Optical Mapping of the Functional Organization of the Rat Trigeminal Nucleus: Initial Expression and Spatiotemporal Dynamics of Sensory Information Transfer during Embryogenesis

Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease.

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Stroke-related alterations in inter-areal communication revealed via Granger causality analysis

10.1101/2021.01.04.425190 ◽

2021 ◽

Author(s):

Michele Allegra ◽

Chiara Favaretto ◽

Nicholas Metcalf ◽

Maurizio Corbetta ◽

Andrea Brovelli

Keyword(s):

Functional Connectivity ◽

Granger Causality ◽

Resting State ◽

Information Transfer ◽

Large Scale ◽

Functional Organization ◽

Information Flows ◽

Causality Analysis ◽

Stroke Patients ◽

Granger Causality Analysis

ABSTRACTNeuroimaging and neurological studies suggest that stroke is a brain network syndrome. While causing local ischemia and cell damage at the site of injury, stroke strongly perturbs the functional organization of brain networks at large. Critically, functional connectivity abnormalities parallel both behavioral deficits and functional recovery across different cognitive domains. However, the reasons for such relations remain poorly understood. Here, we tested the hypothesis that alterations in inter-areal communication underlie stroke-related modulations in functional connectivity (FC). To this aim, we used resting-state fMRI and Granger causality analysis to quantify information transfer between brain areas and its alteration in stroke. Two main large-scale anomalies were observed in stroke patients. First, inter-hemispheric information transfer was strongly decreased with respect to healthy controls. Second, information transfer within the affected hemisphere, and from the affected to the intact hemisphere was reduced. Both anomalies were more prominent in resting-state networks related to attention and language, and they were correlated with impaired performance in several behavioral domains. Overall, our results support the hypothesis that stroke perturbs inter-areal communication within and across hemispheres, and suggest novel therapeutic approaches aimed at restoring normal information flow.SIGNIFICANCE STATEMENTA thorough understanding of how stroke perturbs brain function is needed to improve recovery from the severe neurological syndromes affecting stroke patients. Previous resting-state neuroimaging studies suggested that interaction between hemispheres decreases after stroke, while interaction between areas of the same hemisphere increases. Here, we used Granger causality to reconstruct information flows in the brain at rest, and analyze how stroke perturbs them. We showed that stroke causes a global reduction of inter-hemispheric communication, and an imbalance between the intact and the affected hemisphere: information flows within and from the latter are impaired. Our results may inform the design of stimulation therapies to restore the functional balance lost after stroke.

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Sensory-Motor Modulations of EEG Event-Related Potentials Reflect Walking-Related Macro-Affordances

Brain Sciences ◽

10.3390/brainsci11111506 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1506

Author(s):

Annalisa Tosoni ◽

Emanuele Cosimo Altomare ◽

Marcella Brunetti ◽

Pierpaolo Croce ◽

Filippo Zappasodi ◽

...

Keyword(s):

Large Scale ◽

Functional Organization ◽

Sensory Information ◽

Event Related Potentials ◽

Stimulus Presentation ◽

Fundamental Principle ◽

Facilitation Effect ◽

Extrapersonal Space ◽

Sensory Motor ◽

Related Potentials

One fundamental principle of the brain functional organization is the elaboration of sensory information for the specification of action plans that are most appropriate for interaction with the environment. Using an incidental go/no-go priming paradigm, we have previously shown a facilitation effect for the execution of a walking-related action in response to far vs. near objects/locations in the extrapersonal space, and this effect has been called “macro-affordance” to reflect the role of locomotion in the coverage of extrapersonal distance. Here, we investigated the neurophysiological underpinnings of such an effect by recording scalp electroencephalography (EEG) from 30 human participants during the same paradigm. The results of a whole-brain analysis indicated a significant modulation of the event-related potentials (ERPs) both during prime and target stimulus presentation. Specifically, consistent with a mechanism of action anticipation and automatic activation of affordances, a stronger ERP was observed in response to prime images framing the environment from a far vs. near distance, and this modulation was localized in dorso-medial motor regions. In addition, an inversion of polarity for far vs. near conditions was observed during the subsequent target period in dorso-medial parietal regions associated with spatially directed foot-related actions. These findings were interpreted within the framework of embodied models of brain functioning as arising from a mechanism of motor-anticipation and subsequent prediction error which was guided by the preferential affordance relationship between the distant large-scale environment and locomotion. More in general, our findings reveal a sensory-motor mechanism for the processing of walking-related environmental affordances.

