most of these effects is because anesthetics reduce gap junctional and ATP,purinergic, signaling both requires for calcium waves

Dear Eliseo, this is the physiological mechanism of action of the anesthetics and it is true that these effects impair calcium waves, but the problem is how do these effects mediate the loss of consciousness? Is it because they block calcium waves of for another reason?

Terrence Sejnowski and colleagues are advancing our knowledge of the role of astrocytes in brain computational processes:

Proc Natl Acad Sci U S A. 2014 Jul 28. pii: 201410893. [Epub ahead of print]

Astrocytes contribute to gamma oscillations and recognition memory.

Lee HS, Ghetti A, Pinto-Duarte A, Wang X, Dziewczapolski G, Galimi F, Huitron-Resendiz S, Piña-Crespo JC, Roberts AJ, Verma IM, Sejnowski TJ, Heinemann SF.

Abstract

Glial cells are an integral part of functional communication in the brain. Here we show that astrocytes contribute to the fast dynamics of neural circuits that underlie normal cognitive behaviors. In particular, we found that the selective expression of tetanus neurotoxin (TeNT) in astrocytes significantly reduced the duration of carbachol-induced gamma oscillations in hippocampal slices. These data prompted us to develop a novel transgenic mouse model, specifically with inducible tetanus toxin expression in astrocytes. In this in vivo model, we found evidence of a marked decrease in electroencephalographic (EEG) power in the gamma frequency range in awake-behaving mice, whereas neuronal synaptic activity remained intact. The reduction in cortical gamma oscillations was accompanied by impaired behavioral performance in the novel object recognition test, whereas other forms of memory, including working memory and fear conditioning, remained unchanged. These results support a key role for gamma oscillations in recognition memory. Both EEG alterations and behavioral deficits in novel object recognition were reversed by suppression of tetanus toxin expression. These data reveal an unexpected role for astrocytes as essential contributors to information processing and cognitive behavior.

PMID: 25071179 [PubMed - as supplied by publisher]

New results on calcium waves:

1) Extracellular Electrophysiological Measurements of Cooperative Signals in Astrocytes Populations

Front Neural Circuits. 2017 Oct 23;11:80. doi: 10.3389/fncir.2017.00080.

eCollection 2017.

Mestre ALG(1)(2), Inácio PMC(1)(2), Elamine Y(1)(2), Asgarifar S(1)(2), Lourenço

AS(3)(4), Cristiano MLS(1)(5), Aguiar P(6)(7), Medeiros MCR(8), Araújo IM(3)(4),

Ventura J(9), Gomes HL(1)(2).

Author information:

(1)Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.

(2)Instituto de Telecomunicações, Lisboa, Portugal.

(3)Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro,

Portugal.

(4)Centro de Investigação em Biomedicina, Universidade do Algarve, Faro,

Portugal.

(5)Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal.

(6)Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.

(7)Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto,

Portugal.

(8)Departamento de Engenharia Electrotécnica e de Computadores, Instituto de

Telecomunicações, Universidade de Coimbra, Coimbra, Portugal.

(9)Departamento de Física e Astronomia, Instituto de Física dos Materiais da

Universidade do Porto, Instituto de Nanociências e Nanotecnologia, Universidade

do Porto, Porto, Portugal.

Astrocytes are neuroglial cells that exhibit functional electrical properties

sensitive to neuronal activity and capable of modulating neurotransmission. Thus,

electrophysiological recordings of astroglial activity are very attractive to

study the dynamics of glial signaling. This contribution reports on the use of

ultra-sensitive planar electrodes combined with low noise and low frequency

amplifiers that enable the detection of extracellular signals produced by primary

cultures of astrocytes isolated from mouse cerebral cortex. Recorded activity is

characterized by spontaneous bursts comprised of discrete signals with pronounced

changes on the signal rate and amplitude. Weak and sporadic signals become

synchronized and evolve with time to higher amplitude signals with a

quasi-periodic behavior, revealing a cooperative signaling process. The

methodology presented herewith enables the study of ionic fluctuations of

population of cells, complementing the single cells observation by calcium

imaging as well as by patch-clamp techniques.

DOI: 10.3389/fncir.2017.00080

PMCID: PMC5660104

PMID: 29109679

New results on calcium waves:

2) Three-dimensional Ca2+ imaging advances understanding of astrocyte biology.

Science. 2017 May 19;356(6339). pii: eaai8185. doi: 10.1126/science.aai8185.

