1
|
Cavaglià M, Deriu MA, Tuszynski JA. Toward a holographic brain paradigm: a lipid-centric model of brain functioning. Front Neurosci 2023; 17:1302519. [PMID: 38161798 PMCID: PMC10757614 DOI: 10.3389/fnins.2023.1302519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/04/2023] [Indexed: 01/03/2024] Open
Abstract
Due to the stimulation of neuronal membrane dipoles by action potentials, under suitable conditions coherent dipole oscillations can be formed. We argue that these dipole oscillations satisfy the weak Bose-Einstein condensate criteria of the Froehlich model of biological coherence. They can subsequently generate electromagnetic fields (EMFs) propagating in the inter-neuronal space. When neighboring neurons fire synchronously, EMFs can create interference patterns and hence form holographic images containing analog information about the sensory inputs that trigger neuronal activity. The mirror pattern projected by EMFs inside the neuron can encode information in the neuronal cytoskeleton. We outline an experimental verification of our hypothesis and its consequences for anesthesia, neurodegenerative diseases, and psychiatric states.
Collapse
Affiliation(s)
| | | | - Jack A. Tuszynski
- DIMEAS, Politecnico di Torino, Turin, Italy
- Department of Data Science and Engineering, The Silesian University of Technology, Gliwice, Poland
- Department of Physics, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
2
|
Maex R. Energy optimisation predicts the capacity of ion buffering in the brain. BIOLOGICAL CYBERNETICS 2023; 117:467-484. [PMID: 38103053 DOI: 10.1007/s00422-023-00980-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/23/2023] [Indexed: 12/17/2023]
Abstract
Neurons store energy in the ionic concentration gradients they build across their cell membrane. The amount of energy stored, and hence the work the ions can do by mixing, can be enhanced by the presence of ion buffers in extra- and intracellular space. Buffers act as sources and sinks of ions, however, and unless the buffering capacities for different ion species obey certain relationships, a complete mixing of the ions may be impeded by the physical conditions of charge neutrality and isotonicity. From these conditions, buffering capacities were calculated that enabled each ion species to mix completely. In all valid buffer distributions, the [Formula: see text] ions were buffered most, with a capacity exceeding that of [Formula: see text] and [Formula: see text] buffering by at least an order of magnitude. The similar magnitude of the (oppositely directed) [Formula: see text] and [Formula: see text] gradients made extracellular space behave as a [Formula: see text]-[Formula: see text] exchanger. Anions such as [Formula: see text] were buffered least. The great capacity of the extra- and intracellular [Formula: see text] buffers caused a large influx of [Formula: see text] ions as is typically observed during energy deprivation. These results explain many characteristics of the physiological buffer distributions but raise the question how the brain controls the capacity of its ion buffers. It is suggested that neurons and glial cells, by their great sensitivity to gradients of charge and osmolarity, respectively, sense deviations from electro-neutral and isotonic mixing, and use these signals to tune the chemical composition, and buffering capacity, of the extra- and intracellular matrices.
Collapse
Affiliation(s)
- Reinoud Maex
- School of Physics, Engineering and Computer Science, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK.
| |
Collapse
|
3
|
Zeng L, Chen M, Wang Z, Qiao R, Feng G. Structural Evolution Governs Reversible Heat Generation in Electrical Double Layers. PHYSICAL REVIEW LETTERS 2023; 131:096201. [PMID: 37721826 DOI: 10.1103/physrevlett.131.096201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/01/2023] [Accepted: 07/07/2023] [Indexed: 09/20/2023]
Abstract
Electrical double layer (EDL) formation determines the reversible heat generation of supercapacitors. While classical theories suggest an exothermic nature, experiments revealed that it can be endothermic, depending on the polarization and electrolyte. Here, we perform constant-potential molecular dynamics simulations and develop a lattice gas model to explore the reversible heat of EDL formation in aqueous and ionic liquid (IL) electrolytes. Our Letter reveals that EDL formation in aqueous electrolytes exhibits endothermicity under negative polarization; it shows new complexity of endothermicity followed by exothermicity in ILs, regardless of electrode polarity. These thermal behaviors are determined by the structural evolution during EDL formation, dominated by adsorbed solvent molecules rather than ions in aqueous electrolytes but governed by "demixing" and "vacancy occupation" phenomena in ILs. This Letter provides new insights into the reversible heat of supercapacitors and presents a theoretical approach to investigating thermal behaviors involving the dynamics of EDLs.
