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Istvan Ulbert - One of the best experts on this subject based on the ideXlab platform.
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Processing Stages underlying word recognition in the anteroventral temporal lobe
NeuroImage, 2006Co-Authors: Eric Halgren, Ksenija Marinkovic, Chun Mao Wang, Donald L Schomer, Susanne Knake, Istvan UlbertAbstract:The anteroventral temporal lobe integrates visual, lexical, semantic and mnestic aspects of word Processing, through its reciprocal connections with the ventral visual stream, language areas, and the hippocampal formation. We used linear microelectrode arrays to probe population synaptic currents and neuronal firing in different cortical layers of the anteroventral temporal lobe, during semantic judgments with implicit priming and overt word recognition. Since different extrinsic and associative inputs preferentially target different cortical layers, this method can help reveal the sequence and nature of local Processing Stages at a higher resolution than was previously possible. The initial response in inferotemporal and perirhinal cortices is a brief current sink beginning at approximately 120 ms and peaking at approximately 170 ms. Localization of this initial sink to middle layers suggests that it represents feedforward input from lower visual areas, and simultaneously increased firing implies that it represents excitatory synaptic currents. Until approximately 800 ms, the main focus of transmembrane current sinks alternates between middle and superficial layers, with the superficial focus becoming increasingly dominant after approximately 550 ms. Since superficial layers are the target of local and feedback associative inputs, this suggests an alternation in predominant synaptic input between feedforward and feedback modes. Word repetition does not affect the initial perirhinal and inferotemporal middle layer sink but does decrease later activity. Entorhinal activity begins later (approximately 200 ms), with greater apparent excitatory post-synaptic currents and multiunit activity in neocortically projecting than hippocampal-projecting layers. In contrast to perirhinal and entorhinal responses, entorhinal responses are larger to repeated words during memory retrieval. These results identify a sequence of physiological activation, beginning with a sharp activation from lower level visual areas carrying specific information to middle layers. This is followed by feedback and associative interactions involving upper cortical layers, which are abbreviated to repeated words. Following bottom-up and associative Stages, top-down recollective processes may be driven by entorhinal cortex. Word Processing involves a systematic sequence of fast feedforward information transfer from visual areas to anteroventral temporal cortex followed by prolonged interactions of this feedforward information with local associations and feedback mnestic information from the medial temporal lobe.
Eric Halgren - One of the best experts on this subject based on the ideXlab platform.
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Theta oscillations are sensitive to both early and late conflict Processing Stages: effects of alcohol intoxication.
PloS one, 2012Co-Authors: Sanja Kovacevic, Sheeva Azma, Andrei Irimia, Jason S. Sherfey, Eric Halgren, Ksenija MarinkovicAbstract:Prior neuroimaging evidence indicates that decision conflict activates medial and lateral prefrontal and parietal cortices. Theoretical accounts of cognitive control highlight anterior cingulate cortex (ACC) as a central node in this network. However, a better understanding of the relative primacy and functional contributions of these areas to decision conflict requires insight into the neural dynamics of successive Processing Stages including conflict detection, response selection and execution. Moderate alcohol intoxication impairs cognitive control as it interferes with the ability to inhibit dominant, prepotent responses when they are no longer correct. To examine the effects of moderate intoxication on successive Processing Stages during cognitive control, spatio-temporal changes in total event-related theta power were measured during Stroop-induced conflict. Healthy social drinkers served as their own controls by participating in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg women) and placebo conditions in a counterbalanced design. Anatomically-constrained magnetoencephalography (aMEG) approach was applied to complex power spectra for theta (4-7 Hz) frequencies. The principal generator of event-related theta power to conflict was estimated to ACC, with contributions from fronto-parietal areas. The ACC was uniquely sensitive to conflict during both early conflict detection, and later response selection and execution Stages. Alcohol attenuated theta power to conflict across successive Processing Stages, suggesting that alcohol-induced deficits in cognitive control may result from theta suppression in the executive network. Slower RTs were associated with attenuated theta power estimated to ACC, indicating that alcohol impairs motor preparation and execution subserved by the ACC. In addition to their relevance for the currently prevailing accounts of cognitive control, our results suggest that alcohol-induced impairment of top-down strategic Processing underlies poor self-control and inability to refrain from drinking.