Bindocci E(1), Savtchouk I(1), Liaudet N(1), Becker D(1), Carriero G(1), Volterra

A(2).

Author information:

(1)Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne,

Switzerland.

(2)Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne,

Switzerland. [email protected].

Astrocyte communication is typically studied by two-dimensional calcium ion

(Ca2+) imaging, but this method has not yielded conclusive data on the role of

astrocytes in synaptic and vascular function. We developed a three-dimensional

two-photon imaging approach and studied Ca2+ dynamics in entire astrocyte

volumes, including during axon-astrocyte interactions. In both awake mice and

brain slices, we found that Ca2+ activity in an individual astrocyte is scattered

throughout the cell, largely compartmented between regions, preponderantly local

within regions, and heterogeneously distributed regionally and locally. Processes

and endfeet displayed frequent fast activity, whereas the soma was infrequently

active. In awake mice, activity was higher than in brain slices, particularly in

endfeet and processes, and displayed occasional multifocal cellwide events.

Astrocytes responded locally to minimal axonal firing with time-correlated Ca2+

spots.

Copyright © 2017, American Association for the Advancement of Science.

DOI: 10.1126/science.aai8185

PMID: 28522470

The main target of brain electric stimulation for treating depression:

Astrocytes as a target of transcranial direct current stimulation (tDCS) to treat depression

Hiromu Monai and Hajime Hirase

https://doi.org/10.1016/j.neures.2017.08.012

Highlights

•

tDCS has been shown effective in treating depression, though its mechanisms remain elusive.

•

Astrocytic Ca2+ elevation plays an essential role in tDCS-induced synaptic plasticity in mice.

•

Astrocytic Ca2+ signaling mediates long-term mitigation of depression-like behavior in mice.

•

The literature suggests that astrocytes are a potential therapeutic target for depression.

Abstract

Transcranial direct current stimulation (tDCS) has been reported to be effective in treating mood disorders such as major depressive disorder, however, its detailed mechanism of action is not fully understood. Human and animal experiments have demonstrated that tDCS promotes brain plasticity and have suggested that this consequence may underlie its therapeutic benefits. Nonetheless, the specific neurobiological underpinnings of tDCS-induced brain plasticity have only recently begun to be investigated. While brain plasticity occurs in synapses formed by neurons, astrocytes, a major glial cell type, have recently been shown to support synaptic plasticity via intracellular Ca2+ signaling. In this perspective article, we discuss our recent results demonstrating that tDCS induces the activation of astrocytic calcium signaling that constitutes a required component for treating chronic restraint stress-induced depressive mice. We put forward the notion that activation of astrocytic Ca2+ signaling could be used clinically as a potent remedy for depression.

fMRI of nanoparticles bound by the action of calcium ions - this method measures calcium concentrations in the extracellular space, but may also measure astroglial activity:

Calcium-based MRI sensor enables more sensitive brain imaging

System detects direct signals of neural activity; could reveal patterns underlying behavior

Date: April 30, 2018 Source: Massachusetts Institute of Technology

Summary: Neuroscientists have developed an MRI sensor that lets them monitor neuron activity deep within the brain by tracking calcium ions. This type of sensing could allow researchers to link specific brain functions to their pattern of neuron activity, and to determine how distant brain regions communicate with each other during particular tasks.

https://www.sciencedaily.com/releases/2018/04/180430131920.htm

Probably calcium waves are the main target of ultrasound stimulation too.

https://gizmodo.com/researchers-control-monkeys-decisions-with-bursts-of-ul-1843563970

Alfredo Pereira Junior

Astrocytes support brain dysfunctions not brain functions. Anything otherwise is a fairy tale as much as triple aspect monism is a ghost in the machine and 'pure consciousness' which Frank van den Bovenkamp has been working with his quantum field version of TAM.

R. Poznanski

You are also working with "pure consciousness" only you don't realize. You seem to forget again and again that the way I use "pure consciousness" is purely conceptual, it does not exist objectively, it is not "conscious" and it has nothing to do with (Hindu) cultural ideas. It's just considering the concept of "consciousness" without a physical channel. Besides, my model is QFT-related not QFT-based, and just for the record, DEFINITELY NOT RELATED to Alfredo's TAM (good Lord...). Moreover, as in your view "phenomenal consciousness" does not exist, and also "pure consciousness" does not exist, then what consciousness does exist in your view? Maybe you mean to say that consciousness does not exist?

