Vision, Color Vision, and Visually Guided Behavior: The Novel Toxicological Targets of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47)

Drosophila melanogaster exhibits a robust escape response to objects approaching on a collision course. Although a pair of large command interneurons called the giant fibers (GFs) have been postulated to trigger such behaviors, their role has not been directly demonstrated. Here, we show that escape from visual stimuli like those generated by approaching predators does not rely on the activation of the GFs and consists of a more complex and less stereotyped motor sequence than that evoked by the GFs. Instead, the timing of escape is tightly correlated with the activity of previously undescribed descending interneurons that signal a threshold angular size of the approaching object. The activity pattern of these interneurons shares features with those of visual escape circuits of several species, including pigeons, frogs, and locusts, and may therefore have evolved under similar constraints. These results show that visually evoked escapes in Drosophila can rely on at least two descending neuronal pathways: the GFs and the novel pathway we characterize electrophysiologically. These pathways exhibit very different patterns of sensory activity and are associated with two distinct motor programs.

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Single-Sweep Pulmonary Vein Isolation using the new third-generation laser balloon -- Evolution in ablation style using endoscopic ablation system

10.22541/au.162223100.04469413/v1 ◽

2021 ◽

Author(s):

Shota Tohoku ◽

Stefano Bordignon ◽

Luca Trolese ◽

Simone Zanchi ◽

Lorenzo Bianchini ◽

...

Keyword(s):

Pulmonary Vein ◽

Pulmonary Vein Isolation ◽

The Novel ◽

Visually Guided ◽

Phrenic Nerve Palsy ◽

Endoscopic Ablation ◽

First Pass ◽

The Mean ◽

Ischemic Attack ◽

Total Procedure

Background: The endoscopic ablation system (EAS) is an established ablation device for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). The novel X3 EAS is now equipped with a contiguous circumferential ablation mode (RAPID mode). Aim: To determine the feasibility of single-sweep ablation using X3. Methods: Consecutive patients who underwent AF ablation using X3 were enrolled. We assessed the acute procedural data focusing on “Single-sweep PVI” defined as PVI with a single energy application using RAPID mode to complete the circular lesion set, and on “first-pass isolation” defined as successful visually guided PVI after initial circular lesion set. Results: One-hundred AF patients (56% male, age 68±10 years, 66% paroxysmal AF) were analyzed. A total of 379 of 383 PVs (99%) were isolated with X3. Single-sweep isolation and first-pass-isolation were achieved in 214 PVs (56%) and in 362 PVs (95%), respectively. Single-sweep isolation rates varied across PVs with higher rates at the superior PVs (61.2% vs. inferior PVs:49.5%, P=0.0239) and at PVs with maximal ostial diameter <24mm (57.6% vs. >24mm: 36.8%, P=0.0151). The mean total procedure and fluoroscopy times were 43.0±10 and 4.0±2 mins, respectively. In none of the patients an acute thromboembolic event (stroke or transient ischemic attack) or a pericardial effusion/tamponade occurred. A single transient phrenic nerve palsy was observed. Conclusion: The new X3 EAS allows for single-sweep PVI in 56% of PVs. The new RAPID ablation mode leads to an improved rate of first-pass isolation associated with very short procedure times without compromising safety.

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A Dynamic Neural Field Model of Visual Working Memory and Change Detection

Psychological Science ◽

10.1111/j.1467-9280.2009.02329.x ◽

2009 ◽

Vol 20 (5) ◽

pp. 568-577 ◽

Cited By ~ 66

Author(s):

Jeffrey S. Johnson ◽

John P. Spencer ◽

Steven J. Luck ◽

Gregor Schöner

Keyword(s):

Working Memory ◽

Change Detection ◽

Visual Working Memory ◽

The Novel ◽

Visually Guided ◽

Neural Field Model ◽

Underlying Mechanisms ◽

Considerable Body ◽

Dynamic Neural Field Model ◽

Shed Light

Efficient visually guided behavior depends on the ability to form, retain, and compare visual representations for objects that may be separated in space and time. This ability relies on a short-term form of memory known as visual working memory. Although a considerable body of research has begun to shed light on the neurocognitive systems subserving this form of memory, few theories have addressed these processes in an integrated, neurally plausible framework. We describe a layered neural architecture that implements encoding and maintenance, and links these processes to a plausible comparison process. In addition, the model makes the novel prediction that change detection will be enhanced when metrically similar features are remembered. Results from experiments probing memory for color and for orientation were consistent with this novel prediction. These findings place strong constraints on models addressing the nature of visual working memory and its underlying mechanisms.

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Avoiding pitfalls: Trace conditioning and rapid aversive learning during route navigation in desert ants

10.1101/771204 ◽

2019 ◽

Cited By ~ 3

Author(s):

Antoine Wystrach ◽

Cornelia Buehlmann ◽

Sebastian Schwarz ◽

Ken Cheng ◽

Paul Graham

Keyword(s):

Visual Information ◽

Trace Conditioning ◽

Neural Circuitry ◽

Natural Environments ◽

The Novel ◽

Visually Guided ◽

Aversive Learning ◽

Complex Environments ◽

Learning And Development ◽

Goal Direction

AbstractThe ability of bees and ants to learn long visually guided routes in complex environments is perhaps one of the most spectacular pieces of evidence for the impressive power of their small brains. While flying bees can visit flowers in an optimised sequence over kilometres, walking ants can precisely recapitulate routes of up to a hundred metres in complex environments. It is clear that route following depends largely on learnt visual information and we have good idea how views can guide individuals along them, however little is known about the mechanisms that control route learning and development. Here we show that ants in natural environments can actively learn a route detour to avoid a pit trap and that this depends on a process analogous to aversive trace conditioning. Views experienced before falling into the trap become associated with the ensuing negative outcome and thus trigger salutary turns on the subsequent trip. This drives the ants to orient away from the goal direction and avoid the trap. If the pit is avoided, the novel views experienced during the detour become positively reinforced and the new route crystallises. We discuss how such an interplay between appetitive and aversive memories might be implemented in insect neural circuitry.

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The Influence of Induced Emotions on Distance and Size Perception and on the Grip Scaling During Grasping

Frontiers in Psychology ◽

10.3389/fpsyg.2021.651885 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chuyang Sun ◽

Juan Chen ◽

Yuting Chen ◽

Rixin Tang

Keyword(s):

Visual Feedback ◽

Perception And Action ◽

Negative Emotion ◽

Target Object ◽

Open Loop ◽

Size Perception ◽

The Novel ◽

Visually Guided ◽

Grip Aperture ◽

Wooden Block

Previous studies have shown that our perception of stimulus properties can be affected by the emotional nature of the stimulus. It is not clear, however, how emotions affect visually-guided actions toward objects. To address this question, we used toy rats, toy squirrels, and wooden blocks to induce negative, positive, and neutral emotions, respectively. Participants were asked to report the perceived distance and the perceived size of a target object resting on top of one of the three emotion-inducing objects; or to grasp the same target object either without visual feedback (open-loop) or with visual feedback (closed-loop) of both the target object and their grasping hand during the execution of grasping. We found that the target object was perceived closer and larger, but was grasped with a smaller grip aperture in the rat condition than in the squirrel and the wooden-block conditions when no visual feedback was available. With visual feedback present, this difference in grip aperture disappeared. These results showed that negative emotion influences both perceived size and grip aperture, but in opposite directions (larger perceived size but smaller grip aperture) and its influence on grip aperture could be corrected by visual feedback, which revealed different effects of emotion to perception and action. Our results have implications on the understanding of the relationship between perception and action in emotional condition, which showed the novel difference from previous theories.

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