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Routing information flow by separate neural synchrony frequencies allows for “functionally labeled lines” in higher primate cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1819827116 ◽

2019 ◽

Vol 116 (25) ◽

pp. 12506-12515 ◽

Cited By ~ 14

Author(s):

Mohammad Bagher Khamechian ◽

Vladislav Kozyrev ◽

Stefan Treue ◽

Moein Esghaei ◽

Mohammad Reza Daliri

Keyword(s):

Information Flow ◽

Information Transfer ◽

Sensory Information ◽

Spike Timing ◽

Oscillatory Activity ◽

Attention Task ◽

Cortical Areas ◽

High Gamma ◽

Ventral Pathway ◽

Visual Cortical

Efficient transfer of sensory information to higher (motor or associative) areas in primate visual cortical areas is crucial for transforming sensory input into behavioral actions. Dynamically increasing the level of coordination between single neurons has been suggested as an important contributor to this efficiency. We propose that differences between the functional coordination in different visual pathways might be used to unambiguously identify the source of input to the higher areas, ensuring a proper routing of the information flow. Here we determined the level of coordination between neurons in area MT in macaque visual cortex in a visual attention task via the strength of synchronization between the neurons’ spike timing relative to the phase of oscillatory activities in local field potentials. In contrast to reports on the ventral visual pathway, we observed the synchrony of spikes only in the range of high gamma (180 to 220 Hz), rather than gamma (40 to 70 Hz) (as reported previously) to predict the animal’s reaction speed. This supports a mechanistic role of the phase of high-gamma oscillatory activity in dynamically modulating the efficiency of neuronal information transfer. In addition, for inputs to higher cortical areas converging from the dorsal and ventral pathway, the distinct frequency bands of these inputs can be leveraged to preserve the identity of the input source. In this way source-specific oscillatory activity in primate cortex can serve to establish and maintain “functionally labeled lines” for dynamically adjusting cortical information transfer and multiplexing converging sensory signals.

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Multiple Firing Patterns in Deep Dorsal Horn Neurons of the Spinal Cord: Computational Analysis of Mechanisms and Functional Implications

Journal of Neurophysiology ◽

10.1152/jn.00919.2009 ◽

2010 ◽

Vol 104 (4) ◽

pp. 1978-1996 ◽

Cited By ~ 11

Author(s):

Yann Le Franc ◽

Gwendal Le Masson

Keyword(s):

Spinal Cord ◽

Dorsal Horn ◽

Information Transfer ◽

Network Effects ◽

Neuronal Response ◽

Sensory Information ◽

Firing Patterns ◽

Dorsal Horn Neurons ◽

The Impact

Deep dorsal horn relay neurons (dDHNs) of the spinal cord are known to exhibit multiple firing patterns under the control of local metabotropic neuromodulation: tonic firing, plateau potential, and spontaneous oscillations. This work investigates the role of interactions between voltage-gated channels and the occurrence of different firing patterns and then correlates these two phenomena with their functional role in sensory information processing. We designed a conductance-based model using the NEURON software package, which successfully reproduced the classical features of plateau in dDHNs, including a wind-up of the neuronal response after repetitive stimulation. This modeling approach allowed us to systematically test the impact of conductance interactions on the firing patterns. We found that the expression of multiple firing patterns can be reproduced by changes in the balance between two currents (L-type calcium and potassium inward rectifier conductances). By investigating a possible generalization of the firing state switch, we found that the switch can also occur by varying the balance of any hyperpolarizing and depolarizing conductances. This result extends the control of the firing switch to neuromodulators or to network effects such as synaptic inhibition. We observed that the switch between the different firing patterns occurs as a continuous function in the model, revealing a particular intermediate state called the accelerating mode. To characterize the functional effect of a firing switch on information transfer, we used correlation analysis between a model of peripheral nociceptive afference and the dDHN model. The simulation results indicate that the accelerating mode was the optimal firing state for information transfer.

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Spatiotemporal dynamics driven by the maximization of local information transfer

New Journal of Physics ◽

10.1088/1367-2630/ab0039 ◽

2019 ◽

Vol 21 (1) ◽

pp. 013034

Author(s):

Kohei Nakajima ◽

Taichi Haruna

Keyword(s):

Information Transfer ◽

Local Information ◽

Spatiotemporal Dynamics

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Distinct roles of light-activated channels TRP and TRPL in photoreceptors of Periplaneta americana

The Journal of General Physiology ◽

10.1085/jgp.201611737 ◽

2017 ◽

Vol 149 (4) ◽

pp. 455-464 ◽

Cited By ~ 11

Author(s):

Paulus Saari ◽

Andrew S. French ◽

Päivi H. Torkkeli ◽

Hongxia Liu ◽

Esa-Ville Immonen ◽

...

