scholarly journals Spatial Dependence of Stimulus Competition in the Avian Nucleus Isthmi Pars Magnocellularis

2019 ◽  
Vol 93 (2-3) ◽  
pp. 137-151 ◽  
Author(s):  
Hannah M. Schryver ◽  
Shreesh P. Mysore

The nucleus isthmi pars magnocellularis (Imc) is a group of specialized inhibitory neurons in the midbrain tegmentum, thought to be conserved across vertebrate classes. Past anatomical work in reptiles has suggested a role for it in stimulus selection, which has been supported by recent studies in avians. Additionally, focal inactivation of Imc neurons is known to abolish all competitive interactions in the optic tectum (OT; SC in mammals), a midbrain sensorimotor hub that is critical for the control of spatial attention, thereby revealing a key role for Imc in stimulus selection. However, the functional properties of Imc neurons are not well understood. Here, with electrophysiological experiments in the barn owl Imc, we show that Imc neurons themselves exhibit signatures of stimulus competition. Distant competing stimuli outside the spatial receptive field (RF) suppressed powerfully, and divisively, the responses of Imc neurons to stimuli inside the RF, and did so from all tested locations along the elevation as well as azimuth. Notably, this held true even for locations encoded by the opposite side of the brain from the one containing the recording site. This global divisive inhibition operated independently of the sensory modality of the competing stimulus. Thus, the Imc not only supplies inhibition to the OT to support competition there, but may itself be an active site of stimulus competition. These results from experiments in the barn owl shed light on the functional properties of a vital node in the vertebrate midbrain selection network.

2017 ◽  
Vol 19 (3) ◽  
pp. 349-377
Author(s):  
Leonardo Niro Nascimento

This article first aims to demonstrate the different ways the work of the English neurologist John Hughlings Jackson influenced Freud. It argues that these can be summarized in six points. It is further argued that the framework proposed by Jackson continued to be pursued by twentieth-century neuroscientists such as Papez, MacLean and Panksepp in terms of tripartite hierarchical evolutionary models. Finally, the account presented here aims to shed light on the analogies encountered by psychodynamically oriented neuroscientists, between contemporary accounts of the anatomy and physiology of the nervous system on the one hand, and Freudian models of the mind on the other. These parallels, I will suggest, are not coincidental. They have a historical underpinning, as both accounts most likely originate from a common source: John Hughlings Jackson's tripartite evolutionary hierarchical view of the brain.


Behaviour ◽  
1966 ◽  
Vol 26 (3-4) ◽  
pp. 251-285 ◽  
Author(s):  
Robert S. Schmidt

AbstractRelease calling and warning crying in Rana pipiens are described and compared with breathing. Vokalizations consist of a vocal phase, which is merely a modification of the expiratory phase of breathing, followed by an inspiratory phase, which is identical to inspiratory phase of breathing. Electrical and mechanical stimulation of the brain and brain lesions are used to locate some of the central mechanisms controlling release calling and warning crying in Rana pipiens, and mating calling in Rana pipiens and a number of hylids (mainly Hyla cinerea). It is concluded that the main control mechanisms are in the trigeminoisthmic tegmentum (below the nucleus isthmi). Mating calling requires, in addition, input transmitted through the ventral thalamus from hormone receptors in the preoptic area. Mating calling can be evoked in hylids by presenting them with recordings of specific calls. The mechanisms for responding to an acoustic stimulus are probably located in the anterior medulla and midbrain tegmentum (below the nucleus isthmi). Mating calling was evoked in two Hyla cinerea females after replacing the ovaries with Rana testes and injecting Rana pituitaries. It is suggested that release calling evolved from breathing, and that warning crying and mating calling may then have evolved from release calling.


