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1.
Biol Psychol ; 187: 108767, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38417664

ABSTRACT

Prior theory and evidence suggest that native East Asians tend to down-regulate their emotional arousal to negatively valenced experiences through expressive suppression, an emotion regulation technique focused on suppressing one's emotional experience. One proposed explanation for this choice of regulation strategy and its efficacy is rooted in their commitment to the cultural value of interdependence with others. However, prior work has not yet thoroughly supported this hypothesis using in vivo neural correlates of emotion regulation. Here, we utilized an established electroencephalogram (EEG) correlate of emotional arousal, the late positive potential (LPP), to examine whether down-regulation of the LPP in native East Asians might be particularly pronounced for those relatively high in interdependent self-construal. In this study, native Japanese participants attempted to suppress their emotional reaction to unpleasant images during EEG recording. In support of the hypothesis that emotion suppression among native East Asians is influenced by the cultural value of interdependence, there was a significant effect of interdependent self-construal on the LPP. Specifically, those relatively high in interdependent (versus independent) self-construal exhibited a smaller LPP in response to unpleasant pictures when instructed to suppress their emotions versus a passive viewing condition. However, this effect was negligible for those relatively low in interdependent self-construal, suggesting that cultural values impact the in vivo efficacy of different emotion regulation techniques. These results demonstrate the importance of identifying correspondence between self-report measures and in vivo correlates of emotion regulation in cross-cultural research.


Subject(s)
Emotional Regulation , Evoked Potentials , Humans , Japan , Evoked Potentials/physiology , Emotions/physiology , Electroencephalography
2.
JAMA Psychiatry ; 81(1): 11-12, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-38019526

ABSTRACT

This Viewpoint discusses the type and amount of data needed for machine learning models to accurately predict diagnoses and treatment outcomes at the individual patient level.


Subject(s)
Mental Disorders , Psychiatry , Humans , Machine Learning , Mental Disorders/diagnosis , Mental Disorders/therapy
3.
J Psychopathol Clin Sci ; 132(8): 1060-1071, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37796541

ABSTRACT

Deficits in emotion processing are core features of psychotic disorders. Electrophysiology research in schizophrenia suggests deficits in sustained engagement with emotional content (indexed by the late positive potential [LPP]) may contribute to emotion processing impairments. Despite similar behavioral emotion processing dysfunction in those at clinical high risk (CHR) for psychosis, limited research has examined neural mechanisms of impaired emotion processing in the high-risk period, where research can inform risk models. To examine mechanisms of emotion processing deficits in those at CHR for psychosis, the present study used a passive viewing task to elicit the LPP in response to emotionally engaging and neutral stimuli in 28 CHR and 32 control participants (60% female). Relative to controls, CHR participants showed reduced LPP amplitude when viewing unpleasant images (d = 0.75, p = .005) but similar LPP amplitude in response to both neutral (d = 0.35, p = .19) and pleasant images (d = 0.31, p = .24). This pattern suggests that individuals at CHR for psychosis exhibit a deficit in sustained engagement with unpleasant stimuli. Clinical and trait questionnaires were administered to examine potential exploratory explanations for group differences in LPP amplitude. Consistent with evidence suggesting LPP amplitude reflects engagement of approach/avoidance motivational systems, greater LPP amplitude was associated with greater trait-level behavioral avoidance in control participants (r = .42, p = .032) but not CHR participants (r = -.21, p = .40). Together, the present research is consistent with LPP studies in psychosis and implicates reduced sustained engagement with emotional content in the high-risk period. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Psychotic Disorders , Schizophrenia , Humans , Female , Male , Evoked Potentials/physiology , Electroencephalography/methods , Emotions/physiology
4.
Neuroimage ; 277: 120195, 2023 08 15.
Article in English | MEDLINE | ID: mdl-37286152

