Neural mechanisms underlying hallucinations in schizophrenia: The role of abnormal fronto-temporal interactions.

2004 ◽  
pp. 235-246 ◽  
Author(s):  
Emily Stern ◽  
David Silbersweig
Keyword(s):  
Neural Mechanisms ◽  
Temporal Interactions

Repetition Suppression of Induced Gamma Activity Predicts Enhanced Orienting toward a Novel Stimulus in 6-month-old Infants

2008 ◽  
Vol 20 (12) ◽  
pp. 2137-2152 ◽  
Author(s):  
Kelly A. Snyder ◽  
Andreas Keil
Keyword(s):  
Visual Processing ◽  
Novelty Detection ◽  
Neural Mechanisms ◽  
Human Infant ◽  
Gamma Activity ◽  
Repeated Stimulus ◽  
Repetition Suppression ◽  
The Face ◽  
Over 40 Years

Habituation refers to a decline in orienting or responding to a repeated stimulus, and can be inferred to reflect learning about the properties of the repeated stimulus when followed by increased orienting to a novel stimulus (i.e., novelty detection). Habituation and novelty detection paradigms have been used for over 40 years to study perceptual and mnemonic processes in the human infant, yet important questions remain about the nature of these processes in infants. The aim of the present study was to examine the neural mechanisms underlying habituation and novelty detection in infants. Specifically, we investigated changes in induced alpha, beta, and gamma activity in 6-month-old infants during repeated presentations of either a face or an object, and examined whether these changes predicted behavioral responses to novelty at test. We found that induced gamma activity over occipital scalp regions decreased with stimulus repetition in the face condition but not in the toy condition, and that greater decreases in the gamma band were associated with enhanced orienting to a novel face at test. The pattern and topography of these findings are consistent with observations of repetition suppression in the occipital–temporal visual processing pathway, and suggest that encoding in infant habituation paradigms may reflect a form of perceptual learning. Implications for the role of repetition suppression in infant habituation and novelty detection are discussed with respect to a biased competition model of visual attention.

Intra-arterial instillation of a nociceptive agent modulate cardiorespiratory parameters involving 5-HT3 and TRPV1 receptors in anesthetized rats

2021 ◽  
Vol 21 ◽  
Author(s):  
Sanjeev K. Singh ◽  
M. S. Muthu ◽  
Ravindran Revand ◽  
M. B. Mandal
Keyword(s):  
Transient Receptor Potential ◽  
Sensory Nerve ◽  
Receptor Potential ◽  
Neural Mechanisms ◽  
Transient Receptor Potential Vanilloid ◽  
Anesthetized Rats ◽  
Trpv1 Receptors ◽  
Perivascular Nerves ◽  
Transient Receptor

Background: Since long back, it has been a matter of discussion regarding the role of peripheral blood vessels in regulation of cardiorespiratory (CVR) system. Objective: The role of 5-HT3 and TRPV1 receptors present on perivascular nerves in elicitation of CVR reflexes was examined after intra-arterial instillation of bradykinin in urethane anesthetized rats. Materials and Methods: Femoral artery was cannulated retrogradely and was utilized for the instillation of saline/agonist/antagonist and recording of blood pressure (BP), using a double ported 24G cannula. BP, respiration and ECG were recorded for 30 min after bradykinin (1 µM) in the absence or presence of antagonists. Results: Instillation of bradykinin produced immediate hypotensive (40%), bradycardiac (17%), tachypnoeic (45%) and hyperventilatory (96%) responses of shorter latencies (5-8 s) favoring the neural mechanisms in producing the responses. In lignocaine (2%) pretreated animals, bradykinin-induced hypotensive (10%), bradycardiac (1.7%), tachypnoeic (13%) and hyperventilatory (13%) responses attenuated significantly. Pretreatment with ondansetron (100 µg/kg), 5-HT3-antagonist attenuated the hypotensive (10%), bradycardiac (1.7%), tachypnoeic (11%) and hyperventilatory (11%) responses significantly. Pretreatment with capsazepine (1 mg/kg), transient receptor potential vanilloid 1- antagonist blocked the hypotensive (5%), bradycardiac (1.2%), tachypnoeic (6%) and hyperventilatory (6%) responses significantly. Conclusion: In conclusion, presence of a nociceptive agent in the local segment of an artery evokes vasosensory reflex responses modulating CVR parameters involving TRPV1 and 5-HT3 receptors present on the perivascular sensory nerve terminals in anesthetized rats.

