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1.
J Res Adolesc ; 34(2): 521-525, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38753472

ABSTRACT

Research on adolescence from the Majority World possesses major hidden potential in contributing to global adolescent research and developmental science more broadly. In this commentary, the authors (1) describe the background and the process through which this special issue came into fruition, (2) introduce the emic approaches to study the influences of macro-contextual variations on developmental science and provide several pertinent examples on the contributions of Majority World research, (3) elaborate on challenges and barriers that Majority World scholars often face in conducting and disseminating their research, and (4) a few actionable steps and recommendations in promoting the representation and inclusion of Majority World research into global developmental science. Only when our field fully integrates findings from all regions of the world will we be able to develop a fundamental scientific representation and understanding of what it means to be an adolescent, how adolescents develop over time, and what tasks or phenomena in adolescent development are truly universal or specific to particular groups, regions, or areas.


Subject(s)
Adolescent Development , Humans , Adolescent , Internationality , Research
2.
J Res Adolesc ; 2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38682766

ABSTRACT

The main objective of this rapid systematic review was to examine how the COVID-19 pandemic impacted peer relationships for adolescents (10-25 years of age) around the globe. We focused on four indices of peer relationships: (1) loneliness, (2) social connectedness, (3) social support, and (4) social media use. In addition, we examined gender and age differences. Four databases (APA PsychInfo, PubMed, Scopus, and Web of Science) were searched for articles published from January 2020 to November 2022. A total of 96 studies (cross-sectional: n = 66, longitudinal: n = 30, quantitative: n = 67, qualitative: n = 12, mixed-methods: n = 17) met our inclusion criteria (empirical observational studies with data on at least one of the indices of interest, cross-sectional data on COVID-19-related experiences or longitudinal data collected during the pandemic, age range of 10-25 years, typically developing adolescents). We extracted data and conducted a narrative synthesis. Findings suggest that COVID-19 disruptions negatively impacted peer relationships for youth. Most studies reported either an increase in loneliness over the course of the pandemic or a positive association between loneliness and COVID-19-related experiences. Similar findings were observed for increased social media use as a means of continued communication and connection. Fewer studies focused on social support but those that did reported a decrease or negative association with COVID-19-related experiences. Lastly, findings suggest a mixed impact on social connectedness, which might be due to the strengthening of closer ties and weakening of more distant relationships. Results for gender differences were mixed, and a systematic comparison of differences across ages was not possible. The heterogeneity in measures of COVID-19-related experiences as well as timing of data collection prevented a more nuanced examination of short and more long-term impacts.

3.
Am Psychol ; 79(3): 352-367, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37971842

ABSTRACT

Journal analyses have documented the historical neglect of research pertaining to the Majority World in psychological science, and the need for inclusivity is clearly articulated to ensure a science that is comprehensive and globally applicable. However, no systematic efforts have explored the perspectives of researchers working with Majority World communities regarding the challenges they experience in conducting and disseminating research and ways to address them. Our aim was to explore these challenges from the perspective of these researchers using an embedded mixed-methods design. Based on responses of 232 researchers who engage in psychological research with Majority World communities (68.1% from Africa, Asia, or Latin America, remaining from the Minority World), we identified challenges in three areas: (a) stemming from an inherent bias against Majority World research, (b) experienced by all researchers, which nonetheless are heightened for those engaging in research with Majority World populations, and (c) specific to researchers affiliated with Majority World institutions. Based on the findings, we recommend journal editorial teams and funding agencies: (a) acknowledge and address the bias inherent in the publication and funding process, (b) recruit editorial team members, program officers, and reviewers from the Majority World, (c) train editorial team members, program officers, and reviewers from the Minority World to thoughtfully evaluate Majority World research, and (d) provide resources for researchers affiliated with Majority World institutions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Subject(s)
Minority Groups , Research Personnel , Humans , Research Personnel/psychology
4.
Acta Psychol (Amst) ; 239: 103984, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37523830

ABSTRACT

In this longitudinal, observational study, following 883 adolescents (aged 11-15 years, grades 6th - 8th) we tracked changes in perceived school motivation and effort across four time points during the two years of remote education in Perú as a consequence of COVID-19 (retrospective reports before the pandemic, May 2020, July 2021, and November 2021). Compared to before the pandemic, levels of perceived school motivation and effort dropped sharply in May 2020 and continued to decrease across 2 years. Perceived school motivation was positively associated with perceived school effort at almost all time points. Furthermore, students with lower levels of perceived school motivation had a steeper decline in perceived school effort. In a subsample of 380 students in 8th grade, perceived school effort in July 2021 predicted objective math performance in November 2021. Our findings suggest that COVID-19 has further compounded decreases in subjective and objective indices of school engagement and performance that are typically observed in early adolescence. Our results from a large sample of low- to middle-class Peruvian adolescents highlight the experiences of youth in a country that had particularly long school closures, and that is under-represented in the literature.


