scholarly journals Gravity highlights a dual role of the insula in internal models

2019 ◽  
Author(s):  
Célia Rousseau ◽  
Marie Barbiero ◽  
Thierry Pozzo ◽  
Charalambos Papaxanthis ◽  
Olivier White
Keyword(s):  
Brain Area ◽  
Posterior Part ◽  
Internal Representation ◽  
Insular Cortex ◽  
Mental Simulation ◽  
Anterior Insula ◽  
Psychophysical Experiment ◽  
Vertical Movements ◽  
The Brain

AbstractMovements rely on a mixture of predictive and reactive mechanisms. With experience, the brain builds internal representations of actions in different contexts. Many factors are taken into account in this process among which the immutable presence of gravity. Any displacement of a massive body in the gravitational field generates forces and torques that must be predicted and compensated by appropriate motor commands. Studies have shown that the insular cortex is a key brain area for graviception. However, none attempted to address whether the same internal representation of gravity is shared between reactive and predictive mechanisms. Here, participants either mentally simulated (only predictive) or performed (predictive and reactive) vertical movements of the hand. We found that the posterior part of the insular cortex was engaged when feedback was processed. The anterior insula, however, was activated only in mental simulation of the action. A psychophysical experiment shows participants’ ability to integrate the effects of gravity. Our results demonstrate a dual internal representation of gravity within the insula and discuss how they can conceptually be linked.

Actual and Imagined Movements Reveal a Dual Role of the Insular Cortex for Motor Control

2020 ◽  
Author(s):  
Célia Rousseau ◽  
Marie Barbiero ◽  
Thierry Pozzo ◽  
Charalambos Papaxanthis ◽  
Olivier White
Keyword(s):  
Brain Area ◽  
Posterior Part ◽  
Internal Representation ◽  
Insular Cortex ◽  
Mental Simulation ◽  
Psychophysical Experiment ◽  
Vertical Movements ◽  
Feedback Mechanisms ◽  
Conceptual Link

Abstract Movements rely on a mixture of feedforward and feedback mechanisms. With experience, the brain builds internal representations of actions in different contexts. Many factors are taken into account in this process among which is the immutable presence of gravity. Any displacement of a massive body in the gravitational field generates forces and torques that must be predicted and compensated by appropriate motor commands. The insular cortex is a key brain area for graviception. However, no attempt has been made to address whether the same internal representation of gravity is shared between feedforward and feedback mechanisms. Here, participants either mentally simulated (only feedforward) or performed (feedforward and feedback) vertical movements of the hand. We found that the posterior part of the insular cortex was engaged when feedback was processed. The anterior insula, however, was activated only in mental simulation of the action. A psychophysical experiment demonstrates participants’ ability to integrate the effects of gravity. Our results point toward a dual internal representation of gravity within the insula. We discuss the conceptual link between these two dualities.

scholarly journals Correction to ‘Decoding and encoding models reveal the role of mental simulation in the brain representation of meaning’

2020 ◽  
Vol 7 (8) ◽  
pp. 201162
Author(s):  
David Soto ◽  
Usman Ayub Sheikh ◽  
Ning Mei ◽  
Roberto Santana
Keyword(s):  
Mental Simulation ◽  
The Brain

scholarly journals The Mechanisms of Size Constancy

2015 ◽  
Vol 28 (3-4) ◽  
pp. 253-283 ◽  
Author(s):  
Irene Sperandio ◽  
Irene Sperandio ◽  
Philippe A. Chouinard
Keyword(s):  
Visual Experience ◽  
Distance Perception ◽  
Brain Area ◽  
Size Perception ◽  
Retinal Images ◽  
Size Constancy ◽  
Constant Size ◽  
Sensory Modalities ◽  
The Brain

