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OBJECTIVES: Recent research has shown that message congruency is beneficial to recall of pictorial health warning label (PWL) content after initial exposure. Despite less attention to the text warning, smokers exposed to congruent PWLs were more likely to recall the text and the message. This study aimed to replicate these findings and to examine whether congruency also affects recall after multiple exposures over time. METHODS: A total of 320 daily smokers (39.7% female; cigarettes/day: M = 15.31, SD = 7.15) were randomized to one congruent or incongruent PWL and attended 4 laboratory sessions over 10 days. During each session, eye movements were recorded while viewing the PWL and open-ended recall of label content was assessed after exposure. RESULTS: Smokers who were exposed to a congruent PWL were more likely to recall the text (p = .01) and the message (p = .02) and less likely to recall the image (p = .003) of the PWL after initial exposure. By day 4, incongruent PWLs were recalled equally well as congruent PWLs. Independent of condition, image recall was initially high and remained high whereas text and message recall was relatively low initially but increased over time. It was not until day 7 that about 80% of text and message recall was observed. CONCLUSIONS: Even when exposed to the same PWL over time, smokers require multiple exposures to recall the text and the message of a PWL. More research on the effects of congruency in the natural environment, where smokers are exposed to multiple PWLs, is needed. IMPLICATIONS: The findings of this study, and of previous work showing that message congruency in PWLs is beneficial to initial recall of PWL content, could potentially help to address legal challenges regarding the implementation of PWLs in the United States. Factually correct text warnings have been uncontested on US cigarettes packages since 1966. Congruent PWLs simply provide a means to visually support the same information as the existing text using a medium that better garners attention to the health information. Investigating and understanding longer-term effects of congruency are important and can empirically inform future warning label development, both in the United States via the Family Smoking Prevention and Tobacco Control Act, and via other governing bodies.
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Atenção/fisiologia , Rememoração Mental/fisiologia , Rotulagem de Produtos/métodos , Fumantes/psicologia , Prevenção do Hábito de Fumar/métodos , Produtos do Tabaco/efeitos adversos , Adulto , Idoso , Movimentos Oculares/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rotulagem de Produtos/normas , Prevenção do Hábito de Fumar/normas , Fatores de Tempo , Estados Unidos , Adulto JovemRESUMO
OBJECTIVE: The nine pictorial health warning labels (PWLs) proposed by the US Food and Drug Administration vary in format and feature of visual and textual information. Congruency is the degree to which visual and textual features reflect a common theme. This characteristic can affect attention and recall of label content. This study investigates the effect of congruency in PWLs on smoker's attention and recall of label content. METHODS: 120 daily smokers were randomly assigned to view either congruent or incongruent PWLs, while having their eye movements recorded. Participants were asked to recall label content immediately after exposure and 5 days later. RESULTS: Overall, the image was viewed more and recalled better than the text. Smokers in the incongruent condition spent more time focusing on the text than smokers in the congruent condition (p=0.03), but dwell time of the image did not differ. Despite lower dwell time on the text, smokers in the congruent condition were more likely to correctly recall it on day 1 (p=0.02) and the risk message of the PWLs on both day 1 (p=0.01) and day 5 (p=0.006) than smokers in the incongruent condition. CONCLUSIONS: This study identifies an important design feature of PWLs and demonstrates objective differences in how smokers process PWLs. Our results suggest that message congruency between visual and textual information is beneficial to recall of label content. Moreover, images captured and held smokers' attention better than the text.
