scholarly journals Manipulating neural dynamics to tune motion detection

2021 ◽  
Author(s):  
Aneysis D Gonzalez-Suarez ◽  
Jacob A Zavatone-Veth ◽  
Juyue Chen ◽  
Catherine Matulis ◽  
Bara Badwan ◽  
...  
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Cell Types ◽  
Visual Signals ◽  
Response Dynamics ◽  
Detection Circuit ◽  
Channel Expression ◽  
Motion Detectors ◽  
Specific Neuron

Neurons integrate excitatory and inhibitory signals to produce their outputs, but the role of input timing in this integration remains poorly understood. Motion detection is a paradigmatic example of this integration, since theories of motion detection rely on different delays in visual signals. These delays allow circuits to compare scenes at different times to calculate the direction and speed of motion. It remains untested how response dynamics of individual cell types drive motion detection and velocity sensitivity. Here, we sped up or slowed down specific neuron types in Drosophila's motion detection circuit by manipulating ion channel expression. Altering the dynamics of individual neurons upstream of motion detectors changed their integrating properties and increased their sensitivity to fast or slow visual motion, exposing distinct roles for dynamics in tuning directional signals. A circuit model constrained by data and anatomy reproduced the observed tuning changes. Together, these results reveal how excitatory and inhibitory dynamics jointly tune a canonical circuit computation.

scholarly journals Motion perception and visual signal design in Anolis lizards

2010 ◽  
Vol 277 (1700) ◽  
pp. 3547-3554 ◽  
Author(s):  
Leo J. Fleishman ◽  
Adam C. Pallus
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Behavioural Response ◽  
Head Movements ◽  
Visual Signal ◽  
Signal Design ◽  
Two Dimensional ◽  
Long Distance ◽  
Optimal Movement ◽  
Motion Detectors

Anolis lizards communicate with displays consisting of motion of the head and body. Early portions of long-distance displays require movements that are effective at eliciting the attention of potential receivers. We studied signal-motion efficacy using a two-dimensional visual-motion detection (2DMD) model consisting of a grid of correlation-type elementary motion detectors. This 2DMD model has been shown to accurately predict Anolis lizard behavioural response. We tested different patterns of artificially generated motion and found that an abrupt 0.3° shift of position in less than 100 ms is optimal. We quantified motion in displays of 25 individuals from five species. Four species employ near-optimal movement patterns. We tested displays of these species using the 2DMD model on scenes with and without moderate wind. Display movements can easily be detected, even in the presence of windblown vegetation. The fifth species does not typically use the most effective display movements and display movements cannot be discerned by the 2DMD model in the presence of windblown vegetation. A number of Anolis species use abrupt up-and-down head movements approximately 10 mm in amplitude in displays, and these movements appear to be extremely effective for stimulating the receiver visual system.

scholarly journals The role of hub neurons in modulating cortical dynamics

2021 ◽  
Author(s):  
Eyal Gal ◽  
Oren Amsalem ◽  
Alon Schindel ◽  
Michael London ◽  
Felix Schuermann ◽  
...  
Keyword(s):  
Network Science ◽  
Structural Integrity ◽  
Cell Types ◽  
Brain Regions ◽  
Cortical Layers ◽  
Disease Manifestation ◽  
Cortical Dynamics ◽  
The Impact ◽  
Specific Neuron

Many neurodegenerative diseases are associated with the death of specific neuron types in particular brain regions. What makes the death of specific neuron types particularly harmful for the integrity and dynamics of the respective network is not well understood. To start addressing this question we used the most up-to-date biologically-realistic dense neocortical microcircuit (NMC) of rodent, which has reconstructed a volume of 0.3 mm3 and containing 31,000 neurons, 36 million synapses, and 55 morphological cell types arranged in 6 cortical layers. Using modern network science tools, we identified ״hub-neurons״ in the NMC, that are connected synaptically to a large number of their neighbors and systematically examined the impact of abolishing these cells. In general, the structural integrity of the network is robust to cellsֿ' attack; yet, attacking hub neurons strongly impacted the ״small worldness״ topology of the network, whereas similar attacks on random neurons have a negligible effect. Such hub-specific attacks are also impactful on the network dynamics, both when the network is at its spontaneous synchronous state and when it was presented with synchronized thalamo-cortical visual-like input. We found that attacking layer 5 hub neurons are most harmful to the structural and functional integrity of the NMC. The significance of our results for understanding the role of specific neuron types and cortical layers for disease manifestation is discussed.