ABSTRACT

Connector 'hubs' are brain regions with links to multiple networks. These regions are hypothesized to play a critical role in brain function. While hubs are often identified based on group-average functional magnetic resonance imaging (fMRI) data, there is considerable inter-subject variation in the functional connectivity profiles of the brain, especially in association regions where hubs tend to be located. Here we investigated how group hubs are related to locations of inter-individual variability. To answer this question, we examined inter-individual variation at group-level hubs in both the Midnight Scan Club and Human Connectome Project datasets. The top group hubs defined based on the participation coefficient did not overlap strongly with the most prominent regions of inter-individual variation (termed 'variants' in prior work). These hubs have relatively strong similarity across participants and consistent cross-network profiles, similar to what was seen for many other areas of cortex. Consistency across participants was further improved when these hubs were allowed to shift slightly in local position. Thus, our results demonstrate that the top group hubs defined with the participation coefficient are generally consistent across people, suggesting they may represent conserved cross-network bridges. More caution is warranted with alternative hub measures, such as community density (which are based on spatial proximity to network borders) and intermediate hub regions which show higher correspondence to locations of individual variability.


Subject(s)
Connectome , Nerve Net , Humans , Neural Pathways , Brain/diagnostic imaging , Magnetic Resonance Imaging/methods , Connectome/methods
5.
Neurosci Biobehav Rev ; 152: 105259, 2023 09.
Article in English | MEDLINE | ID: mdl-37268180

ABSTRACT

A main goal in translational neuroscience is to identify neural correlates of psychopathology ("biomarkers") that can be used to facilitate diagnosis, prognosis, and treatment. This goal has led to substantial research into how psychopathology symptoms relate to large-scale brain systems. However, these efforts have not yet resulted in practical biomarkers used in clinical practice. One reason for this underwhelming progress may be that many study designs focus on increasing sample size instead of collecting additional data within each individual. This focus limits the reliability and predictive validity of brain and behavioral measures in any one person. As biomarkers exist at the level of individuals, an increased focus on validating them within individuals is warranted. We argue that personalized models, estimated from extensive data collection within individuals, can address these concerns. We review evidence from two, thus far separate, lines of research on personalized models of (1) psychopathology symptoms and (2) fMRI measures of brain networks. We close by proposing approaches uniting personalized models across both domains to improve biomarker research.


Subject(s)
Brain , Psychiatry , Humans , Reproducibility of Results , Brain/diagnostic imaging , Brain Mapping/methods , Biomarkers
6.
J Psychopathol Clin Sci ; 131(4): 375-391, 2022 May.
Article in English | MEDLINE | ID: mdl-35511525

ABSTRACT

Motor abnormalities are a core feature of psychotic disorders observed from the premorbid period through chronic illness, suggesting motor dysfunction may reflect the pathophysiology of psychosis. Electrophysiology research in schizophrenia suggests impaired motor activation and preparation may underlie these motor abnormalities. Despite behavioral studies suggesting similar motor dysfunction in those at clinical high-risk (CHR) for psychosis, there have been no studies examining neural mechanisms of motor dysfunction in the CHR period, where research can inform pathophysiological and risk models. The present study used the lateralized readiness potential (LRP), an event-related potential index of motor activation and preparation, to examine mechanisms of motor dysfunction in 42 CHR and 41 control participants (N = 83, 56% female). Response competition was manipulated to determine whether deficits are secondary to cognitive control impairments or reflect primary motor deficits. Behaviorally, CHR participants exhibited overall slower responses than controls. Further, relative to controls, CHR participants showed reduced activation of correct but not incorrect responses, reflected in blunted LRP amplitude under weak response competition and no difference in amplitude associated with the incorrect response under strong response competition. This pattern of results suggests individuals at CHR for psychosis exhibit primary motor deficits in activating and preparing behavioral responses and are contrary to a deficit in cognitive control. Further, blunted LRP amplitude was associated with worsening of negative symptoms at 12-month follow-up. Together, these findings are consistent with LRP studies in psychosis and implicate motor activation deficits as potential mechanisms of motor dysfunction in the high-risk period. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Cognitive Dysfunction , Psychotic Disorders , Contingent Negative Variation/physiology , Evoked Potentials , Evoked Potentials, Motor/physiology , Female , Humans , Male , Psychotic Disorders/diagnosis , Psychotic Disorders/physiopathology , Schizophrenia/diagnosis
7.
J Exp Psychol Gen ; 151(8): 1904-1918, 2022 Aug.
Article in English | MEDLINE | ID: mdl-34807709