Size constancy is the result of cognitive scaling operations that enable us to perceive an object as having the same size when presented at different viewing distances. In this article, we review the literature on size and distance perception to form an overarching synthesis of how the brain might combine retinal images and distance cues of retinal and extra-retinal origin to produce a perceptual visual experience of a world where objects have a constant size. A convergence of evidence from visual psychophysics, neurophysiology, neuropsychology, electrophysiology and neuroimaging highlight the primary visual cortex (V1) as an important node in mediating size–distance scaling. It is now evident that this brain area is involved in the integration of multiple signals for the purposes of size perception and does much more than fulfil the role of an entry position in a series of hierarchical cortical events. We also discuss how information from other sensory modalities can also contribute to size–distance scaling and shape our perceptual visual experience.

scholarly journals Complex of global functional network as the core of consciousness

2021 ◽  
Author(s):  
Keiichi Onoda
Keyword(s):  
Dynamic System ◽  
Brain Activity ◽  
Posterior Part ◽  
Neural Basis ◽  
Attention Networks ◽  
The Core ◽  
Hierarchical Partition ◽  
Brain Fmri ◽  
The Brain

Finding the neural basis of consciousness is a challenging issue, and it is still inconclusive where the core of consciousness is distributed in the brain. The global neuronal workspace theory (GNWT) emphasizes the role of the frontoparietal regions, whereas the integrated information theory (IIT) argues that the posterior part of the brain is the core of consciousness. IIT has proposed “main complex” as the core of consciousness in a dynamic system, which is a set of elements that the information loss in a hierarchical partition approach is the largest among that of all its supersets and subsets. However, no experimental study has reported the core of consciousness using the main complex for actual brain activity. This study estimated the main complex of brain dynamics using a functional MRI. The whole-brain fMRI data of eight conditions (seven tasks and a rest state) were divided into multiple elements based on network atlases, and the main complex of the dynamic system was estimated for each condition. It is assumed that, if there is a set of elements in the complex that are common to all conditions, the set is likely to contain the core of consciousness. Executive control, salience, and dorsal/ventral attention networks were commonly included in the main complex across all conditions, implying that these networks are responsible for the core of consciousness. This finding is consistent with the GNWT, as these networks are across the prefrontal and parietal regions.

scholarly journals Importance of the Paraventricular Nucleus of the Hypothalamus as a Component of a Neural Pathway between the Brain and the Testes that Modulates Testosterone Secretion Independently of the Pituitary

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 594-598 ◽  
Author(s):  
Daniel J. Selvage ◽  
Catherine Rivier
Keyword(s):  
Paraventricular Nucleus ◽  
Leydig Cell ◽  
Pseudorabies Virus ◽  
Cell Function ◽  
Brain Area ◽  
Male Rats ◽  
Neural Pathway ◽  
Electrolytic Lesions ◽  
The Brain

We previously reported that in adult male rats, the intracerebroventricular (icv) injection of corticotropin-releasing factor (CRF) or the β-adrenergic agonist isoproterenol (ISO) significantly inhibited the ability of human chorionic gonadotropin (hCG) to stimulate testosterone (T) secretion. The finding that this phenomenon also took place when LH release had been blocked with an LHRH antagonist suggested that icv CRF and ISO did not alter Leydig cell function by influencing the activity of pituitary gonadotrophs. We therefore proposed the existence of a neural pathway connecting the brain to the testes, whose activation by icv CRF or ISO interfered with T secretion. Based on the intratesticular injection of the transganglionic tracer pseudorabies virus, we recently identified the paraventricular nucleus (PVN) of the hypothalamus as a component of this neural link. The aim of the present work was to investigate the functional role of this brain area in mediating the ability of CRF and ISO to inhibit the ability of hCG to stimulate T secretion. We first demonstrated that local microinfusion of CRF or ISO directly into the PVN mimicked the effect of their icv injection, suggesting that the PVN does indeed represent a site of action of ISO and CRF in altering Leydig cell responsiveness to gonadotropin. In contrast, neither CRF nor ISO microinfusion into the central amygdala or the frontal cortex influenced hCG-stimulated T secretion. To further investigate the role of the PVN in ISO- and CRF-induced blunting of hCG stimulation of T, we determined the effect of icv CRF or ISO on testicular activity of rats with electrolytic lesions of the PVN. These lesions, which did not in themselves influence Leydig cell responsiveness to hCG, blocked the effect of both icv ISO and CRF on hCG-induced T release. Collectively, these results support the hypothesis that CRF- and ISO-induced activation of cells in the area of the PVN decreases the ability of gonadotropin to release T and suggests that this nucleus represents an important site of the proposed neural connection between the brain and the testes.

