scholarly journals Intertemporal preference reversals are associated with early activation of insula and sustained preferential processing of immediate rewards in visual cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sathya Narayana Sharma ◽  
Azizuddin Khan
Keyword(s):  
Visual Cortex ◽  
Source Localization ◽  
Event Related Potentials ◽  
Decision Makers ◽  
Self Control ◽  
Preference Reversals ◽  
Related Potentials ◽  
Control Failure ◽  
Neural Underpinnings ◽  
Increased Activity

AbstractDecision makers tend to give magnified significance to immediately available rewards which leads to intertemporal preference reversals, which is a form of self-control failure. The objective of the present study was to understand the cognitive and neural underpinnings of this phenomenon using event-related potentials (ERP) and their source localization using standardized low-resolution brain electromagnetic tomography analysis (sLORETA). Twenty-four participants performed a money choice task, where they made choices between a smaller-sooner and a larger-later reward, which included trials with and without an immediately available option, while their electroencephalography (EEG) activity was recorded. Trials with and without immediacy were identical except that the latter involved a front-end delay added to both the rewards. Results showed that presence of immediacy made the choices significantly more impulsive. Presence of immediate reward elicited larger visual P2 and late positive potential (LPP), indicating enhanced capture of automatic and sustained attention respectively, and smaller N2, indicative of diminished engagement of cognitive control processes. Source localization revealed increased activity in the visual cortex in the presence of immediacy, signifying higher valuation. Higher activation of areas of insula during P2—suggesting increased awareness of visceral signals—predicted larger impulsive preference reversals. The results suggest that presence of immediate reward biases the choice very early during the decision making process by precipitating visceral states that triggers approach behaviour, and highlight the need to adopt strategies like precommitment to counter the effect.

Source Localization of Subtopographic Brain Maps for Event Related Potentials (ERP)

2008 ◽  
pp. 1247-1252
Author(s):  
Adil Deniz Duru ◽  
Ali Bayram ◽  
Tamer Demiralp ◽  
Ahmet Ademoglu
Keyword(s):  
Source Localization ◽  
Temporal Frequency ◽  
Event Related Potentials ◽  
Functional Brain Imaging ◽  
Frequency Content ◽  
Brain Potentials ◽  
Functional Brain ◽  
Brain Responses ◽  
Related Potentials ◽  
The Brain

Event-related potentials (ERP) are transient brain responses to cognitive stimuli, and they consist of several stationary events whose temporal frequency content can be characterized in terms of oscillations or rhythms. Precise localization of electrical events in the brain, based on the ERP data recorded from the scalp, has been one of the main challenges of functional brain imaging. Several currentDensity estimation techniques for identifying the electrical sources generating the brain potentials are developed for the so-called neuroelectromagnetic inverse problem in the last three decades (Baillet, Mosher, & Leahy, 2001; Koles, 1998; Michela, Murraya, Lantza, Gonzaleza, Spinellib, & Grave de Peraltaa, 2004; Scherg & von Cramon, 1986).

scholarly journals Psychophysiology and Imaging of Visual Cortical Functions in the Blind: A Review

2008 ◽  
Vol 20 (3-4) ◽  
pp. 71-81 ◽  
Author(s):  
Stephanie L. Simon-Dack ◽  
P. Dennis Rodriguez ◽  
Wolfgang A. Teder-Sälejärvi
Keyword(s):  
Visual Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Visual Information ◽  
Magnetic Stimulation ◽  
Late Onset ◽  
Event Related Potentials ◽  
Cortical Activation ◽  
Future Research ◽  
Related Potentials ◽  
Visual Cortical

Imaging, transcranial magnetic stimulation, and psychophysiological recordings of the congenitally blind have confirmed functional activation of the visual cortex but have not extensively explained the functional significance of these activation patterns in detail. This review systematically examines research on the role of the visual cortex in processing spatial and non-visual information, highlighting research on individuals with early and late onset blindness. Here, we concentrate on the methods utilized in studying visual cortical activation in early blind participants, including positron emissions tomography (PET), functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), and electrophysiological data, specifically event-related potentials (ERPs). This paper summarizes and discusses findings of these studies. We hypothesize how mechanisms of cortical plasticity are expressed in congenitally in comparison to adventitiously blind and short-term visually deprived sighted participants and discuss potential approaches for further investigation of these mechanisms in future research.

scholarly journals Pre-Stimulus Alpha-Band Phase Gates Afferent Visual Cortex Responses

2021 ◽  
Author(s):  
Wei Dou ◽  
Audrey Morrow ◽  
Luca Iemi ◽  
Jason Samaha
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Time Window ◽  
Event Related Potentials ◽  
Alpha Phase ◽  
Alpha Activity ◽  
Alpha Band ◽  
Visual Responses ◽  
Alpha Oscillations ◽  
Related Potentials