ABSTRACT

European Americans are self-enhancing, whereas East Asians are sometimes self-critical. However, the mechanisms underlying this cultural difference remain unclear. Here, we addressed this gap by testing 32 Taiwanese and 32 American young adults, who indicated whether their self-esteem would change in various episodes involving success or failure. We monitored their electroencephalogram (EEG) and assessed upper-alpha band power in response to the outcome information. An increase in upper-alpha power indicates internally directed attention; therefore, it is an index of self-referential processing when assessed during a judgment about the self. As predicted, Americans judged that their self-esteem (but not another's) would increase more after a success than it would decrease after a failure, thereby showing the previously observed self-enhancing pattern. Taiwanese tended to show the opposite pattern, self-criticism. Notably, Americans, but not Taiwanese, showed an increase in upper-alpha band power in response to the self's successes (vs. failures). This bias in the EEG index of self-referential processing predicted the cultural difference in self-enhancement (vs. criticism). The role of self-referential processing in self-enhancement is discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Electroencephalography , Self Concept , Humans , Judgment , Self-Assessment , White People , Young Adult
8.
Schizophr Bull ; 48(1): 90-99, 2022 01 21.
Article in English | MEDLINE | ID: mdl-34111294

ABSTRACT

Impairments in early visual face perception are well documented in patients with schizophrenia. Specifically, event-related potential (ERP) research in patients with schizophrenia has demonstrated deficits in early sensory processing of stimulus properties (P1 component) and the structural encoding of faces (N170 component). However, it is not well understood if similar impairments are present in individuals at clinical high risk (CHR) for psychosis (ie, those in the putative prodromal stage of the illness). Thus, it is unknown if face perception deficits are the result of illness onset or are present in the high-risk period for the illness. The present study used the ERP technique to examine neural activation when viewing facial emotion expressions and objects in 44 CHR and 47 control adolescents and young adults (N = 91). P1 amplitude was similar across groups, indicating that early sensory processing impairments did not substantially contribute to face perception deficits in CHR youth. CHR youth exhibited reduced N170 amplitude compared to controls when viewing faces but not objects, implicating a specific deficit in the structural encoding of faces rather than a general perceptual deficit. Further, whereas controls demonstrated the expected face-selective N170 effect (ie, larger amplitude for faces than objects), CHR youth did not, which suggests that facial emotion expressions do not elicit the expected preferential perceptual processing for critical social information in individuals at CHR for psychosis. Together, these findings provide valuable information regarding the specific impairments contributing to face perception deficits in the high-risk period where treatment stands to aid in preventing illness progression.


Subject(s)
Cognitive Dysfunction/physiopathology , Evoked Potentials/physiology , Facial Recognition/physiology , Prodromal Symptoms , Psychotic Disorders/physiopathology , Social Perception , Adolescent , Adult , Cognitive Dysfunction/etiology , Disease Susceptibility , Facial Expression , Female , Humans , Male , Psychotic Disorders/complications , Risk , Young Adult
9.
Biol Psychol ; 163: 108118, 2021 07.
Article in English | MEDLINE | ID: mdl-34019966

ABSTRACT

In the current cultural psychology literature, it is commonly assumed that the personal self is cognitively more salient for those with an independent (vs. interdependent) self-construal (SC). So far, however, this assumption remains largely untested. Here, we drew on evidence that resting state alpha power (RSAP) reflects mental processes constituting the personal self, and tested whether RSAP is positively correlated with independent (vs. interdependent) SC. Study 1 tested European Americans and Taiwanese, whereas Study 2 tested European Americans and Japanese (total N = 164). A meta-analysis performed on the combined data confirmed a reliable association between independent (vs. interdependent) SC and RSAP. However, this association was only reliable when participants had their eyes closed. Even though European Americans were consistently more independent than East Asians, RSAP was no greater for European Americans than for East Asians. Our data helps explore a missing link in the theorizing of contemporary cultural psychology.