Frank van den Bovenkamp

"You are also working with "pure consciousness" only you don't realize."

No, I knew of the trap of "pure consciousness" so you will see when you read a copy of Panexperiential materialism we avoided this trap.

R. Poznanski

"I knew of the trap of "pure consciousness""

Ok I see, yes I agree it could be a trap when not properly explained. The best of course is to have a theory or model which naturally avoids such a trap. To resort to "materialism" instead also gives off a dubious signal as it plays right into the hands of, well, materialism. That is problematic, because materialism does not help the mind to evolve (i.e. become more subtle, or "ennoble the mind" - Lee Smolin), and thus become conscious in the first place. Instead it crudifies the mind (just watch Donald Trump for 10 seconds). So, "materialism" is also a trap, even as consciousness comes from matter, matter comes from consciousness and it is the latter as an attractor that provides the evolutionary drive. I.e. trap or not, it is the premisse of "pure consciousness" that would make panexperiential materialism a plausible theory. In other words, the submolecular basis of consciousness is consciousness. It's not a panpsychist concept.

Frank van den Bovenkamp

1. "even as consciousness comes from matter, matter comes from consciousness...."

2. . "pure consciousness" that would make panexperiential materialism a plausible theory."

Steps 1 and 2 would make the framework fall into nondualism and idealism, respectively. We avoided this trap.

"In other words, the submolecular basis of consciousness is consciousness. It's not a panpsychist concept."

Better if we read as

In other words, the submolecular basis of consciousness is not a panpsychist concept."

Frank van den Bovenkamp

"my model is QFT-related not QFT-based, and just for the record, DEFINITELY NOT RELATED to Alfredo's TAM (good Lord...). "

So are you saying Alfredo Pereira Junior TAM is chicken fat?

Moreover, as in your view "phenomenal consciousness" does not exist, and also "pure consciousness" does not exist, then what consciousness does exist in your view? Maybe you mean to say that consciousness does not exist?

Good point! You will see when you read panexperiential materialism soon.

R. Poznanski wrote:

"Astrocytes support brain dysfunctions not brain functions"

Alfredo: The dysfunction is a change in function, therefore they support functions.

For instance, they support sleep and wakefulness cycles. Do you think that sleep is a dysfunction?

Alfredo Pereira Junior

You have been reading the wrong papers. Computational neuroscience is an appendix to biological cybernetics not medical research.

Astrocytes are the principal glial cells in the brain, which play critical roles in neural support and neural regulation. They can coordinate changes of vascular tone, prevent spillover of the transmitter, modulate excitotoxicity, help blood-brain barrier (BBB) formation and integrity maintenance, release pro- and anti-inflammatory molecules etc They are mere helpers!

R. Poznanski

"So are you saying Alfredo Pereira Junior TAM is chicken fat? "

No. Chicken fat still has some use.

"Good point! "

It may sound strange, but the idea that consciousness (quote on quote) does not exist rings better with me than that "pure consciousness" does not exist. I've been thinking about it lately.

"Steps 1 and 2 would make the framework fall into idealism. We avoided this trap. "

The term "idealism" has too many associations. "Pure consciousness" the way I prefer to use it is not a philosophical approach. It only claims that there is an unchanging factor which is superior to and inferred by its effects, similar to energy in physics.

" In other words, the submolecular basis of consciousness is not a panpsychist concept."

That's always good. But then what is the overall characteristic of the submolecular basis of consciousness?

R. Poznanski Which papers about astrocytes do you recommend? Please do not suggest old textbooks.

Frank van den Bovenkamp

"idea that consciousness..."

You don't need to think too much we have done it for you in panexperiential materialism. Consciousness does exist and it constitutes many processes.

Indeed we have filled the gap in Karl Pribram's holonomic brain theory.

That's always good. But then what is the overall characteristic of the submolecular basis of consciousness?

The density matrix

Holonomic brain theory is a branch of neuroscience investigating the idea that human consciousness is formed by quantum effects in or between brain cells. ... This specific theory of quantum consciousness was developed by neuroscientist Karl Pribram initially in collaboration with physicist David Bohm.

--From wikipedia

R. Poznanski

" The density matrix "

It seems like the density matrix might be a useful framework or placeholder for what is contemplated with panexperiential materialism, if the latter provides at least a non-probabilistic interpretation. Without non-linearity I don't see how that could happen. If you indeed propose non-linear density matrices, this seems technically not wildly disparate from 4C/TAM/QFT, which basically says that the TAM (~consciousness) lives inside the self-interacting quantum field (as e.g. in my 2016 video). I'm curious if and how you realize self-reference.