scholarly journals Midkine Is a Novel Regulator of Amphetamine-Induced Striatal Gliosis and Cognitive Impairment: Evidence for a Stimulus-Dependent Regulation of Neuroinflammation by Midkine

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Marta Vicente-Rodríguez ◽  
Rosalía Fernández-Calle ◽  
Esther Gramage ◽  
Carmen Pérez-García ◽  
María P. Ramos ◽  
...  
Keyword(s):  
Brain Area ◽  
Memory Task ◽  
Long Term Effects ◽  
Y Maze ◽  
Amphetamine Treatment ◽  
Microglial Response ◽  
First Time ◽  
The Brain

Midkine (MK) is a cytokine that modulates amphetamine-induced striatal astrogliosis, suggesting a possible role of MK in neuroinflammation induced by amphetamine. To test this hypothesis, we studied astrogliosis and microglial response induced by amphetamine (10 mg/kg i.p. four times, every 2 h) in different brain areas of MK−/− mice and wild type (WT) mice. We found that amphetamine-induced microgliosis and astrocytosis are enhanced in the striatum of MK−/− mice in a region-specific manner. Surprisingly, LPS-induced astrogliosis in the striatum was blocked in MK−/− mice. Since striatal neuroinflammation induced by amphetamine-type stimulants correlates with the cognitive deficits induced by these drugs, we also tested the long-term effects of periadolescent amphetamine treatment (3 mg/kg i.p. daily for 10 days) in a memory task in MK−/− and WT mice. Significant deficits in the Y-maze test were only observed in amphetamine-pretreated MK−/− mice. The data demonstrate for the first time that MK is a novel modulator of neuroinflammation depending on the inflammatory stimulus and the brain area considered. The data indicate that MK limits amphetamine-induced striatal neuroinflammation. In addition, our data demonstrate that periadolescent amphetamine treatment in mice results in transient disruption of learning and memory processes in absence of endogenous MK.

Psychiatry and the Frontal Lobes

1990 ◽  
Vol 24 (1) ◽  
pp. 113-132 ◽  
Author(s):  
Janice D. Russell ◽  
Milton G. Roxanas
Keyword(s):  
Frontal Lobe ◽  
Psychiatric Symptoms ◽  
Brain Area ◽  
Neuropsychological Testing ◽  
Frontal Lobes ◽  
Biological Data ◽  
Frontal Lobe Damage ◽  
Psychiatric Conditions ◽  
The Brain

The frontal lobes of the brain have long been regarded as enigmatic in their function and perhaps should be considered even more so in states of dysfunction. Observed associations between structural lesions and psychiatric symptoms and the demonstration of disturbed function and morphology in the frontal lobes of individuals suffering from major psychiatric disorders have led to increased interest in this brain area. Psychiatrists have been particularly concerned with seeking the aetiogenesis of common diagnostic entities and this article attempts to synthesize the available facts. A brief overview of relevant biological data precedes a description of methods of neuropsychological testing and the clinical features arising from frontal lobe damage. A discussion of the role of the frontal lobes in some aspects of personality function follows. Neuropsychiatric features associated with known frontal lobe pathology are described, prefacing a discussion of those psychiatric conditions where an aetiological role for frontal lobe dysfunction has been proposed.

scholarly journals Damage to the right insula disrupts the perception of affective touch