Subject(s)
Cross-Cultural Comparison , Self Concept , Humans , White People
10.
Neuroimage ; 229: 117743, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33454409

ABSTRACT

Recent work has demonstrated that individual-specific variations in functional networks (termed "network variants") can be identified in individuals using resting state functional magnetic resonance imaging (fMRI). These network variants exhibit reliability over time, suggesting that they may be trait-like markers of individual differences in brain organization. However, while networks variants are reliable at rest, is is still untested whether they are stable between task and rest states. Here, we use precision data from the Midnight Scan Club (MSC) to demonstrate that (1) task data can be used to identify network variants reliably, (2) these network variants show substantial spatial overlap with those observed in rest, although state-specific effects are present, (3) network variants assign to similar canonical functional networks in task and rest states, and (4) single tasks or a combination of multiple tasks produce similar network variants to rest. Together, these findings further reinforce the trait-like nature of network variants and demonstrate the utility of using task data to define network variants.


Subject(s)
Brain/diagnostic imaging , Brain/physiology , Nerve Net/diagnostic imaging , Nerve Net/physiology , Psychomotor Performance/physiology , Rest/physiology , Data Analysis , Databases, Factual/trends , Humans , Magnetic Resonance Imaging/trends
11.
J Dairy Sci ; 104(3): 2787-2793, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33485677

ABSTRACT

Ice cream handling and serving conditions on the consumer side may result in temperature abuse before consumption. Under some extreme conditions, even the sporadic presence of injured bacterial cells might pose a health risk due to the possibility of recovery of those cells. We conducted this investigation to evaluate the potential of injured cells of Listeria innocua to recover under ice cream temperature abuse conditions and on exposure to simulated gastrointestinal (GI) fluids. Ice cream mix samples (42% total solids), spiked with 4 log10 cfu/g of Listeria innocua, were thermally treated at 69°C for 30 min. Potential heat-injured cells were recovered in buffered Listeria broth (BLEB), followed by isolation on Listeria-specific modified Oxford agar (MOX). The ice cream mix samples, containing potentially injured cells of Listeria innocua, were followed through overnight aging (7°C), freezing (-3.3°C), and overnight hardening (-40°C) steps to obtain the final ice cream samples. To simulate temperature abuse conditions, the samples were held for 12 h at 4.4°C, followed by 30 min at room temperature (22°C); this treatment was considered the first cycle of temperature abuse. To generate a worst-case scenario, the samples were exposed to 3 such consecutive temperature abuse cycles. At the end of each cycle, direct plating was done on MOX to recover viable cells, and BLEB enrichment verified the presence of potential injured cells. In addition, the ice cream samples, containing potential injured cells, were passed through simulated GI fluids. As a first step, samples were mixed (1:1) with simulated gastric fluids (pH 1.0 and 2.0 before mixing) and held at 37°C in a shaker incubator. Samples drawn at 15, 30, and 60 min were analyzed for viable and potential injured cells. To study the effect of sequential transit through simulated intestinal fluid, a mixture of ice cream and gastric fluid (1:1) from the gastric fluid experiment above was added to simulated intestinal fluid (pH 6.8) and held at 37°C. Samples were analyzed at 30 and 360 min for viable and potential injured cells. Three trials were conducted and the samples collected in duplicates. The temperature abuse or GI fluid exposure studies did not result in the recovery of potential injured cells of Listeria innocua in the ice cream samples under the conditions tested. Exposure to gastric fluids, however, did not eliminate the potential injured cells. Further studies are necessary to understand the exact risk implications of these findings.


