Astrocytes and human cognition: Modeling information integration and modulation of neuronal activity

Pereira, Alfredo; Furlan, Fábio Augusto

doi:10.1016/j.pneurobio.2010.07.001

Cited by 156 publications

(118 citation statements)

References 123 publications

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“…It is also possible that dynamical coupling in the morphology of microstructures allows the formation of networks to represent the plasticity-related morphological changes following brain stimulation protocols. The morphology of dendritic spines can modulate synaptic efficacy and plasticity (3,4,38); therefore, it is possible that the nodes in the identified networks can indirectly achieve long-distance coupling with each other by modulating synaptic plasticity or efficacy of the transsynaptic signaling (39).…”

Section: Discussionmentioning

confidence: 99%

Water diffusion reveals networks that modulate multiregional morphological plasticity after repetitive brain stimulation

Abe

Fukuyama

Mima

2014

Proc. Natl. Acad. Sci. U.S.A.

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Repetitive brain stimulation protocols induce plasticity in the stimulated site in brain slice models. Recent evidence from network models has indicated that additional plasticity-related changes occur in nonstimulated remote regions. Despite increasing use of brain stimulation protocols in experimental and clinical settings, the neural substrates underlying the additional effects in remote regions are unknown. Diffusion-weighted MRI (DWI) probes water diffusion and can be used to estimate morphological changes in cortical tissue that occur with the induction of plasticity. Using DWI techniques, we estimated morphological changes induced by application of repetitive transcranial magnetic stimulation (rTMS) over the left primary motor cortex (M1). We found that rTMS altered water diffusion in multiple regions including the left M1. Notably, the change in water diffusion was retained longest in the left M1 and remote regions that had a correlation of baseline fluctuations in water diffusion before rTMS. We conclude that synchronization of water diffusion at rest between stimulated and remote regions ensures retention of rTMS-induced changes in water diffusion in remote regions. Synchronized fluctuations in the morphology of cortical microstructures between stimulated and remote regions might identify networks that allow retention of plasticityrelated morphological changes in multiple regions after brain stimulation protocols. These results increase our understanding of the effects of brain stimulation-induced plasticity on multiregional brain networks. DWI techniques could provide a tool to evaluate treatment effects of brain stimulation protocols in patients with brain disorders.R epetitive electrical brain stimulation induces long-term potentiation (LTP) or depression (LTD) at the stimulated neurons (1-4). In humans, repetitive transcranial magnetic stimulation (rTMS) alters cortical excitability at the stimulated site that outlasts the end of the stimulation, analogous to LTP or LTD in animal models (5, 6), but also affects remote regions, possibly through transsynaptic pathways (7,8). Although rTMS has been proposed as a potential treatment for neurological and psychiatric disorders (9, 10) and as a method to facilitate learning (11), the neural substrates underlying the effects of rTMS on remote regions of the brain remain poorly understood.Diffusion-weighted MRI (DWI) probes water diffusion, a thermal physical phenomena that is characterized by random motion of water molecules (12). Water diffusion is altered by the structures of gray matter (12). DWI can be used to evaluate morphological changes in cortical microstructures (13)(14)(15)(16)(17)(18)(19) and can function as a probe to estimate immediate and transient changes in water diffusion that are associated with ischemia (17) or neuronal firing (13,16,19) and delayed and persistent changes that are associated with long-term plasticity in experimental settings (20) or pathological conditions (15,18,21). Here, using DWI techniques, we examined whether subt...

