Baroreflex sensitivity during rest and executive functioning in attention-deficit/hyperactivity disorder. The TRAILS study
ABSTRACT Children with attention-deficit/hyperactivity disorder (ADHD) often show executive function (EF) problems and neurophysiological hypoarousal. Baroreceptor activation, as part of the baroreflex short-term blood pressure regulatory mechanism, has been linked to cortical inhibition and attenuated cognitive-attentional functioning. We investigated the hypothesis that higher resting baroreflex sensitivity (BRS) predicts poorer EF performance in children with ADHD. EF measures of speed and accuracy were regressed upon resting BRS in 10-12-year-old children with ADHD from a clinic-referred sample (n=181) and healthy (n=194) and clinic-referred (n=260) comparison samples. Resting BRS was positively associated with poorer EF performance (e.g., response variability, working memory, response inhibition), especially in ADHD combined type, boys, and unmedicated children. Comparison samples partly suggested negative associations. We conclude that higher resting BRS is related to poorer cognitive performance in children with ADHD. Findings suggest afferent influences of the body's visceral state on higher-order cognitive functioning and imply energetic state dysregulation in ADHD.
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ABSTRACT: KILLEEN, P.R., V.A. Russell and J.A. Sergeant. A behavioral neuroenergetics theory of ADHD. NEUROSCI BIOBEHAV REV 37(4) XXX_XXX 2013- Energetic insufficiency in neurons due to inadequate lactate supply is implicated in several neuropathologies, including attention-deficit/hyperactivity disorder (ADHD). By formalizing the mechanism and implications of such constraints on function, the behavioral Neuroenergetics Theory (NeT) predicts the results of many neuropsychological tasks involving individuals with ADHD and kindred dysfunctions, and entails many novel predictions. The associated diffusion model predicts that response times will follow a mixture of Wald distributions from the attentive state, and ex-Wald distributions after attentional lapses. It is inferred from the model that ADHD participants can bring only 75-85% of the neurocognitive energy to bear on tasks, and allocate only about 85% of the cognitive resources of comparison groups. Parameters derived from the model in specific tasks predict performance in other tasks, and in clinical conditions often associated with ADHD. The primary action of therapeutic stimulants is the increase they cause in norepinephrine, which activates glial adrenoceptors, increasing the release of lactate from astrocytes to fuel depleted neurons. The theory is aligned with other approaches and integrated with more general theories of ADHD. Therapeutic implications are explored.Neuroscience & Biobehavioral Reviews 02/2013; 37(4). DOI:10.1016/j.neubiorev.2013.02.011 · 10.28 Impact Factor
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ABSTRACT: The baroreflex consists of a negative feedback loop adjusting heart activity to blood pressure fluctuations. This review is concerned with interactions between baroreflex function and behavior. In addition to changes in baroreflex cardiac control subject to behavioral manipulations, interindividual differences in reflex function predicted psychological and central nervous features. The sensitivity of the reflex was inversely related to cognitive performance, evoked potential amplitudes, experimental pain sensitivity, and the severity of clinical pain. Possible variables moderating the strength of the associations are tonic blood pressure, gender, and psychiatric disease. It is suggested that these observations reflect inhibition of higher brain function by baroreceptor afferents. While in many cases increased baroreflex function implies stronger inhibition, individual and situational factors modulate the behavioral impact of cardiac regulation.Psychophysiology 08/2013; 50(12). DOI:10.1111/psyp.12136 · 3.18 Impact Factor
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ABSTRACT: This study analyzes differences in blood pressure (BP) and baroreflex sensitivity (BRS) in relation to trait worry. Thirty-six high worry and 21 low worry females were selected from scores on the Penn State Worry Questionnaire. Cardiovascular parameters were obtained during rest, a self-induced worry period, and defense reflex to intense auditory stimulation. Low worry participants exhibited greater BP during baseline and greater BRS both during baseline and the self-induced worry period than high worry participants. During the defense reflex, low worriers present a greater increase in BP. It is concluded that low proneness to worry is associated with greater BP and BRS. Increases in BP during aversive stimulation activated a negative feedback mechanism to inhibit distress and emotional reactivity to negative stimulation. These results support the BP-emotional dampening hypothesis and suggest that the baroreflex can be a relevant mechanism in mediating this effect.Biological psychology 11/2013; 96. DOI:10.1016/j.biopsycho.2013.11.005 · 3.47 Impact Factor