Subject(s)
Listeria monocytogenes , Listeria , Animals , Colony Count, Microbial/veterinary , Food Microbiology , Temperature
12.
Biol Psychol ; 157: 107970, 2020 11.
Article in English | MEDLINE | ID: mdl-33096149

ABSTRACT

Prior evidence suggests that external threat motivates people to monitor norm violations. However, the effect of threat may be attenuated for those high in interdependent self-construal (SC) because this SC affords a sense of protection against the threat. Here, we tested this possibility by priming or not priming young American adults with a pathogen threat. We then had participants read norm-violating or normal behaviors while assessing two electrocortical markers: N400 (indexing the detection of norm violations) and suppression of upper α-band power (indexing vigilance to the violations). In the threat priming condition, interdependent SC predicted decreased responsiveness to norm violations. In the control priming condition, however, interdependent SC predicted increased responsiveness. Our work suggests that interdependent SC may provide a sense of security under threat.


Subject(s)
Electroencephalography , Evoked Potentials , Fear , Adult , Humans , Self Concept , United States
13.
Schizophr Bull ; 46(5): 1144-1154, 2020 Sep 21.
Article in English | MEDLINE | ID: mdl-32221557

ABSTRACT

The contingent negative variation (CNV) is an event-related potential that provides a neural index of psychomotor processes (eg, attention and motor planning) well known to be dysfunctional in schizophrenia. Although evidence suggests that CNV amplitude is blunted in patients with schizophrenia (SZ) compared to healthy controls (HCs), there is currently no meta-analytic evidence for the size of the effect. Further, it is unknown how CNV blunting compares to closely related measures of psychomotor dysfunction, such as reaction time slowing. We used random-effects models to calculate the pooled effect size (ES) across 30 studies investigating CNV amplitude differences between patients and HCs (NSZ = 685, NHC = 714). Effect sizes for reaction time slowing across the studies were also quantified. Potential moderators, including sample characteristics and aspects of the CNV measurement, were examined. There was robust blunting of CNV activity in patients compared to HCs (ES = -0.79). The magnitude of this effect did not differ from reaction time slowing. Notably, CNV blunting in patients was significantly greater at central sites (ES = -0.87) compared to frontal sites (ES = -0.48). No other assessed methodological characteristics significantly moderated the magnitude of CNV differences. There is a large effect for CNV blunting in SZ that appears robust to potential confounds or methodological moderators. In addition, reduced CNV activity was statistically comparable to that of reaction time slowing. Blunting was the largest at central electrodes, which has been implicated in motor preparation. These findings speak to the complexity of psychomotor dysfunction in SZ and suggest significant promise for a biomarker.

14.
Biol Psychiatry ; 88(1): 28-39, 2020 07 01.
Article in English | MEDLINE | ID: mdl-31916942

ABSTRACT

Studies comparing diverse groups have shown that many psychiatric diseases involve disruptions across distributed large-scale networks of the brain. There is hope that functional magnetic resonance imaging (fMRI) functional connectivity techniques will shed light on these disruptions, providing prognostic and diagnostic biomarkers as well as targets for therapeutic interventions. However, to date, progress on clinical translation of fMRI methods has been limited. Here, we argue that this limited translation is driven by a combination of intersubject heterogeneity and the relatively low reliability of standard fMRI techniques at the individual level. We review a potential solution to these limitations: the use of new "precision" fMRI approaches that shift the focus of analysis from groups to single individuals through the use of extended data acquisition strategies. We begin by discussing the potential advantages of fMRI functional connectivity methods for improving our understanding of functional neuroanatomy and disruptions in psychiatric disorders. We then discuss the budding field of precision fMRI and findings garnered from this work. We demonstrate that precision fMRI can improve the reliability of functional connectivity measures, while showing high stability and sensitivity to individual differences. We close by discussing the application of these approaches to clinical settings.


Subject(s)
Neuroanatomy , Psychiatry , Brain/diagnostic imaging , Brain Mapping , Humans , Magnetic Resonance Imaging , Reproducibility of Results
15.
Proc Natl Acad Sci U S A ; 116(45): 22851-22861, 2019 11 05.
Article in English | MEDLINE | ID: mdl-31611415

ABSTRACT

Resting-state functional magnetic resonance imaging (fMRI) has provided converging descriptions of group-level functional brain organization. Recent work has revealed that functional networks identified in individuals contain local features that differ from the group-level description. We define these features as network variants. Building on these studies, we ask whether distributions of network variants reflect stable, trait-like differences in brain organization. Across several datasets of highly-sampled individuals we show that 1) variants are highly stable within individuals, 2) variants are found in characteristic locations and associate with characteristic functional networks across large groups, 3) task-evoked signals in variants demonstrate a link to functional variation, and 4) individuals cluster into subgroups on the basis of variant characteristics that are related to differences in behavior. These results suggest that distributions of network variants may reflect stable, trait-like, functionally relevant individual differences in functional brain organization.