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Louise P Kirsch ◽  
Sahba Besharati ◽  
Christina Papadaki ◽  
Laura Crucianelli ◽  
Sara Bertagnoli ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Anterior Insula ◽  
Affective Touch ◽  
Cortical Organization ◽  
Touch Perception ◽  
Posterior Insula ◽  
The Right ◽  
Tactile System ◽  
The Brain

Specific, peripheral C-tactile afferents contribute to the perception of tactile pleasure, but the brain areas involved in their processing remain debated. We report the first human lesion study on the perception of C-tactile touch in right hemisphere stroke patients (N = 59), revealing that right posterior and anterior insula lesions reduce tactile, contralateral and ipsilateral pleasantness sensitivity, respectively. These findings corroborate previous imaging studies regarding the role of the posterior insula in the perception of affective touch. However, our findings about the crucial role of the anterior insula for ipsilateral affective touch perception open new avenues of enquiry regarding the cortical organization of this tactile system.

scholarly journals β-Naphtoflavone and Ethanol Induce Cytochrome P450 and Protect towards MPP+ Toxicity in Human Neuroblastoma SH-SY5Y Cells

2018 ◽  
Vol 19 (11) ◽  
pp. 3369 ◽  
Author(s):  
Jesus Fernandez-Abascal ◽  
Mariantonia Ripullone ◽  
Aurora Valeri ◽  
Cosima Leone ◽  
Massimo Valoti
Keyword(s):  
Cytochrome P450 ◽  
Brain Metabolism ◽  
Brain Area ◽  
Human Neuroblastoma ◽  
In Vitro System ◽  
Protein Levels ◽  
The Brain ◽  
Cyp Isozymes

Cytochrome P450 (CYP) isozymes vary their expression depending on the brain area, the cell type, and the presence of drugs. Some isoforms are involved in detoxification and/or toxic activation of xenobiotics in central nervous system. However, their role in brain metabolism and neurodegeneration is still a subject of debate. We have studied the inducibility of CYP isozymes in human neuroblastoma SH-SY5Y cells, treated with β-naphtoflavone (β-NF) or ethanol (EtOH) as inducers, by qRT-PCR, Western blot (WB), and metabolic activity assays. Immunohistochemistry was used to localize the isoforms in mitochondria and/or endoplasmic reticulum (ER). Tetrazolium (MTT) assay was performed to study the role of CYPs during methylphenyl pyridine (MPP+) exposure. EtOH increased mRNA and protein levels of CYP2D6 by 73% and 60% respectively. Both β-NF and EtOH increased CYP2E1 mRNA (4- and 1.4-fold, respectively) and protein levels (64% both). The 7-ethoxycoumarin O-deethylation and dextromethorphan O-demethylation was greater in treatment samples than in controls. Furthermore, both treatments increased by 22% and 18%, respectively, the cell viability in MPP+-treated cells. Finally, CYP2D6 localized at mitochondria and ER. These data indicate that CYP is inducible in SH-SY5Y cells and underline this in vitro system for studying the role of CYPs in neurodegeneration.

scholarly journals Running Changes the Brain: the Long and the Short of It

Physiology ◽  
2017 ◽  
Vol 32 (6) ◽  
pp. 410-424 ◽  
Author(s):  
Carmen Vivar ◽  
Henriette van Praag
Keyword(s):  
Brain Area ◽  
Adult Brain ◽  
Dynamic Changes ◽  
Initial Development ◽  
Neuron Number ◽  
Neurotransmitter Systems ◽  
Afferent Connections ◽  
The Brain

Exercise is a simple intervention that profoundly benefits cognition. In rodents, running increases neurogenesis in the hippocampus, a brain area important for memory. We describe the dynamic changes in new neuron number and afferent connections throughout their maturation. We highlight the effects of exercise on the neurotransmitter systems involved, with a focus on the role of glutamate and acetylcholine in the initial development of new neurons in the adult brain.

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