Phase Difference between Model Cortical Areas Determines Level of Information Transfer

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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A NEUROBIOLOGICAL THEORY OF MEANING IN PERCEPTION PART III: MULTIPLE CORTICAL AREAS SYNCHRONIZE WITHOUT LOSS OF LOCAL AUTONOMY

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127403008260 ◽

2003 ◽

Vol 13 (10) ◽

pp. 2845-2856 ◽

Cited By ~ 38

Author(s):

WALTER J. FREEMAN ◽

GYöNGYI GAÁL ◽

REBECKA JORSTEN

Keyword(s):

Information Transfer ◽

Phase Locking ◽

Pulse Frequency ◽

Inhibitory Neurons ◽

Oscillatory Activity ◽

Electrode Arrays ◽

Ensemble Averaging ◽

Pulse Frequency Modulation ◽

Cortical Areas ◽

Gamma Range

Information transfer and integration among functionally distinct areas of cerebral cortex of oscillatory activity require some degree of phase synchrony of the trains of action potentials that carry the information prior to the integration. However, propagation delays are obligatory. Delays vary with the lengths and conduction velocities of the axons carrying the information, causing phase dispersion. In order to determine how synchrony is achieved despite dispersion, we recorded EEG signals from multiple electrode arrays on five cortical areas in cats and rabbits, that had been trained to discriminate visual or auditory conditioned stimuli. Analysis by time-lagged correlation, multiple correlation and PCA, showed that maximal correlation was at zero lag and averaged 0.7, indicating that 50% of the power in the gamma range among the five areas was at zero lag irrespective of phase or frequency. There were no stimulus-related episodes of transiently increased phase locking among the areas, nor EEG "bursts" of transiently increased amplitude above the sustained level of synchrony. Three operations were identified to account for the sustained correlation. Cortices broadcast their outputs over divergent–convergent axonal pathways that performed spatial ensemble averaging; synaptic interactions between excitatory and inhibitory neurons in cortex operated as band pass filters for gamma; and signal coarse-graining by pulse frequency modulation at trigger zones enhanced correlation. The conclusion is that these three operations enable continuous linkage of multiple cortical areas by activity in the gamma range, providing the basis for coordinated cortical output to other parts of the brain, despite varying axonal conduction delays, something like the back plane of a main frame computer.

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Synaptic Properties of Thalamic and Intracortical Inputs to Layer 4 of the First- and Higher-Order Cortical Areas in the Auditory and Somatosensory Systems

Journal of Neurophysiology ◽

10.1152/jn.90391.2008 ◽

2008 ◽

Vol 100 (1) ◽

pp. 317-326 ◽

Cited By ~ 96

Author(s):

Charles C. Lee ◽

S. Murray Sherman

Keyword(s):

Information Transfer ◽

Higher Order ◽

Thalamic Nuclei ◽

First Order ◽

Metabotropic Glutamate ◽

Cortical Areas ◽

Layer 4 ◽

Auditory Systems ◽

Initial Processing ◽

Whole Cell Recordings

The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, “higher-order” thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these “higher-order” thalamic nuclei share similar synaptic properties with the “first-order” thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.

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Corticothalamic Pathways in Auditory Processing: Recent Advances and Insights From Other Sensory Systems

Frontiers in Neural Circuits ◽

10.3389/fncir.2021.721186 ◽

2021 ◽

Vol 15 ◽

Author(s):

Flora M. Antunes ◽

Manuel S. Malmierca

Keyword(s):

Auditory Processing ◽

Information Transfer ◽

Predictive Processing ◽

Descending Pathways ◽

Perceptual Inference ◽

Cortical Areas ◽

Dynamic Circuits ◽

Bidirectional Communication ◽

Cortical Hierarchy ◽

Cortical Regions

The corticothalamic (CT) pathways emanate from either Layer 5 (L5) or 6 (L6) of the neocortex and largely outnumber the ascending, thalamocortical pathways. The CT pathways provide the anatomical foundations for an intricate, bidirectional communication between thalamus and cortex. They act as dynamic circuits of information transfer with the ability to modulate or even drive the response properties of target neurons at each synaptic node of the circuit. L6 CT feedback pathways enable the cortex to shape the nature of its driving inputs, by directly modulating the sensory message arriving at the thalamus. L5 CT pathways can drive the postsynaptic neurons and initiate a transthalamic corticocortical circuit by which cortical areas communicate with each other. For this reason, L5 CT pathways place the thalamus at the heart of information transfer through the cortical hierarchy. Recent evidence goes even further to suggest that the thalamus via CT pathways regulates functional connectivity within and across cortical regions, and might be engaged in cognition, behavior, and perceptual inference. As descending pathways that enable reciprocal and context-dependent communication between thalamus and cortex, we venture that CT projections are particularly interesting in the context of hierarchical perceptual inference formulations such as those contemplated in predictive processing schemes, which so far heavily rely on cortical implementations. We discuss recent proposals suggesting that the thalamus, and particularly higher order thalamus via transthalamic pathways, could coordinate and contextualize hierarchical inference in cortical hierarchies. We will explore these ideas with a focus on the auditory system.

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The neurobiology of gut feelings

10.1093/oso/9780198811930.003.0005 ◽

2018 ◽

Cited By ~ 1

Author(s):

Qasim Aziz ◽

James K. Ruffle

Keyword(s):

Mental Health ◽

Sensory Neurons ◽

Information Transfer ◽

Gastrointestinal Function ◽

Afferent Neurons ◽

Physical And Mental Health ◽

Cortical Areas ◽

Gut Feelings ◽

Health And Disease ◽

The Brain

“It’s a gut feeling.” Indeed, how and why do we get “gut feelings?” After the brain, the gut is the second most innervated bodily organ, diffusely interconnected with gastrointestinal afferent neurons. Whilst sensory neurons from the gut ascend by means of the spinal cord and vagal nerve to subcortical and higher cortical areas of the brain, caudally descending motor efferents from brain to gut seek to modulate gastrointestinal function. Such is the construct of the “brain–gut axis,” a bi-directional body nexus permitting constant information transfer between both brain and gut so as to provide us with visceral interoception. This chapter reviews the neurobiology of gut feelings and discuss their role in both physical and mental health and disease.

