This study investigated the neural regions involved in blood pressure reactions to negative stimuli and their possible modulation by attention.Twenty-fourhealthyhumansubjects(11females;age24.752.49years)participatedinanaffectiveperceptualloadtask thatmanipulatedattentiontonegative/neutraldistractorpictures.fMRIdatawerecollectedsimultaneouslywithcontinuousrecordingof peripheral arterial blood pressure. A parametric modulation analysis examined the impact of attention and emotion on the relation between neural activation and blood pressure reactivity during the task. When attention was available for processing the distractor pictures,negativepicturesresultedinbehavioralinterference,neuralactivationinbrainregionspreviouslyrelatedtoemotion,atransient decrease of blood pressure, and a positive correlation between blood pressure response and activation in a network including prefrontalandparietalregions,theamygdala,caudate,andmid-brain.Theseeffectsweremodulatedbyattention;behavioralandneural responsestohighlynegativedistractorpictures(comparedwithneutralpictures)weresmallerordiminished,aswasthenegativeblood pressureresponsewhenthecentraltaskinvolvedhighperceptualload.Furthermore,comparinghighandlowloadrevealedenhanced activationinfrontoparietalregionsimplicatedinattentioncontrol.Ourresultsfittheoriesemphasizingtheroleofattentioninthecontrol of behavioral and neural reactions to irrelevant emotional distracting information. Our findings furthermore extend the function of attention to the control of autonomous reactions associated with negative emotions by showing altered blood pressure reactions to emotionalstimuli,thelatterbeingofpotentialclinicalrelevance.
Introduction Threatening stimuli prototypically facilitate adaptive motor behavior and activate the autonomic nervous system, affecting heart rate and blood pressure (Lang et al., 2000). These vascular responsescanaggravatewhenthethreateningsituationdevelops into stress for the organism. It has been shown that, among healthy subjects, those with higher blood pressure responses are morelikelytosubsequentlydevelophypertension(Matthewsetal., 2004). It is therefore highly relevant to identify neural mechanisms forthevascularresponseandpotentialwaystomodulateit. Studies on the neural underpinnings of vascular response to stressidentifiedbrainareasknowntobeassociatedwithemotion processing, including the amygdala, insula, and cingulate (Gian
aros and Sheu, 2009). These pioneer studies used intermittent bloodpressuremeasurementsbetweenfunctionalneuroimaging andwerethereforelimitedtolonger-lasting“stressperiods.”Recent technical developments (Gray et al., 2009), however, on which we build here, allow for simultaneous recording of blood pressure during fMRI to match neural activity associated with brief (threatening) events closely to blood pressure changes. Regarding potential ways to modulate emotion-related autonomicresponses,acrucialquestionconcernsthedegreetowhich reactions to emotional stimuli are affected by cognitive mechanisms. A debate exists on whether processing of emotional items depends on allocation of sufficient attention to them (see Pessoa et al., 2002 and Evans et al., 2011 for similar effects on attention bias to drug-related cues in drug-addicts). Recent models propose that projections from frontoparietal regions to amygdala modulatereactionstoemotionalstimuli(cf.Pessoa,2009,Pourtois et al., 2013). Conversely, it has been suggested that although attentioninfluencesemotionprocessing,itmaynotaffectneural activation related to defensive motor responses (Pichon et al., 2012). If the latter were coupled to autonomic responses, this would mean that (action-related) vascular responses to emotional stimuli could occur independently of attention to them. Motivatedbytheseconsiderations,theaimsofthisstudywereto identifyneuralregionsinvolvedinbloodpressureresponsestoemo
ReceivedFeb
Introduction Threatening stimuli prototypically facilitate adaptive motor behavior and activate the autonomic nervous system, affecting heart rate and blood pressure (Lang et al., 2000). These vascular responsescanaggravatewhenthethreateningsituationdevelops into stress for the organism. It has been shown that, among healthy subjects, those with higher blood pressure responses are morelikelytosubsequentlydevelophypertension(Matthewsetal., 2004). It is therefore highly relevant to identify neural mechanisms forthevascularresponseandpotentialwaystomodulateit. Studies on the neural underpinnings of vascular response to stressidentifiedbrainareasknowntobeassociatedwithemotion processing, including the amygdala, insula, and cingulate (Gian
aros and Sheu, 2009). These pioneer studies used intermittent bloodpressuremeasurementsbetweenfunctionalneuroimaging andwerethereforelimitedtolonger-lasting“stressperiods.”Recent technical developments (Gray et al., 2009), however, on which we build here, allow for simultaneous recording of blood pressure during fMRI to match neural activity associated with brief (threatening) events closely to blood pressure changes. Regarding potential ways to modulate emotion-related autonomicresponses,acrucialquestionconcernsthedegreetowhich reactions to emotional stimuli are affected by cognitive mechanisms. A debate exists on whether processing of emotional items depends on allocation of sufficient attention to them (see Pessoa et al., 2002 and Evans et al., 2011 for similar effects on attention bias to drug-related cues in drug-addicts). Recent models propose that projections from frontoparietal regions to amygdala modulatereactionstoemotionalstimuli(cf.Pessoa,2009,Pourtois et al., 2013). Conversely, it has been suggested that although attentioninfluencesemotionprocessing,itmaynotaffectneural activation related to defensive motor responses (Pichon et al., 2012). If the latter were coupled to autonomic responses, this would mean that (action-related) vascular responses to emotional stimuli could occur independently of attention to them. Motivatedbytheseconsiderations,theaimsofthisstudywereto identifyneuralregionsinvolvedinbloodpressureresponsestoemo
ReceivedFeb