Visual-Vestibular Interactions During Vestibular Compensation: Role of the Pretectal NOT in Horizontal VOR Recovery After Hemilabyrinthectomy in Rhesus Monkey

2005 ◽  
Vol 94 (4) ◽  
pp. 2653-2666 ◽  
Author(s):  
C. Matthew Stewart ◽  
Michael J. Mustari ◽  
Adrian A. Perachio
Keyword(s):  
Visual Information ◽  
Visual Motion ◽  
Optic Tract ◽  
Visual Signals ◽  
Vestibular Compensation ◽  
Spontaneous Nystagmus ◽  
Whole Body ◽  
Slow Phase ◽  
Eye Velocity

Damage to the vestibular labyrinth leads to profound nystagmus and vertigo. Over time, the vestibular-ocular system recovers in a process called vestibular compensation leading to reduced nystagmus and vertigo provided visual signals are available. Our study was directed at identifying sources of visual information that could play a role in vestibular compensation. Specifically, we investigated the role of the pretectal nucleus of the optic tract (NOT) in vestibular compensation after hemilabyrinthectomy (HL) in rhesus monkeys. We chose the NOT because this structure provides critical visual motion information for adaptive modification of the vestibular ocular reflex (VOR). We produced bilateral NOT lesions by injecting the excitotoxin ibotenic acid. We compared vestibular compensation after HL in NOT-lesioned and control animals with intact NOTs. We measured eye movements with an electromagnetic method employing scleral search coils. Measurements included slow-phase eye velocity during spontaneous nystagmus, per- and postrotatory nystagmus and the horizontal VOR (hVOR) gain (eye-velocity/head velocity) associated with per- and postrotatory and sinusoidal (0.2–2.0 Hz; 30–90°/s) whole body oscillation around the earth-vertical axis. VOR gain was low (<0.5) for rotation toward the HL side. Our control animal evinced significant vestibular compensation with VOR gains approaching unity by 100 days post HL. In contrast, monkeys with bilateral lesions of the NOT never obtained this significant recovery with hVOR gains well below unity at 100 days and beyond. Therefore our studies demonstrate that the NOT is an essential source of visual signals for the process of vestibular compensation after HL.

scholarly journals A visual motion detection circuit suggested by Drosophila connectomics

Nature ◽  
2013 ◽  
Vol 500 (7461) ◽  
pp. 175-181 ◽  
Author(s):  
Shin-ya Takemura ◽  
Arjun Bharioke ◽  
Zhiyuan Lu ◽  
Aljoscha Nern ◽  
Shiv Vitaladevuni ◽  
...  
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Detection Circuit ◽  
Visual Motion Detection

scholarly journals Second-order cues to figure motion enable object detection during prey capture by praying mantises

2019 ◽  
Vol 116 (52) ◽  
pp. 27018-27027 ◽  
Author(s):  
Vivek Nityananda ◽  
James O’Keeffe ◽  
Diana Umeton ◽  
Adam Simmons ◽  
Jenny C. A. Read
Keyword(s):  
Motion Detection ◽  
Prey Capture ◽  
Second Order ◽  
Prey Detection ◽  
Motion Sensitivity ◽  
Motion Cues ◽  
First Order ◽  
Motion Detectors ◽  
Do So

