scholarly journals Boosting Brain Signal Variability Underlies Liberal Shifts in Decision Bias

2019 ◽  
Author(s):  
Niels A. Kloosterman ◽  
Julian Q. Kosciessa ◽  
Ulman Lindenberger ◽  
Johannes Jacobus Fahrenfort ◽  
Douglas D. Garrett
Keyword(s):  
Event Related Potentials ◽  
Response Strategy ◽  
Unique Contribution ◽  
Time Frequency ◽  
Decision Bias ◽  
Decision Biases ◽  
Related Potentials ◽  
Neural Variability ◽  
Environmental Demands ◽  
Liberal Bias

AbstractStrategically adopting decision biases allows organisms to tailor their choices to environmental demands. For example, a liberal response strategy pays off when target detection is crucial, whereas a conservative strategy is optimal for avoiding false alarms. Using conventional time-frequency analysis of human electroencephalographic (EEG) activity, we previously showed that bias setting entails adjustment of evidence accumulation in sensory regions (Kloosterman et al., 2019), but the presumed prefrontal signature of a strategic conservative-to-liberal bias shift has remained elusive. Here, we show that a liberal bias shift relies on frontal regions adopting a more unconstrained neural regime (boosted entropy) that is suited to the detection of unpredictable events. Overall EEG variation, spectral power and event-related potentials could not explain this relationship, highlighting the unique contribution of moment-to-moment neural variability to bias shifts. Neural variability modulation through prefrontal cortex appears instrumental for permitting an organism to tailor its decision bias to environmental demands.Impact statementMoment-to-moment variability is a prominent feature of neural activity. Rather than representing mere noise, this variability might enable us to flexibly adapt our decision biases to the environment.

scholarly journals Boosts in brain signal variability track liberal shifts in decision bias

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Niels A Kloosterman ◽  
Julian Q Kosciessa ◽  
Ulman Lindenberger ◽  
Johannes Jacobus Fahrenfort ◽  
Douglas D Garrett
Keyword(s):  
Spectral Power ◽  
Event Related Potentials ◽  
Response Strategy ◽  
False Alarms ◽  
Time Frequency ◽  
Decision Bias ◽  
Related Potentials ◽  
Neural Variability ◽  
Environmental Demands ◽  
Liberal Bias

Adopting particular decision biases allows organisms to tailor their choices to environmental demands. For example, a liberal response strategy pays off when target detection is crucial, whereas a conservative strategy is optimal for avoiding false alarms. Using conventional time-frequency analysis of human electroencephalographic (EEG) activity, we previously showed that bias setting entails adjustment of evidence accumulation in sensory regions (Kloosterman et al., 2019), but the presumed prefrontal signature of a conservative-to-liberal bias shift has remained elusive. Here, we show that a liberal bias shift is reflected in a more unconstrained neural regime (boosted entropy) in frontal regions that is suited to the detection of unpredictable events. Overall EEG variation, spectral power and event-related potentials could not explain this relationship, highlighting that moment-to-moment neural variability uniquely tracks bias shifts. Neural variability modulation through prefrontal cortex appears instrumental for permitting an organism to adapt its biases to environmental demands.

Brain Responses to World Knowledge Violations: A Comparison of Stimulus- and Fixation-triggered Event-related Potentials and Neural Oscillations

2015 ◽  
Vol 27 (5) ◽  
pp. 1017-1028 ◽  
Author(s):  
Paul Metzner ◽  
Titus von der Malsburg ◽  
Shravan Vasishth ◽  
Frank Rösler
Keyword(s):  
Word Meaning ◽  
Event Related Potentials ◽  
Visual Presentation ◽  
World Knowledge ◽  
N400 Effect ◽  
Brain Potentials ◽  
Time Frequency ◽  
Gamma Range ◽  
Brain Responses ◽  
Related Potentials

Recent research has shown that brain potentials time-locked to fixations in natural reading can be similar to brain potentials recorded during rapid serial visual presentation (RSVP). We attempted two replications of Hagoort, Hald, Bastiaansen, and Petersson [Hagoort, P., Hald, L., Bastiaansen, M., & Petersson, K. M. Integration of word meaning and world knowledge in language comprehension. Science, 304, 438–441, 2004] to determine whether this correspondence also holds for oscillatory brain responses. Hagoort et al. reported an N400 effect and synchronization in the theta and gamma range following world knowledge violations. Our first experiment (n = 32) used RSVP and replicated both the N400 effect in the ERPs and the power increase in the theta range in the time–frequency domain. In the second experiment (n = 49), participants read the same materials freely while their eye movements and their EEG were monitored. First fixation durations, gaze durations, and regression rates were increased, and the ERP showed an N400 effect. An analysis of time–frequency representations showed synchronization in the delta range (1–3 Hz) and desynchronization in the upper alpha range (11–13 Hz) but no theta or gamma effects. The results suggest that oscillatory EEG changes elicited by world knowledge violations are different in natural reading and RSVP. This may reflect differences in how representations are constructed and retrieved from memory in the two presentation modes.