Collapse
Affiliation(s)
- Liang Zeng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ming Chen
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhenxiang Wang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rui Qiao
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Guang Feng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
4
|
Wazawa T, Nagai T. Joule heating involving ion currents through channel proteins. Biophys Physicobiol 2023; 20:e200030. [PMID: 38124793 PMCID: PMC10728626 DOI: 10.2142/biophysico.bppb-v20.0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/26/2023] [Indexed: 12/23/2023] Open
Abstract
Ion currents associated with channel proteins in the presence of membrane potential are ubiquitous in cellular and organelle membranes. When an ion current occurs through a channel protein, Joule heating should occur. However, this Joule heating seems to have been largely overlooked in biology. Here we show theoretical investigation of Joule heating involving channel proteins in biological processes. We used electrochemical potential to derive the Joule's law for an ion current through an ion transport protein in the presence of membrane potential, and we suggest that heat production and absorption can occur. Simulation of temperature distribution around a single channel protein with the Joule heating revealed that the temperature increase was as small as <10-3 K, although an ensemble of channel proteins was suggested to exhibit a noticeable temperature increase. Thereby, we theoretically investigated the Joule heating of systems containing ensembles of channel proteins. Nerve is known to undergo rapid heat production followed by heat absorption during the action potential, and our simulation of Joule heating for a squid giant axon combined with the Hodgkin-Huxley model successfully reproduced the feature of the heat. Furthermore, we extended the theory of Joule heating to uncoupling protein 1 (UCP1), a solute carrier family transporter, which is important to the non-shivering thermogenesis in brown adipose tissue mitochondria (BATM). Our calculations showed that the Joule heat involving UCP1 was comparable to the literature calorimetry data of BATM. Joule heating of ion transport proteins is likely to be one of important mechanisms of cellular thermogenesis.
Collapse
Affiliation(s)
| | - Takeharu Nagai
- SANKEN, Osaka University, Ibaraki, Osaka 567-0047, Japan
| |
Collapse
|
5
|
Härtel A, Bültmann M, Coupette F. Anomalous Underscreening in the Restricted Primitive Model. PHYSICAL REVIEW LETTERS 2023; 130:108202. [PMID: 36962045 DOI: 10.1103/physrevlett.130.108202] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/19/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Underscreening is a collective term for charge correlations in electrolytes decaying slower than the Debye length. Anomalous underscreening refers to phenomenology that cannot be attributed alone to steric interactions. Experiments with concentrated electrolytes and ionic fluids report anomalous underscreening, which so far has not been observed in simulation. We present Molecular Dynamics simulation results exhibiting anomalous underscreening that can be connected to cluster formation. A theory that accounts for ion pairing confirms the trend. Our results challenge the classic understanding of dense electrolytes impacting the design of technologies for energy storage and conversion.