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Section: Discussionmentioning

confidence: 99%

Water diffusion reveals networks that modulate multiregional morphological plasticity after repetitive brain stimulation

Abe

Fukuyama

Mima

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The strengths of magnetic fields in neocortex may be at a threshold to directly influence synaptic interactions with astrocytes, as proposed for long-term memory (LTM) [8] and short-term memory (STM) [9], [10] rise to even stronger magnetic fields. Columnar excitatory and inhibitory processes largely take place in different neocortical laminae, providing possibilities for more specific mechanisms.…”

Section: A Magnetism Influences In Living Systemsmentioning

confidence: 99%

Influence of Macrocolumnar EEG on Ca Waves

Ingber¹

2012

SSRN Journal

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Abstract-A "smoking gun" for explicit top-down neocortical mechanisms that directly drive bottom-up processes that describe memory, attention, etc. The top-down mechanism considered are macrocolumnar EEG firings in neocortex, as described by a statistical mechanics of neocortical interactions (SMNI), developed as a magnetic vector potential A. The bottom-up process considered are Ca 2+ waves prominent in synaptic and extracellar processes that are considered to greatly influence neuronal firings. Here, the complimentary effects are considered, i.e., the influence of A on Ca 2+ momentum, p. The canonical momentum of a charged particle in an electromagnetic field, Π = p + qA (SI units), is calculated, where the charge of Ca 2+ is q = 2e, e is the magnitude of the charge of an electron, valid in both classical and quantum mechanics. It is shown that A is large enough to influence p. This suggests that, instead of the common assumption that Ca 2+ waves contribute to neuronal activity, they may in fact at times be caused by the influence of A of larger-scale EEG.Index Terms-short-term memory, astrocytes, neocortical dynamics, vector potential I. SMOKING GUN FOR TOP-DOWN PROCESSESThere is a growing awareness of the importance of multiple scales in many physical and biological systems, including neuroscience [1], [2]. As yet, there does not seem to be any "smoking gun" for explicit top-down mechanisms that directly drive bottom-up processes that describe memory, attention, etc. Of course, there are many top-down type studies demonstrating that neuromodulator [3] and neuronal firing states, e.g., as defined by EEG frequencies, can modify the milieu or context of individual synaptic and neuronal activity, which is still consistent with ultimate bottom-up paradigms. However, there is a logical difference between top-down milieu as conditioned by some prior external or internal conditions, and some direct top-down processes that direct cause bottom-up interactions specific to STM. Here, the operative word is "cause". A. Magnetism Influences in Living SystemsThere is a body of evidence that suggests a specific topdown mechanism for neocortical STM processing.An example of a direct physical mechanism that affects neuronal processing not part of "standard" sensory influences is the strong possibility of magnetic influences in birds at quantum levels of interaction [4]- [6]. It should be noted that this is just a proposed mechanism [7].The strengths of magnetic fields in neocortex may be at a threshold to directly influence synaptic interactions with astrocytes, as proposed for long-term memory (LTM) [ rise to even stronger magnetic fields. Columnar excitatory and inhibitory processes largely take place in different neocortical laminae, providing possibilities for more specific mechanisms. II. SMNI CONTEXTSince 1981 about 30 papers on a statistical mechanics of neocortical interactions (SMNI) has been detailed properties of short-term memory, long-term memory, EEG analyses, and other properties of neocortex [11]-[16].This disc...

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“…Pereira and Furlan 17,18 have attempted to define the kind of astroglial activity that covariates with consciousness: the large scale amplitude modulated coherent intercellular calcium waveform that occurs when a threshold of excitation is reached.…”

Section: Fig 2 -The Glutamatergic Synapse Glu Released From the Prementioning

confidence: 99%

“…These are fulfilled by a model of neuro-astroglial interactions presented in a series of publications, including position papers and reviews of empirical results. 16,17,18,19 …”

Section: Introductionmentioning

confidence: 99%

Biophysical Mechanisms Supporting Conscious Perception: Prospects for an Artificial Astrocyte

Pereira¹

2011

Nature Precedings

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Astrocytes and human cognition: Modeling information integration and modulation of neuronal activity

Cited by 156 publications

References 123 publications

Water diffusion reveals networks that modulate multiregional morphological plasticity after repetitive brain stimulation

Water diffusion reveals networks that modulate multiregional morphological plasticity after repetitive brain stimulation

Influence of Macrocolumnar EEG on Ca Waves

Biophysical Mechanisms Supporting Conscious Perception: Prospects for an Artificial Astrocyte

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