothesis) is discussed, and before the question is raised as to which are the relevant dysequilibrated components, some indication will be given as to why such an hypothesis appears plausible.

scholarly journals Evidence for a Lactate Pool in the Rat Brain That is Not Used as an Energy Supply under Normoglycemic Conditions

2003 ◽  
Vol 23 (8) ◽  
pp. 933-941 ◽  
Author(s):  
Gea Leegsma-Vogt ◽  
Kor Venema ◽  
Jakob Korf
Keyword(s):  
Energy Source ◽  
Energy Supply ◽  
Blood Circulation ◽  
Cerebral Metabolism ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Flow Injection Analysis System ◽  
Analysis System ◽  
Lactate Infusion ◽  
The Brain

Lactate derived from glucose can serve as an energy source in the brain. However, it is not certain how much lactate, directly taken from the blood circulation, may replace glucose as an energy source. This study aimed to estimate the uptake, release, and utilization of lactate entering the brain from the blood circulation. The change in cerebral venous-arterial glucose and lactate differences after lactate infusions in the anesthetized rat were measured. Ultrafiltration probes were placed in the aorta and in the jugular vein, and connected to a flow injection analysis system with biosensors for glucose and lactate. Measurements were taken every minute. Lactate efflux was observed at baseline, whereas an influx of lactate was seen during lactate infusion. Immediately after the infusion there was a net efflux of lactate from the brain. The results suggest that the majority of lactate moving into the brain is not used as an energy substrate, and that lactate does not replace glucose as an energy source. Instead, the authors propose the concept of a lactate pool in the brain that can be filled and emptied in accordance with the blood lactate concentration, but which is not used as an energy supply for cerebral metabolism.

scholarly journals Dissociated Expression of Mitochondrial and Cytosolic Creatine Kinases in the Human Brain: A New Perspective on the Role of Creatine in Brain Energy Metabolism

2013 ◽  
Vol 33 (8) ◽  
pp. 1295-1306 ◽  
Author(s):  
Matthew TJ Lowe ◽  
Eric H Kim ◽  
Richard LM Faull ◽  
David L Christie ◽  
Henry J Waldvogel
Keyword(s):  
Energy Metabolism ◽  
Human Brain ◽  
High Energy ◽  
Cellular Energy ◽  
Neuronal Populations ◽  
Neurologic Function ◽  
New Perspective ◽  
The Brain ◽  
Brain Energy

The phosphocreatine/creatine kinase (PCr/CK) system in the brain is defined by the expression of two CK isozymes: the cytosolic brain-type CK (BCK) and the ubiquitous mitochondrial CK (uMtCK). The system plays an important role in supporting cellular energy metabolism by buffering adenosine triphosphate (ATP) consumption and improving the flux of high-energy phosphoryls around the cell. This system is well defined in muscle tissue, but there have been few detailed studies of this system in the brain, especially in humans. Creatine is known to be important for neurologic function, and its loss from the brain during development can lead to mental retardation. This study provides the first detailed immunohistochemical study of the expression pattern of BCK and uMtCK in the human brain. A strikingly dissociated pattern of expression was found: uMtCK was found to be ubiquitously and exclusively expressed in neuronal populations, whereas BCK was dominantly expressed in astrocytes, with a low and selective expression in neurons. This pattern indicates that the two CK isozymes are not widely coexpressed in the human brain, but rather are selectively expressed depending on the cell type. These results suggest that the brain cells may use only certain properties of the PCr/CK system depending on their energetic requirements.

scholarly journals Modeling Cerebral Arteriovenous Lactate Kinetics after Intravenous Lactate Infusion in the Rat

2004 ◽  
Vol 24 (10) ◽  
pp. 1071-1080 ◽  
Author(s):  
Gea Leegsma-Vogt ◽  
Siebren van der Werf ◽  
Kor Venema ◽  
Jakob Korf
Keyword(s):  
Mathematical Model ◽  
Flow Injection Analysis ◽  
Brain Volume ◽  
Venous Blood ◽  
High Temporal Resolution ◽  
Arterial Lactate ◽  
Lactate Kinetics ◽  
Subsequent Application ◽  
Lactate Infusion ◽  
The Brain

Venous-arterial lactate differences across the brain during lactate infusion in rats were studied, and the fate of lactate was described with a mathematical model that includes both cerebral and extracerebral kinetics. Ultrafiltration was used to sample continuously and simultaneously arterial and venous blood. Subsequent application of flow injection analysis and biosensors allowed the measurement of glucose and lactate concentrations every minute. Because of the high temporal resolution, arteriovenous lactate kinetics could be modeled in individual experiments. The existence of both a cerebral lactate sink and a lactate exchangeable compartment, representing approximately 24% of brain volume, was thus modeled.

scholarly journals 0147 Dynamic Alterations in Functional Connectivity Between Sleep- and Wake-Promoting Regions of the Human Brain at the Sleep Onset Period

