DYNAMICS OF THE GHOSTS—GAUGE-FIXED ACTION

2020 ◽  
pp. 234-252
Keyword(s):  
Fixed Action

scholarly journals Mesolimbic dopamine projections mediate cue-motivated reward seeking but not reward retrieval in rats

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Briac Halbout ◽  
Andrew T Marshall ◽  
Ali Azimi ◽  
Mimi Liljeholm ◽  
Stephen V Mahler ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Nucleus Accumbens ◽  
Suppressive Effect ◽  
Maladaptive Behavior ◽  
Dopamine Neurons ◽  
Action Sequence ◽  
Reward Seeking ◽  
Fixed Action ◽  
Dopamine Circuits ◽  
Goal Directed Behavior

Efficient foraging requires an ability to coordinate discrete reward-seeking and reward-retrieval behaviors. We used pathway-specific chemogenetic inhibition to investigate how rats’ mesolimbic and mesocortical dopamine circuits contribute to the expression and modulation of reward seeking and retrieval. Inhibiting ventral tegmental area dopamine neurons disrupted the tendency for reward-paired cues to motivate reward seeking, but spared their ability to increase attempts to retrieve reward. Similar effects were produced by inhibiting dopamine inputs to nucleus accumbens, but not medial prefrontal cortex. Inhibiting dopamine neurons spared the suppressive effect of reward devaluation on reward seeking, an assay of goal-directed behavior. Attempts to retrieve reward persisted after devaluation, indicating they were habitually performed as part of a fixed action sequence. Our findings show that complete bouts of reward seeking and retrieval are behaviorally and neurally dissociable from bouts of reward seeking without retrieval. This dichotomy may prove useful for uncovering mechanisms of maladaptive behavior.

scholarly journals Ethological description of a fixed action pattern in a kissing bug (Triatominae): vision, gustation, proboscis extension and drinking of water and guava

2018 ◽  
Vol 36 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Oscar Páez-Rondón ◽  
Elis Aldana ◽  
Joseph Dickens ◽  
Fernando Otálora-Luna
Keyword(s):  
Triatoma Infestans ◽  
Action Pattern ◽  
Guava Fruit ◽  
Fixed Action Pattern ◽  
Link Type ◽  
Video Images ◽  
Fixed Action ◽  
Triatomine Species ◽  
Proboscis Extension ◽  
Panstrongylus Geniculatus

Abstract Triatomines (Heteroptera, Reduviidae) are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in America. These true bugs have traditionally been considered to be blood suckers, although some species have been catalogued as being entomophagous. By using their highly specialized mouthparts, these insects have evolved a stereotyped habit which includes lifting up the proboscis, piercing and sucking, when the occasion arises. Most triatomines bite their sleeping and unaware vertebrate or invertebrate hosts, but they can also search for other targets, guided, in part, by visual and chemical stimuli. In this study, we observed that triatomines apparently visually identify a drop of water in the distance, then taste it with their legs, upon which proboscis extension and sucking ensues. This invariant behavior or fixed action pattern, observed in several triatomine species (Rhodnius prolixus, Triatoma infestans and Panstrongylus geniculatus), was also elicited by a dummy drop of water and guava fruit. We discuss evolutionary and ethological aspects of this innate behavior. Digital video images related to this article are available at http://www.momo-p.com/showdetail-e.php?movieid=momo180314rp01a and http://www.momo-p.com/showdetail-e.php?movieid=momo180314rp03a.

Chiral strings, topological branes, and a generalised Weyl-invariance

2019 ◽  
Vol 34 (06n07) ◽  
pp. 1950031 ◽  
Author(s):  
Alex S. Arvanitakis
Keyword(s):  
Field Theory ◽  
Sigma Model ◽  
Space Time ◽  
Symplectic Space ◽  
Topological Field Theory ◽  
Brst Operator ◽  
Weyl Invariance ◽  
Fixed Action ◽  
Twistor Strings ◽  
Topological Field

We introduce a sigma model Lagrangian generalising a number of new and old models which can be thought of as chiral, including the Schild string, ambitwistor strings, and the recently introduced tensionless AdS twistor strings. This “chiral sigma model” describes maps from a [Formula: see text]-brane worldvolume into a symplectic space and is manifestly invariant under diffeomorphisms as well as under a “generalised Weyl invariance” acting on space–time coordinates and worldvolume fields simultaneously. Construction of the Batalin–Vilkovisky master action leads to a BRST operator under which the gauge-fixed action is BRST-exact; we discuss whether this implies that the chiral brane sigma model defines a topological field theory.

COVARIANT QUANTIZATION OF BROKEN TWISTED N=2 SUPERPARTICLE

1992 ◽  
Vol 07 (17) ◽  
pp. 4053-4071 ◽  
Author(s):  
M. HUQ
Keyword(s):  
Infinite Sequence ◽  
Covariant Quantization ◽  
Brst Operator ◽  
Fixed Action ◽  
Gauge Choice

We have considered a superparticle action consisting of an infinite tower of Siegel superparticle actions plus a term breaking all the twisted N=2 supersymmetries down to the required N=1 supersymmetry. With appropriate gauge choice we arrive at a quadratic gauge-fixed action, which naturally possesses an infinite sequence of twisted N=2 supersymmetries, but the BRST operator picks out the correct physical states for the Brink-Casalbuoni-Schwarz superparticle.

scholarly journals No evidence of contagious yawning in the red-footed tortoise Geochelone carbonaria

2011 ◽  
Vol 57 (4) ◽  
pp. 477-484 ◽  
Author(s):  
Anna Wilkinson ◽  
Natalie Sebanz ◽  
Isabella Mandl ◽  
Ludwig Huber
Keyword(s):  
Mental State ◽  
Perception And Action ◽  
Social Processes ◽  
Action Pattern ◽  
Social Stimuli ◽  
Contagious Yawning ◽  
Mental State Attribution ◽  
Fixed Action Pattern ◽  
Fixed Action ◽  
Significant Difference

Abstract Three hypotheses have attempted to explain the phenomenon of contagious yawning. It has been hypothesized that it is a fixed action pattern for which the releasing stimulus is the observation of another yawn, that it is the result of non-conscious mimicry emerging through close links between perception and action or that it is the result of empathy, involving the ability to engage in mental state attribution. This set of experiments sought to distinguish between these hypotheses by examining contagious yawning in a species that is unlikely to show nonconscious mimicry and empathy but does respond to social stimuli: the red-footed tortoise Geochelone carbonaria. A demonstrator tortoise was conditioned to yawn when presented with a red square-shaped stimulus. Observer tortoises were exposed to three conditions: observation of conditioned yawn, non demonstration control, and stimulus only control. We measured the number of yawns for each observer animal in each condition. There was no difference between conditions. Experiment 2 therefore increased the number of conditioned yawns presented. Again, there was no significant difference between conditions. It seemed plausible that the tortoises did not view the conditioned yawn as a real yawn and therefore a final experiment was run using video recorded stimuli. The observer tortoises were presented with three conditions: real yawn, conditioned yawns and empty background. Again there was no significant difference between conditions. We therefore conclude that the red-footed tortoise does not yawn in response to observing a conspecific yawn. This suggests that contagious yawning is not the result of a fixed action pattern but may involve more complex social processes.

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