scholarly journals Encoding model for continuous motion-sensitive neurons in the intermediate and deep layers of the pigeon optic tectum

Neuroscience ◽  
2022 ◽  
Author(s):  
Songwei Wang ◽  
Quangong Ma ◽  
Longlong Qian ◽  
Mengyu Zhao ◽  
Zhizhong Wang ◽  
...  
Keyword(s):  
Optic Tectum ◽  
Continuous Motion ◽  
Deep Layers

scholarly journals Encoding model for continuous motion-sensitive neurons in the intermediate and deep layers of pigeon Optic Tectum

2021 ◽  
Author(s):  
Songwei Wang ◽  
Mengyu Zhao ◽  
Longlong Qian ◽  
Zhizhong Wang ◽  
Li Shi
Keyword(s):  
Optic Tectum ◽  
Detection Algorithm ◽  
Random Motion ◽  
Activation Mechanism ◽  
Small Target ◽  
Moving Targets ◽  
Continuous Motion ◽  
Information Encoding ◽  
Deep Layers

AbstractThere are typical neurons in the intermediate and deep layers of the optic tectum of avian, which are sensitive to small continuous moving targets. Based on this sensitivity of these neurons to continuous moving targets, the hypothesis of directed energy accumulation in dendrite field of these neurons is proposed. Based on the phenomenon that single dendrite activation can induce somatic spikes in vitro, the hypothesis of sequential probability activation mechanism of soma is proposed. Combined with the above hypotheses, the information encoding model of these typical neurons is constructed. Moreover, electrophysiological experiments and model simulations are carried out to obtain the response of neurons to visual stimuli of sequential motion, random motion and random sequential motion. Results show that the encoding model fits the response properties of continuous motion-sensitive neurons well. This study is of great significance for understanding the neurophysiological process of small-target perception for avian tectofugal pathway and the construction of the brain-inspired small-target detection algorithm.

scholarly journals Space coding by gamma oscillations in the barn owl optic tectum

2011 ◽  
Vol 105 (5) ◽  
pp. 2005-2017 ◽  
Author(s):  
Devarajan Sridharan ◽  
Kwabena Boahen ◽  
Eric I. Knudsen
Keyword(s):  
Optic Tectum ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Stimulus Location ◽  
Gamma Band ◽  
Sensory Stimuli ◽  
Visual Contrast ◽  
Wide Range ◽  
Gamma Power ◽  
Deep Layers

Gamma-band (25–140 Hz) oscillations of the local field potential (LFP) are evoked by sensory stimuli in the mammalian forebrain and may be strongly modulated in amplitude when animals attend to these stimuli. The optic tectum (OT) is a midbrain structure known to contribute to multimodal sensory processing, gaze control, and attention. We found that presentation of spatially localized stimuli, either visual or auditory, evoked robust gamma oscillations with distinctive properties in the superficial (visual) layers and in the deep (multimodal) layers of the owl's OT. Across layers, gamma power was tuned sharply for stimulus location and represented space topographically. In the superficial layers, induced LFP power peaked strongly in the low-gamma band (25–90 Hz) and increased gradually with visual contrast across a wide range of contrasts. Spikes recorded in these layers included presumptive axonal (input) spikes that encoded stimulus properties nearly identically with gamma oscillations and were tightly phase locked with the oscillations, suggesting that they contribute to the LFP oscillations. In the deep layers, induced LFP power was distributed across the low and high (90–140 Hz) gamma-bands and tended to reach its maximum value at relatively low visual contrasts. In these layers, gamma power was more sharply tuned for stimulus location, on average, than were somatic spike rates, and somatic spikes synchronized with gamma oscillations. Such gamma synchronized discharges of deep-layer neurons could provide a high-resolution temporal code for signaling the location of salient sensory stimuli.

Synchronization of neuronal responses in the optic tectum of awake pigeons

1996 ◽  
Vol 13 (3) ◽  
pp. 575-584 ◽  
Author(s):  
Sergio Neuenschwander ◽  
Andreas K. Engel ◽  
Peter König ◽  
Wolf Singer ◽  
Francisco J. Varela
Keyword(s):  
Optic Tectum ◽  
Visual Processing ◽  
Cross Correlation ◽  
Spike Trains ◽  
Neuronal Firing ◽  
Neuronal Responses ◽  
Temporal Relationships ◽  
Cross Correlation Analysis ◽  
Deep Layers ◽  
Zero Phase

AbstractMultiunit activity was recorded in the optic tectum of awake pigeons with two electrodes at sites varying in depth and separated by 0.3 to 3.0 mm. Autocorrelation and cross-correlation functions were computed from the recorded spike trains to determine temporal relationships in the neuronal firing patterns. Cross-correlation analysis revealed that spatially separate groups of cells in the tectum show synchronous responses to a visual stimulus. Strong synchronization occurred in both superficial and deep layers of the tectum, in general with zero-phase shift. The response synchronization in the avian optic tectum resembles that observed in the mammalian cortex, suggesting that it may subserve common functions in visual processing.

