scholarly journals A gradient of electrophysiological novelty responses along the human hippocampal long axis.

2021 ◽  
Author(s):  
Mar Yebra ◽  
Ole Jensen ◽  
Lukas Kunz ◽  
Stephan Moratti ◽  
Nikolai Axmacher ◽  
...  

The hippocampus is implicated in novelty detection, thought to be important for regulating entry of information into long-term memory. Whether electrophysiological responses to novelty differ along the human hippocampal long axis is currently unknown. By recording from electrodes implanted longitudinally in the hippocampus of epilepsy patients, here we show a gradual increase of theta frequency oscillatory power from anterior to posterior in response to unexpected stimuli, superimposed on novelty responses common to all long axis portions. Intracranial event-related potentials (iERPs) were larger for unexpected vs. expected stimuli and demonstrated a polarity inversion between the hippocampal head (HH) and body (HB). We observed stronger theta coherence between HH and hippocampal tail (HT) than between HB and HT, similarly for expected and unexpected stimuli. This was accompanied by theta and alpha traveling waves with surprisingly variable direction of travel characterized by a ~180 degree phase lag between hippocampal poles. Interestingly, this phase lag showed a pronounced phase offset between anterior and middle (HH-HB) hippocampal portions coinciding anatomically with a drop in theta coherence and the novelty iERP polarity inversion. Our findings indicate common response properties along the hippocampal long axis to unexpected stimuli, as well as a multifaceted, non-uniform engagement along the long axis for novelty processing.

1999 ◽  
Vol 11 (6) ◽  
pp. 598-609 ◽  
Author(s):  
Charan Ranganath ◽  
Ken A. Paller

Previous neuropsychological and neuroimaging results have implicated the prefrontal cortex in memory retrieval, although its precise role is unclear. In the present study, we examined patterns of brain electrical activity during retrieval of episodic and semantic memories. In the episodic retrieval task, participants retrieved autobiographical memories in response to event cues. In the semantic retrieval task, participants generated exemplars in response to category cues. Novel sounds presented intermittently during memory retrieval elicited a series of brain potentials including one identifiable as the P3a potential. Based on prior research linking P3a with novelty detection and with the frontal lobes, we predicted that P3a would be reduced to the extent that novelty detection and memory retrieval interfere with each other. Results during episodic and semantic retrieval tasks were compared to results during a task in which subjects attended to the auditory stimuli. P3a amplitudes were reduced during episodic retrieval, particularly at right lateral frontal scalp locations. A similar but less lateralized pattern of frontal P3a reduction was observed during semantic retrieval. These findings support the notion that the right prefrontal cortex is engaged in the service of memory retrieval, particularly for episodic memories.


2021 ◽  
Author(s):  
Tzu-Yu Hsu ◽  
Tzu-Ling Liu ◽  
Paul Z. Cheng ◽  
Hsin-Chien Lee ◽  
Timothy J. Lane ◽  
...  

AbstractBackgroundRumination, a tendency to focus on negative self-related thoughts, is a central symptom of depression. Studying the self-related aspect of such symptoms is challenging due to the need to distinguish self effects per se from the emotional content of task stimuli. This study employs an emotionally neutral self-related paradigm to investigate possible altered self processing in depression and its link to rumination.MethodsPeople with unipolar depression (MDD; n = 25) and controls (n = 25) underwent task-based EEG recording. Late event-related potentials were studied along with low frequency oscillatory power. EEG metrics were compared between groups and correlated with depressive symptoms and reported rumination.ResultsThe MDD group displayed a difference in late potentials across fronto-central electrodes between self-related and non-self-related conditions. No such difference was seen in controls. The magnitude of this difference was positively related with depressive symptoms and reported rumination. MDD also had elevated theta oscillation power at central electrodes in self-related conditions, which was not seen in controls.ConclusionsRumination appears linked to altered self-related processing in depression, independently of stimuli-related emotional confounds. This connection between self-related processing and depression may point to self-disorder being a core component of the condition.


2004 ◽  
Vol 16 (8) ◽  
pp. 1363-1374 ◽  
Author(s):  
Teresa V. Mitchell ◽  
Helen J. Neville

Recent reports have documented greater plasticity in the dorsal visual stream as compared with the ventral visual stream. This study sought to test the hypothesis that this greater plasticity may be related to a more protracted period of development in the dorsal as compared with the ventral stream. Age-related effects on event-related potentials (ERPs) elicited by motion and color stimuli, designed to activate the two visual streams, were assessed in healthy individuals aged 6 years through adulthood. Although significant developmental effects were observed in amplitudes of ERPs to both color and motion stimuli, marked latency effects were observed only in response to motion. These results provide support for the hypothesis that the dorsal stream displays a longer developmental time course across the early school years than the ventral stream. Implications for neural and behavioral plasticity are discussed.