Subject(s)
COVID-19 , Motivation , Humans , Adolescent , Peru , Retrospective Studies , Pandemics , COVID-19/epidemiology , Schools , Longitudinal Studies
5.
J Affect Disord ; 338: 92-99, 2023 10 01.
Article in English | MEDLINE | ID: mdl-37230269

ABSTRACT

INTRODUCTION: Adolescence is a period of vulnerability for emotion regulation and sleep difficulties, risks that might be compounded by intense COVID-19 lockdowns and challenges. The aim of this study was to investigate how sleep quality related to emotion regulation difficulties in adolescents during lockdown in Perú. METHODS: Participants were 2563 adolescents enrolled in Innova school in Perú (11 - -17 years) in May 2020. Hypotheses were derived from exploring one half of the sample, preregistered at https://osf.io/fuetz/, and then confirmed in the second half of the sample. Participants completed subjective surveys of sleep quality (short PSQI) and the Difficulties in Emotion Regulation Scale Short Form (DERS-SF). RESULTS: Worse sleep quality was robustly associated with more difficulties in emotion regulation across both samples. The association was found particularly for emotion regulation subscales related to the ability to engage in goal directed behavior in the face of distress, emotional clarity and strategies to deal with feeling distressed. In contrast, there was no robust association between sleep and the ability to regulate impulses in the context of negative emotions, and no association with the ability to accept emotions. Girls and older adolescents robustly endorsed worse sleep quality and more difficulties in emotion regulation. LIMITATIONS: The cross-sectional nature of this study prevents us from determining the direction of the association. Data were collected using adolescent self-report which, while informative of adolescent perceptions, might diverge from objective measures of sleep or emotion regulation difficulties. CONCLUSIONS: Our findings with adolescents in Perú contribute to our understanding of the association between sleep and emotion regulation at a broader global scale.


Subject(s)
COVID-19 , Emotional Regulation , Female , Humans , Adolescent , Sleep Quality , Cross-Sectional Studies , Communicable Disease Control , Emotions/physiology
6.
J Res Adolesc ; 33(1): 74-91, 2023 03.
Article in English | MEDLINE | ID: mdl-35799311

ABSTRACT

This study aimed to examine changes in depression and anxiety symptoms from before to during the first 6 months of the COVID-19 pandemic in a sample of 1,339 adolescents (9-18 years old, 59% female) from three countries. We also examined if age, race/ethnicity, disease burden, or strictness of government restrictions moderated change in symptoms. Data from 12 longitudinal studies (10 U.S., 1 Netherlands, 1 Peru) were combined. Linear mixed effect models showed that depression, but not anxiety, symptoms increased significantly (median increase = 28%). The most negative mental health impacts were reported by multiracial adolescents and those under 'lockdown' restrictions. Policy makers need to consider these impacts by investing in ways to support adolescents' mental health during the pandemic.


Subject(s)
COVID-19 , Adolescent , Female , Humans , Child , Male , Pandemics , Depression/epidemiology , Anxiety/epidemiology , Ethnicity
7.
Child Adolesc Ment Health ; 28(1): 83-89, 2023 02.
Article in English | MEDLINE | ID: mdl-36565015

ABSTRACT

OBJECTIVE: Evaluate the preliminary effectiveness of a school-based intervention to promote digital citizenship (DC) in Perú. METHODS: We piloted a translation and cultural adaptation of a DC curriculum originally designed for the U.S. with students in Perú. Students were assigned to either the Intervention group (n = 136, 52% female; mean age = 13.3) or Control group (n = 130, 55% female; mean age = 13.4). Students in the Control group continued with "business-as-usual" during their advisory period while the Intervention group received the DC curriculum. RESULTS: We found limited evidence that the DC curriculum can promote positive online experience and online conflict resolution skills, as well as increase knowledge regarding DC terms and concepts. However, the lack of strong effects suggests the need to revise materials, improve implementation and consider further adaptations. Nonetheless, results from this proof-of-concept study provide building blocks for future implementations of DC interventions for youth in Latin America.