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INTRODUCTION: Antitobacco media campaigns using public service announcements (PSAs) have shown promise in reducing smoking initiation and increasing intentions to quit. Research on what makes an effective PSA has had mixed outcomes. The present study tested the effects of specific message features in antitobacco PSAs, using theory-based physiological and self-report outcomes. METHODS: PSAs were categorized as high or low in message sensation value (MSV) and strength of argument and presented to 200 current smokers in a 2 x 2 factorial design. Physiological responses-specifically, heart rate, skin conductance, zygomaticus major, and corrugator supercilii-were assessed while participants viewed the PSAs. Beliefs, attitudes, efficacy, norms, and intentions to quit were assessed immediately following viewing. RESULTS: Corrugator activity was significantly greater in the high MSV condition. Among those low in sensation seeking, low MSV PSAs elicited higher self-efficacy, whereas the reverse was true for high sensation seekers. High MSV PSAs elicited higher negative beliefs in low sensation seekers. Adding physiological measures to a model predicting intention to quit did not improve the explained variance. DISCUSSION: The present study represents the first comprehensive theory-based experimental investigation of the effects of different features of antitobacco PSAs and provides a framework for future research in identifying effective features of such PSAs. Results illustrate the importance of considering individual differences, characterizing both PSA content and format, and outcome and response measures when evaluating antitobacco PSAs.
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Comportamentos Relacionados com a Saúde , Monitorização Fisiológica/métodos , Avaliação de Resultados em Cuidados de Saúde/métodos , Comunicação Persuasiva , Prática de Saúde Pública , Abandono do Hábito de Fumar/psicologia , Adulto , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Motivação , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: To assess the effect of gestational cocaine exposure on the prefrontal cortex (PFC) with functional magnetic resonance imaging (fMRI). STUDY DESIGN: Using an n-back task, we obtained fMRI with a 3T Siemens scanner on 49 adolescents, 25 who were exposed to cocaine and 24 who were not exposed. The primary outcome was PFC activation during task performance. Five functionally derived regions of interest (ROI) were defined; in addition, 2 a priori anatomical ROIs were generated for Brodmann regions 10 and 46. RESULTS: Of the 49 adolescents who underwent imaging, data from 17 who were exposed to cocaine and 17 who were not exposed were in the final analysis. Groups had similar performance on the n-back task (P >/= .4), with both showing a fewer number of correct responses on the 2-back than the 1-back (P < .001), indicating increased demands on working memory with greater task difficulty. In functionally derived ROIs, imaging results showed increased activation for both groups in the 2-back versus the 1-back condition. In anatomical ROIs, both groups showed greater activation in the 2-back versus the 1-back condition, with activation in the non-exposed group proportionally greater for the left prefrontal region (P = .05). CONCLUSION: In this sample of adolescents, participants who were exposed to cocaine and participants who were not exposed were similar in performance on an executive function task and in fMRI activation patterns during task performance.
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Cocaína/efeitos adversos , Imageamento por Ressonância Magnética/métodos , Transtornos da Memória/diagnóstico , Transtornos da Memória/etiologia , Córtex Pré-Frontal/patologia , Efeitos Tardios da Exposição Pré-Natal/diagnóstico , Adolescente , Análise de Variância , Mapeamento Encefálico/métodos , Estudos de Coortes , Feminino , Seguimentos , Idade Gestacional , Humanos , Masculino , Exposição Materna/efeitos adversos , Transtornos da Memória/epidemiologia , Memória de Curto Prazo/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Probabilidade , Valores de Referência , Estudos Retrospectivos , Medição de Risco , Estatísticas não Paramétricas , Análise e Desempenho de Tarefas , Fatores de TempoRESUMO
The similarity of e-cigarettes to tobacco cigarettes with regard to shape and usage raises the question of whether e-cigarette cues have the same incentive motivational properties as tobacco cigarette cues. The objective of the present study was to examine whether e-cigarette cues capture and hold smokers' and former smokers' attention and whether the attentional focus is associated with subsequent craving for tobacco cigarettes. It was also examined whether device type (cigalike or mod) moderated this relationship. Participants (46 current daily smokers, 38 former smokers, 48 non-smokers) were randomly assigned to a device type condition in which their eye-movements were assessed while completing a visual probe task. Craving was assessed before and after the task. Smokers, but not former or non-smokers, maintained their gaze longer on e-cigarette than on neutral pictures ( p = 0.004). No difference in dwell time was found between device type. None of the smoking status groups showed faster initial fixations or faster reaction times to e-cigarette compared with neutral cues. Baseline craving was associated with dwell time on e-cigarette cues ( p = 0.004). Longer dwell time on e-cigarette cues was associated with more favorable attitudes towards e-cigarettes. These findings indicate that e-cigarette cues may contribute to craving for tobacco cigarettes and suggest the potential regulation of e-cigarette marketing.