Detecting motion is essential for animals to perform a wide variety of functions. In order to do so, animals could exploit motion cues, including both first-order cues—such as luminance correlation over time—and second-order cues, by correlating higher-order visual statistics. Since first-order motion cues are typically sufficient for motion detection, it is unclear why sensitivity to second-order motion has evolved in animals, including insects. Here, we investigate the role of second-order motion in prey capture by praying mantises. We show that prey detection uses second-order motion cues to detect figure motion. We further present a model of prey detection based on second-order motion sensitivity, resulting from a layer of position detectors feeding into a second layer of elementary-motion detectors. Mantis stereopsis, in contrast, does not require figure motion and is explained by a simpler model that uses only the first layer in both eyes. Second-order motion cues thus enable prey motion to be detected, even when perfectly matching the average background luminance and independent of the elementary motion of any parts of the prey. Subsequent to prey detection, processes such as stereopsis could work to determine the distance to the prey. We thus demonstrate how second-order motion mechanisms enable ecologically relevant behavior such as detecting camouflaged targets for other visual functions including stereopsis and target tracking.

scholarly journals The Role of Hub Neurons in Modulating Cortical Dynamics

2021 ◽  
Vol 15 ◽  
Author(s):  
Eyal Gal ◽  
Oren Amsalem ◽  
Alon Schindel ◽  
Michael London ◽  
Felix Schürmann ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Small World ◽  
Cell Types ◽  
Brain Regions ◽  
Cortical Layers ◽  
Disease Manifestation ◽  
Cortical Dynamics ◽  
The Impact ◽  
Specific Neuron

Many neurodegenerative diseases are associated with the death of specific neuron types in particular brain regions. What makes the death of specific neuron types particularly harmful for the integrity and dynamics of the respective network is not well understood. To start addressing this question we used the most up-to-date biologically realistic dense neocortical microcircuit (NMC) of the rodent, which has reconstructed a volume of 0.3 mm3 and containing 31,000 neurons, ∼37 million synapses, and 55 morphological cell types arranged in six cortical layers. Using modern network science tools, we identified hub neurons in the NMC, that are connected synaptically to a large number of their neighbors and systematically examined the impact of abolishing these cells. In general, the structural integrity of the network is robust to cells’ attack; yet, attacking hub neurons strongly impacted the small-world topology of the network, whereas similar attacks on random neurons have a negligible effect. Such hub-specific attacks are also impactful on the network dynamics, both when the network is at its spontaneous synchronous state and when it was presented with synchronized thalamo-cortical visual-like input. We found that attacking layer 5 hub neurons is most harmful to the structural and functional integrity of the NMC. The significance of our results for understanding the role of specific neuron types and cortical layers for disease manifestation is discussed.

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

1982 ◽  
Vol 40 ◽  
pp. 132-133
Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Replication Rate ◽  
Enzymatic Dissociation ◽  
Growth Assay ◽  
Epidermal Growth ◽  
Fetal Bovine ◽  
Esophageal Epithelial Cells ◽  
Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

Role of PKC isozymes in water transport in toad urinary bladder

1991 ◽  
Vol 49 ◽  
pp. 302-303
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Apical Membrane ◽  
Membrane Surface ◽  
Protein A ◽  
Cell Types ◽  
Leukemic Cells ◽  
Toad Urinary Bladder ◽  
Pkc Isozymes ◽  
Antibody Labeling

Protein kinase C (PKC) isozymes, when activated, are translocated to particulate membrane fractions for transport to the apical membrane surface in a variety of cell types. Evidence of PKC translocation was demonstrated in human megakaryoblastic leukemic cells, and in cardiac myocytes and fibroblasts, using FTTC immunofluorescent antibody labeling techniques. Recently, we reported immunogold localizations of PKC subtypes I and II in toad urinary bladder epithelia, following 60 min stimulation with Mezerein (MZ), a PKC activator, or antidiuretic hormone (ADH). Localization of isozyme subtypes I and n was carried out in separate grids using specific monoclonal antibodies with subsequent labeling with 20nm protein A-gold probes. Each PKC subtype was found to be distributed singularly and in discrete isolated patches in the cytosol as well as in the apical membrane domains. To determine if the PKC isozymes co-localized within the cell, a double immunogold labeling technique using single grids was utilized.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

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