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Processing Stages underlying word recognition in the anteroventral temporal lobe
NeuroImage, 2006Co-Authors: Eric Halgren, Ksenija Marinkovic, Chun Mao Wang, Donald L Schomer, Susanne Knake, Istvan UlbertAbstract:The anteroventral temporal lobe integrates visual, lexical, semantic and mnestic aspects of word Processing, through its reciprocal connections with the ventral visual stream, language areas, and the hippocampal formation. We used linear microelectrode arrays to probe population synaptic currents and neuronal firing in different cortical layers of the anteroventral temporal lobe, during semantic judgments with implicit priming and overt word recognition. Since different extrinsic and associative inputs preferentially target different cortical layers, this method can help reveal the sequence and nature of local Processing Stages at a higher resolution than was previously possible. The initial response in inferotemporal and perirhinal cortices is a brief current sink beginning at approximately 120 ms and peaking at approximately 170 ms. Localization of this initial sink to middle layers suggests that it represents feedforward input from lower visual areas, and simultaneously increased firing implies that it represents excitatory synaptic currents. Until approximately 800 ms, the main focus of transmembrane current sinks alternates between middle and superficial layers, with the superficial focus becoming increasingly dominant after approximately 550 ms. Since superficial layers are the target of local and feedback associative inputs, this suggests an alternation in predominant synaptic input between feedforward and feedback modes. Word repetition does not affect the initial perirhinal and inferotemporal middle layer sink but does decrease later activity. Entorhinal activity begins later (approximately 200 ms), with greater apparent excitatory post-synaptic currents and multiunit activity in neocortically projecting than hippocampal-projecting layers. In contrast to perirhinal and entorhinal responses, entorhinal responses are larger to repeated words during memory retrieval. These results identify a sequence of physiological activation, beginning with a sharp activation from lower level visual areas carrying specific information to middle layers. This is followed by feedback and associative interactions involving upper cortical layers, which are abbreviated to repeated words. Following bottom-up and associative Stages, top-down recollective processes may be driven by entorhinal cortex. Word Processing involves a systematic sequence of fast feedforward information transfer from visual areas to anteroventral temporal cortex followed by prolonged interactions of this feedforward information with local associations and feedback mnestic information from the medial temporal lobe.
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rapid distributed fronto parieto occipital Processing Stages during working memory in humans
Cerebral Cortex, 2002Co-Authors: Eric Halgren, C Boujon, Jeffrey M Clarke, C Wang, Patrick ChauvelAbstract:Cortical potentials were recorded from implanted electrodes during a difficult working memory task requiring rapid storage, modification and retrieval of multiple memoranda. Synchronous event-related potentials were generated in distributed occipital, parietal, Rolandic and prefrontal sites beginning approximately 130 ms after stimulus onset and continuing for >500 ms. Coherent phase-locked, event-related oscillations supported interaction between these dorsal stream structures throughout the task period. The Rolandic structures generated early as well as sustained potentials to sensory stimuli in the absence of movement. Activation peaks and phase lags between synaptic populations suggested that perceptual Processing occurred exclusively in the visual association cortex from approximately 90 to 130 ms, with its results projected to fronto-parietal areas for interpretation from approximately 130 to 280 ms. The direction of interaction then appeared to reverse from approximately 300 to 400 ms, consistent with mental arithmetic being performed by fronto-parietal areas operating upon a visual scratch pad in the dorsolateral occipital cortex. A second reversal, from approximately 420 to 600 ms, may have represented an updating of memoranda stored in fronto-parietal sites. Lateralized perisylvian oscillations suggested an articulatory loop. Anterior cingulate activity was evoked by feedback signals indicating errors. These results indicate how a fronto-centro-parietal 'central executive' might interact with an occipital visual scratch pad, perisylvian articulatory loop and limbic monitor to implement the sequential Stages of a complex mental operation.
Stanislas Dehaene - One of the best experts on this subject based on the ideXlab platform.
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Track It to Crack It: Dissecting Processing Stages with Finger Tracking.
