Tag Archives: EEG

Optimizing Signal Detection: A Parametric Approach to Assessment and Training

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Principal investigator: Spencer Lynn
Source: US Army Research Institute for the Behavioral and Social Sciences
Award: W911NF-16-1-0192
Dates: 5/16/16-5/15/17
Amount: $89,978

Can inaccuracies in a person’s subjective “cognitive model” of the operational environment be identified and corrected, to improve decision making? In our prior ARI-funded work we developed a signal detection theory (SDT) framework to define and manipulate environmental parameters in a social threat perception task and to measure individual differences predictive of threat detection abilities. Here, we propose to extend that work, developing means to quantitatively assess perceivers’ cognitive model of the environment, provide individually tailored training targeting a person’s environmental parameter “misestimate,” and describe neurophysiological (EEG) correlates of parameter estimation and training effectiveness. In a one-year project, 100 participants will complete a baseline social-threat perception test. Results will determine individual vulnerabilities to misestimating three environmental parameters known from SDT to control threat detection effectiveness. Subsequently, participants will receive a training protocol and a retest. We hypothesize that participants who receive training specific to their misestimated parameter will show greater improvement than participants who receive training on an accurately estimated parameter. We will assess how executive function and personality traits may modulate the efficacy of neurophysiological measures as putative markers of parameter estimation and training effectiveness. We will address High Priority Research Questions concerning: assessing learning processes and learner status to tailor training individually, linking constructs of adaptability to job performance, and determining neurophysiological individual differences related to core military skills. Therefore, if successful this project could transition to applications relevant to Army objectives in Learning in Formal & Informal Environments, Personnel Testing & Performance, and Psychophysiology of Individual Differences.

Optimizing Threat Detection Under Signal-Borne Risk

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Principal investigator: Spencer Lynn
Source: US Army Research Institute for the Behavioral and Social Sciences
Contract: W5J9CQ-12-C-0028
Dates: 9/27/12-9/26/15
Amount: $434,499

Emotion perception research has revealed marked variability in people’s abilities to infer the emotional states of others. This variability is a function of (i) the uncertainty and risk in the environment inherent to perception (perceivers cannot be certain about what they are experiencing, and errors of perception may be costly) and (ii) factors internal to individual perceivers (physical and psychological states and traits). Using a novel utility-based signal detection framework, we will examine how individual differences in affective reactivity, executive function, and motivation contribute to this variability in perception and decision-making, under conditions of changing environmental uncertainty and risk.

Neurophysiological correlates of comprehending emotional meaning in context

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Although the neurocognitive mechanisms of nonaffective language comprehension have been studied extensively, relatively less is known about how the emotional meaning of language is processed. In this study, electrophysiological responses to affectively positive, negative, and neutral words, presented within nonconstraining, neutral contexts, were evaluated under conditions of explicit evaluation of emotional content (Experiment 1) and passive reading (Experiment 2). In both experiments, a widely distributed Late Positivity was found to be larger to negative than to positive words (a ‘‘negativity bias’’). In addition, in Experiment 2, a small, posterior N400 effect to negative and positive (relative to neutral) words was detected, with no differences found between N400 magnitudes to negative and positive words. Taken together, these results suggest that comprehending the emotional meaning of words following a neutral context requires an initial semantic analysis that is relatively more engaged for emotional than for nonemotional words, whereas a later, more extended, attention-modulated process distinguishes the specific emotional valence (positive vs. negative) of words. Thus, emotional processing networks within the brain appear to exert a continuous influence, evident at several stages, on the construction of the emotional meaning of language.

Holt, D.J., S.K. Lynn, and G.R. Kuperberg. 2009. Neurophysiological correlates of comprehending emotional meaning in context. Journal of Cognitive Neuroscience.

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Attenuated modulation of the N170 ERP by facial expressions in schizophrenia

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In psychiatrically-well subjects the modulation of event related potentials (ERPs) by emotional facial expressions is found in several ERPs from ~100 ms and later. A face-related EPR, the N170, is abnormally reduced in schizophrenia to faces relative to other complex objects and research suggests emotional modulation of N170 may be reduced as well. To further examine facial emotion modulation of N170, subjects detected neutral facial expressions from among five emotional expressions (happy, sad, fearful, angry, and disgusted). Over occipitotemporal sites, psychiatrically-well subjects showed bilateral differences in N170 amplitude among expressions (P=0.014). Schizophrenia subjects failed to show this modulation (P=0.551). Accuracy on the task did not differ between groups, nor did the pattern of errors. However, in patients, greater positive and negative symptom ratings were associated with increased failure to button press to neutral faces, suggesting misattribution of emotion to neutral expressions in the more ill patients. Because the N170 is largely specific to faces, these results suggest that an impairment specific to the visual processing of facial expressions contributes to the well-known behavioral abnormalities in facial emotion tasks in schizophrenia.

Lynn, S.K., and D.F. Salisbury. 2008. Attenuated modulation of the N170 ERP by facial expressions in schizophrenia. Journal of Clinical EEG & Neuroscience 39(2):108-111.

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Quantifying a Multiple Deficits Approach to Impaired Facial Affect Processing in Schizophrenia

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Principal Investigator: Spencer Lynn
Source: Harvard Medical School, Department of Psychiatry
Award: Livingston Award
Dates: 7/1/2007-6/30/2008
Amount: $10,000

The objective of this study was to investigate the causes of emotional impairments and their specificity to schizophrenia by examining event related brain potentials elicited by an important social stimulus–emotional facial expressions–in the context of emotional and non-emotional impairments.

Neurophysiological Correlates of Facial Emotion Perception in Schizophrenia and Manic Psychosis

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Role: Post-doctoral Fellow
Source: Clinical Research Training Program in Biological and Social/Developmental Psychiatry, Judge Baker Children’s Center, Department of Psychiatry, Harvard Medical School (T32 MH016259).
Dates: 7/1/2005-6/30/2007
Preceptor: Dean Salisbury, PhD, Cognitive Neuroscience Laboratory, McLean Hospital, Belmont, Massachusetts