scholarly journals Neural mechanisms of extinguishing drug and pleasant cue associations in human addiction: role of the VMPFC

2017 ◽  
Vol 24 (1) ◽  
pp. 88-99 ◽  
Author(s):  
Anna B. Konova ◽  
Muhammad A. Parvaz ◽  
Vladimir Bernstein ◽  
Anna Zilverstand ◽  
Scott J. Moeller ◽  
...  
Keyword(s):  
Neural Mechanisms

scholarly journals Neural mechanisms underlying regulation of empathy and altruism by beliefs of others' pain

2021 ◽  
Author(s):  
Tao Yu ◽  
Shihui Han
Keyword(s):  
Real Life ◽  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Altruistic Behavior ◽  
Emotional States ◽  
Neural Responses ◽  
Temporoparietal Junction ◽  
Subjective Estimation ◽  
Show Evidence

Perceived cues signaling others' pain induce empathy that in turn motivates altruistic behavior toward those who appear suffering. This perception-emotion-behavior reactivity is the core of human altruism but does not always occur in real life situations. Here, by integrating behavioral and multimodal neuroimaging measures, we investigate neural mechanisms underlying the functional role of beliefs of others' pain in modulating empathy and altruism. We show evidence that decreasing (or enhancing) beliefs of others' pain reduces (or increases) subjective estimation of others' painful emotional states and monetary donations to those who show pain expressions. Moreover, decreasing beliefs of others' pain attenuates neural responses to perceived cues signaling others' pain within 200 ms after stimulus onset and modulate neural responses to others' pain in the frontal cortices and temporoparietal junction. Our findings highlight beliefs of others' pain as a fundamental cognitive basis of human empathy and altruism and unravel the intermediate neural architecture.

Contralesional plasticity following constraint-induced movement therapy benefits outcome: contributions of the intact hemisphere to functional recovery

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Abigail L. Kerr
Keyword(s):  
Functional Recovery ◽  
Daily Living ◽  
Animal Studies ◽  
Movement Therapy ◽  
Lesion Size ◽  
Neural Mechanisms ◽  
Constraint Induced Movement Therapy ◽  
Current Review ◽  
Paretic Limb

Abstract Stroke is a leading cause of death and disability worldwide. A common, chronic deficit after stroke is upper limb impairment, which can be exacerbated by compensatory use of the nonparetic limb. Resulting in learned nonuse of the paretic limb, compensatory reliance on the nonparetic limb can be discouraged with constraint-induced movement therapy (CIMT). CIMT is a rehabilitative strategy that may promote functional recovery of the paretic limb in both acute and chronic stroke patients through intensive practice of the paretic limb combined with binding, or otherwise preventing activation of, the nonparetic limb during daily living exercises. The neural mechanisms that support CIMT have been described in the lesioned hemisphere, but there is a less thorough understanding of the contralesional changes that support improved functional outcome following CIMT. Using both human and non-human animal studies, the current review explores the role of the contralesional hemisphere in functional recovery of stroke as it relates to CIMT. Current findings point to a need for a better understanding of the functional significance of contralesional changes, which may be determined by lesion size, location, and severity as well stroke chronicity.

Time and Ensemble Dynamics in Indeterminacy: John Cage’s Concert for Piano and Orchestra

2021 ◽  
pp. 504-526
Author(s):  
Emily Payne
Keyword(s):  
Observational Studies ◽  
Experimental Music ◽  
Apartment House ◽  
Time Consciousness ◽  
Musical Interactions ◽  
Music Ensemble ◽  
Temporal Interactions

This chapter examines ensemble dynamics and time consciousness in indeterminate music, using John Cage’s Concert for Piano and Orchestra (1957–8) as a case study. Drawing on interviews and observational studies undertaken with the experimental music ensemble Apartment House, I examine the role of temporal indeterminacy in the socio-musical interactions that characterize performance, and its implications for the musicians’ experiences. In doing so, the chapter makes a broader contribution in its consideration of the ways in which issues of authorship and authority are negotiated in such temporal interactions, and how the dynamics of these negotiations present a sociality based on a ‘separate togetherness’, whereby performers play together (out of time) with one another.

scholarly journals Exploring the role of expectations and stimulus relevance on stimulus-specific neural representations and conscious report