Trends in cognitive sciences, 2019Co-Authors: Dror Dotan, Pedro Pinheiro-chagas, Fosca Al Roumi, Stanislas DehaeneAbstract:A central goal in cognitive science is to parse the series of Processing Stages underlying a cognitive task. A powerful yet simple behavioral method that can resolve this problem is finger trajectory tracking: by continuously tracking the finger position and speed as a participant chooses a response, and by analyzing which stimulus features affect the trajectory at each time point during the trial, we can estimate the absolute timing and order of each Processing stage, and detect transient effects, changes of mind, serial versus parallel Processing, and real-time fluctuations in subjective confidence. We suggest that trajectory tracking, which provides considerably more information than mere response times, may provide a comprehensive understanding of the fast temporal dynamics of cognitive operations.
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Decoding the Processing Stages of mental arithmetic with magnetoencephalography.
Cortex; a journal devoted to the study of the nervous system and behavior, 2018Co-Authors: Pedro Pinheiro-chagas, Manuela Piazza, Stanislas DehaeneAbstract:Abstract Elementary arithmetic is highly prevalent in our daily lives. However, despite decades of research, we are only beginning to understand how the brain solves simple calculations. Here, we applied machine learning techniques to magnetoencephalography (MEG) signals in an effort to decompose the successive Processing Stages and mental transformations underlying elementary arithmetic. Adults subjects verified single-digit addition and subtraction problems such as 3 + 2 = 9 in which each successive symbol was presented sequentially. MEG signals revealed a cascade of partially overlapping brain states. While the first operand could be transiently decoded above chance level, primarily based on its visual properties, the decoding of the second operand was more accurate and lasted longer. Representational similarity analyses suggested that this decoding rested on both visual and magnitude codes. We were also able to decode the operation type (additions vs. subtraction) during practically the entire trial after the presentation of the operation sign. At the decision stage, MEG indicated a fast and highly overlapping temporal dynamics for (1) identifying the proposed result, (2) judging whether it was correct or incorrect, and (3) pressing the response button. Surprisingly, however, the internally computed result could not be decoded. Our results provide a first comprehensive picture of the unfolding Processing Stages underlying arithmetic calculations at a single-trial level, and suggest that externally and internally generated neural codes may have different neural substrates.
John R. Anderson - One of the best experts on this subject based on the ideXlab platform.
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Tracking cognitive Processing Stages with MEG: A spatio-temporal model of associative recognition in the brain
NeuroImage, 2016Co-Authors: Jelmer P. Borst, Avniel Singh Ghuman, John R. AndersonAbstract:In this study, we investigated the cognitive Processing Stages underlying associative recognition using MEG. Over the last four decades, a model of associative recognition has been developed in the ACT-R cognitive architecture. This model was first exclusively based on behavior, but was later evaluated and improved based on fMRI and EEG data. Unfortunately, the limited spatial resolution of EEG and the limited temporal resolution of fMRI have made it difficult to fully understand the spatiotemporal dynamics of associative recognition. We therefore conducted an associative recognition experiment with MEG, which combines excellent temporal resolution with reasonable spatial resolution. To analyze the data, we applied non-parametric cluster analyses and a multivariate classifier. This resulted in a detailed spatio-temporal model of associative recognition. After the visual encoding of the stimuli in occipital regions, three separable memory processes took place: a familiarity process (temporal cortex), a recollection process (temporal cortex and supramarginal gyrus), and a representational process (dorsolateral prefrontal cortex). A late decision process (superior parietal cortex) then acted upon the recollected information represented in the prefrontal cortex, culminating in a late response process (motor cortex). We conclude that existing theories of associative recognition, including the ACT-R model, should be adapted to include these processes.
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The discovery of Processing Stages: Extension of Sternberg's method.