Subject(s)
Citizenship , Curriculum , Humans , Adolescent , Female , Male , Peru , Students
8.
Dev Cogn Neurosci ; 58: 101172, 2022 12.
Article in English | MEDLINE | ID: mdl-36368089

ABSTRACT

Early pubertal timing has been linked to increased risk for internalizing psychopathology in adolescents. Work in older adolescents and adults suggests that heightened reward sensitivity may buffer risk for internalizing symptoms. However, few studies have investigated these associations during the early transition to puberty, a window of vulnerability to mental health risk. In this preregistered study, we investigated the associations among pubertal timing, internalizing symptoms, and reward sensitivity in a large, population-based sample of 11,224 9-10 year-olds from the ABCD Study®. Using split-half analysis, we tested for within-sample replications of hypothesized effects across two age- and sex-matched subsets of the sample. Early pubertal timing was associated with higher internalizing symptoms in female and male participants across samples, with 9-10 year-olds in the mid-pubertal stage at the highest risk for internalizing symptoms. Additionally, early pubertal timing was robustly associated with greater self-reported reward sensitivity in both female and male participants. We observed inconsistent evidence for a moderating role of reward sensitivity across measurement domains (self-report, behavioral, and fMRI data), several of which differed by sex, but none of these interactions replicated across samples. Together, these findings provide unique insights into early indicators of risk for internalizing psychopathology during the transition to puberty in a large, population-based, demographically diverse sample of youth.


Subject(s)
Puberty , Reward , Adolescent , Adult , Humans , Male , Female , Magnetic Resonance Imaging
9.
Res Child Adolesc Psychopathol ; 50(11): 1429-1444, 2022 11.
Article in English | MEDLINE | ID: mdl-35675003

ABSTRACT

The COVID-19 pandemic has touched the lives of adolescents around the world. This short-term longitudinal, observational study followed 1,334 adolescents (11-17 yo) to investigate whether social-ecological resilience relates to intra- and inter-personal resources and/or the caregiver relationship relates to changes in internalizing symptoms during five stressful weeks of COVID-19 lockdown in Perú. In this work, we contextualize social-ecological resilience in relation to culturally-relevant personal and caregiver resources that youth can use to adapt to stressful situations. We found that adolescents who reported higher levels of personal, caregiver, and overall resilience had lower levels of anxiety and depressive symptoms at week six. We also find that personal, caregiver, and overall resilience moderated the change in anxiety symptoms from week 6 to week 11 of lockdown in 2020. Our findings underscore the importance of social-ecological resilience related to both intra/interpersonal resources and the caregiver relationship for minimizing the harmful impacts of COVID-19 on adolescent internalizing symptoms.


Subject(s)
COVID-19 , Adolescent , Humans , Depression/epidemiology , Pandemics , Peru , Communicable Disease Control
10.
Curr Opin Psychol ; 46: 101318, 2022 08.
Article in English | MEDLINE | ID: mdl-35439684

ABSTRACT

Despite the rapid proliferation of digital technologies in the Global South, most academic research on social media and adolescent well-being has primarily focused on the Global North. This review investigates how social media impacts adolescent well-being in the Global South. We first review five regions (Sub-Saharan Africa, Middle East & North Africa, Latin America, China and South & South-East Asia) to highlight the complex ways social media interacts with well-being around the world. We then outline research gaps in the current understanding of the impacts of social media use on adolescent populations in diverse cultural contexts. We finally highlight potential lines of inquiry that future researchers could explore to build a nuanced, contextual perspective of the risks and opportunities of social media use.


Subject(s)
Adolescent Health , Social Media , Adolescent , Humans , Latin America
11.
J Pain Res ; 15: 857-865, 2022.
Article in English | MEDLINE | ID: mdl-35386425