The neurogenesis of alpha-band (8-13 Hz) activity has been characterized across many different animal experiments. However, the functional role that alpha oscillations play in perception and behavior has largely been attributed to two contrasting hypotheses, with human evidence in favor of either (or both or neither) remaining sparse. On the one hand, alpha generators have been observed in relay sectors of the visual thalamus and are postulated to phasically inhibit afferent visual input in a feedforward manner 1-4. On the other hand, evidence also suggests that the direction of influence of alpha activity propagates backwards along the visual hierarchy, reflecting a feedback influence upon the visual cortex 5-9. The primary source of human evidence regarding the role of alpha phase in visual processing has been on perceptual reports 10-16, which could be modulated either by feedforward or feedback alpha activity. Thus, although these two hypotheses are not mutually exclusive, human evidence clearly supporting either one is lacking. Here, we present human subjects with large, high-contrast visual stimuli that elicit robust C1 event-related potentials (ERP), which peak between 70-80 milliseconds post-stimulus and are thought to reflect afferent primary visual cortex (V1) input 17-20. We find that the phase of ongoing alpha oscillations modulates the global field power (GFP) of the EEG during this first volley of stimulus processing (the C1 time-window). On the standard assumption 21-23 that this early activity reflects postsynaptic potentials being relayed to visual cortex from the thalamus, our results suggest that alpha phase gates visual responses during the first feed-forward sweep of processing.

Stereotactic electroencephalography in humans reveals multisensory signal in early visual and auditory cortices

2019 ◽  
Author(s):  
Stefania Ferraro ◽  
Markus J. Van Ackeren ◽  
Roberto Mai ◽  
Laura Tassi ◽  
Francesco Cardinale ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Auditory Cortex ◽  
Auditory Processing ◽  
Multisensory Processing ◽  
Low Frequency ◽  
Event Related Potentials ◽  
Stimulus Onset ◽  
Oscillatory Activity ◽  
Visual Responses ◽  
Related Potentials

AbstractUnequivocally demonstrating the presence of multisensory signals at the earliest stages of cortical processing remains challenging in humans. In our study, we relied on the unique spatio-temporal resolution provided by intracranial stereotactic electroencephalographic (SEEG) recordings in patients with drug-resistant epilepsy to characterize the signal extracted from early visual (calcarine and pericalcarine) and auditory (Heschl’s gyrus and planum temporale) regions during a simple audio-visual oddball task. We provide evidences that both cross-modal responses (visual responses in auditory cortex or the reverse) and multisensory processing (alteration of the unimodal responses during bimodal stimulation) can be observed in intracranial event-related potentials (iERPs) and in power modulations of oscillatory activity at different temporal scales within the first 150 ms after stimulus onset. The temporal profiles of the iERPs are compatible with the hypothesis that MSI occurs by means of direct pathways linking early visual and auditory regions. Our data indicate, moreover, that MSI mainly relies on modulations of the low-frequency bands (foremost the theta band in the auditory cortex and the alpha band in the visual cortex), suggesting the involvement of feedback pathways between the two sensory regions. Remarkably, we also observed high-gamma power modulations by sounds in the early visual cortex, thus suggesting the presence of neuronal populations involved in auditory processing in the calcarine and pericalcarine region in humans.

Auditory click stimuli evoke event-related potentials in the visual cortex

Neuroreport ◽  
2013 ◽  
Vol 24 (15) ◽  
pp. 837-840 ◽  
Author(s):  
Susan Pockett ◽  
Suzanne C. Purdy ◽  
Barry J. Brennan ◽  
Mark D. Holmes
Keyword(s):  
Visual Cortex ◽  
Event Related Potentials ◽  
Related Potentials

Volatile Anesthetics Enhance Flash-induced γ Oscillations in Rat Visual Cortex

2005 ◽  
Vol 102 (5) ◽  
pp. 937-947 ◽  
Author(s):  
Olga A. Imas ◽  
Kristina M. Ropella ◽  
B Douglas Ward ◽  
James D. Wood ◽  
Anthony G. Hudetz
Keyword(s):  
Visual Cortex ◽  
Event Related Potentials ◽  
Volatile Anesthetics ◽  
Gamma Oscillations ◽  
Cortical Response ◽  
Bipolar Electrode ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Gamma Power ◽  
Related Potentials

Background The authors sought to understand neural correlates of anesthetic-induced unconsciousness. Cortical gamma oscillations have been associated with neural processes supporting conscious perception, but the effect of general anesthesia on these oscillations is controversial. In this study, the authors examined three volatile anesthetics, halothane, isoflurane, and desflurane, and compared their effects on flash-induced gamma oscillations in terms of equivalent concentrations producing the loss of righting reflex (1 minimum alveolar concentration for the loss of righting [MAC(LR)]). Methods Light flashes were presented every 5 s for 5 min, and event-related potentials were recorded from primary visual cortex of 15 rats with a chronically implanted bipolar electrode at increasing anesthetic concentrations (0-2.4 MAC(LR)). Early cortical response was obtained by averaging poststimulus (0-100 ms) potentials filtered at 20-60 Hz across 60 trials. Late (100-1,000 ms) gamma power was calculated using multitaper power spectral technique. Wavelet decomposition was used to determine spectral and temporal distributions of gamma power. Results The authors found that (1) halothane, isoflurane, and desflurane enhanced the flash-evoked early cortical response in a concentration-dependent manner; (2) the effective concentration for this enhancement was the lowest for isoflurane, intermediate for halothane, and the highest for desflurane when compared at equal fractions of the concentration that led to a loss of righting; (3) the power of flash-induced late (> 100 ms) gamma oscillations was augmented at intermediate concentrations of all three anesthetic agents; and (4) flash-induced gamma power was not reduced below waking baseline even in deep anesthesia. Conclusions These findings suggest that a reduction in flash-induced gamma oscillations in rat visual cortex is not a unitary correlate of anesthetic-induced unconsciousness.

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