scholarly journals Top-down control of hippocampal signal-to-noise by prefrontal long-range inhibition

2021 ◽  
Author(s):  
Ruchi Malik ◽  
Yi Li ◽  
Selin Schamiloglu ◽  
Vikaas S. Sohal
Keyword(s):  
Information Processing ◽  
Long Range ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Top Down ◽  
Object Exploration ◽  
Hippocampal Activity ◽  
The Brain ◽  
Stimulation Of

SummaryThe prefrontal cortex (PFC) is postulated to exert ‘top-down control’ by modulating information processing throughout the brain to promote specific actions based on current goals. However, the pathways mediating top-down control remain poorly understood. In particular, knowledge about direct prefrontal connections that might facilitate top-down prefrontal control of information processing in the hippocampus remains sparse. Here we describe novel monosynaptic long-range GABAergic projections from PFC to hippocampus. These preferentially inhibit vasoactive intestinal polypeptide expressing interneurons, which are known to disinhibit hippocampal microcircuits. Indeed, stimulating prefrontal–hippocampal GABAergic projections increases hippocampal feedforward inhibition and reduces hippocampal activity in vivo. The net effect of these actions is to specifically enhance the signal-to-noise ratio for hippocampal representations of objects. Correspondingly, stimulation of PFC-to-hippocampus GABAergic projections promotes object exploration. Together, these results elucidate a novel top-down pathway in which long-range GABAergic projections target disinhibitory microcircuits, thereby enhancing signals and network dynamics underlying exploratory behavior.

Age and Information Processing

1982 ◽  
Vol 26 (2) ◽  
pp. 184-188 ◽  
Author(s):  
Jan Moraal
Keyword(s):  
Information Processing ◽  
Signal To Noise Ratio ◽  
The Other ◽  
General Nature ◽  
Sense Organs ◽  
Signal To Noise ◽  
Processing Stage ◽  
Research Findings ◽  
Stage Analysis ◽  
The Brain

The question is raised whether the slowing of behavior with age is of a general nature, affecting all subprocesses or stages of information processing, or whether it can be ‘localized’ in one or more specific stages. Based upon studies on the stage analysis of the reaction process, it is concluded that there is no converging empirical evidence to answer this question in favor of one of the alternatives. The research findings seem to fit very well in the assumption of a lowering of the signal-to-noise ratio with increasing age, i.e. a lowering of the strength of the signals coming from the sense organs to the brain and from one processing stage to the other.

scholarly journals Signal-to-noise ratio in the membrane potential of the owl's auditory coincidence detectors

2012 ◽  
Vol 108 (10) ◽  
pp. 2837-2845 ◽  
Author(s):  
Go Ashida ◽  
Kazuo Funabiki ◽  
Paula T. Kuokkanen ◽  
Richard Kempter ◽  
Catherine E. Carr
Keyword(s):  
Neural Circuit ◽  
Signal To Noise Ratio ◽  
Phase Locking ◽  
Low Frequency ◽  
Membrane Potentials ◽  
Signal To Noise ◽  
Theoretical Predictions ◽  
Noise Ratio ◽  
Band Limited

Owls use interaural time differences (ITDs) to locate a sound source. They compute ITD in a specialized neural circuit that consists of axonal delay lines from the cochlear nucleus magnocellularis (NM) and coincidence detectors in the nucleus laminaris (NL). Recent physiological recordings have shown that tonal stimuli induce oscillatory membrane potentials in NL neurons (Funabiki K, Ashida G, Konishi M. J Neurosci 31: 15245–15256, 2011). The amplitude of these oscillations varies with ITD and is strongly correlated to the firing rate. The oscillation, termed the sound analog potential, has the same frequency as the stimulus tone and is presumed to originate from phase-locked synaptic inputs from NM fibers. To investigate how these oscillatory membrane potentials are generated, we applied recently developed signal-to-noise ratio (SNR) analysis techniques (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010) to the intracellular waveforms obtained in vivo. Our theoretical prediction of the band-limited SNRs agreed with experimental data for mid- to high-frequency (>2 kHz) NL neurons. For low-frequency (≤2 kHz) NL neurons, however, measured SNRs were lower than theoretical predictions. These results suggest that the number of independent NM fibers converging onto each NL neuron and/or the population-averaged degree of phase-locking of the NM fibers could be significantly smaller in the low-frequency NL region than estimated for higher best-frequency NL.