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Atenção/efeitos dos fármacos , Viés de Atenção/efeitos dos fármacos , Fumar/efeitos adversos , Fumar/fisiopatologia , Produtos do Tabaco/efeitos adversos , Tabagismo/fisiopatologia , Adulto , Fissura/efeitos dos fármacos , Sinais (Psicologia) , Sistemas Eletrônicos de Liberação de Nicotina/métodos , Movimentos Oculares/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Motivação/efeitos dos fármacos , Tempo de Reação/efeitos dos fármacos , Fumantes , Adulto JovemRESUMO
BACKGROUND: Tobacco companies have deliberately used explicit and implicit misleading information in marketing campaigns. The aim of the current study was to experimentally investigate whether the editing of explicit and implicit content of a print advertisement improves smokers' risk beliefs and smokers' knowledge of explicit and implicit information. METHODS: Using a 2(explicit/implicit)×2(accurate/misleading) between-subject design, 203 smokers were randomly assigned to one of four advertisement conditions. The manipulation of graphic content was examined as an implicit factor to convey product harm. The inclusion of a text corrective in the body of the ad was defined as the manipulated explicit factor. Participants' eye movements and risk beliefs/recall were measured during and after ad exposure, respectively. RESULTS: Results indicate that exposure to a text corrective decreases false beliefs about the product (p<.01) and improves correct recall of information provided by the corrective (p<.05). Accurate graphic content did not alter the harmfulness of the product. Independent of condition, smokers who focused longer on the warning label made fewer false inferences about the product (p=.01) and were more likely to correctly recall the warning information (p<.01). Nonetheless, most smokers largely ignored the text warning. CONCLUSIONS: Embedding a corrective statement in the body of the ad is an effective strategy to convey health information to consumers, which can be mandated under the Tobacco Control Act. Eye-tracking results objectively demonstrate that text-only warnings are not viewed by smokers, thus minimizing their effectiveness for conveying risk information.
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Conhecimentos, Atitudes e Prática em Saúde , Rotulagem de Produtos , Leitura , Comportamento de Redução do Risco , Movimentos Sacádicos , Fumar/efeitos adversos , Fumar/legislação & jurisprudência , Fumar/psicologia , Produtos do Tabaco/efeitos adversos , Produtos do Tabaco/legislação & jurisprudência , Adulto , Idoso , Feminino , Política de Saúde/legislação & jurisprudência , Humanos , Masculino , Pessoa de Meia-Idade , Estados Unidos , Adulto JovemRESUMO
BACKGROUND: The U.S. FDA has the authority to reduce cigarette nicotine content if found to benefit public health. Reduced nicotine content (RNC) cigarette use does not appear to increase harm exposure, but studies have not rigorously assessed smoking behavior or used a comprehensive panel of biomarkers. This study examined the effects of progressively decreasing RNC cigarettes on smoking behaviors, biomarkers of exposure, and subjective ratings. METHODS: One hundred and fifty-eight daily, non-treatment-seeking smokers participated in a 35-day randomized, unblinded, parallel study. After a 5-day baseline period, participants were randomly assigned to an experimental group (n = 80) that smoked progressively decreasing RNC cigarettes during three 10-day periods, or control group (n = 78) that smoked their own brand throughout the study. RESULTS: Daily cigarette consumption significantly increased for the intermediate RNCs (P's < 0.001) but approached baseline rate for the lowest RNC (P = 0.686); in contrast, puffing behavior significantly decreased at intermediate levels and increased for the lowest RNC (P's < 0.001). Cotinine and NNAL significantly decreased by RNC period (P's ≤ 0.001-0.02), whereas CO boost initially increased (P's = 0.001-0.005). 1-HOP did not change by period (P = 0.109). CONCLUSIONS: Smoking behaviors changed by RNC period via CPD and puffing behavior. Biomarkers of exposure generally decreased with nicotine content. IMPACT: Findings suggest that RNC use does not ubiquitously reduce smoking behaviors or biomarkers, yet the lowest RNC level tested may reduce harm exposure. This emphasizes the importance of using multiple behavioral and biologic measures to address the impact of RNC cigarette smoking. Cancer Epidemiol Biomarkers Prev; 25(7); 1125-33. ©2016 AACR.
