18 research outputs found
Subjective decision threshold for accurate visual detection performance in rats
No full textAbstractThe dissociation between a subjective-criterion performance and forced performance in a sensory detection can provide critical insights into the neural correlates of sensory awareness. Here, we established a behavioral task for rats to test their spatial-visual cue detection ability, using a two alternative choice task with and without a third choice option where animals get rewards only in the objective absence of a visual cue. In the trials without the third option, spatial choice accuracy decreased from near perfect to near chance levels as the visual cue brightness decreased. In contrast, with the third option, the rats exhibited >90% spatial choice accuracy regardless of the cue brightness. The rats chose the third choice option less frequently when the cue was brighter, suggesting that rats have a generalized strategy to make spatial choices only when their internal detection criterion is met. Interestingly, even when the animals chose the third option, they could still significantly and correctly choose the direction of the visual stimuli if they were forced. Our data suggest that the rats’ variable detection performance with identical set of stimuli is derived from stochastic processing of visual signals with a certain internal detection threshold rather than general motivational threshold.</jats:p
Temporal dynamics of endogenous attentional modulation without cue awareness
No full textABSTRACTInvisible visual stimuli can regulate our broad cognitive performance in the pursuit of current goals. Endogenous spatial attention is an important modulator of cognitive performance, and it can be triggered by unconscious cues. However, how its effect changes with time remains unclear. Here, we show that endogenous attention was triggered by an arrow-cue whose direction participants reported being unaware of but which affected the task performance in a time-dependent manner. Participants were asked to remember the directions of eight Landolt c rings (target memory array) after arrow-cue presentation, which was designed to orient their attention to a certain c ring. Then, we applied a delay, ranging from 83 ms to 1000 ms, between the arrow-cue and the target memory array presentation (the possible delays were equally spaced on a logarithmic scale). The attentional effect was greater for the 83, 183, 250 and 333 ms delays than the other six possible delays. In contrast, its effect was maintained irrespective of the delay when the participants reported being aware of the cue direction. Thus, awareness of arrow-cue direction was necessary to maintain endogenous attentional modulation, and its modulation without arrow-cue direction awareness was limited in a time-dependent manner.</jats:p
State representation of non-sensory neurons in visual cortical areas in the rat
No full textapplication/pd
Multiple Approaches to the Investigation of Cell Assembly in Memory Research—Present and Future
No full textIn this review article we focus on research methodologies for detecting the actual activity of cell assemblies, which are populations of functionally connected neurons that encode information in the brain. We introduce and discuss traditional and novel experimental methods and those currently in development and briefly discuss their advantages and disadvantages for the detection of cell-assembly activity. First, we introduce the electrophysiological method, i.e., multineuronal recording, and review former and recent examples of studies showing models of dynamic coding by cell assemblies in behaving rodents and monkeys. We also discuss how the firing correlation of two neurons reflects the firing synchrony among the numerous surrounding neurons that constitute cell assemblies. Second, we review the recent outstanding studies that used the novel method of optogenetics to show causal relationships between cell-assembly activity and behavioral change. Third, we review the most recently developed method of live-cell imaging, which facilitates the simultaneous observation of firings of a large number of neurons in behaving rodents. Currently, all these available methods have both advantages and disadvantages, and no single measurement method can directly and precisely detect the actual activity of cell assemblies. The best strategy is to combine the available methods and utilize each of their advantages with the technique of operant conditioning of multiple-task behaviors in animals and, if necessary, with brain–machine interface technology to verify the accuracy of neural information detected as cell-assembly activity
An intra-oral flavor detection task in freely moving mice
No full textFlavor plays a critical role in the pleasure of food. Flavor research has mainly focused on human subjects and revealed that many brain regions are involved in flavor perception. However, animal models for elucidating the mechanisms of neural circuits are lacking. Herein, we demonstrate the use of a novel behavioral task in which mice are capable of flavor detection. When the olfactory pathways of the mice were blocked, they could not perform the task. However, behavioral accuracy was not affected when the gustatory pathway was blocked by benzocaine. These results indicate that the mice performed this detection task mainly based on the olfaction. We conclude that this novel task can contribute to research on the neural mechanisms of flavor perception.journal articl
State representation of non-sensory neurons in visual cortical areas in the rat
No full textdoctoral thesi
Multiple Approaches to the Investigation of Cell Assembly in Memory Research—Present and Future
No full textClinical Factors Associated with SFTS Diagnosis and Severity in Cats
No full textSevere fever with thrombocytopenia syndrome (SFTS) is a potentially fatal tick-borne zoonosis caused by SFTS virus (SFTSV). In addition to tick bites, animal-to-human transmission of SFTSV has been reported, but little is known about feline SFTSV infection. In this study, we analyzed data on 187 cats with suspected SFTS to identify biomarkers for SFTS diagnosis and clinical outcome. Body weight, red and white blood cell and platelet counts, and serum aspartate aminotransferase and total bilirubin levels were useful for SFTS diagnosis, whereas alanine aminotransferase, aspartate aminotransferase and serum SFTSV RNA levels were associated with clinical outcome. We developed a scoring model to predict SFTSV infection. In addition, we performed a phylogenetic analysis to reveal the relationship between disease severity and viral strain. This study provides comprehensive information on feline SFTS and could contribute to the protection of cat owners, community members, and veterinarians from the risk of cat-transmitted SFTSV infection.長崎大学学位論文 学位記番号:博(医歯薬)甲第1646号 学位授与年月日:令和6年9月20日Author: Hiromu Osako, Qiang Xu, Takeshi Nabeshima, Jean Claude Balingit, Khine Mya Nwe, Fuxun Yu, Shingo Inoue, Daisuke Hayasaka, Mya Myat Ngwe Tun, Kouichi Morita and Yuki TakamatsuCitation: Viruses, 16(6), art. no. 874; 2024Nagasaki University (長崎大学), 博士(医学) (2024-09-20
Clinical Factors Associated with SFTS Diagnosis and Severity in Cats
No full textNagasaki University (長崎大学)博士(医学)Severe fever with thrombocytopenia syndrome (SFTS) is a potentially fatal tick-borne zoonosis caused by SFTS virus (SFTSV). In addition to tick bites, animal-to-human transmission of SFTSV has been reported, but little is known about feline SFTSV infection. In this study, we analyzed data on 187 cats with suspected SFTS to identify biomarkers for SFTS diagnosis and clinical outcome. Body weight, red and white blood cell and platelet counts, and serum aspartate aminotransferase and total bilirubin levels were useful for SFTS diagnosis, whereas alanine aminotransferase, aspartate aminotransferase and serum SFTSV RNA levels were associated with clinical outcome. We developed a scoring model to predict SFTSV infection. In addition, we performed a phylogenetic analysis to reveal the relationship between disease severity and viral strain. This study provides comprehensive information on feline SFTS and could contribute to the protection of cat owners, community members, and veterinarians from the risk of cat-transmitted SFTSV infection.長崎大学学位論文 学位記番号:博(医歯薬)甲第1646号 学位授与年月日:令和6年9月20日Author: Hiromu Osako, Qiang Xu, Takeshi Nabeshima, Jean Claude Balingit, Khine Mya Nwe, Fuxun Yu, Shingo Inoue, Daisuke Hayasaka, Mya Myat Ngwe Tun, Kouichi Morita and Yuki TakamatsuCitation: Viruses, 16(6), art. no. 874; 2024Nagasaki University (長崎大学), 博士(医学) (2024-09-20)doctoral thesi