ABSTRACT

Objective: Pain constitutes an essential alarm for preserving the organism's integrity. Damage to the nervous system produces a pathological condition known as neuropathic pain. Purpose: Blood oxygenation level-dependent (BOLD) and functional magnetic resonance imaging (fMRI) have been widely used to map neuroanatomy and the active regions of interest (ROI) of nociceptive processing. Our study explored the brain's BOLD response in rats after thermal noxious stimulation, immediately after sciatic nerve damage and during 75 minutes after surgical lesion of the sciatic nerve. Methods: Nine male Wistar rats were tested; the experiments were performed on a 7-Tesla /21-cm Varian Agilent system. This approach allowed, for the first time, to measure in vivo the BOLD changes in brain regions involved with the pain process: cingulated (ACC), somatosensory (S1), and insular cortices (IC), as well as thalamus (Th) and ventral tegmental area (VTA) related with acute thermal pain and during the early stages of sciatic denervation that produce neuropathic pain. Results: During thermonociception scan, all subjects showed BOLD activation in the ROIs determined as ACC, S1, Th, IC and VTA. After denervation, these regions continued to show activation with a slow decrement in intensity for the duration of the experiment. The results suggest that these brain structures are overactive during the genesis of neuropathic pain. Conclusion: The study shows for the first time continuous activation of the pain matrix following an acute thermal nociceptive stimulus followed by neuropathic damage. These results have given insight into the early stages of the development of neuropathic pain in vivo.

12.
J Res Adolesc ; 31(3): 717-733, 2021 09.
Article in English | MEDLINE | ID: mdl-34448303

ABSTRACT

Global COVID-19 lockdowns have disrupted adolescents' in-person social networks, increasing likelihood of loneliness. Social media can help adolescents maintain and develop peer relationships across distance. In this short longitudinal study with 735 Peruvian adolescents (ages: 11-17) from low-to-middle-income urban settings, we investigated whether online experiences relate to loneliness during initial stages of lockdown. Loneliness remained constant between week 6 and 11 of lockdown, was higher for females and similar across school-grades. Positive and negative online experiences were more frequent for older students, and females experienced more negative online experiences than males. Greater positive online experiences related to lower loneliness, with the reverse pattern for negative online experiences. Our results suggest that positive online experiences may mitigate loneliness during physical isolation.


Subject(s)
COVID-19 , Loneliness , Adolescent , Child , Communicable Disease Control , Female , Humans , Longitudinal Studies , Male , Peru , SARS-CoV-2
13.
Front Endocrinol (Lausanne) ; 12: 608575, 2021.
Article in English | MEDLINE | ID: mdl-34025573

ABSTRACT

The Adolescent Brain Cognitive Development℠ (ABCD) Study is an ongoing, diverse, longitudinal, and multi-site study of 11,880 adolescents in the United States. The ABCD Study provides open access to data about pubertal development at a large scale, and this article is a researcher's guide that both describes its pubertal variables and outlines recommendations for use. These considerations are contextualized with reference to cross-sectional empirical analyses of pubertal measures within the baseline ABCD dataset by Herting, Uban, and colleagues (2021). We discuss strategies to capitalize on strengths, mitigate weaknesses, and appropriately interpret study limitations for researchers using pubertal variables within the ABCD dataset, with the aim of building toward a robust science of adolescent development.


Subject(s)
Models, Biological , Puberty/physiology , Adolescent , Adolescent Development/physiology , Brain/growth & development , Child , Cognition/physiology , Cross-Sectional Studies , Datasets as Topic , Female , Humans , Longitudinal Studies , Male , Practice Guidelines as Topic , Psychology, Adolescent , Puberty/psychology
14.
Front Psychol ; 12: 632713, 2021.
Article in English | MEDLINE | ID: mdl-33967899

ABSTRACT

The rapidly expanding universe of information, media, and learning experiences available through digital technology is creating unique opportunities and vulnerabilities for children and adolescents. These issues are particularly salient during the developmental window at the transition from childhood into adolescence. This period of early adolescence is a time of formative social and emotional learning experiences that can shape identity development in both healthy and unhealthy ways. Increasingly, many of these foundational learning experiences are occurring in on-line digital environments. These expanding vulnerabilities and opportunities are being further amplified for young adolescents growing up in low resourced settings around the world. Cultural and contextual factors influence access, use, and appropriation of digital technology. Further, neurobehavioral changes associated with the onset of puberty often coincide with entry into social media and more autonomous use of technology. In low-and-middle-income countries (LMICs), disparities in access, use, and appropriation of digital media can amplify prevailing economic gaps, and compound gender inequalities during early adolescence. In LMICs, adolescents are often the early adopters of mobile technology and social media platforms. While the impact of social media on the well-being, particularly mental health, of young adolescents has been a focus of research in high-income countries (HICs), much less is known about the impacts of social media use on young adolescents in LMICs. In this paper, we review what is known about the interaction between digital media and early adolescent development. We highlight crucial gaps in the evidence in LMICs; and describe some hypotheses and areas for future research to address these compelling issues.