In this paper there is no direct reference to the role of astrocytes, but the infra-slow waves of calcium ions are surely mediated by them. Are mitral cells similar to astrocytes? If a morphologist or physiologist can explain this similarity of structure and function, I will be grateful!

Article Synchronous Infra-Slow Oscillations Organize Ensembles of Ac...

Frank van den Bovenkamp

"I'm curious if and how you realize self-reference."

Holism is a property of self-reference

In the antidepressant action of ketamine, calcium waves mediate the action of potassium ions on neurons

Article Astrocytes in rapid ketamine antidepressant action

A new tool for the analysis of calcium waves reaching neurons:

Article An open source tool for automatic spatiotemporal assessment ...

"" Beneficial and detrimental roles of IP3R-dependent Ca²⁺ release in astrocytes have been revealed in wide variety of disorders in the brain, strongly suggesting astrocytic IP3-Ca²⁺ signaling as a novel and promising therapeutic target."

Article Astrocytic Ca2+ signaling mediated by the endoplasmic reticu...

The below result with the use of ultrasound can be interpreted as inducing a rise in astroglial calcium waves, leading to awakening of the person.

Ultrasound brain zap wakes man from minimally conscious stateHealth 25 August 2016 By Helen Thomson Hope for people in a minimally conscious state What an awakening. A man has been roused from a minimally conscious state by stimulating his brain with ultrasound.

The 25-year-old man, who had suffered a severe brain injury after a road traffic accident, progressed from having only a fleeting awareness of the outside world to being able to answer questions and attempt to walk.

He was the first person in the world to undergo an experimental procedure that stimulates the thalamus deep inside the brain, using pulses of ultrasound. “It’s only in one person but it’s extremely exciting,” says Martin Monti at the University of California, Los Angeles.

Monti and his team have been searching for a way to help people with brain injuries that result in disorders of consciousness, for whom there are few treatments. One kind of disorder is a minimally conscious state, in which a person shows fluctuating signs of awareness, but cannot communicate.

Animal experiments suggested that stimulating the thalamus might help promote arousal. Rats under anaesthesia can be woken faster after thalamic stimulation, for example. But the thalamus is deep inside the brain, making it difficult to try on people.

It is possible to use deep brain stimulation. In 2007, a 38-year-old man who had been in a minimally conscious state for six years showed some signs of recovery after receiving deep brain stimulation to his thalamus, but this involved implanting electrodes into his brain, a procedure that risks damaging other areas.

Monti’s team decided to try using low intensity ultrasound instead, which can safely modulate deep brain tissues without harming the surrounding areas.

Trying to communicate

They tried this technique on a patient who had been in a minimally conscious state for almost three weeks. Monti placed an ultrasound transducer on the patient’s temple, and used brain scans to check he had positioned it correctly. “[the temple] is the perfect window to the thalamus, which lies seven centimetres below,” says Monti.

They then stimulated the man’s thalamus for 10 minutes, alternating between 30 seconds of ultrasound and 30 seconds rest.

Immediately afterwards, the man scored worse on tests of consciousness. “This wasn’t surprising,” says Monti. “Taking part in procedures like this fatigues the injured brain very quickly.”

But the following morning was a different story. The patient was starting to vocalise and gesture in response to questions, behaviours he had not shown before treatment. “He seemed to clearly understand language and was trying to communicate,” says Monti.

Fist-bumping

Over the next three days the man started answering questions by nodding or shaking his head. “I made a fist with my hand and said ‘can you fist bump me?'” says Monti. “He was young, I thought he’d like that – and he immediately put out his fist out and bumped me, no pause or anything.” A week later, the patient tried to walk.

But we can’t know yet whether his recovery might have been a coincidence. “I’d love to start yelling success, this is exactly what we hoped we would see,” says Monti. “But we can’t get too excited before testing it on others. The patient could have spontaneously recovered in that period of time. It would have been serendipitous, but possible. But it’s extremely exciting and encouraging.”

Mohamad Koubeissi, associate professor of neurology at George Washington University, Washington DC, agrees that Monti’s report of the procedure is both interesting and promising. However, he also says that young individuals can recover spontaneously. “A controlled trial in patients with various [disorders of consciousness] is warranted before making any definitive conclusions,” he says.