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Nicotina/análise , Fumar/epidemiologia , Produtos do Tabaco , Adulto , Biomarcadores/urina , Monóxido de Carbono/análise , Estudos de Casos e Controles , Cotinina/urina , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Nicotina/toxicidade , Autorrelato , Fumar/psicologia , Produtos do Tabaco/classificaçãoRESUMO
BACKGROUND: As part of the Family Smoking Prevention and Tobacco Control Act, the U.S. Food and Drug Administration charged the Tobacco Products Scientific Advisory Committee with developing a report and recommendations about the effect of menthol in cigarettes on the public health. The purpose of this study was to examine smoking behaviors, biomarkers of exposure, and subjective responses when switching from a novel menthol cigarette to a non-menthol cigarette to isolate the effect of menthol and to approximate the effect a menthol ban might have on smokers. METHODS: Thirty-two adult smokers completed this 35-day randomized, open-label, laboratory study. After a 5-day baseline period, participants were randomized to the experimental group (n = 22) where they would smoke menthol Camel crush for 15 days followed by 15 days of non-menthol Camel crush, or the control group (n = 10) where they smoked their own brand cigarette across all periods. Participants attended study visits every 5 days and completed measures of smoking rate, smoking topography, biomarkers of exposure, and subjective responses. RESULTS: Although total puff volume tended to increase when the experimental group switched from menthol to non-menthol (P = 0.06), there were no corresponding increases in cigarette consumption or biomarkers of exposure (P > 0.1). Subjective ratings related to taste and smell decreased during the non-menthol period (P < 0.01), compared with the menthol. CONCLUSIONS: Results suggest menthol has minimal impact on smoking behaviors, biomarkers of exposure, and subjective ratings. IMPACT: When controlling for all other cigarette design features, menthol in cigarettes had minimal effect on outcome measures.
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Biomarcadores/análise , Desoxiguanosina/análogos & derivados , Exposição Ambiental/análise , Comportamentos Relacionados com a Saúde , Mentol/farmacologia , Fumar/tendências , 8-Hidroxi-2'-Desoxiguanosina , Adulto , Idoso , Cromatografia Líquida , Desoxiguanosina/análise , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Olfato/efeitos dos fármacos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Paladar/efeitos dos fármacos , Adulto JovemRESUMO
BACKGROUND: The Family Smoking Prevention and Control Act gave the U.S. Food and Drug Administration (FDA) legal authority to mandate graphic warning labels on cigarette advertising and packaging. The FDA requires that these graphic warning labels be embedded into cigarette advertising and packaging by September 2012. PURPOSE: The aim of this study was to examine differences in recall and viewing patterns of text-only versus graphic cigarette warning labels and the association between viewing patterns and recall. METHODS: Participants (current daily smokers; N=200) were randomized to view a cigarette advertisement with either text-only or graphic warning labels. Viewing patterns were measured using eye-tracking, and recall was later assessed. Sessions were conducted between November 2008 and November 2009. Data analysis was conducted between March 2011 and July 2011. RESULTS: There was a significant difference in percentage correct recall of the warning label between those in the text-only versus graphic warning label condition, 50% vs 83% (χ(2)=23.74, p=0.0001). Time to first viewing of the graphic warning label text and dwell time duration (i.e., time spent looking) on the graphic image were significantly associated with correct recall. Warning labels that drew attention more quickly and resulted in longer dwell times were associated with better recall. CONCLUSIONS: Graphic warning labels improve smokers' recall of warning and health risks; these labels do so by drawing and holding attention.
