scholarly journals Out of balance: how a binaural coincidence detection circuit responds to unilateral deafferentation

2018 ◽  
Vol 596 (10) ◽  
pp. 1787-1788
Author(s):  
Michael T. Roberts
Keyword(s):  
Coincidence Detection ◽  
Detection Circuit

scholarly journals Siah2 integrates mitogenic and extracellular matrix signals linking neuronal progenitor ciliogenesis with germinal zone occupancy

2019 ◽  
Author(s):  
Taren Ong ◽  
Niraj Trivedi ◽  
Randall Wakefield ◽  
Sharon Frase ◽  
David J. Solecki
Keyword(s):  
Extracellular Matrix ◽  
Primary Cilia ◽  
Mapk Signaling ◽  
Coincidence Detection ◽  
Dependent Manner ◽  
Neuronal Progenitor ◽  
Germinal Zone ◽  
Detection Circuit ◽  
Proliferation And Differentiation ◽  
Developing Neurons

Evidence is lacking as to how developing neurons integrate mitogenic signals with microenvironment cues to control proliferation and differentiation. We determined that the Siah2 E3 ubiquitin ligase functions in a coincidence detection circuit linking responses to the Shh mitogen and the extracellular matrix to control cerebellar granule neurons (CGN) germinal zone (GZ) occupancy. We found that Shh maintains Siah2 expression in CGN progenitors (GNPs) in a Ras/Mapk-dependent manner. Siah2 supports ciliogenesis in a feed-forward fashion by restraining ciliogenic targets. Efforts to identify GZ sources of Ras/Mapk signaling led us to discover that GNPs respond to laminin, but not vitronectin, in the microenvironment via integrin β1 receptors, which engages the Ras/Mapk cascade, and that this niche interaction is essential for promoting GNP ciliogenesis. As GNPs leave the GZ, differentiation is seamlessly driven by changing extracellular cues that diminish Siah2-activity leading to primary cilia retraction and attenuation of mitogenic responses.

scholarly journals Siah2 integrates mitogenic and extracellular matrix signals linking neuronal progenitor ciliogenesis with germinal zone occupancy

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Taren Ong ◽  
Niraj Trivedi ◽  
Randall Wakefield ◽  
Sharon Frase ◽  
David J. Solecki
Keyword(s):  
Extracellular Matrix ◽  
Primary Cilia ◽  
Mapk Signaling ◽  
Coincidence Detection ◽  
Dependent Manner ◽  
Neuronal Progenitor ◽  
Germinal Zone ◽  
Detection Circuit ◽  
Proliferation And Differentiation ◽  
Developing Neurons

Abstract Evidence is lacking as to how developing neurons integrate mitogenic signals with microenvironment cues to control proliferation and differentiation. We determine that the Siah2 E3 ubiquitin ligase functions in a coincidence detection circuit linking responses to the Shh mitogen and the extracellular matrix to control cerebellar granule neurons (CGN) GZ occupancy. We show that Shh signaling maintains Siah2 expression in CGN progenitors (GNPs) in a Ras/Mapk-dependent manner. Siah2 supports ciliogenesis in a feed-forward fashion by restraining cilium disassembly. Efforts to identify sources of the Ras/Mapk signaling led us to discover that GNPs respond to laminin, but not vitronectin, in the GZ microenvironment via integrin β1 receptors, which engages the Ras/Mapk cascade with Shh, and that this niche interaction is essential for promoting GNP ciliogenesis. As GNPs leave the GZ, differentiation is driven by changing extracellular cues that diminish Siah2-activity leading to primary cilia shortening and attenuation of the mitogenic response.

scholarly journals Control of a Depolarizing GABAergic Input in an Auditory Coincidence Detection Circuit

2009 ◽  
Vol 102 (3) ◽  
pp. 1672-1683 ◽  
Author(s):  
Zheng-Quan Tang ◽  
Hongxiang Gao ◽  
Yong Lu
Keyword(s):  
Inhibitory Action ◽  
Metabotropic Glutamate Receptor ◽  
Phase Locking ◽  
Reversal Potential ◽  
Coincidence Detection ◽  
Third Order ◽  
Interaural Time Differences ◽  
Metabotropic Glutamate ◽  
Detection Circuit ◽  
Excitatory Action