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Synchronization and phase between model cortical areas determine information transfer

BMC Neuroscience ◽

10.1186/1471-2202-14-s1-p387 ◽

2013 ◽

Vol 14 (S1) ◽

Author(s):

Marije ter Wal ◽

Paul Tiesinga

Keyword(s):

Information Transfer ◽

Cortical Areas

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A single-cell anatomical blueprint for intracortical information transfer from primary visual cortex

10.1101/148031 ◽

2017 ◽

Cited By ~ 3

Author(s):

Yunyun Han ◽

Justus M Kebschull ◽

Robert AA Campbell ◽

Devon Cowan ◽

Fabia Imhof ◽

...

Keyword(s):

Visual Cortex ◽

Long Range ◽

Primary Visual Cortex ◽

Information Transfer ◽

Target Area ◽

V1 Neurons ◽

Cortical Areas ◽

Axonal Projections ◽

High Throughput Dna Sequencing ◽

Axonal Arbors

The wiring diagram of the neocortex determines how information is processed across dozens of cortical areas. Each area communicates with multiple others via extensive long-range axonal projections 1–6, but the logic of inter-area information transfer is unresolved. Specifically, the extent to which individual neurons send dedicated projections to single cortical targets or distribute their signals across multiple areas remains unclear5,7–20. Distinguishing between these possibilities has been challenging because axonal projections of only a few individual neurons have been reconstructed. Here we map the projection patterns of axonal arbors from 591 individual neurons in mouse primary visual cortex (V1) using two complementary methods: whole-brain fluorescence-based axonal tracing21,22 and high-throughput DNA sequencing of genetically barcoded neurons (MAPseq)23. Although our results confirm the existence of dedicated projections to certain cortical areas, we find these are the exception, and that the majority of V1 neurons broadcast information to multiple cortical targets. Furthermore, broadcasting cells do not project to all targets randomly, but rather comprise subpopulations that either avoid or preferentially innervate specific subsets of cortical areas. Our data argue against a model of dedicated lines of intracortical information transfer via “one neuron – one target area” mapping. Instead, long-range communication between a sensory cortical area and its targets may be based on a principle whereby individual neurons copy information to, and potentially coordinate activity across, specific subsets of cortical areas.

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Determination of the Best Emulsion for the Microscopy of Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096886 ◽

1981 ◽

Vol 39 ◽

pp. 32-33

Author(s):

David A. Grano ◽

Kenneth H. Downing

Keyword(s):

Spatial Frequency ◽

Information Transfer ◽

Signal To Noise Ratio ◽

Experimental Situation ◽

Photographic Emulsion ◽

Modulation Transfer ◽

Signal To Noise ◽

Frequency Space ◽

Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

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Ultimate resolution and information in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086787 ◽

1991 ◽

Vol 49 ◽

pp. 496-497

Author(s):

D. Van Dyck

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Transfer Function ◽

Information Transfer ◽

Communication Channel ◽

Structural Information ◽

Information Rate ◽

Noise Power ◽

Signal Power ◽

Imaging Device

An (electron) microscope can be considered as a communication channel that transfers structural information between an object and an observer. In electron microscopy this information is carried by electrons. According to the theory of Shannon the maximal information rate (or capacity) of a communication channel is given by C = B log2 (1 + S/N) bits/sec., where B is the band width, and S and N the average signal power, respectively noise power at the output. We will now apply to study the information transfer in an electron microscope. For simplicity we will assume the object and the image to be onedimensional (the results can straightforwardly be generalized). An imaging device can be characterized by its transfer function, which describes the magnitude with which a spatial frequency g is transferred through the device, n is the noise. Usually, the resolution of the instrument ᑭ is defined from the cut-off 1/ᑭ beyond which no spadal information is transferred.

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What Is Left Is Right

European Psychologist ◽

10.1027/1016-9040.14.1.78 ◽

2009 ◽

Vol 14 (1) ◽

pp. 78-89 ◽

Cited By ~ 8

Author(s):

Kenneth Hugdahl ◽

René Westerhausen

Keyword(s):

Speech Processing ◽

Information Transfer ◽

Hemispheric Asymmetry ◽

Functional Neuroimaging ◽

Gray Matter Volume ◽

Functional Anatomy ◽

Posterior Part ◽

Functional Asymmetry ◽

Planum Temporale ◽

Evolution Of Speech

The present paper is based on a talk on hemispheric asymmetry given by Kenneth Hugdahl at the Xth European Congress of Psychology, Praha July 2007. Here, we propose that hemispheric asymmetry evolved because of a left hemisphere speech processing specialization. The evolution of speech and the need for air-based communication necessitated division of labor between the hemispheres in order to avoid having duplicate copies in both hemispheres that would increase processing redundancy. It is argued that the neuronal basis of this labor division is the structural asymmetry observed in the peri-Sylvian region in the posterior part of the temporal lobe, with a left larger than right planum temporale area. This is the only example where a structural, or anatomical, asymmetry matches a corresponding functional asymmetry. The increase in gray matter volume in the left planum temporale area corresponds to a functional asymmetry of speech processing, as indexed from both behavioral, dichotic listening, and functional neuroimaging studies. The functional anatomy of the corpus callosum also supports such a view, with regional specificity of information transfer between the hemispheres.

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