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Publicidade , Medições dos Movimentos Oculares , Rememoração Mental , Fotografação , Rotulagem de Produtos , Prevenção do Hábito de Fumar , Adulto , Idoso , Atenção , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rotulagem de Produtos/legislação & jurisprudência , Embalagem de Produtos , Fumar/epidemiologia , Fumar/legislação & jurisprudência , Estados Unidos/epidemiologia , Adulto JovemRESUMO
Varenicline promotes smoking cessation and reduces urges to smoke. However, the mechanisms associated with these effects and their time course are not well characterized. One mechanism may be extinction, but the duration of the current dosing protocol may not be sufficient. We examined the effect of extended pre-treatment with varenicline on smoking behavior among 17 non-treatment seeking adult smokers. Using a within-subjects, double-blind, placebo-controlled crossover design, participants received standard dosing of varenicline for 21 days, followed by a 14-day washout period and 21 days of placebo; order counterbalanced. Cigarettes per day (CPD), smoking topography, smoking urges (QSU), and side effects were assessed every three days. Biomarkers (e.g. nicotine metabolites) were collected on days 1, 7, and 21. There was a significant drug by time interaction indicating a reduction in CPD during varenicline phase (between days 10-21), but no reduction during placebo. Varenicline also led to reductions in nicotine metabolites and urges to smoke. Among this sample of non-treatment seeking smokers, varenicline significantly reduced smoking behavior. Results have important treatment implications because changes in CPD and craving did not occur until after the typical one-week run-up period. This suggests that a longer duration of pre-treatment may be beneficial for some smokers.
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Comportamento Aditivo/prevenção & controle , Benzazepinas/uso terapêutico , Agonistas Nicotínicos/uso terapêutico , Quinoxalinas/uso terapêutico , Abandono do Hábito de Fumar , Síndrome de Abstinência a Substâncias/prevenção & controle , Adulto , Comportamento Aditivo/etiologia , Benzazepinas/efeitos adversos , Biomarcadores/urina , Cotinina/urina , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Nicotina/urina , Agonistas Nicotínicos/efeitos adversos , Aceitação pelo Paciente de Cuidados de Saúde , Pennsylvania , Quinoxalinas/efeitos adversos , Receptores Nicotínicos/química , Receptores Nicotínicos/metabolismo , Síndrome de Abstinência a Substâncias/fisiopatologia , Síndrome de Abstinência a Substâncias/urina , Fatores de Tempo , Vareniclina , Adulto Jovem , Receptor Nicotínico de Acetilcolina alfa7RESUMO
The Internet is a major source of health information and several notable health web sites contain information on the risks associated with cigar smoking. Previous research indicates that Internet pages containing health information on cigars have high reading levels and are restricted to text material, which can decrease understanding. We examined the effects of existing text-only (from the United States National Cancer Institute website) versus novel graphic-enhanced information on smokers' perceptions of health risks associated with cigar smoking. The study was a laboratory-based single session of current cigarette smokers (n=102) who viewed cigar smoking risk information on a computer monitor then completed cigar risk questionnaire items. Participants were randomized to view either text-only or graphic-enhanced cigar information. The graphic version contained additional risk information about cigarillos and little cigars. Text-only participants were more likely to underestimate perceived health risks associated with cigar smoking compared to graphic-enhanced participants (47.1% versus 17.7%, p=.001); and, graphic-enhanced participants were more likely to report that they would share the cigar health risk information with friends compared to those viewing text-only, 47.0% versus 27.4%, p=.005. Employing graphics to convey health risks associated with cigar smoking increases understanding and likeliness to share information. Integrating information about little cigar and cigarillo risk in conjunction with large cigar risk information is an effective public health strategy to provide more comprehensive risk information. Utilizing graphics on health information internet pages can increase knowledge and perceived risks of cigar smoking.