Thalamic intervention

The thalamus is a kind of hub situated in the centre of the brain, which acts as a relay between many other regions. It is thought to be vital to sleep and wakefulness.

Monti says it’s not yet clear whether the thalamus underlies the fundamental aspects of conscious awareness, or if it is instead involved in helping patients produce behaviours that give a sign that they are aware of the world around them.

“It’s difficult to tease these two things apart,’ he says.

“By stimulating the thalamus, did we allow him to start integrating different areas of the brain and buzz him back into consciousness, or was he conscious before and we just gave him the ability to plan movements that showed us he was aware?”

Monti asked the patient whether he was aware of having the procedure and he said no. “This doesn’t tell us much though, because he could have been aware of the procedure and then experienced memory loss,” says Monti.

His team is now hoping to test the procedure on 10 to 15 more people with disorders of consciousness. They also want to trial it on healthy people, to help understand the effects of stimulating the thalamus. “I’d love to know what happens if we inhibit the healthy person’s thalamus – would it prevent them from moving and answering questions or would it make them unconscious?”

Journal reference: Brain Stimulation, doi.org/bpkb

Source: https://www.newscientist.com/article/2102487-ultrasound-brain-zap-wakes-man-from-minimally-conscious-state/#ixzz6ZUMk8mka

--

A great methodological advancement!

Article Accurate quantification of astrocyte and neurotransmitter fl...

Connexins are involved in both calcium waves and distribution of metabolitesArticle Redistribution of metabolic resources through astrocyte netw...

Frank van den Bovenkamp

According to Pan Mat the answer to this thread is no because of the abundance of gap-junctions found within the glial cell membranes.

R. Poznanski Gap junctions are operative for the propagation of the waves and promotion of inter-cellular information integration in neural (neuronal + glial) tissue. Experimental deletion of connexin genes cause severe cognitive and behavioral impairment in mice.

Alfredo Pereira Junior Frank van den Bovenkamp

"Experimental deletion of connexin genes cause severe cognitive and behavioral impairment in mice."

True but what has this got to do with consciousness unless for you consciousness is objective cognition.

Quantum effects are impossible in cases where there are gap junction present. Therefore it is not possible for subjective consciousness to exist.

R. Poznanski Conscious experience includes the integration of feeling, knowing (cognition) and action control neural functions.

Please explain what is the relation you imagine to exist between gap junctions and quantum effects. Also neurons have this type of structure when they display electrical synapses, and Hameroff has a paper arguing that electrical synapses propagate quantum effects generated within microtubules!

Article The “conscious pilot”—dendritic synchrony moves through the ...

The "conscious pilot"-dendritic synchrony moves through the brain to mediate consciousness

Stuart Hameroff

Abstract

Cognitive brain functions including sensory processing and control of behavior are understood as "neurocomputation" in axonal-dendritic synaptic networks of "integrate-and-fire" neurons. Cognitive neurocomputation with consciousness is accompanied by 30- to 90-Hz gamma synchrony electroencephalography (EEG), and non-conscious neurocomputation is not. Gamma synchrony EEG derives largely from neuronal groups linked by dendritic-dendritic gap junctions, forming transient syncytia ("dendritic webs") in input/integration layers oriented sideways to axonal-dendritic neurocomputational flow. As gap junctions open and close, a gamma-synchronized dendritic web can rapidly change topology and move through the brain as a spatiotemporal envelope performing collective integration and volitional choices correlating with consciousness. The "conscious pilot" is a metaphorical description for a mobile gamma-synchronized dendritic web as vehicle for a conscious agent/pilot which experiences and assumes control of otherwise non-conscious auto-pilot neurocomputation.

Alfredo Pereira Junior Frank van den Bovenkamp

The main weakness of the ORCH OR model is the combination problem through gap junctions.

See Pan Mat for further information.

Investigation of taste with calcium imaging and implanted microprisms (!!). The physiological process cannot be restricted to neurons, because calcium waves are generated and propagated in astrocytes

https://www.cell.com/current-biology/pdfExtended/S0960-9822(20)31518-9

This review reiterates what I wrote with Furlan ten years ago:

Article Astrocytes—The Ultimate Effectors of Long-Range Neuromodulat...

Chinese advances - calcium imaging in freely moving animals

Article Monitoring Astrocytic Ca 2+ Activity in Freely Behaving Mice