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A58-A58
Author(s):  
T Ishii ◽  
T Koike ◽  
E Nakagawa ◽  
M Sumiya ◽  
N Sadato
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Transition Period ◽  
Sleep Stage ◽  
Sleep Onset ◽  
Sleep Stages ◽  
Alpha Power ◽  
Onset Period ◽  
The Brain

Abstract Introduction The sleep onset period, involving so-called stage N1 sleep largely, is characterized by a reduction in the amount of alpha activity compared to wakefulness. Various kinds of physiological and psychological changes are also apparent, such as slow eye movements, changes in muscle tonus, and the hypnagogic dream-like mentation. These phenomena are thought to be the reflection of dynamic alterations in the brain during the transition period, however, details of these changes have still been uncovered. Methods We aimed to investigate a dynamic shift in the brain connectivity at sleep onset using the method of EEG-fMRI simultaneous recording. Twenty-three healthy subjects participated. EEG/fMRI were recorded simultaneously during an hour’s nap in a 3T-MRI scanner and real-time monitoring of EEG was performed. To record the transition period between multiple times, an experimenter inside a scanner room touched a subject’s foot for inducing arousal when a shift to NREM sleep stage 1 was observed. EEG data were scored according to the AASM criteria. Based on sleep stages defined by polysomnographic findings, we investigated alterations in functional connectivity of sleep- and wake- promoting regions within the hypothalamus and other areas including the thalamus. Results Posterior alpha power showed significant positive correlation with BOLD signals in the anterior and medial dorsal thalamus. Connectivity between the thalamus and cortical regions reduced sharply in the descent to sleep stage. Meanwhile, BOLD signals of the sleep- and wake- promoting regions within the hypothalamus fluctuated with certain temporal lags from fluctuations of alpha rhythm at sleep onset. Conclusion Present findings provide preliminary evidence of dynamics of wake- and sleep- promoting regions in the human brain in vivo. Our data also support the hypothesis that reduced thalamocortical connectivity which limits the capacity to integrate information is associated with the transition of consciousness at sleep onset. Support None

scholarly journals Corpora Amylacea in the Human Brain Exhibit Neoepitopes of a Carbohydrate Nature

2021 ◽  
Vol 12 ◽  
Author(s):  
Marta Riba ◽  
Elisabet Augé ◽  
Iraida Tena ◽  
Jaume del Valle ◽  
Laura Molina-Porcel ◽  
...  
Keyword(s):  
Human Brain ◽  
Natural Immunity ◽  
Corpora Amylacea ◽  
Inhibitory Effects ◽  
Cervical Lymph Nodes ◽  
Polyglucosan Bodies ◽  
The Brain ◽  
Standard Techniques

Corpora amylacea (CA) in the human brain are polyglucosan bodies that accumulate residual substances originated from aging and both neurodegenerative and infectious processes. These structures, which act as waste containers, are released from the brain to the cerebrospinal fluid, reach the cervical lymph nodes via the meningeal lymphatic system and may be phagocytosed by macrophages. Recent studies indicate that CA present certain neoepitopes (NEs) that can be recognized by natural antibodies of the IgM class, and although evidence of different kinds suggests that these NEs may be formed by carbohydrate structures, their precise nature is unknown. Here, we adapted standard techniques to examine this question. We observed that the preadsorption of IgMs with specific carbohydrates has inhibitory effects on the interaction between IgMs and CA, and found that the digestion of CA proteins had no effect on this interaction. These findings point to the carbohydrate nature of the NEs located in CA. Moreover, the present study indicates that, in vitro, the binding between certain natural IgMs and certain epitopes may be disrupted by certain monosaccharides. We wonder, therefore, whether these inhibitions may also occur in vivo. Further studies should now be carried out to assess the possible in vivo effect of glycemia on the reactivity of natural IgMs and, by extension, on natural immunity.

scholarly journals A High-Resolution In Vivo Atlas of the Human Brain’s Benzodiazepine Binding Site of GABAA Receptors

2020 ◽  
Author(s):  
Martin Nørgaard ◽  
Vincent Beliveau ◽  
Melanie Ganz ◽  
Claus Svarer ◽  
Lars H Pinborg ◽  
...  
Keyword(s):  
High Resolution ◽  
Human Brain ◽  
Mrna Expression ◽  
Brain Regions ◽  
Mrna Levels ◽  
Gamma Aminobutyric Acid ◽  
Healthy Human ◽  
Brain Functions ◽  
The Brain

ABSTRACTGamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the human brain and plays a key role in several brain functions and neuropsychiatric disorders such as anxiety, epilepsy, and depression. The binding of benzodiazepines to the benzodiazepine receptor sites (BZR) located on GABAA receptors (GABAARs) potentiates the inhibitory effect of GABA leading to the anxiolytic, anticonvulsant and sedative effects used for treatment of those disorders. However, the function of GABAARs and the expression of BZR protein is determined by the GABAAR subunit stoichiometry (19 genes coding for individual subunits), and it remains to be established how the pentamer composition varies between brain regions and individuals.Here, we present a quantitative high-resolution in vivo atlas of the human brain BZRs, generated on the basis of [11C]flumazenil Positron Emission Tomography (PET) data. Next, based on autoradiography data, we transform the PET-generated atlas from binding values into BZR protein density. Finally, we examine the brain regional association with mRNA expression for the 19 subunits in the GABAAR, including an estimation of the minimally required expression of mRNA levels for each subunit to translate into BZR protein.This represents the first publicly available quantitative high-resolution in vivo atlas of the spatial distribution of BZR densities in the healthy human brain. The atlas provides a unique neuroscientific tool as well as novel insights into the association between mRNA expression for individual subunits in the GABAAR and the BZR density at each location in the brain.

scholarly journals A taxonomy of the brain’s white matter: Twenty-one major tracts for the twenty-first century

2021 ◽  
Author(s):  
Daniel N. Bullock ◽  
Elena A. Hayday ◽  
Mark D. Grier ◽  
Wei Tang ◽  
Franco Pestilli ◽  
...  
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Brain Connectivity ◽  
First Century ◽  
Brain Areas ◽  
Behavior Development ◽  
The Brain ◽  
Brain Connections ◽  
Computational Properties

The functional and computational properties of brain areas are determined, in large part, by their connectivity profiles. Advances in neuroimaging and network neuroscience allow us to characterize the human brain noninvasively and in vivo, but a comprehensive understanding of the human brain demands an account of the anatomy of brain connections. Long-range anatomical connections are instantiated by white matter and organized into tracts. Here, we aim to characterize the connections, morphology, traversal, and functions of the major white matter tracts in the brain. It is clear that there are significant discrepancies across different accounts of white matter tract anatomy, hindering our attempts to accurately map the connectivity of the human brain. We thoroughly synthesize accounts from multiple methods, but especially nonhuman primate tract-tracing and human diffusion tractography. Ultimately, we suggest that our synthesis provides an essential reference for neuroscientists and clinicians interested in brain connectivity and anatomy, allowing for the study of the association of white matter’s macro and microstructural properties with behavior, development, and disordered processes.

scholarly journals The Prospects of Whole Brain Emulation within the next Half- Century

2013 ◽  
Vol 4 (3) ◽  
pp. 130-152 ◽  
Author(s):  
Daniel Eth ◽  
Juan-Carlos Foust ◽  
Brandon Whale
Keyword(s):  
Human Brain ◽  
Science Fiction ◽  
Social Effects ◽  
Whole Brain ◽  
Neural Data ◽  
Half Century ◽  
The Brain

Abstract Whole Brain Emulation (WBE), the theoretical technology of modeling a human brain in its entirety on a computer-thoughts, feelings, memories, and skills intact-is a staple of science fiction. Recently, proponents of WBE have suggested that it will be realized in the next few decades. In this paper, we investigate the plausibility of WBE being developed in the next 50 years (by 2063). We identify four essential requisite technologies: scanning the brain, translating the scan into a model, running the model on a computer, and simulating an environment and body. Additionally, we consider the cultural and social effects of WBE. We find the two most uncertain factors for WBE’s future to be the development of advanced miniscule probes that can amass neural data in vivo and the degree to which the culture surrounding WBE becomes cooperative or competitive. We identify four plausible scenarios from these uncertainties and suggest the most likely scenario to be one in which WBE is realized, and the technology is used for moderately cooperative ends

scholarly journals MAPSSIC, a communicating MAPS-based intracerebral positrons probe for deep brain imaging in awake and freely-moving rats

2020 ◽  
Vol 225 ◽  
pp. 09002
Author(s):  
F. Gensolen ◽  
L. Ammour ◽  
M. Bautista ◽  
J. Heymes ◽  
S. Fieux ◽  
...  
Keyword(s):  
Human Brain ◽  
Neural Mechanisms ◽  
Small Animals ◽  
Biological Mechanisms ◽  
Behavioral Experiments ◽  
Freely Moving ◽  
The Brain ◽  
Significant Model ◽  
Deep Brain

Radioisotope imaging is a powerful tool to understand the biological mechanisms in-vivo, especially in the brain of small animals, providing a significant model to study the human brain. In this context, we have developed and built a pixelated intracerebral positron probe to be embedded on awake and freely moving small animals, typically rats. This pixelated probe will represent a key instrument for neuroscientists to study neural mechanisms and correlate them to behavioral experiments. We describe in this paper the simulations carried out to design the intracerebral sensor, its architecture, and the detection of positrons in a volume with a couple of sensors assembled back-to-back. We also depict the architecture of the wireless acquisition system. Finally, we present the first measurements performed in real-time by this miniaturized probe with sealed radioactive sources and a 18F solution.

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