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Erik L Meijs ◽  
Pim Mostert ◽  
Heleen A Slagter ◽  
Floris P de Lange ◽  
Simon van Gaal
Keyword(s):  
Attentional Blink ◽  
Neural Activity ◽  
Subjective Experience ◽  
Activity Patterns ◽  
Neural Mechanisms ◽  
Top Down ◽  
Neural Representations ◽  
Dependent Signal ◽  
Task Irrelevant

Abstract Subjective experience can be influenced by top-down factors, such as expectations and stimulus relevance. Recently, it has been shown that expectations can enhance the likelihood that a stimulus is consciously reported, but the neural mechanisms supporting this enhancement are still unclear. We manipulated stimulus expectations within the attentional blink (AB) paradigm using letters and combined visual psychophysics with magnetoencephalographic (MEG) recordings to investigate whether prior expectations may enhance conscious access by sharpening stimulus-specific neural representations. We further explored how stimulus-specific neural activity patterns are affected by the factors expectation, stimulus relevance and conscious report. First, we show that valid expectations about the identity of an upcoming stimulus increase the likelihood that it is consciously reported. Second, using a series of multivariate decoding analyses, we show that the identity of letters presented in and out of the AB can be reliably decoded from MEG data. Third, we show that early sensory stimulus-specific neural representations are similar for reported and missed target letters in the AB task (active report required) and an oddball task in which the letter was clearly presented but its identity was task-irrelevant. However, later sustained and stable stimulus-specific representations were uniquely observed when target letters were consciously reported (decision-dependent signal). Fourth, we show that global pre-stimulus neural activity biased perceptual decisions for a ‘seen’ response. Fifth and last, no evidence was obtained for the sharpening of sensory representations by top-down expectations. We discuss these findings in light of emerging models of perception and conscious report highlighting the role of expectations and stimulus relevance.

scholarly journals Evidence that nitric oxide mechanisms regulate small intestinal motility in humans

Gut ◽  
1999 ◽  
Vol 44 (1) ◽  
pp. 72-76 ◽  
Author(s):  
A Russo ◽  
R Fraser ◽  
K Adachi ◽  
M Horowitz ◽  
G Boeckxstaens
Keyword(s):  
Motor Activity ◽  
Intestinal Motility ◽  
Random Order ◽  
Neural Mechanisms ◽  
Phase Iii ◽  
First Episode ◽  
Small Intestinal Motility ◽  
Small Intestinal ◽  
Synthase Inhibitor

BackgroundNon-cholinergic non-adrenergic neural mechanisms involving nerves containing NO have been shown to modulate smooth muscle in the gastrointestinal tract, and it has been suggested that release from tonic NO inhibition may be important in the regulation of cyclical fasting small intestinal motility.AimsTo evaluate the role of NO mechanisms in the regulation of fasting small intestinal motor activity in humans using a specific NO synthase inhibitor,NG-monomethyl-l-arginine ( l-NMMA).MethodsIn seven healthy male volunteers, duodenal and jejunal pressures were measured for four hours with a nine lumen manometric catheter. Volunteers attended on four separate days on which they received an intravenous infusion of either saline or l-NMMA (0.5, 2, or 4 mg/kg/h) in random order. Intravenous infusions began 10 minutes after completion of phase III of the migrating motor complex (MMC).ResultsThe first episode of phase III activity occurred earlier after infusion of 2 and 4 mg/kg/h l-NMMA than after infusion of 0.5 mg/kg/hl-NMMA or saline (mean (95% confidence interval) 52 (36–68) and 57 (18–97) v 116 (69–193) and 145 (64–226) minutes respectively) with a resultant MMC cycle length of 82 (59–105) and 86 (46–126) v 132 (49–198) and 169 (98–240) minutes respectively. The total number of phase III activities during the four hour recording was increased (p<0.05) by l-NMMA at a dose of 4 mg/kg/h (2 (1–3)) but not at 2 mg/kg/h (1.5 (1–2)) or 0.5 mg/kg/h (1.3 (1–2)) compared with saline (1.3 (0.6–2)). l-NMMA had no effect on the duration, velocity, number of contractions per minute, length of migration, or site of origin of phase III of the MMC. The duration of phase I activity was shorter (p<0.05) with 4 mg/kg/hl-NMMA than with saline (12 (1–23)v 31 (19–44) minutes).ConclusionsThese observations suggest that NO mechanisms play a role in the regulation of fasting small intestinal motor activity in humans.

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