Psychological review, 2016Co-Authors: John R. Anderson, Jelmer P. Borst, Qiong Zhang, Matthew M. WalshAbstract:We introduce a method for measuring the number and durations of Processing Stages from the electroencephalographic signal and apply it to the study of associative recognition. Using an extension of past research that combines multivariate pattern analysis with hidden semi-Markov models, the approach identifies on a trial-by-trial basis where brief sinusoidal peaks (called bumps) are added to the ongoing electroencephalographic signal. We propose that these bumps mark the onset of critical cognitive Stages in Processing. The results of the analysis can be used to guide the development of detailed process models. Applied to the associative recognition task, the hidden semi-Markov models multivariate pattern analysis method indicates that the effects of associative strength and probe type are localized to a memory retrieval stage and a decision stage. This is in line with a previously developed the adaptive control of thought-rational process model, called ACT-R, of the task. As a test of the generalization of our method we also apply it to a data set on the Sternberg working memory task collected by Jacobs, Hwang, Curran, and Kahana (2006). The analysis generalizes robustly, and localizes the typical set size effect in a late comparison/decision stage. In addition to providing information about the number and durations of Stages in associative recognition, our analysis sheds light on the event-related potential components implicated in the study of recognition memory. (PsycINFO Database Record
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The Discovery of Processing Stages: Analyzing EEG data with Hidden Semi-Markov Models
NeuroImage, 2014Co-Authors: Jelmer P. Borst, John R. AndersonAbstract:In this paper we propose a new method for identifying Processing Stages in human information Processing. Since the 1860s scientists have used different methods to identify Processing Stages, usually based on reaction time (RT) differences between conditions. To overcome the limitations of RT-based methods we used hidden semi-Markov models (HSMMs) to analyze EEG data. This HSMM-EEG methodology can identify Stages of Processing and how they vary with experimental condition. By combining this information with the brain signatures of the identified Stages one can infer their function, and deduce underlying cognitive processes. To demonstrate the method we applied it to an associative recognition task. The stage-discovery method indicated that three major processes play a role in associative recognition: a familiarity process, an associative retrieval process, and a decision process. We conclude that the new stage-discovery method can provide valuable insight into human information Processing.
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CogSci - Discovering Processing Stages by combining EEG with Hidden Markov Models
Cognitive Science, 2013Co-Authors: Jelmer P. Borst, John R. AndersonAbstract:Discovering Processing Stages by combining EEG with Hidden Markov Models Jelmer P. Borst (jelmer@cmu.edu) John R. Anderson (ja+@cmu.edu) Dept. of Psychology, Carnegie Mellon University Abstract with condition. Using this information, and by comparing EEG signatures between states and experimental conditions, one can interpret the functional characteristics of the identified Processing Stages. Our approach is based on a similar method that was used to analyze fMRI data (Anderson & Fincham, in press; Anderson et al., 2010). For instance, Anderson and Fincham (in press) applied the method to mathematical problem solving, and discovered four Stages: encoding the problems, planning a solution strategy, solving the problems, and entering a response. Although these results were promising, the temporal resolution of fMRI is severely limited, both by having scans that typically last one to two seconds and by the sluggish nature of the hemodynamic response. EEG, on the other hand, has a millisecond resolution, allowing for the discovery of Processing Stages in fast-paced tasks. We applied the HMM-EEG analysis to an associative recognition task. During the study phase of this task, subjects were asked to learn word pairs. In a subsequent test phase – during which EEG data were collected – subjects were again presented with word pairs, which could be the same pairs as they learned previously (targets), rearranged pairs (re-paired foils), or pairs consisting of novel words (new foils). Subjects had to decide whether they had seen the pair during the study phase or not. Successful discrimination required remembering not only that the words were studied (item information), but also how the words were paired during study (associative information). A conventional EEG analysis and a classifier analysis of this study were reported elsewhere (Borst et al., submitted). Currently, we are interested in finding out how many Stages the subjects went through while determining a correct response. A new method is demonstrated for identifying Processing Stages in a task. Since the 1860s cognitive scientists have used different methods to identify Processing Stages, usually based on reaction time (RT) differences between conditions. To overcome the limitations of RT-based methods we used Hidden Markov Models (HMMs) to