Collapse
Affiliation(s)
- Andreas Härtel
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Moritz Bültmann
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Fabian Coupette
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| |
Collapse
|
6
|
Petrini G, Tomagra G, Bernardi E, Moreva E, Traina P, Marcantoni A, Picollo F, Kvaková K, Cígler P, Degiovanni IP, Carabelli V, Genovese M. Nanodiamond-Quantum Sensors Reveal Temperature Variation Associated to Hippocampal Neurons Firing. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202014. [PMID: 35876403 PMCID: PMC9534962 DOI: 10.1002/advs.202202014] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Indexed: 05/17/2023]
Abstract
Temperature is one of the most relevant parameters for the regulation of intracellular processes. Measuring localized subcellular temperature gradients is fundamental for a deeper understanding of cell function, such as the genesis of action potentials, and cell metabolism. Notwithstanding several proposed techniques, at the moment detection of temperature fluctuations at the subcellular level still represents an ongoing challenge. Here, for the first time, temperature variations (1 °C) associated with potentiation and inhibition of neuronal firing is detected, by exploiting a nanoscale thermometer based on optically detected magnetic resonance in nanodiamonds. The results demonstrate that nitrogen-vacancy centers in nanodiamonds provide a tool for assessing various levels of neuronal spiking activity, since they are suitable for monitoring different temperature variations, respectively, associated with the spontaneous firing of hippocampal neurons, the disinhibition of GABAergic transmission and the silencing of the network. Conjugated with the high sensitivity of this technique (in perspective sensitive to < 0.1 °C variations), nanodiamonds pave the way to a systematic study of the generation of localized temperature gradients under physiological and pathological conditions. Furthermore, they prompt further studies explaining in detail the physiological mechanism originating this effect.
Collapse
Affiliation(s)
- Giulia Petrini
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
- Physics Department, University of Torinovia P. Giuria 1Torino10125Italy
- Department of Drug and Science Technology, University of TorinoCorso Raffaello 30Torino10125Italy
| | - Giulia Tomagra
- Department of Drug and Science Technology, University of TorinoCorso Raffaello 30Torino10125Italy
- NIS Inter‐departmental Centrevia G. Quarello 15Torino10135Italy
| | - Ettore Bernardi
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
| | - Ekaterina Moreva
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
| | - Paolo Traina
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
| | - Andrea Marcantoni
- Department of Drug and Science Technology, University of TorinoCorso Raffaello 30Torino10125Italy
- NIS Inter‐departmental Centrevia G. Quarello 15Torino10135Italy
| | - Federico Picollo
- Physics Department, University of Torinovia P. Giuria 1Torino10125Italy
- Istituto Nazionale di Fisica Nucleare (INFN) Sez. Torinovia P. Giuria 1Torino10125Italy
| | - Klaudia Kvaková
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of SciencesFlemingovo nam. 2Prague 6166 10Czechia
- Institute of Medical Biochemistry and Laboratory DiagnosticsFirst Faculty of MedicineCharles University
Katerinska 1660/32Prague 2121 08Czechia
| | - Petr Cígler
- Institute of Medical Biochemistry and Laboratory DiagnosticsFirst Faculty of MedicineCharles University
Katerinska 1660/32Prague 2121 08Czechia
| | - Ivo Pietro Degiovanni
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
- Istituto Nazionale di Fisica Nucleare (INFN) Sez. Torinovia P. Giuria 1Torino10125Italy
| | - Valentina Carabelli
- Department of Drug and Science Technology, University of TorinoCorso Raffaello 30Torino10125Italy
- NIS Inter‐departmental Centrevia G. Quarello 15Torino10135Italy
| | - Marco Genovese
- Istituto Nazionale di Ricerca MetrologicaStrada delle cacce 91Torino10135Italy
- Istituto Nazionale di Fisica Nucleare (INFN) Sez. Torinovia P. Giuria 1Torino10125Italy
| |
Collapse
|
7
|
Pelagejcev P, Glatzel F, Härtel A. Extension of the primitive model by hydration shells and its impact on the reversible heat production during the buildup of the electric double layer. J Chem Phys 2022; 156:034901. [DOI: 10.1063/5.0077526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Philipp Pelagejcev
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Fabian Glatzel
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Andreas Härtel
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| |
Collapse
|
8
|