Subject(s)
Brain/physiology , Brain Mapping/methods , Humans , Magnetic Resonance Imaging , Neural Pathways/physiology
16.
Biol Psychol ; 146: 107733, 2019 09.
Article in English | MEDLINE | ID: mdl-31352031

ABSTRACT

Although people with high interdependent self-construal (SC) are often assumed to be competent in emotion suppression, direct evidence is missing. We tested whether interdependent SC would predict the ability to down-regulate emotional arousal. Americans of both East Asian and European descent were shown a series of pictures. They were instructed to suppress or attend to their emotions. Their electroencephalogram was recorded and analyzed. The late positive potential (LPP) evoked by unpleasant (vs. neutral) pictures (a marker of emotional arousal) was reduced in the suppress (vs. attend) condition. This effect of emotion suppression was more pronounced for those high in interdependent SC than for those low in it. Curiously, the resulting valence x condition x interdependent SC interaction was robust among those of Asian descent, but not those of European descent. The 4-way interaction involving culture was statistically significant. Our work suggests that the purported link between interdependent SC and emotion suppression may be culture-bound.


Subject(s)
Asian/psychology , Emotions , Self Concept , Adolescent , Arousal , Culture , Electrocorticography , Electroencephalography , Evoked Potentials/physiology , Female , Humans , Individuality , Male , Photic Stimulation , United States , White People , Young Adult
17.
Biol Psychol ; 145: 84-95, 2019 07.
Article in English | MEDLINE | ID: mdl-30999009

ABSTRACT

Prior work has demonstrated that the serial order effect is commonly observed during the Alternative Uses Task, where generated uses become more creative over time while fluency decreases. Yet the neural correlates of the serial order effect are still relatively unexplored. The present study aimed to investigate the electrophysiological correlates underlying this effect. EEG alpha activity was measured using a task-related power paradigm while participants completed both the Alternative Uses Task as well as a Category Fluency Task. The results indicated that left hemisphere alpha power increased relative to right alpha power as a function of the serial order effect in the Alternative Uses Task, but not in the Category Fluency Task. This finding provides evidence that the pattern of observed EEG alpha activity changes over the course of the serial order effect.


Subject(s)
Alpha Rhythm/physiology , Thinking/physiology , Adult , Brain/physiology , Creativity , Electroencephalography/methods , Female , Humans , Male , Trail Making Test
18.
J Dairy Sci ; 101(11): 9659-9669, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30172406

ABSTRACT

Listeriosis is a life-threatening infection caused by foods contaminated with Listeria monocytogenes. Some of the major ice cream recalls in recent years reaffirm the ability of this food-borne pathogen to survive in diverse dairy processing environments and cause cross contamination. Inspection reports revealed certain lapses in implementing adequate hygienic practices for Listeria persistence in the processing environment, leading to cross contamination of ice cream. The higher levels of cross contamination of raw ice cream mix might result in random heat-injured cells when exposed to minimum heat treatment (69°C for 30 min). These heat-injured cells could later recover under abusive storage and handling conditions and pose a health risk. Evidence about the presence of injured cells in ice cream mix may thus prove useful to establish the overall Listeria risk, which was the aim of this study. Challenge studies were conducted to evaluate the dose-dependent presence of heat-injured cells of Listeria. Ice cream mix formulations of 4 different types (36, 40, 42, and 45% total solids) were inoculated at 2.0, 3.0, and 4.0 log cfu/g levels of Listeria innocua (an established surrogate). The dose levels were selected based on a likely cross contamination on the raw side from environmental Listeria, especially due to their resident nature and growth in harborage sites. The samples were exposed to minimum heat treatment (69°C for 30 min) and the survivors, including heat-injured cells, were enumerated using standard protocols. A binary logistic regression model was fitted for evaluating the severity of risk. The influence of total solids, water activity, and pH variability were also studied on Listeria survival. The enrichment protocol, using buffered Listeria enrichment broth, followed by plating on modified oxford agar and Rapid L'mono medium, revealed the random presence of heat-injured cells in buffered Listeria enrichment broth, only at the highest dose level of 4+ logs. Any potential risk from heat-injured cells was thus limited only to the highest levels of cross contamination, irrespective of the type of the mix. Significantly, none of the pasteurized ice cream mix samples supported the recovery of any heat-injured cells of Listeria during 72 h holding at 7°C, even at the highest dose level of 4+ logs, under the conditions of experimentation. The level of cross contamination (dose) emerged as a predictor of the potential presence of heat-injured cells of Listeria exposed to minimum pasteurization treatment.