Neurons in the chicken nucleus laminaris (NL), the third-order auditory neurons that detect the interaural time differences that enable animals to localize sounds in the horizontal plane, receive glutamatergic excitation from the cochlear nucleus magnocellularis (NM) and GABAergic inhibition from the ipsilateral superior olivary nucleus. Here, we study metabotropic glutamate receptor (mGluR)- and GABAB receptor (GABABR)-mediated modulation of synaptic transmission in NL neurons. Gramicidin-perforated recordings from acute brain stem slice preparations showed that the reversal potential of the GABAergic responses in NL neurons was more depolarized than the spike threshold. Activation of the GABAergic input produced a mix of inhibitory and excitatory actions in NL neurons. The inhibitory action is known to be critical in improving the acuity of temporal processing of sounds. The excitatory action, however, would reduce the phase locking fidelity of NL neurons in response to their excitatory inputs from the NM. We show that activation of presynaptic mGluRs or GABABRs by either exogenous agonists or synaptically released neurotransmitters reduced the GABAergic responses, preventing the excitatory action of GABA while leaving the inhibitory action intact. Unlike most CNS synapses, the glutamatergic transmission in the NL was not modulated by either mGluRs or GABABRs, indicating that fixed (nonmodulatory) excitatory inputs to the NL may be optimal for coincidence detection. This study contributes to our understanding of how selective neuromodulation is achieved to suit a particular function of neuronal circuits in the brain.

F-18-FDG Positron Imaging in Oncological Patients: Gamma Camera Coincidence Detection versus Dedicated PET

1999 ◽  
Vol 38 (04) ◽  
pp. 108-114 ◽  
Author(s):  
H.-J. Kaiser ◽  
U. Cremerius ◽  
O. Sabri ◽  
M. Schreckenberger ◽  
P. Reinartz ◽  
...  
Keyword(s):  
Attenuation Correction ◽  
Spatial Resolution ◽  
Gamma Camera ◽  
Lesion Detection ◽  
Coincidence Detection ◽  
System Sensitivity ◽  
Oncological Patients ◽  
Phantom Studies ◽  
Pet System ◽  
Dedicated Pet

Summary Aim of the present study was to investigate the feasibility of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) imaging in oncological patients with a dual head gamma camera modified for coincidence detection (MCD). Methods: Phantom studies were done to determine lesion detection at various lesion-to-background ratios, system sensitivity and spatial resolution. Thirty-two patients with suspected or known malignant disease were first studied with a dedicated full-ring PET system (DPET) applying measured attenuation correction and subsequently with an MCD system without attenuation correction. MCD images were first interpreted without knowledge of the DPET findings. In a second reading, MCD and DPET were evaluated simultaneously. Results: The phantom studies revealed a comparable spatial resolution for DPET and MCD (5.9 × 6.3 × 4.2 mm vs. 5.9 × 6.5 × 6.0 mm). System sensitivity of MCD was less compared to DPET (91 cps/Bq/ml/cmF0V vs. 231 cps/ Bq/ml/cmFOv). At a lesion-to-background ratio of 4:1, DPET depicted a minimal phantom lesion of 1.0 cm in diameter, MCD a minimal lesion of 1.6 cm. With DPET, a total of 91 lesions in 27 patients were classified as malignant. MCD without knowledge of DPET results revealed increased FDG uptake in all patients with positive DPET findings. MCD detected 72 out of 91 DPET lesions (79.1 %). With knowledge of the DPET findings, 11 additional lesions were detected (+12%). MCD missed lesions in six patients with relevance for staging in two patients. All lesions with a diameter above 18 mm were detected. Conclusion: MCD FDG imaging yielded results comparable to dedicated PET in most patients. However, a considerable number of small lesions clearly detectable with DPET were not detected by MCD alone. Therefore, MCD cannot yet replace dedicated PET in all oncological FDG studies. Further technical refinement of this new method is needed to improve image quality (e.g. attenuation correction).

Design of micro current detection circuit for FAIMS

2011 ◽  
Vol 25 (8) ◽  
pp. 711-715 ◽  
Author(s):  
Shujiang Yan ◽  
Fei Tang ◽  
Xiaohao Wang ◽  
Fan Wang ◽  
Tao Yang
Keyword(s):  
Detection Circuit ◽  
Current Detection

scholarly journals Investigation on a Novel Capacitive Electrode for Geophysical Surveys

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Zhiyu Wang ◽  
Shun Wang ◽  
Guangyou Fang ◽  
Qunying Zhang
Keyword(s):  
Electrical Contact ◽  
Capacitive Coupling ◽  
Environmental Damage ◽  
Good Prospect ◽  
Test Results ◽  
Geophysical Surveys ◽  
Detection Circuit ◽  
Operating Bandwidth ◽  
Capacitive Electrode ◽  
Alternative Structure

Nonpolarizable electrodes are applied widely in the electric field measurement for geophysical surveys. However, there are two major problems: (1) systematic errors caused by poor electrical contact in the high resistive terrains and (2) environmental damage associated with using nonpolarizable electrodes. A new alternative structure of capacitive electrode, which is capable of sensing surface potential through weak capacitive coupling, is presented to solve the above problems. A technique is introduced to neutralize distributed capacitance and input capacitance of the detection circuit. With the capacitance neutralization technique, the transmission coefficient of capacitive electrode remains stable when environmental conditions change. The simulation and field test results indicate that the new capacitive electrode has an operating bandwidth range from 0.1 Hz to 1 kHz. The capacitive electrodes have a good prospect of the applications in geophysical prospecting, especially in resistive terrains.

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