Impulsiveness in Patients with Bulimia Nervosa: Electrophysiological Evidence of Reduced Inhibitory Control

Abstract

Objectives: Bulimia nervosa (BN) is associated with a deficit of self-regulatory control and impulsivity. The present study aimed to clarify whether an impaired inhibitory control due to hyperarousal underlies impulsivity in BN subjects. Methods: Event-related potentials (ERPs) were recorded in 17 female patients with BN and 17 healthy controls during a three-tone oddball task. ERP components related to inhibition of irrelevant distractor stimuli, as well as effortful processing, were analyzed. Standardized low-resolution electromagnetic tomography (sLORETA) was used to assess ERP source activity. Results: Compared to healthy controls, BN patients showed reduced amplitude and shorter latency of the N200 (N2), increased amplitude and shorter latency of the target slow wave (SW), and higher amplitude of the P300 for distractor stimuli (P3a) and for targets (P3b). sLORETA showed the following: (1) higher activity of the P3a generators in the left parietal cortex, bilateral precuneus and right frontal and anterior cingulate for distractor stimuli and (2) lower activity of the SW generators in the left medial frontal gyrus, bilateral superior frontal, anterior cingulate and cuneus for target stimuli. The reduction of the N2 latency was associated with the Barratt scores for impulsiveness. Conclusions: The observed electrophysiological abnormalities suggest a condition of hyperarousal, with impaired suppression of irrelevant stimuli due to abnormal cortical activation and reduced signal-to-noise ratio. Our findings point to functional abnormalities within a neural system that subserves attention and self-regulatory control, which may contribute to impulsive behaviors in BN.

Greater positive schizotypy relates to reduced N100 activity during rejection scenes

“…Reduced P300 during auditory attention indicates poor discrimination of innocuous auditory tones in recent-onset schizophrenia and positive schizotypy (Sumich et al, 2008a;Sumich et al, 2008b). The dACC is the neural generator of the frontal early P300 when processing SCHIZOTYPY AND REJECTION SENSITIVITY 7 personally-salient faces and detecting novelty in auditory odd-ball tasks (Dai, Zhai, Zhou, Gong, & Luo, 2013;Friedman, Cycowicz, & Gaeta, 2001;Merlotti et al, 2013). The LSW occurs at approximately 600 ms as a frontal negative potential and a centro-parietal positive potential (Bartholow, 2010;Foti, Hajcak, & Dien, 2009) and reflects evaluation of the motivational salience of affective stimuli and behavioural control in the context of emotions (Aguado, Dieguez-Risco, Mendez-Bertolo, Pozo, & Hinojosa, 2012;Gibbons, 2009).…”

Impulsividade e controle inibitório nos transtornos alimentares: revisão sistemática

“…Também foram encontrados estudos que utilizaram tomografia de emissão de prótons, como os dos autores Bailer et al (2011) e o de Merlotti et al (2013). O estudo de Bailer et al (2013) apontou para a possibilidade de o receptor 5-HT1A contribuir para a capacidade de inibir ou controlar alguns comportamentos relacionados com estímulos de raiva e impulsividade característicos de indivíduos com TAs.…”

“…O estudo de Bailer et al (2013) apontou para a possibilidade de o receptor 5-HT1A contribuir para a capacidade de inibir ou controlar alguns comportamentos relacionados com estímulos de raiva e impulsividade característicos de indivíduos com TAs. Já no estudo de Merlotti et al (2013), foram verificadas anomalias funcionais relacionadas com a atenção e a autorregulação, que podem contribuir para comportamentos impulsivos em bulímicos. Alguns estudos utilizaram ressonância magnética funcional, e, entre os dados encontrados, cabe enfatizar diferenças funcionais em relação ao controle inibitório em sujeitos com TAs (Lock et al, 2011;Oberndorfer et al, 2011).…”

Bidirectional and context-dependent changes in theta and gamma oscillatory brain activity in noradrenergic cell-specificHypocretin/Orexin receptor 1-KO mice

“…These traits were hypothesized to result from emotional blunting associated with HCRT deficiency. Thus, although increased sleepiness is a cardinal symptom of narcolepsy, other symptoms such as increased impulsivity, or binge-eating behavior, might suggest forms of hyperarousal 110,111 .…”