Author(s):  
Claudia Krasowski ◽  
Sebastian Schindler ◽  
Maximilian Bruchmann ◽  
Robert Moeck ◽  
Thomas Straube

AbstractFaces transmit rich information about a unique personal identity. Recent studies examined how negative evaluative information affects event-related potentials (ERPs), the relevance of individual differences, such as trait anxiety, neuroticism, or agreeableness, for these effects is unclear. In this preregistered study, participants (N = 80) were presented with neutral faces, either associated with highly negative or neutral biographical information. Faces were shown under three different task conditions that varied the attentional focus on face-unrelated features, perceptual face information, or emotional information. Results showed a task-independent increase of the N170 component for faces associated with negative information, while interactions occurred for the Early Posterior Negativity (EPN) and the Late Positive Potential (LPP), showing ERP differences only when paying attention to the evaluative information. Trait anxiety and neuroticism did not influence ERP differences. Low agreeableness increased EPN differences during perceptual distraction. Thus, we observed that low agreeableness leads to early increased processing of potentially hostile faces, although participants were required to attend to a face-unrelated feature.


2002 ◽  
Vol 16 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Marc Antony Serfaty ◽  
Robert Bothwell ◽  
Richard Marsh ◽  
Heather Ashton ◽  
Robert Blizard ◽  
...  

Abstract Background: Depressed subjects and euthymic controls demonstrate differences in cognitive processing and brain electrophysiology. Contingent negative variation (CNV) and postimperative negative variation (PINV) was used to investigate the relationship between cognition and cortical event related potentials. Method: Electrophysiological responses and memory of different personality trait adjectives were measured in 15 patients with major depressive disorder and 15 euthymic controls. The words were presented acoustically to elicit event-related potentials. The subjects were asked to indicate whether the words were self-referential. Responses were measured separately for self referential and non-self referential, neutral, positively and negatively toned words. Results: Depressed patients chose more negative and fewer positive words as self-referential, though no significant differences between groups in CNV magnitude for any of the words were found. Persistence of cortical negativity after the motor response (PINV) was significantly (P < 0.02) greater in patients for all non-self-referential words, and reaction times were significantly longer for all words. Recall of positive words and recognition of all words were significantly impaired in patients. Conclusions: Both electrophysiological measures and memory tests found differences between depressed patients and controls, suggesting that the PINV wave may be a useful electrophysiological probe to clarify the neurophysiological basis of cognitive processes.


2019 ◽  
Vol 22 (8) ◽  
pp. 1277-1284 ◽  
Author(s):  
David W Frank ◽  
Paul M Cinciripini ◽  
Menton M Deweese ◽  
Maher Karam-Hage ◽  
George Kypriotakis ◽  
...  

Abstract Introduction By improving our understanding of the neurobiological mechanisms underlying addiction, neuroimaging research is helping to identify new targets for personalized treatment interventions. When trying to quit, smokers with larger electrophysiological responses to cigarette-related, compared with pleasant, stimuli (“C &gt; P”) are more likely to relapse than smokers with the opposite brain reactivity profile (“P &gt; C”). Aim and Method The goal was to (1) build a classification algorithm to identify smokers characterized by P &gt; C or C &gt; P neuroaffective profiles and (2) validate the algorithm’s classification outcomes in an independent data set where we assessed both smokers’ electrophysiological responses at baseline and smoking abstinence during a quit attempt. We built the classification algorithm applying discriminant function analysis on the event-related potentials evoked by emotional images in 180 smokers. Results The predictive validity of the classifier showed promise in an independent data set that included new data from 177 smokers interested in quitting; the algorithm classified 111 smokers as P &gt; C and 66 as C &gt; P. The overall abstinence rate was low; 15 individuals (8.5% of the sample) achieved CO-verified 12-month abstinence. Although individuals classified as P &gt; C were nearly 2.5 times more likely to be abstinent than smokers classified as C &gt; P (12 vs. 3, or 11% vs. 4.5%), this result was nonsignificant, preliminary, and in need of confirmation in larger trials. Conclusion These results suggest that psychophysiological techniques have the potential to advance our knowledge of the neurobiological underpinnings of nicotine addiction and improve clinical applications. However, larger sample sizes are necessary to reliably assess the predictive ability of our algorithm. Implications We assessed the clinical relevance of a neuroimaging-based classification algorithm on an independent sample of smokers enrolled in a smoking cessation trial and found those with the tendency to attribute more relevance to rewards than cues were nearly 2.5 times more likely to be abstinent than smokers with the opposite brain reactivity profile (11% vs. 4.5%). Although this result was not statistically significant, it suggests our neuroimaging-based classification algorithm can potentially contribute to the development of new precision medicine interventions aimed at treating substance use disorders. Regardless, these findings are still preliminary and in need of confirmation in larger trials.