scholarly journals Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jay W. Reddy ◽  
Maya Lassiter ◽  
Maysamreza Chamanzar
Keyword(s):  
Optical Waveguides ◽  
Brain Activity ◽  
Low Loss ◽  
Parylene C ◽  
Optogenetic Stimulation ◽  
Patterned Illumination ◽  
The Brain ◽  
532 Nm ◽  
Stimulation Of

Abstract Targeted light delivery into biological tissue is needed in applications such as optogenetic stimulation of the brain and in vivo functional or structural imaging of tissue. These applications require very compact, soft, and flexible implants that minimize damage to the tissue. Here, we demonstrate a novel implantable photonic platform based on a high-density, flexible array of ultracompact (30 μm × 5 μm), low-loss (3.2 dB/cm at λ = 680 nm, 4.1 dB/cm at λ = 633 nm, 4.9 dB/cm at λ = 532 nm, 6.1 dB/cm at λ = 450 nm) optical waveguides composed of biocompatible polymers Parylene C and polydimethylsiloxane (PDMS). This photonic platform features unique embedded input/output micromirrors that redirect light from the waveguides perpendicularly to the surface of the array for localized, patterned illumination in tissue. This architecture enables the design of a fully flexible, compact integrated photonic system for applications such as in vivo chronic optogenetic stimulation of brain activity.

scholarly journals Re-membering the body: applications of computational neuroscience to the top-down control of regeneration of limbs and other complex organs

2015 ◽  
Vol 7 (12) ◽  
pp. 1487-1517 ◽  
Author(s):  
G. Pezzulo ◽  
M. Levin
Keyword(s):  
Information Processing ◽  
Pattern Formation ◽  
Computational Neuroscience ◽  
Memory System ◽  
The Body ◽  
Signaling Networks ◽  
Control Mechanisms ◽  
Top Down ◽  
The Brain

How do regenerating bodies know when to stop remodeling? Bioelectric signaling networks guide pattern formation and may implement a somatic memory system. Deep parallels may exist between information processing in the brain and morphogenetic control mechanisms.

Fluorescence Information Processing Based on Wavelet De-Noising

2015 ◽  
Vol 734 ◽  
pp. 56-63
Author(s):  
Yong Xin Shao ◽  
Xiao Ping Yang ◽  
Zhi Yong Wang ◽  
Ya Juan Yang
Keyword(s):  
Information Processing ◽  
Fluorescence Lifetime ◽  
Temperature Sensor ◽  
Signal To Noise Ratio ◽  
Measurement Precision ◽  
Measurement Reliability ◽  
Signal To Noise ◽  
Noise Interference ◽  
System Noise ◽  
Interference Measurement

<p>In this paper ,the method of the fluorescence lifetime (FL) in fluorescence optical fiber temperature sensor is used to measure the temperature. During the fluorescence information processing , because of existence of the system noise interference, measurement reliability of fluorescence lifetime has been greatly affected, thereby reducing the temperature measurement precision. This paper presents an improved wavelet threshold de-noising method to signal processing, which improves the signal-to-noise ratio and increases the measurement of fluorescence lifetime precision, reduce the error of temperature measurements at the same time. The experimental results demonstrate that this method is effective.</p>

scholarly journals Sequential average segmented microscopy for high signal-to-noise ratio motion-artifact-free in vivo heart imaging

2013 ◽  
Vol 4 (10) ◽  
pp. 2095 ◽  
Author(s):  
Claudio Vinegoni ◽  
Sungon Lee ◽  
Paolo Fumene Feruglio ◽  
Pasquina Marzola ◽  
Matthias Nahrendorf ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Motion Artifact ◽  
High Signal ◽  
Signal To Noise ◽  
Heart Imaging ◽  
Noise Ratio

scholarly journals On the Reconstruction of Magnetic Resonance Current Density Images of the Human Brain: Pitfalls and Perspectives

2021 ◽  
Author(s):  
Hasan H. Eroğlu ◽  
Oula Puonti ◽  
Cihan Göksu ◽  
Fróði Gregersen ◽  
Hartwig R. Siebner ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Human Brain ◽  
Current Density ◽  
Signal To Noise Ratio ◽  
Ground Truth ◽  
Statistical Testing ◽  
Signal To Noise ◽  
Testing Approach ◽  
Resonance Current