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Gráficos por Computador , Internet , Nicotiana/efeitos adversos , Fumar/psicologia , Adulto , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Assunção de Riscos , Fumar/efeitos adversos , Estados UnidosRESUMO
BACKGROUND: Variability in smoking behavior is partly attributable to heritable individual differences in nicotine clearance rates. This can be assessed as the ratio of the metabolites cotinine and 3'-hydroxycotinine (referred to as the nicotine metabolism ratio; NMR). We hypothesized that faster NMR would be associated with greater cigarette puff volume and higher levels of total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a carcinogen biomarker. METHODS: Current smokers (n = 109) smoked one of their preferred brand cigarettes through a smoking topography device and provided specimens for NMR and total NNAL assays. RESULTS: Faster nicotine metabolizers (third and fourth quartiles versus first quartile) based on the NMR exhibited significantly greater total puff volume and total NNAL; the total puff volume by daily cigarette consumption interaction was a significant predictor of total NNAL level. CONCLUSION: A heritable biomarker of nicotine clearance predicts total cigarette puff volume and total NNAL. IMPACT: If validated, the NMR could contribute to smoking risk assessment in epidemiologic studies and potentially in clinical practice.
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Cotinina/análogos & derivados , Cotinina/sangue , Nicotina/farmacocinética , Nitrosaminas/urina , Piridinas/urina , Fumar/metabolismo , Adolescente , Adulto , Idoso , Hidrocarboneto de Aril Hidroxilases/genética , Biomarcadores/sangue , Biomarcadores/urina , Citocromo P-450 CYP2A6 , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Medição de Risco , Fumar/genética , Taxa de Sobrevida , Adulto JovemRESUMO
Filter vent blocking on best-selling light cigarettes increases smoke yield during standard machine testing but not in clinical investigations of smokers. The purpose of the study was to investigate the effect of (a) manipulating cigarette filter vent blocking and (b) blocking status of first cigarette of the day on carbon monoxide (CO) boost. Participants (n = 25; Marlboro Lights nonmenthol cigarette smokers, age range 21-60 years, minimum 15 daily cigarettes, and daily smoking for a minimum 5 years) completed the laboratory-based, within-subject, double-blind, cross-over design of 2 smoking sessions, one utilizing a smoking topography device, one without. Each session consisted of smoking 4 cigarettes; 2 with filter vents blocked and 2 with filter vents unblocked. Spent first daily cigarette filters collected between sessions were scored for evidence of filter vent blocking. Smoking cigarettes with blocked filter vents significantly increased CO boost in both laboratory sessions (p < .001). Those who blocked their first cigarette of the day (n = 10) had significantly greater CO boost when smoking a blocked cigarette, in relation to smoking an unblocked cigarette and in comparison with nonblockers (p = .04). Total puff volume was a significant predictor of CO boost when smoking unblocked and blocked cigarettes (ps < .04). Blocking filter vents significantly increased smoke exposure in relation to when filter vents are not blocked, particularly for those who block filter vents on their first cigarette of the day. Total puff volume predicted CO boost, and results suggest that smokers adjust their smoking behavior by cigarette blocking status. Those smokers who block filter vents may be increasing their exposure by 30%.
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Filtração/métodos , Nicotiana , Abandono do Hábito de Fumar/psicologia , Fumar/psicologia , Administração por Inalação , Adulto , Monóxido de Carbono/análise , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Promoção da Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Fumar/metabolismo , Adulto JovemRESUMO
We present a new shape-based approach for regional group activation analysis in fMRI studies. The method restricts anatomical normalization, spatial smoothing and random effects statistical analysis to the space inside and around a structure of interest. Normalization involves finding intersubject correspondences between manually outlined masks, and it leverages the continuous medial representation, which makes it possible to extend surface-based shape correspondences to the space inside and outside of structures. Our approach is an alternative to whole-brain normalization in cases where the latter may fail due to anatomical variability or pathology. It also provides an opportunity to analyze the shape and thickness of structures concurrently with functional activation. We apply the technique to the hippocampus and evaluate it using data from a visual scene encoding fMRI study, where activation in the hippocampus is expected. We produce detailed statistical maps of hippocampal activation, as well as maps comparing activation inside and outside of the hippocampus. We find that random effects statistics computed by the new approach are more significant than those produced using the Statistical Parametric Mapping framework (Friston, K.J., Holmes, A.P., Worsley, K.J., Poline, J.-P., Firth, C.D., Frackowiak, R.S.J. 1994, Statistical parametric maps in functional imaging: a general linear approach. Human Brain Mapping, 2(4): 189-210) at low levels of smoothing, suggesting that greater specificity can be achieved by the new method without a severe tradeoff in sensitivity.