Glatzel F, Janssen M, Härtel A. Reversible heat production during electric double layer buildup depends sensitively on the electrolyte and its reservoir. J Chem Phys 2021; 154:064901. [PMID: 33588538 DOI: 10.1063/5.0037218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several modern technologies for energy storage and conversion are based on the screening of electric charge on the surface of porous electrodes by ions in an adjacent electrolyte. This so-called electric double layer (EDL) exhibits an intricate interplay with the electrolyte's temperature that was the focus of several recent studies. In one of them, Janssen et al. [Phys. Rev. Lett. 119, 166002 (2017)] experimentally determined the ratio Qrev/Wel of reversible heat flowing into a supercapacitor during an isothermal charging process and the electric work applied therein. To rationalize that data, here, we determine Qrev/Wel within different models of the EDL using theoretical approaches such as density functional theory (DFT) as well as molecular dynamics simulations. Applying mainly the restricted primitive model, we find quantitative support for a speculation of Janssen et al. that steric ion interactions are key to the ratio Qrev/Wel. Here, we identified the entropic contribution of certain DFT functionals, which grants direct access to the reversible heat. We further demonstrate how Qrev/Wel changes when calculated in different thermodynamic ensembles and processes. We show that the experiments of Janssen et al. are explained best by a charging process at fixed bulk density or in a "semi-canonical" system. Finally, we find that Qrev/Wel significantly depends on parameters such as pore and ion size, salt concentration, and valencies of the cations and anions of the electrolyte. Our findings can guide further heat production measurements and can be applied in studies on, for instance, nervous conduction, where reversible heat is a key element.
Collapse
Affiliation(s)
- Fabian Glatzel
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Mathijs Janssen
- Mechanics Division, Department of Mathematics, University of Oslo, 0316 Oslo, Norway
| | - Andreas Härtel
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| |
Collapse
|
9
|
Peyrard M. How is information transmitted in a nerve? J Biol Phys 2020; 46:327-341. [PMID: 33037976 DOI: 10.1007/s10867-020-09557-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/10/2020] [Indexed: 11/25/2022] Open
Abstract
In the last 15 years, a debate has emerged about the validity of the famous Hodgkin-Huxley model for nerve impulse. Mechanical models have been proposed. This note reviews the experimental properties of the nerve impulse and discusses the proposed alternatives. The experimental data, which rule out some of the alternative suggestions, show that while the Hodgkin-Huxley model may not be complete, it nevertheless includes essential features that should not be overlooked in the attempts made to improve, or supersede, it.
Collapse
Affiliation(s)
- Michel Peyrard
- Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Cédex 07, Lyon, France.
| |
Collapse
|
10
|
Heimburg T. The important consequences of the reversible heat production in nerves and the adiabaticity of the action potential. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:26-40. [PMID: 32805276 DOI: 10.1016/j.pbiomolbio.2020.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/30/2020] [Accepted: 07/23/2020] [Indexed: 02/05/2023]
Abstract
It has long been known that there is no measurable heat production associated with the nerve pulse. Rather, one finds that heat production is biphasic, and a heat release during the first phase of the action potential is followed by the reabsorption of a similar amount of heat during the second phase. We review the long history the measurement of heat production in nerves and provide a new analysis of these findings focusing on the thermodynamics of adiabatic and isentropic processes. We begin by considering adiabatic oscillations in gases, waves in layers, oscillations of springs and the reversible (or irreversible) charging and discharging of capacitors. We then apply these ideas to the heat signature of nerve pulses. Finally, we compare the temperature changes expected from the Hodgkin-Huxley model and the soliton theory for nerves. We demonstrate that heat production in nerves cannot be explained as an irreversible charging and discharging of a membrane capacitor as it is proposed in the Hodgkin-Huxley model. Instead, we conclude that it is consistent with an adiabatic pulse. However, if the nerve pulse is adiabatic, completely different physics is required to explain its features. Membrane processes must then be reversible and resemble the oscillation of springs more than resembling "a burning fuse of gunpowder" (quote A. L. Hodgkin). Theories acknowledging the adiabatic nature of the nerve pulse have recently been discussed by various authors. It forms the central core of the soliton model, which considers the nerve pulse as a localized sound pulse.
Collapse
Affiliation(s)
- Thomas Heimburg
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen Ø, Denmark.
| |
Collapse
|