ABSTRACTMagnetic resonance current density imaging (MRCDI) of the human brain aims to reconstruct the current density distribution caused by transcranial electric stimulation from MR-based measurements of the current-induced magnetic fields. The reconstruction problem is challenging due to a low signal-to-noise ratio and a limited volume coverage of the MR-based measurements, the lack of data from the scalp and skull regions and because MRCDI is only sensitive to the component of the current-induced magnetic field parallel to the scanner field. Most existing reconstruction approaches have been validated using simulation studies and measurements in phantoms with simplified geometries. Only one reconstruction method, the projected current density algorithm, has been applied to human in-vivo data so far, however resulting in blurred current density estimates even when applied to noise-free simulated data.We analyze the underlying causes for the limited performance of the projected current density algorithm when applied to human brain data. In addition, we compare it with an approach that relies on the optimization of the conductivities of a small number of tissue compartments of anatomically detailed head models reconstructed from structural MR data. Both for simulated ground truth data and human in-vivo MRCDI data, our results indicate that the estimation of current densities benefits more from using a personalized volume conductor model than from applying the projected current density algorithm. In particular, we introduce a hierarchical statistical testing approach as a principled way to test and compare the quality of reconstructed current density images that accounts for the limited signal-to-noise ratio of the human in-vivo MRCDI data and the fact that the ground truth of the current density is unknown for measured data. Our results indicate that the statistical testing approach constitutes a valuable framework for the further development of accurate volume conductor models of the head. Our findings also highlight the importance of tailoring the reconstruction approaches to the quality and specific properties of the available data.

scholarly journals Self-Reset Image Sensor With a Signal-to-Noise Ratio Over 70 dB and Its Application to Brain Surface Imaging

2021 ◽  
Vol 15 ◽  
Author(s):  
Thanet Pakpuwadon ◽  
Kiyotaka Sasagawa ◽  
Mark Christian Guinto ◽  
Yasumi Ohta ◽  
Makito Haruta ◽  
...  
Keyword(s):  
Neural Activity ◽  
Signal To Noise Ratio ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
High Signal ◽  
Unstable State ◽  
Signal To Noise ◽  
Compact Size ◽  
Noise Ratio

In this study, we propose a complementary-metal-oxide-semiconductor (CMOS) image sensor with a self-resetting system demonstrating a high signal-to-noise ratio (SNR) to detect small intrinsic signals such as a hemodynamic reaction or neural activity in a mouse brain. The photodiode structure was modified from N-well/P-sub to P+/N-well/P-sub to increase the photodiode capacitance to reduce the number of self-resets required to decrease the unstable stage. Moreover, our new relay board was used for the first time. As a result, an effective SNR of over 70 dB was achieved within the same pixel size and fill factor. The unstable state was drastically reduced. Thus, we will be able to detect neural activity. With its compact size, this device has significant potential to become an intrinsic signal detector in freely moving animals. We also demonstrated in vivo imaging with image processing by removing additional noise from the self-reset operation.

scholarly journals Theranostic cranial implant for hyperspectral light delivery and microcirculation imaging without scalp removal

2019 ◽  
Author(s):  
Nami Davoodzadeh ◽  
Mildred S. Cano-Velázquez ◽  
Carrie R. Jonak ◽  
David L. Halaney ◽  
Devin K. Binder ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Image Resolution ◽  
Laser Speckle ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Optical Access ◽  
Optical Attenuation ◽  
Cranial Implant ◽  
The Brain

Light based techniques for imaging, diagnosing and treating the brain have become widespread clinical tools, but application of these techniques is limited by optical attenuation in the scalp and skull. This optical attenuation reduces the achievable spatial resolution, precluding the visualization of small features such as brain microvessels. The goal of this study was to assess a strategy for providing ongoing optical access to the brain without the need for repeated craniectomy or retraction of the scalp. This strategy involves the use of a transparent cranial implant and skin optical clearing agents, and was tested in mice to assess improvements in optical access which could be achieved for laser speckle imaging of cerebral microvasculature. Combined transmittance of the optically cleared scalp overlying the transparent cranial implant was as high as 89% in the NIR range, 50% in red range, 24% in green range, and 20% in blue range. In vivo laser speckle imaging experiments of mouse cerebral blood vessels showed that the proposed optical access increased signal-to-noise ratio and image resolution, allowing for visualization of microvessels through the transparent implant, which was not possible through the uncleared scalp and intact skull.

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