15.
J Cogn Neurosci ; 32(10): 1924-1945, 2020 10.
Article in English | MEDLINE | ID: mdl-32644880

ABSTRACT

Prospective memory (PM) refers to the cognitive processes associated with remembering to perform an intended action after a delay. Varying the salience of PM cues while keeping the intended response constant, we investigated the extent to which participants relied on strategic monitoring, through sustained, top-down control, or on spontaneous retrieval via transient bottom-up processes. There is mixed evidence regarding developmental improvements in event-based PM performance after the age of 13 years. We compared PM performance and associated sustained and transient neural correlates in 28 typically developing adolescents (12-17 years old) and 19 adults (23-30 years old). Lower PM cue salience associated with slower ongoing task (OT) RTs, reflected by increased µ ex-Gaussian parameter, and sustained increases in frontoparietal activation during OT blocks, both thought to reflect greater proactive control supporting cue monitoring. Behavioral and neural correlates of PM trials were not specifically modulated by cue salience, revealing little difference in reactive control between conditions. The effect of cue salience was similar across age groups, suggesting that adolescents are able to adapt proactive control engagement to PM task demands. Exploratory analyses showed that younger, but not older, adolescents were less accurate and slower in PM trials relative to OT trials than adults and showed greater transient activation in PM trials in an occipito-temporal cluster. These results provide evidence of both mature and still maturing aspects of cognitive processes associated with implementation of an intention after a delay during early adolescence.


Subject(s)
Memory, Episodic , Adolescent , Adult , Child , Cues , Humans , Intention , Mental Recall , Young Adult
16.
Soc Cogn Affect Neurosci ; 14(11): 1219-1232, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31820793

ABSTRACT

Cognitive control allows the coordination of cognitive processes to achieve goals. Control may be sustained in anticipation of goal-relevant cues (proactive control) or transient in response to the cues themselves (reactive control). Adolescents typically exhibit a more reactive pattern than adults in the absence of incentives. We investigated how reward modulates cognitive control engagement in a letter-array working memory (WM) task in 30 adolescents (12-17 years) and 20 adults (23-30 years) using a mixed block- and event-related functional magnetic resonance imaging design. After a Baseline run without rewards, participants performed a Reward run where 50% trials were monetarily rewarded. Accuracy and reaction time (RT) differences between Reward and Baseline runs indicated engagement of proactive control, which was associated with increased sustained activity in the bilateral anterior insula (AI), right dorsolateral prefrontal cortex (PFC) and right posterior parietal cortex (PPC). RT differences between Reward and No reward trials of the Reward run suggested additional reactive engagement of cognitive control, accompanied with transient activation in bilateral AI, lateral PFC, PPC, supplementary motor area, anterior cingulate cortex, putamen and caudate. Despite behavioural and neural differences during Baseline WM task performance, adolescents and adults showed similar modulations of proactive and reactive control by reward.


Subject(s)
Brain/physiology , Motivation/physiology , Reward , Adolescent , Adult , Cerebral Cortex/physiology , Cues , Female , Humans , Magnetic Resonance Imaging , Male , Memory, Short-Term , Parietal Lobe , Prefrontal Cortex/physiology , Young Adult
17.
J Cogn Neurosci ; 29(10): 1739-1754, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28562207

ABSTRACT

Reasoning during social interactions requires the individual manipulation of mental representations of one's own traits and those of other people as well as their joint consideration (relational integration). Research using nonsocial paradigms has linked relational integration to activity in the rostrolateral PFC. Here, we investigated whether social reasoning is supported by the same general system or whether it additionally relies on regions of the social brain network, such as the medial PFC. We further assessed the development of social reasoning. In the social task, participants evaluated themselves or a friend, or compared themselves with their friend, on a series of traits. In the nonsocial task, participants evaluated their hometown or another town or compared the two. In a behavioral study involving 325 participants (11-39 years old), we found that integrating relations, compared with performing single relational judgments, improves during adolescence, both for social and nonsocial information. Thirty-nine female participants (10-31 years old) took part in a neuroimaging study using a similar task. Activation of the relational integration network, including the rostrolateral PFC, was observed in the comparison condition of both the social and nonsocial tasks, whereas the medial PFC showed greater activation when participants processed social as opposed to nonsocial information across conditions. Developmentally, the right anterior insula showed greater activity in adolescents compared with adults during the comparison of nonsocial versus social information. This study shows parallel recruitment of the social brain and the relational reasoning network during the relational integration of social information in adolescence and adulthood.