Subject(s)
Food Microbiology/methods , Food Preservation/methods , Hot Temperature , Ice Cream/microbiology , Listeria monocytogenes/isolation & purification , Agar , Animals , Colony Count, Microbial , Listeria monocytogenes/growth & development , Listeria monocytogenes/physiology , Microbial Viability , Pasteurization
19.
Biol Psychol ; 136: 39-45, 2018 07.
Article in English | MEDLINE | ID: mdl-29782970

ABSTRACT

Interhemispheric transfer measured via differences in right- or left-handed motoric responses to lateralized visual stimuli, known as the crossed-uncrossed difference (CUD), is one way of identifying patterns of processing that are vital for understanding the transfer of neural signals. Examination of interhemispheric transfer by means of the CUD is not entirely explained by simple measures of response time. Multiple processes contribute to wide variability observed in CUD reaction times. Prior research has suggested that intra-hemispheric inhibitory processes may be involved in regulation of speed of transfer. Our study examined electroencephalography recordings and time-locked alpha frequency activity while 18 participants responded to lateralized targets during performance of the Poffenberger Paradigm. Our results suggest that there are alpha frequency differences at fronto-central lateral electrodes based on target, hand-of-response, and receiving hemisphere. These findings suggest that early motoric inhibitory mechanisms may help explain the wide range of variability typically seen with the CUD.


Subject(s)
Alpha Rhythm/physiology , Functional Laterality/physiology , Adolescent , Attention/physiology , Electrodes, Implanted , Electroencephalography , Female , Humans , Male , Photic Stimulation , Psychomotor Performance/physiology , Reaction Time/physiology , Young Adult
20.
Neuroreport ; 29(2): 79-83, 2018 Jan 17.
Article in English | MEDLINE | ID: mdl-29189634

ABSTRACT

Trait anxiety has been shown to cause significant impairments on attentional tasks. Current research has identified alpha band frequency differences between low-trait and high-trait anxious individuals. Here, we further investigated the underlying alpha band frequency differences between low-trait and high-trait anxious individuals during their resting state and the completion of an inhibition executive functioning task. Using human participants and quantitative electroencephalographic recordings, we measured alpha band frequency in individuals both high and low in trait anxiety during their resting state, and while they completed an Eriksen Flanker Task. Results indicated that high-trait anxious individuals exhibit a desynchronization in alpha band frequency from a resting state to when they complete the Eriksen Flanker Task. This suggests that high-trait anxious individuals maintain fewer attentional resources at rest and must martial resources for task performance as compared with low-trait anxious individuals, who appear to maintain stable cognitive resources between rest and task performance. These findings add to the cognitive neuroscience literature surrounding the role of alpha band frequency in low-trait and high-trait anxious individuals.


Subject(s)
Alpha Rhythm , Anxiety/physiopathology , Brain/physiology , Personality/physiology , Anxiety/psychology , Attention/physiology , Electroencephalography , Executive Function/physiology , Female , Humans , Inhibition, Psychological , Male , Neuropsychological Tests , Personality Tests , Rest , Young Adult
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