scholarly journals Panoramic visual representation in the dorsal visual pathway and its role in reorientation

2019 ◽  
Author(s):  
Tianyi Li ◽  
Angelo Arleo ◽  
Denis Sheynikhovich

AbstractWhile primates are primarily visual animals, how visual information is processed on its way to memory structures and contributes to the generation of visuospatial behaviors is poorly understood. Recent imaging data demonstrate the existence of scene-sensitive areas in the dorsal visual path that are likely to combine visual information from successive egocentric views, while behavioral evidence indicates the memory of surrounding visual space in extraretinal coordinates. The present work focuses on the computational nature of a panoramic representation that is proposed to link visual and mnemonic functions during natural behavior. In a spiking neural network model of the dorsal visual path it is shown how time-integration of spatial views can give rise to such a representation and how it can subsequently be used to perform memory-based spatial reorientation and visual search. More generally, the model predicts a common role of view-based allocentric memory storage in spatial and non-spatial mnemonic behaviors.


2021 ◽  
Author(s):  
Anna Phan ◽  
Juan Carlos Martinez Cervantes ◽  
Isaac Cervantes Sandoval

Learning and memory storage is a complex process that has proven challenging to tackle. It is likely that, in real nature, the instructive value of reinforcing experiences is acquired rather than innate. The association between seemingly neutral stimuli increases the gamut of possibilities to create meaningful associations and increases the predictive power of moment-by-moment experiences. Here we report physiological and behavioral evidence of olfactory unimodal sensory preconditioning in fruit flies. We show that the presentation of a pair of odors (S1 and S2) before one of them (S1) is associated with electric shocks elicits a conditional response not only to the trained odor (S1) but to the odor previously paired with it (S2). This occurs even if the S2 odor was never presented in contiguity with the aversive stimulus. In addition, we show that inhibition of the small G protein and known forgetting regulator Rac1 facilitates the association between S1/S2 odors. These results indicate that flies can infer value to non-paired odor based on the previous associative structure between odors, and inhibition of Rac1 lengthens the time of olfactory sensory buffer, allowing linking of neutral odors presented in sequence.



Author(s):  
Vincenzo Butticè ◽  
Silvio Vismara

AbstractNowadays equity crowdfunding plays an important role in the entrepreneurial finance markets. To better understand the functioning of the industry, it is important to consider the entire equity crowdfunding process and all the actors involved. Equity crowdfunding platforms match indeed the demand of capital from entrepreneurial ventures with the supply of capital by investors. This manuscript is a first step in this direction, by (1) comparing equity crowdfunding with traditional sources of entrepreneurial finance; (2) discussing the potential and the perils of equity crowdfunding for inclusivity and democratization; (3) highlighting the role of visual information in digital finance; and (4) providing first insights on the industrial dynamics in equity crowdfunding. The paper gives researchers and practitioners orientation about recent developments in equity crowdfunding literature and provides relevant research directions.



Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 724
Author(s):  
Alberto Cesarani ◽  
Giuseppe Pulina

The concept of welfare applied to farm animals has undergone a remarkable evolution. The growing awareness of citizens pushes farmers to guarantee the highest possible level of welfare to their animals. New perspectives could be opened for animal welfare reasoning around the concept of domestic, especially farm, animals as partial human artifacts. Therefore, it is important to understand how much a particular behavior of a farm animal is far from the natural one of its ancestors. This paper is a contribution to better understand the role of genetics of the farm animals on their behavior. This means that the naïve approach to animal welfare regarding returning animals to their natural state should be challenged and that welfare assessment should be considered.



Author(s):  
Lorenzo Cangiano ◽  
Sabrina Asteriti

AbstractIn the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.



2016 ◽  
Vol 12 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Ceylan Özdem ◽  
Marcel Brass ◽  
Laurens Van der Cruyssen ◽  
Frank Van Overwalle


Endocrinology ◽  
2014 ◽  
Vol 155 (11) ◽  
pp. 4356-4367 ◽  
Author(s):  
Jennifer E. Richard ◽  
Imre Farkas ◽  
Fredrik Anesten ◽  
Rozita H. Anderberg ◽  
Suzanne L. Dickson ◽  
...  

Abstract The parabrachial nucleus (PBN) is a key nucleus for the regulation of feeding behavior. Inhibitory inputs from the hypothalamus to the PBN play a crucial role in the normal maintenance of feeding behavior, because their loss leads to starvation. Viscerosensory stimuli result in neuronal activation of the PBN. However, the origin and neurochemical identity of the excitatory neuronal input to the PBN remain largely unexplored. Here, we hypothesize that hindbrain glucagon-like peptide 1 (GLP-1) neurons provide excitatory inputs to the PBN, activation of which may lead to a reduction in feeding behavior. Our data, obtained from mice expressing the yellow fluorescent protein in GLP-1-producing neurons, revealed that hindbrain GLP-1-producing neurons project to the lateral PBN (lPBN). Stimulation of lPBN GLP-1 receptors (GLP-1Rs) reduced the intake of chow and palatable food and decreased body weight in rats. It also activated lPBN neurons, reflected by an increase in the number of c-Fos-positive cells in this region. Further support for an excitatory role of GLP-1 in the PBN is provided by electrophysiological studies showing a remarkable increase in firing of lPBN neurons after Exendin-4 application. We show that within the PBN, GLP-1R activation increased gene expression of 2 energy balance regulating peptides, calcitonin gene-related peptide (CGRP) and IL-6. Moreover, nearly 70% of the lPBN GLP-1 fibers innervated lPBN CGRP neurons. Direct intra-lPBN CGRP application resulted in anorexia. Collectively, our molecular, anatomical, electrophysiological, pharmacological, and behavioral data provide evidence for a functional role of the GLP-1R for feeding control in the PBN.



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