Subject(s)
Brain/physiology , Judgment/physiology , Social Perception , Adolescent , Adult , Analysis of Variance , Brain/diagnostic imaging , Brain Mapping , Child , Female , Friends , Humans , Magnetic Resonance Imaging , Male , Neural Pathways/diagnostic imaging , Neural Pathways/physiology , Neuropsychological Tests , Problem Solving/physiology , Young Adult
18.
Psychol Sci ; 26(5): 583-92, 2015 May.
Article in English | MEDLINE | ID: mdl-25810453

ABSTRACT

Adolescence is a period of life in which peer relationships become increasingly important. Adolescents have a greater likelihood of taking risks when they are with peers rather than alone. In this study, we investigated the development of social influence on risk perception from late childhood through adulthood. Five hundred and sixty-three participants rated the riskiness of everyday situations and were then informed about the ratings of a social-influence group (teenagers or adults) before rating each situation again. All age groups showed a significant social-influence effect, changing their risk ratings in the direction of the provided ratings; this social-influence effect decreased with age. Most age groups adjusted their ratings more to conform to the ratings of the adult social-influence group than to the ratings of the teenager social-influence group. Only young adolescents were more strongly influenced by the teenager social-influence group than they were by the adult social-influence group, which suggests that to early adolescents, the opinions of other teenagers about risk matter more than the opinions of adults.


Subject(s)
Adolescent Behavior/psychology , Risk-Taking , Social Behavior , Adolescent , Adult , Child , Decision Making , Female , Humans , Male , Middle Aged , Peer Group , Young Adult
19.
Inflammation ; 36(3): 658-64, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23307337

ABSTRACT

The temporal activation of the sensory systems, especially in pain, determines intermediate states that define the future of the response to sensory stimulation. In this work, we interfere pharmacologically with those states that produce peripheral and central sensitisation after an acute inflammatory process, inhibiting at the periphery the COX-2 with celecoxib and using taurine (glycine A receptor agonist) for central pain relief. We tested the paw withdrawal reflex latencies to thermo- and mechanonociception after the induction of an acute inflammatory process with carrageenan. Celecoxib at low doses [0.13 and 1.3 mg/kg, intraperitoneal (i.p.)] in combination with taurine (300 mg/kg, i.p.) produces a decrease of the nociceptive response in thermo- and mechanonociception, as compared with the effect of both drugs alone. We propose that the enhancement of the analgesic effect of celecoxib in combination with taurine could be due the simultaneous action of these drugs at both, peripheral and central levels.


Subject(s)
Analgesics/therapeutic use , Cyclooxygenase 2 Inhibitors/therapeutic use , Pain/drug therapy , Pyrazoles/therapeutic use , Sulfonamides/therapeutic use , Taurine/therapeutic use , Animals , Carrageenan , Celecoxib , Drug Synergism , Drug Therapy, Combination , Inflammation/drug therapy , Male , Pain/chemically induced , Pain Measurement , Rats , Rats, Wistar
20.
Neuroimage ; 56(3): 1293-300, 2011 Jun 01.
Article in English | MEDLINE | ID: mdl-21315160

ABSTRACT

Stimulus counterbalance is critical for studies of neural habituation, bias, anticipation, and (more generally) the effect of stimulus history and context. We introduce de Bruijn cycles, a class of combinatorial objects, as the ideal source of pseudo-random stimulus sequences with arbitrary levels of counterbalance. Neuro-vascular imaging studies (such as BOLD fMRI) have an additional requirement imposed by the filtering and noise properties of the method: only some temporal frequencies of neural modulation are detectable. Extant methods of generating counterbalanced stimulus sequences yield neural modulations that are weakly (or not at all) detected by BOLD fMRI. We solve this limitation using a novel "path-guided" approach for the generation of de Bruijn cycles. The algorithm encodes a hypothesized neural modulation of specific temporal frequency within the seemingly random order of events. By positioning the modulation between the signal and noise bands of the neuro-vascular imaging method, the resulting sequence markedly improves detection power. These sequences may be used to study stimulus context and history effects in a manner not previously possible.


Subject(s)
Brain/anatomy & histology , Cerebrovascular Circulation/physiology , Magnetic Resonance Imaging/methods , Adaptation, Physiological/physiology , Algorithms , Blood Vessels/anatomy & histology , Computer Simulation , Data Interpretation, Statistical , Humans , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/statistics & numerical data , Models, Neurological , Models, Statistical , Oxygen/blood
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