Intramodal and crossmodal refractory effects: Evidence from oscillatory brain activity

2012 ◽  
Vol 25 (0) ◽  
pp. 192
Author(s):  
Davide Bottari ◽  
Sophie Rohlf ◽  
Marlene Hense ◽  
Boukje Habets ◽  
Brigitte Roeder
Keyword(s):  
Brain Activity ◽  
Event Related Potentials ◽  
Random Order ◽  
Oddball Paradigm ◽  
Brain Response ◽  
Time Frequency ◽  
Tactile Stimuli ◽  
Related Potentials ◽  
Oscillatory Brain Activity ◽  
Auditory Cortices

Event-related potentials (ERP) to the second stimulus of a pair are known to be reduced in amplitude. The magnitude of this ‘refractoriness’ is modulated by both the interstimulus interval and the similarity between the two stimuli. Intramodal refractoriness is interpreted as an index of a temporary decrement in neural responsiveness. So, cross-modal refractoriness might be an indicator of shared neural generators between modalities. We analysed oscillatory neuronal activity while participants were engaged in an oddball paradigm with auditory (4000 Hz, 50 ms-long, 90 db, bilateral) and tactile stimuli (50 ms-long, 125 Hz-vibrations, index fingers) presented in a random order with an ISI of either 1000 or 2000 ms. Participants were required to detect rare tactile (middle fingers) and auditory deviants (600 Hz). A time–frequency analysis of the brain response to the second stimulus of each pair (T-T, A-A, T-A and A-T) contrasting Short and Long ISIs revealed a reduced refractory effect after Long ISI with respect to Short ISI, in all pairs (both intramodal and cross-modal). This emerged as a broadly distributed increase of evoked theta activity (3–7 Hz, 100–500 ms). Only in intramodal tactile pairs and cross-modal tactile-auditory pairs we also observed that Long ISI with respect to Short ISI determined a decrease of induced alpha (8–12 Hz, 200–700 ms), a typical sign of enhanced neural excitability and thus decreased refractoriness. These data suggest that somatosensory and auditory cortices display different neural markers of refractoriness and that the auditory cortex might have a stronger low level degree of influence on the tactile cortex than vice-versa.

scholarly journals Risk and Resilience in an Acute Stress Paradigm: Evidence From Salivary Cortisol and Time-Frequency Analysis of the Reward Positivity

2020 ◽  
Vol 8 (5) ◽  
pp. 872-889 ◽  
Author(s):  
Paige Ethridge ◽  
Nida Ali ◽  
Sarah E. Racine ◽  
Jens C. Pruessner ◽  
Anna Weinberg
Keyword(s):  
Frequency Band ◽  
Acute Stress ◽  
Event Related Potentials ◽  
Risk And Resilience ◽  
Neural Responses ◽  
Time Frequency ◽  
Reward Positivity ◽  
Before And After ◽  
Related Potentials ◽  
Reward Responsivity

Both abnormal stress and reward responsivity are consistently linked to multiple forms of psychopathology; however, the nature of the associations between stress and reward sensitivity remains poorly understood. In the present study, we examined associations between the hypothalamic-pituitary-adrenal-axis stress response and event-related potentials sensitive to the receipt of reward-related feedback in a pre–post experimental paradigm. Neural responses were recorded while male participants completed a simple monetary-reward guessing task before and after the Montreal Imaging Stress Task. Results demonstrated that acute psychosocial stress significantly reduced the magnitude of neural responses to feedback in the reward-sensitive delta-frequency band but not the loss-sensitive theta-frequency band. In addition, a larger delta-frequency response to rewards at baseline predicted reduced overall cortisol response in the stress condition. These findings suggest, therefore, that neural reward circuitry may be associated with both risk for and resilience to stress-related psychopathology.

Adapted wavelet transform improves time-frequency representations: a study of auditory elicited P300-like event-related potentials in rats

2017 ◽  
Vol 14 (2) ◽  
pp. 026012 ◽  
Author(s):  
Nelly Richard ◽  
Bettina Laursen ◽  
Morten Grupe ◽  
Asbjørn M Drewes ◽  
Carina Graversen ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Event Related Potentials ◽  
Time Frequency ◽  
Related Potentials

Induced Gamma Band Deficits in Early Psychosis

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
M. Constante ◽  
M. Shaikh ◽  
I. Williams ◽  
R. Murray ◽  
E. Bramon
Keyword(s):  
Cognitive Processing ◽  
Psychotic Disorders ◽  
Event Related Potentials ◽  
Gamma Band ◽  
Early Psychosis ◽  
Gamma Activity ◽  
Total Power ◽  
Oddball Paradigm ◽  
Time Frequency ◽  
Related Potentials

Objective:Abnormalities in event related potentials (ERPs) have long been looked at as markers of disease in Schizophrenia. Over recent years there is a trend in the field to move from averaged trials ERPs analysis in the time-voltage domain, to time-frequency single trials analysis. Oscillations in the Gamma band (30-50Hz) have received particular attention in the context of the theories of core deficits in neuronal synchronization in Schizophrenia. in this study we aimed at replicating previously found Gamma band deficits in a sample of Early Psychosis patients.Methods:EEG was collected from 15 patients and 15 age matched controls using an auditory oddball paradigm. Time-frequency analysis in the Gamma band was performed using a Morlet wavelet transform. We tested differences between the groups using the Wilcoxon rank sum test, given the nonparametric nature of the data, to compare each group's average single trial Gamma power, maximizing the signal-to-noise ratio.Results:Patients with Early Psychosis showed, following target tones, a reduction in the total power of Gamma band activation (p< 0.01) as well as in induced Gamma band activation (p< 0.01). This was observed in a late latency interval at 400-500ms. the late burst of Gamma activity was not found in the frequent condition, for neither subjects group.Conclusion:The findings are compatible with previous studies suggesting deficits in the late intrinsically generated cognitive processing of auditory stimuli in Schizophrenia, already present in its early stage. They add further evidence of deficits in neuronal synchronisation in the early stages of psychotic disorders.

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