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

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.

2019 ◽  
Author(s):  
Niels A. Kloosterman ◽  
Julian Q. Kosciessa ◽  
Ulman Lindenberger ◽  
Johannes Jacobus Fahrenfort ◽  
Douglas D. Garrett

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.


2013 ◽  
Vol 479-480 ◽  
pp. 480-485
Author(s):  
Ming Chung Ho ◽  
Chin Fei Huang ◽  
Chia Yi Chou ◽  
Ming Chi Lu ◽  
Chen Hsieh ◽  
...  

Brain dynamics is an important issue in understanding child development. However, very little research of the event-related responses has been used to explore changes during childhood. The aim of this study was to investigate mature changes in spatiotemporal organization of brain dynamics. We hypothesized that oscillatory event-related brain activity were affected by age-related changes. The sample include three age groups, namely 7 years (N = 18), 11 years (N = 18), and adults (N = 18). The event-related spectral power (ERPSP), and inter-trial phase locking (ITPL) of the event-related potentials (ERPs) were obtained from the time-frequency analysis of the auditory oddball task. Results revealed that: (a) decreased theta power, but alpha power increased with age; (b) the values of ITPL in the theta and alpha bands increased with age. These suggest that ERPSP, and ITPL provide useful indicators of cognitive maturation processes in children aged 7 and 11 years.


Cephalalgia ◽  
2020 ◽  
pp. 033310242095150
Author(s):  
Adrià Vilà-Balló ◽  
Angela Marti-Marca ◽  
Marta Torres-Ferrús ◽  
Alicia Alpuente ◽  
Victor José Gallardo ◽  
...  

Background The characteristics of the hypersensitivity to auditory stimuli during the interictal period in episodic migraine are discussed. The combined use of event-related potentials, time-frequency power and phase-synchronization can provide relevant information about the time-course of sensory-attentional processing in migraine and its underlying mechanisms. Objective The aim of this nested case-control study was to examine these processes in young, female, episodic migraine patients interictally and compare them to controls using an active auditory oddball task. Method We recorded, using 20 channels, the electrophysiological brain activity of 21 women with episodic migraine without aura and 21 healthy matched controls without family history of migraine, during a novelty oddball paradigm. We collected sociodemographic and clinical data as well as scores related to disability, quality of life, anxiety and depression. We calculated behavioural measures including reaction times, hit rates and false alarms. Spectral power and phase-synchronization of oscillatory activity as well as event-related potentials were obtained for standard stimuli. For target and novel stimuli, event-related potentials were acquired. Results There were no significant differences at the behavioural level. In migraine patients, we found an increased phase-synchronization at the theta frequency range and a higher N1 response to standard trials. No differences were observed in spectral power. No evidence for a lack of habituation in any of the measures was seen between migraine patients and controls. The Reorienting Negativity was reduced in migraine patients as compared to controls on novel but not on target trials. Conclusion Our findings suggest that migraine patients process stimuli as more salient, seem to allocate more of their attentional resources to their surrounding environment, and have less available resources to reorient attention back to the main task.


2015 ◽  
Vol 27 (5) ◽  
pp. 1017-1028 ◽  
Author(s):  
Paul Metzner ◽  
Titus von der Malsburg ◽  
Shravan Vasishth ◽  
Frank Rösler

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.


2012 ◽  
Vol 25 (0) ◽  
pp. 192
Author(s):  
Davide Bottari ◽  
Sophie Rohlf ◽  
Marlene Hense ◽  
Boukje Habets ◽  
Brigitte Roeder

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.


2020 ◽  
Vol 8 (5) ◽  
pp. 872-889 ◽  
Author(s):  
Paige Ethridge ◽  
Nida Ali ◽  
Sarah E. Racine ◽  
Jens C. Pruessner ◽  
Anna Weinberg

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.


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