Is there a trade-off between cognitive and motor recovery after traumatic brain injury due to competition for limited neural resources?

The status of neurorehabilitation for traumatic brain injury (TBI) is under active debate because of a dearth of research findings demonstrating effectiveness. This may be due, in part, to limitations in our understanding of basic mechanisms of cognitive and motor recovery,including those that might impede recovery. In this regard, we examined whether overall recovery following TBI might be undermined by competition between cognitive and motor functions for finite neural resources during recovery. In this preliminary study, 21 moderately and severely impaired patients were administered cognitive and motor assessments at 1, 4, and 12 months post-TBI, and recovery of cognitive and motor functions was measured using regression residuals. Negative correlations between recovery of cognitive versus motor functions were used as the index of competition. We found suggestive evidence that there may indeed be a trade-off between the recovery of cognitive and motor functions after TBI. Implications for rehabilitation are discussed.     

Changing food preference as a function of mood

The authors investigated the effect of mood on food selection. Participants (N = 98) indicated the likelihood of general eating and the likelihood of eating specific foods after reading and projecting themselves onto the events and emotions described in a sad and a happy vignette. Both men and women believed they were more likely to consume food following a happy versus a sad event, and men believed they were significantly more likely to eat than did women. However, the type of food men and women believed they would consume interacted with the type of event experienced. Vegetarian snack foods were more likely to be consumed following a happy versus a sad event, with men more likely to eat snack foods. Men did not significantly change in likelihood of consuming sweet foods as their mood changed. However, women believed they were more likely to consume sweet foods following a sad event. The authors discuss the results in terms of a self-medication hypothesis and the effect of carbohydrates on central serotonin and endogenous opioids. Overall, results demonstrated that mood influences belief in the likelihood of food selection.     

Overlooking the Obvious: Incentives to Lie

Over the years, people have searched for deception cues in the liar's behavior. However, the sender's incentives to lie might be more revealing than behavior. In Experiment 1, an incentive was developed that was predictive of lying. Judges with access to incentive information in addition to behavior achieved almost perfect lie/truth detection. This was not a result of the speakers' behavior being transparent (Experiment 2) but because incentive information was useful to separate lies from truths (Experiments 2 and 3). Experiment 3 revealed that people may forego perfectly diagnostic contextual cues to base their judgments on illusory behavioral cues.     

Women Inmate Substance Abusers’ Reactivity to Visual Alcohol, Cigarette, Marijuana, and Crack-Cocaine Cues: Approach and Avoidance as Separate Dimensions of Reactivity

Despite the growing recognition for multidimensional assessments of cue-elicited craving, few studies have attempted to measure multiple response domains associated with craving. The present study evaluated the Ambivalence Model of Craving (Breiner et al. Alcohol Research and Health 23:197–206, 1999; Stritzke et al. 2007) using a unique cue reactivity methodology designed to capture both the desire to use (approach inclination) and desire to not consume (avoidance inclination) in a clinical sample of incarcerated female substance abusers. Participants were 155 incarcerated women who were participating in or waiting to begin participation in a nine-month drug treatment program. Results indicated that all four substance cue-types (alcohol, cigarette, marijuana, and crack cocaine) had good reliability and showed high specificity. Also, the validity of measuring approach and avoidance as separate dimensions was supported, as demonstrated by meaningful clinical distinctions between groups evincing different reactivity patterns and incremental prediction of avoidance inclinations on measures of stages of change readiness. Taken together, results continue to highlight the importance of measuring both approach and avoidance inclinations in the study of cue-elicited craving.     

Cue competition effects in the planarian

The learning abilities of planarian worms (Dugesia tigrina) were assessed by using a number of Pavlovian conditioning paradigms. Experiment 1 showed that planaria were susceptible to basic conditioning in that they readily developed a conditioned response to a change in ambient luminance when it was consistently paired with an electric shock over a number of trials. In Experiment 2, the change in luminance was presented in a compound with a vibration stimulus during conditioning. Subsequent tests revealed poor conditioning of the elements compared with control groups in which the animals were conditioned in the presence of the elements alone, an instance of overshadowing. In Experiment 3, pre-training of one of the elements before compound conditioning resulted in blocking of learning about the other element. These results add to other studies that have reported cue competition effects in animal species belonging to different phyla (chordate, mollusk, arthropod), suggesting that learning in these phyla could be ruled by similar principles. The results are discussed adopting an evolutionary-comparative approach.