Keyword(s):

Information Transfer ◽

Periplaneta Americana ◽

Transient Receptor Potential ◽

Trp Channels ◽

Light Stimulus ◽

Gaussian White Noise ◽

Sensory Information ◽

Receptor Potential ◽

Light Sensitivity ◽

Low Noise

Electrophysiological studies in Drosophila melanogaster and Periplaneta americana have found that the receptor current in their microvillar photoreceptors is generated by two light-activated cationic channels, TRP (transient receptor potential) and TRPL (TRP-like), each having distinct properties. However, the relative contribution of the two channel types to sensory information coding by photoreceptors remains unclear. We recently showed that, in contrast to the diurnal Drosophila in which TRP is the principal phototransduction channel, photoreceptors of the nocturnal P. americana strongly depend on TRPL. Here, we perform a functional analysis, using patch-clamp and intracellular recordings, of P. americana photoreceptors after RNA interference to knock down TRP (TRPkd) and TRPL (TRPLkd). Several functional properties were changed in both knockdown phenotypes: cell membrane capacitance was reduced 1.7-fold, light sensitivity was greatly reduced, and amplitudes of sustained light-induced currents and voltage responses decreased more than twofold over the entire range of light intensities. The information rate (IR) was tested using a Gaussian white-noise modulated light stimulus and was lower in TRPkd photoreceptors (28 ± 21 bits/s) than in controls (52 ± 13 bits/s) because of high levels of bump noise. In contrast, although signal amplitudes were smaller than in controls, the mean IR of TRPLkd photoreceptors was unchanged at 54 ± 29 bits/s1 because of proportionally lower noise. We conclude that TRPL channels provide high-gain/high-noise transduction, suitable for vision in dim light, whereas transduction by TRP channels is relatively low-gain/low-noise and allows better information transfer in bright light.

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Proprioception From a Spinocerebellar Perspective

Physiological Reviews ◽

10.1152/physrev.2001.81.2.539 ◽

2001 ◽

Vol 81 (2) ◽

pp. 539-568 ◽

Cited By ~ 160

Author(s):

G. Bosco ◽

R. E. Poppele

Keyword(s):

Spinal Cord ◽

Nervous System ◽

Functional Organization ◽

Body Position ◽

Historical Context ◽

Sensory Information ◽

Functional Relationships ◽

Central Neurons ◽

Global Representation ◽

Limb Kinematics

This review explores how proprioceptive sensory information is organized at spinal cord levels as it relates to a sense of body position and movement. The topic is considered in an historical context and develops a different framework that may be more in tune with current views of sensorimotor processing in other central nervous system structures. The dorsal spinocerebellar tract (DSCT) system is considered in detail as a model system that may be considered as an end point for the processing of proprioceptive sensory information in the spinal cord. An analysis of this system examines sensory processing at the lowest levels of synaptic connectivity with central neurons in the nervous system. The analysis leads to a framework for proprioception that involves a highly flexible network organization based in some way on whole limb kinematics. The functional organization underlying this framework originates with the biomechanical linkages in the limb that establish functional relationships among the limb segments. Afferent information from limb receptors is processed further through a distributed neural network in the spinal cord. The result is a global representation of hindlimb parameters rather than a muscle-by-muscle or joint-by-joint representation.

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Information flow in the nervous system

European Review ◽

10.1017/s1062798700000363 ◽

1993 ◽

Vol 1 (1) ◽

pp. 31-39

Author(s):

Arnold Burgen

Keyword(s):

Information Flow ◽

Information Transfer ◽

Sensory Information ◽

Nerve Fibres ◽

Ionic Transfer ◽

Electrical Pulses ◽

Specific Receptors ◽

Stored Information ◽

High Level ◽

Memory And Recall

Information is carried along nerve fibres by electrical pulses generated by ionic transfer; it is digitally coded. Information transfer between nerve cells depends on the release of a chemical transmitter which acts on specific receptors on the second neurone. This is a non-digital, analogue process which is highly non-linear. It involves the summation of inputs from highly divergent sources. In sensory systems such as vision, extensive compression, feature extraction and other high-level processing occur before presentation to the cerebral cortex, where a massive expansion in distribution of information occurs. Huge numbers of neurones are involved in the central presentation of even simple sensory information. This is because the neural events are relatively slow, so that a massive parallel information flow and processing occurs. Learning and memory involve changes in synaptic efficiency and the development of new stable connective patterns. Memory and recall must involve a comparison of contemporary events with stored information, but cannot involve a one-on-one comparison because it can deal with extensive transformation of sensory information.

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