analyze EEG data. The HMMs indicate for how many Stages there is evidence in the data, and how the durations of these Stages vary with experimental condition. This method was applied to an associative recognition task in which associative strength and target/foil type were manipulated. The HMM-EEG method identified six different Processing Stages for targets and re- paired foils, whereas four similar Stages were identified for new foils. The duration of the third, fifth and sixth stage varied with associative strength for targets and re-paired foils. We present an interpretation of the identified Stages, and conclude that the method can provide valuable insight in human information Processing. Keywords: EEG; HMM, Processing Stages. Introduction One of the main goals of cognitive science is to understand how humans perform tasks. To this end, scientists have long tried to identify different Processing Stages in human information Processing. The first to do this in a systematic manner was probably Franciscus Donders. Almost 150 years ago, Donders proposed a method to measure the duration of cognitive Stages (1868). By subtracting the RTs of two tasks that were hypothesized to share all but one Processing stage, the duration of that stage could be calculated. A strong – and often problematic – assumption of Donders’ subtractive method is the idea that it is possible to add an entire stage without changing the duration of other Stages. To test whether different Stages exist in the first place, Sternberg proposed the additive-factor method (1969). Although Sternberg overcame a limitation of Donders’ method, the additive-factors method has its own drawbacks: it can only indicate the minimum number of Stages in a task and it does not yield duration estimates of the Stages. To improve on these inherent problems of RT- based methods and get better insight in stage existence and duration we propose a new method that uses HMMs (e.g., Rabiner, 1989) to analyze EEG data. The basic idea of our method is to fit HMMs with different numbers of states to the EEG data (note that we use ‘Processing Stages’ and ‘HMM states’ interchangeably throughout the paper). The optimal number of states can then be determined by comparing the log-likelihoods of the fitted HMMs. Subsequently, the durations of the different states can be inspected, as well as how these durations vary Methods Subjects Twenty individuals from the Carnegie Mellon University community participated in a single 3-hr session for monetary compensation (9 males and 11 females, ages ranging from 18 to 40 years with a mean age of 26 years). All were right-handed and none reported a history of neurological impairment. Design The experiment consisted of a study phase in which subjects learned word pairs and a test phase in which they were tested on these word pairs. In addition to probe type (targets, re-paired foils, or new foils), we manipulated word length and associative strength. Words could either be short (4 or 5
Alain Berthoz - One of the best experts on this subject based on the ideXlab platform.
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timing of posterior parahippocampal gyrus activity reveals multiple scene Processing Stages
Human Brain Mapping, 2013Co-Authors: Julien Bastin, Giorgia Committeri, Philippe Kahane, Lorella Minotti, Jean-philippe Lachaux, Gaspare Galati, Alain BerthozAbstract:Posterior parahippocampal gyrus (PPHG) is strongly involved during scene recognition and spatial cognition. How PPHG electrophysiological activity could underlie these functions, and whether they share similar timing mechanisms is unknown. We addressed this question in two intracerebral experiments which revealed that PPHG neural activity dissociated an early stimulus-driven effect (>200 and 600 and <800 ms). Strongest PPHG gamma band (50-150 Hz) activities were found early when subjects passively viewed scenes (scene selectivity effect) and lately when they had to estimate the position of an object relative to the environment (allocentric effect). Based on single trial analyses, we were able to predict when patients viewed scenes (compared to other visual categories) and when they performed allocentric judgments (compared to other spatial judgments). The anatomical location corresponding to the strongest effects was in the depth of the col- lateral sulcus. Our findings directly affect current theories of visual scene Processing and spatial orien- tation by providing new timing constraints and by demonstrating the existence of separable information Processing Stages in the functionally defined parahippocampal place area. Hum Brain
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Timing of posterior parahippocampal gyrus activity reveals multiple scene Processing Stages.
Human Brain Mapping, 2012Co-Authors: Julien Bastin, Giorgia Committeri, Philippe Kahane, Lorella Minotti, Jean-philippe Lachaux, Gaspare Galati, Alain BerthozAbstract:Posterior parahippocampal gyrus (PPHG) is strongly involved during scene recognition and spatial cognition. How PPHG electrophysiological activity could underlie these functions, and whether they share similar timing mechanisms is unknown. We addressed this question in two intracerebral experiments which revealed that PPHG neural activity dissociated an early stimulus-driven effect (>200 and 600 and