2020 ◽  
Vol 8 (5) ◽  
pp. 1615-1618 ◽  

Every year, more than 1 million people undergo limb amputations, and nearly one in six of the world’s population suffer from neurological disorders. Most of the afflicted are unable to perform basic day to day tasks. Until few years ago prosthetic arms served no actual utility to the one wearing it apart from giving an illusion of the limb, but now with the development of technology, prosthetic arms can be given utility to emulate the real functions of limbs. Using brain implants to read the brain signals, one can control prosthetic robotic arms which are fitted in place of the limbs. However, this procedure is invasive, risky and very expensive. Hence, not many people can afford this technology. Our paper attempts to shed light on a nonevasive cheaper approach to mind wave-controlled prosthetics without the use of brain implants. We have used an EEG headset to read the brainwaves allowing the user to move the robotic arm without having any implants. EEG headset is also a cheaper alternative to the expensive brain implants and it can be easily worn on the head and removed whenever needed. This allows us to help a wider demographic by proposing an affordable mind controlled prosthetic arm.


2018 ◽  
Author(s):  
Nagaraj R. Mahajan ◽  
Shreesh P. Mysore

The ability to select the most salient stimulus among competing ones is essential for animal behavior and operates regardless of the spatial locations that stimuli occupy. Here, we reveal that the brain employs a combinatorially optimized strategy to solve such location-invariant stimulus selection. With experiments in a key inhibitory nucleus in the vertebrate midbrain selection network, called isthmi pars magnocellularis (Imc) in owls, we discovered that the central element is a ‘multilobe’ neuron, which encodes visual locations with multiple firing fields. This multilobed coding of space is necessitated by scarcity of Imc neurons. Although distributed seemingly randomly in space, the locations of these lobes are optimized across the high firing Imc neurons, allowing them to cooperatively suppress stimuli throughout 2D visual space while minimizing metabolic and circuit wiring costs. Our work suggests that combinatorial coding of space by sparse inhibitory neurons may be a general functional module for spatial selection.


2018 ◽  
Vol 23 (1) ◽  
pp. 10-13
Author(s):  
James B. Talmage ◽  
Jay Blaisdell

Abstract Injuries that affect the central nervous system (CNS) can be catastrophic because they involve the brain or spinal cord, and determining the underlying clinical cause of impairment is essential in using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), in part because the AMA Guides addresses neurological impairment in several chapters. Unlike the musculoskeletal chapters, Chapter 13, The Central and Peripheral Nervous System, does not use grades, grade modifiers, and a net adjustment formula; rather the chapter uses an approach that is similar to that in prior editions of the AMA Guides. The following steps can be used to perform a CNS rating: 1) evaluate all four major categories of cerebral impairment, and choose the one that is most severe; 2) rate the single most severe cerebral impairment of the four major categories; 3) rate all other impairments that are due to neurogenic problems; and 4) combine the rating of the single most severe category of cerebral impairment with the ratings of all other impairments. Because some neurological dysfunctions are rated elsewhere in the AMA Guides, Sixth Edition, the evaluator may consult Table 13-1 to verify the appropriate chapter to use.


2021 ◽  
pp. 109634802098727
Author(s):  
Josip Mikulić ◽  
Damir Krešić ◽  
Maja Šerić

The current study intends to contribute to a better understanding of the medical tourism experience. In particular, this study uses data from a survey-based study conducted on a sample of 1,209 medical tourists in Croatia. On the one hand, this study aims to explore and shed light on the decision-making process of medical tourists, and, on the other hand, to reveal which elements of both the medical institution and the destination where it is located, have largest potentials to drive medical tourist delight and/or frustration, in accordance with the three-factor theory of customer satisfaction.


2021 ◽  
Vol 11 (8) ◽  
pp. 3397
Author(s):  
Gustavo Assunção ◽  
Nuno Gonçalves ◽  
Paulo Menezes

Human beings have developed fantastic abilities to integrate information from various sensory sources exploring their inherent complementarity. Perceptual capabilities are therefore heightened, enabling, for instance, the well-known "cocktail party" and McGurk effects, i.e., speech disambiguation from a panoply of sound signals. This fusion ability is also key in refining the perception of sound source location, as in distinguishing whose voice is being heard in a group conversation. Furthermore, neuroscience has successfully identified the superior colliculus region in the brain as the one responsible for this modality fusion, with a handful of biological models having been proposed to approach its underlying neurophysiological process. Deriving inspiration from one of these models, this paper presents a methodology for effectively fusing correlated auditory and visual information for active speaker detection. Such an ability can have a wide range of applications, from teleconferencing systems to social robotics. The detection approach initially routes auditory and visual information through two specialized neural network structures. The resulting embeddings are fused via a novel layer based on the superior colliculus, whose topological structure emulates spatial neuron cross-mapping of unimodal perceptual fields. The validation process employed two publicly available datasets, with achieved results confirming and greatly surpassing initial expectations.