2021 ◽  
Vol 15 ◽  
Author(s):  
Haoye Sun ◽  
Willem J. M. I. Verbeke ◽  
Frank Belschak ◽  
Jan van Strien ◽  
Lei Wang

The dual-process theory is a significant theory in both organizational theory and social psychology and two conjectures about this theory are considered in this manuscript; the default-interventionist vs. parallel-competitive account. Our research goal is to empirically investigate these two views. In concrete terms, by using event-related potentials (ERPs), we seek to study the fine-grained brain processes and self-reported feelings involved in managers’ evaluations of target employees within an economic context (firing employees) vs. a social network context (excluding employees). Using the stereotype content model categories, each target employee has high (or low) warmth and high (or low) levels of competence. In the fine-grained ERP analysis of the brain process, we focus on three time windows of interest: novelty detection (N2) and goal violation detection (N400) at the unconscious level, and we then evaluate conscious emotional arousal (late positive potential, LPP). Finally, we focus on the self-reported feelings when having to fire or exclude target employees. As goal pursuit theory predicts, the brain dynamics and self-reported measures differ widely across the two organizational contexts; in concrete terms, processes at a later stage overrule early stages depending on the context. This implies that the data bespeaks more for the parallel-competitive account than the default-interventionist account. We discuss the implications of these findings for research in management and management practice.


2018 ◽  
Vol 30 (12) ◽  
pp. 1916-1938 ◽  
Author(s):  
Tal Ness ◽  
Aya Meltzer-Asscher

It was recently proposed that lexical prediction in sentence context encompasses two qualitatively distinct prediction mechanisms: “pre-activation,” namely, activating representations stored in long-term memory, and “pre-updating,” namely, updating the sentence's representation, built online in working memory (WM), to include the predicted content [Lau, E. F., Holcomb, P. J., & Kuperberg, G. R. Dissociating N400 effects of prediction from association in single-word contexts. Journal of Cognitive Neuroscience, 25, 484–502, 2013]. The current study sought to find evidence for pre-updating and test the influence of individual differences in WM capacity on the tendency to engage in this process. Participants read strongly and weakly constraining sentences. ERPs were measured on the predictable noun as well as on the preceding verb, where the prediction is generated. Increased P600 amplitude was observed at the verb in the strongly constraining sentences, reflecting integration of the predicted upcoming argument, thus providing evidence for pre-updating. This effect was greater for participants with higher WM capacity, indicating that the tendency to engage in pre-updating is highly affected by WM capacity. The opposite effect was observed at the noun, that is, for participants with higher WM span, a greater decrease in P600 amplitude in the strongly constraining sentences was observed, indicating that the integration of a pre-updated word was easier. We discuss these results in light of previous literature and propose a plausible architecture to account for the interplay between pre-activation and pre-updating, mediating the influence of factors such as WM capacity.


2021 ◽  
Author(s):  
Santiago Morales ◽  
Maureen Bowers

EEG provides a rich measure of brain activity that can be characterized as neuronal oscillations. However, most developmental EEG work to date has focused on analyzing EEG data as Event-Related Potentials (ERPs) or power based on the Fourier transform. While these measures have been productive, they do not leverage all the information contained within the EEG signal. Namely, ERP analyses ignore non-phase-locked signals and Fourier-based power analyses ignore temporal information. Time-frequency analyses can better characterize the oscillations contained in the EEG data. By separating power and phase information across different frequencies, time-frequency measures provide a closer interpretation of the neurophysiological mechanisms, facilitate translation across neurophysiology disciplines, and capture processes not observed by ERP or Fourier-based analyses (e.g., connectivity). Despite their unique contributions, a literature review of this journal reveals that time-frequency analyses of EEG are yet to be embraced by the developmental cognitive neuroscience field. This manuscript presents a conceptual introduction to time-frequency analyses for developmental researchers. To facilitate the use of time-frequency analyses, we include a tutorial of accessible scripts, based on Cohen (2014), to calculate time-frequency power (signal strength), inter-trial phase synchrony (signal consistency), and two types of phase-based connectivity (inter-channel phase synchrony and weighted phase lag index).


2021 ◽  
Vol 13 ◽  
Author(s):  
Ricardo J. Alejandro ◽  
Pau A. Packard ◽  
Tineke K. Steiger ◽  
Lluis Fuentemilla ◽  
Nico Bunzeck

Learning novel information can be promoted if it is congruent with already stored knowledge. This so-called semantic congruence effect has been broadly studied in healthy young adults with a focus on neural encoding mechanisms. However, the impacts on retrieval, and possible impairments during healthy aging, which is typically associated with changes in declarative long-term memory, remain unclear. To investigate these issues, we used a previously established paradigm in healthy young and older humans with a focus on the neural activity at a final retrieval stage as measured with electroencephalography (EEG). In both age groups, semantic congruence at encoding enhanced subsequent long-term recognition memory of words. Compatible with this observation, semantic congruence led to differences in event-related potentials (ERPs) at retrieval, and this effect was not modulated by age. Specifically, congruence modulated old/new ERPs at a fronto-central (Fz) and left parietal (P3) electrode in a late (400–600 ms) time window, which has previously been associated with recognition memory processes. Importantly, ERPs to old items also correlated with the positive effect of semantic congruence on long-term memory independent of age. Together, our findings suggest that semantic congruence drives subsequent recognition memory across the lifespan through changes in neural retrieval processes.


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