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Hipocampo/anatomia & histologia , Hipocampo/fisiologia , Adulto , Algoritmos , Artefatos , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Modelos Anatômicos , Modelos NeurológicosRESUMO
Arterial spin labeling (ASL) perfusion fMRI is an emerging method in clinical neuroimaging. Its non-invasiveness, absence of low frequency noise, and ability to quantify the absolute level of cerebral blood flow (CBF) make the method ideal for longitudinal designs or low frequency paradigms. Despite the usefulness in the study of cognitive dysfunctions in clinical populations, perfusion activation studies to date have been conducted for simple sensorimotor paradigms or with single-slice acquisition, mainly due to technical challenges. Using our recently developed amplitude-modulated continuous ASL (CASL) perfusion fMRI protocol, we assessed the feasibility of a higher level cognitive activation study in twelve healthy subjects. Taking advantage of the ASL noise properties, we were able to study tonic CBF changes during uninterrupted 6-min continuous performance of working memory and sustained attention tasks. For the visual sustained attention task, regional CBF increases (6-12 ml/100 g/min) were detected in the right middle frontal gyrus, the bilateral occipital gyri, and the anterior cingulate/medial frontal gyri. During the 2-back working memory task, significantly increased activations (7-11 ml/100 g/min) were found in the left inferior frontal/precentral gyri, the left inferior parietal lobule, the anterior cingulate/medial frontal gyri, and the left occipital gyrus. Locations of activated and deactivated areas largely concur with previous PET and BOLD fMRI studies utilizing similar paradigms. These results demonstrate that CASL perfusion fMRI can be successfully utilized for the investigation of the tonic CBF changes associated with high level cognitive operations. Increased applications of the method to the investigation of cognitively impaired populations are expected to follow.
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Encéfalo/irrigação sanguínea , Cognição/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Oxigênio/sangue , Adulto , Atenção/fisiologia , Encéfalo/fisiologia , Mapeamento Encefálico , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/fisiologia , Dominância Cerebral/fisiologia , Estudos de Viabilidade , Feminino , Lobo Frontal/irrigação sanguínea , Lobo Frontal/fisiologia , Giro do Cíngulo/irrigação sanguínea , Giro do Cíngulo/fisiologia , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Rede Nervosa/fisiologia , Lobo Occipital/irrigação sanguínea , Lobo Occipital/fisiologia , Lobo Parietal/irrigação sanguínea , Lobo Parietal/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Fluxo Sanguíneo Regional/fisiologiaRESUMO
A new approach to group activation analysis in fMRI studies that test hypotheses focused on specific brain structures is presented and used to analyze hippocampal activation in a visual scene encoding study. The approach leverages the cm-rep method to normalize hippocampal anatomy and project intra-subject hippocampal activation maps into a common reference space, eliminating normalization errors inherent in whole-brain approaches and guaranteeing that peaks detected in the random effects activation map are indeed associated with the hippocampus. When applied to real fMRI data, the method detects more significant hippocampal activation than the established whole-brain method.
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Algoritmos , Mapeamento Encefálico/métodos , Potenciais Evocados/fisiologia , Hipocampo/anatomia & histologia , Hipocampo/fisiologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Reconhecimento Automatizado de Padrão/métodos , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The use of functional imaging to identify encoding-related areas in the medial temporal lobe has previously been explored for presurgical evaluation in patients with temporal lobe epilepsy. Optimizing sensitivity in such paradigms is critical for the reliable detection of regions most closely engaged in memory encoding. A variety of experimental designs have been used to detect encoding-related activity, including blocked, sparse event-related, and rapid event-related designs. Although blocked designs are generally more sensitive than event-related designs, design and analysis advantages could potentially overcome this difference. In the present study, we directly contrast different experimental designs in terms of the intensity, extent, and lateralization of activation detected in healthy subjects. Our results suggest that although improved design augments the sensitivity of event-related designs, these benefits are not sufficient to overcome the sensitivity advantages of traditional blocked designs.