Ongoing activity in the optic tectum is correlated on a trial-by-trial basis with the pupil dilation response

2014 ◽  
Vol 111 (5) ◽  
pp. 918-929 ◽  
Author(s):  
Shai Netser ◽  
Arkadeb Dutta ◽  
Yoram Gutfreund
Keyword(s):  
Neural Activity ◽  
Optic Tectum ◽  
Internal State ◽  
Field Potential ◽  
Behavioral Responses ◽  
Orienting Response ◽  
Pupil Dilation ◽  
Ongoing Activity ◽  
Potential Oscillations ◽  
Deep Layers

The selection of the appropriate stimulus to induce an orienting response is a basic task thought to be partly achieved by tectal circuitry. Here we addressed the relationship between neural activity in the optic tectum (OT) and orienting behavioral responses. We recorded multiunit activity in the intermediate/deep layers of the OT of the barn owl simultaneously with pupil dilation responses (PDR, a well-known orienting response common to birds and mammals). A trial-by-trial analysis of the responses revealed that the PDR generally did not correlate with the evoked neural responses but significantly correlated with the rate of ongoing neural activity measured shortly before the stimulus. Following this finding, we characterized ongoing activity in the OT and showed that in the intermediate/deep layers it tended to fluctuate spontaneously. It is characterized by short periods of high ongoing activity during which the probability of a PDR to an auditory stimulus inside the receptive field is increased. These high-ongoing activity periods were correlated with increase in the power of gamma band local field potential oscillations. Through dual recordings, we showed that the correlation coefficients of ongoing activity decreased as a function of distance between recording sites in the tectal map. Significant correlations were also found between recording sites in the OT and the forebrain entopallium. Our results suggest that an increase of ongoing activity in the OT reflects an internal state during which coupling between sensory stimulation and behavioral responses increases.

scholarly journals N2O dynamics in the western Arctic Ocean during the summer of 2017

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jang-Mu Heo ◽  
Seong-Su Kim ◽  
Sung-Ho Kang ◽  
Eun Jin Yang ◽  
Ki-Tae Park ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Environmental Changes ◽  
Chukchi Sea ◽  
Hot Spot ◽  
Open Water ◽  
Northern Region ◽  
The Arctic ◽  
Western Arctic Ocean ◽  
Deep Layers ◽  
Western Arctic

AbstractThe western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0–50 m) and deep layers (200–2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0–50 m) of the southern Chukchi Sea and the intermediate (50–200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 μmol N2O m−2 day−1), whereas the northern region acted as a sink (mean − 1.3 ± 1.5 μmol N2O m−2 day−1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O “hot spot”, and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.

scholarly journals Critical Effects on Akt Signaling in Adult Zebrafish Brain Following Alterations in Light Exposure

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 637
Author(s):  
Nicholas S. Moore ◽  
Robert A. Mans ◽  
Mackenzee K. McCauley ◽  
Colton S. Allgood ◽  
Keri A. Barksdale
Keyword(s):  
Optic Tectum ◽  
Visual Processing ◽  
Environmental Enrichment ◽  
Glycogen Synthase ◽  
Light Exposure ◽  
Hsp70 Expression ◽  
Light Cycle ◽  
Adult Zebrafish ◽  
Sleep State ◽  
Zebrafish Brain

Evidence from human and animal studies indicate that disrupted light cycles leads to alterations of the sleep state, poor cognition, and the risk of developing neuroinflammatory and generalized health disorders. Zebrafish exhibit a diurnal circadian rhythm and are an increasingly popular model in studies of neurophysiology and neuropathophysiology. Here, we investigate the effect of alterations in light cycle on the adult zebrafish brain: we measured the effect of altered, unpredictable light exposure in adult zebrafish telencephalon, homologous to mammalian hippocampus, and the optic tectum, a significant visual processing center with extensive telencephalon connections. The expression of heat shock protein-70 (HSP70), an important cell stress mediator, was significantly decreased in optic tectum of adult zebrafish brain following four days of altered light exposure. Further, pSer473-Akt (protein kinase B) was significantly reduced in telencephalon following light cycle alteration, and pSer9-GSK3β (glycogen synthase kinase-3β) was significantly reduced in both the telencephalon and optic tectum of light-altered fish. Animals exposed to five minutes of environmental enrichment showed significant increase in pSer473Akt, which was significantly attenuated by four days of altered light exposure. These data show for the first time that unpredictable light exposure alters HSP70 expression and dysregulates Akt-GSK3β signaling in the adult zebrafish brain.

scholarly journals Multiview deep learning based on tensor decomposition and its application in fault detection of overhead contact systems

2021 ◽  
Author(s):  
Xuewu Zhang ◽  
Yansheng Gong ◽  
Chen Qiao ◽  
Wenfeng Jing
Keyword(s):  
High Speed ◽  
Tensor Decomposition ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Feature Maps ◽  
Training Time ◽  
Detection Model ◽  
Railway Line ◽  
Result Show ◽  
Deep Layers

AbstractThis article mainly focuses on the most common types of high-speed railways malfunctions in overhead contact systems, namely, unstressed droppers, foreign-body invasions, and pole number-plate malfunctions, to establish a deep-network detection model. By fusing the feature maps of the shallow and deep layers in the pretraining network, global and local features of the malfunction area are combined to enhance the network's ability of identifying small objects. Further, in order to share the fully connected layers of the pretraining network and reduce the complexity of the model, Tucker tensor decomposition is used to extract features from the fused-feature map. The operation greatly reduces training time. Through the detection of images collected on the Lanxin railway line, experiments result show that the proposed multiview Faster R-CNN based on tensor decomposition had lower miss probability and higher detection accuracy for the three types faults. Compared with object-detection methods YOLOv3, SSD, and the original Faster R-CNN, the average miss probability of the improved Faster R-CNN model in this paper is decreased by 37.83%, 51.27%, and 43.79%, respectively, and average detection accuracy is increased by 3.6%, 9.75%, and 5.9%, respectively.

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