Author(s):  
Juan P. Martínez ◽  
Inmaculada Méndez ◽  
Esther Secanilla ◽  
Ana Benavente ◽  
Julia García Sevilla

Starting from previous studies in professional caregivers of people with dementia and other diseases in institutionalized centers of different regions, the aim of this study was to compare burnout levels that workers present depending on the center, to create a caregiver profile with high professional accomplishment and to describe the quality of life that residents perceive Murcia and Barcelona. The instruments used were the Maslach Burnout Inventory (MBI), the Professional Caregiver Survey developed ad hoc and the Brief Questionnaire of Quality of Life (CUBRECAVI in Spanish) on residents. The results show, on the one hand, that levels of professional accomplishment may be paradoxically higher in the case of catastrophe and, on the other hand, the 98.2% of users are satisfied with the residence in which is located and 81.8% with the manner in which occupy the time. The conclusions that are extrapolated from the study shed light on the current situation of workers and residents and the influence that an earthquake can have on them.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
E Soltanmohammadi ◽  
Y Zhang ◽  
I Chatzistamou ◽  
H. Kiaris

Abstract Background Genes that belong to the same network are frequently co-expressed, but collectively, how the coordination of the whole transcriptome is perturbed during aging remains unclear. To explore this, we calculated the correlation of each gene in the transcriptome with every other, in the brain of young and older outbred deer mice (P. leucopus and P. maniculatus). Results In about 25 % of the genes, coordination was inversed during aging. Gene Ontology analysis in both species, for the genes that exhibited inverse transcriptomic coordination during aging pointed to alterations in the perception of smell, a known impairment occurring during aging. In P. leucopus, alterations in genes related to cholesterol metabolism were also identified. Among the genes that exhibited the most pronounced inversion in their coordination profiles during aging was THBS4, that encodes for thrombospondin-4, a protein that was recently identified as rejuvenation factor in mice. Relatively to its breadth, abolishment of coordination was more prominent in the long-living P. leucopus than in P. maniculatus but in the latter, the intensity of de-coordination was higher. Conclusions There sults suggest that aging is associated with more stringent retention of expression profiles for some genes and more abrupt changes in others, while more subtle but widespread changes in gene expression appear protective. Our findings shed light in the mode of the transcriptional changes occurring in the brain during aging and suggest that strategies aiming to broader but more modest changes in gene expression may be preferrable to correct aging-associated deregulation in gene expression.


2016 ◽  
Vol 74 (8) ◽  
pp. 632-637 ◽  
Author(s):  
Vernon Furtado da Silva ◽  
Mauricio Rocha Calomeni ◽  
Rodolfo Alkmim Moreira Nunes ◽  
Carlos Elias Pimentel ◽  
Gabriela Paes Martins ◽  
...  

ABSTRACT This study focused upon the functional capacity of mirror neurons in autistic children. 30 individuals, 10 carriers of the autistic syndrome (GCA), 10 with intellectual impairments (GDI), and 10 non-autistics (GCN) had registered eletroencephalogram from the brain area theoretically related to mirror neurons. Data collection procedure occurred prior to brain stimulation and after the stimulation session. During the second session, participants had to alternately process figures evoking neutral, happy, and/or sorrowful feelings. Results proved that, for all groups, the stimulation process in fact produced additional activation in the neural area under study. The level of activation was related to the format of emotional stimuli and the likelihood of boosting such stimuli. Since the increase of activation occurred in a model similar to the one observed for the control group, we may suggest that the difficulty people with autism have at expressing emotions is not due to nonexistence of mirror neurons.


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