In appetitive conditioning, a neutral stimulus (CS) is conditioned to elicit a positive emotional response by pairing it with a positive/appetitive unconditioned stimulus (US). This method is useful for studying emotional disorders and emotion in general. Studying appetitive conditioning in humans has been hampered by the lack of adequate positive unconditioned stimuli. This study investigated multimodal social stimuli as potential unconditioned stimuli in an appetitive conditioning paradigm. Neutral faces (CS+’giggle’ and CS+’woohoo’) were paired with two multimodal unconditioned stimuli consisting of the same smiling face and two different sound stimuli (US‘giggle’ and US‘woohoo’). The dependent variable was participant skin conductance response (SCR) alongside participant emotional ratings of the stimuli, that together indexes the conditioned response. CS+’giggle’ was hypothesized to be rated as happier, and less fearful than CS+’woohoo’. Successful conditioning was evidenced by higher happiness ratings for both stimuli after acquisition compared to habituation. However, no effect of acquisition was found on SCR.  US’woohoo’ was also rated as more fearful and arousing and less happy and pleasant than the US’giggle’. In sum, this thesis presents a paradigm that can be used in future studies on appetitive conditioning.

Thesis advisor: Michael Numan / Maternal behavior is a primary social characteristic of mammals. By studying maternal behavior in rats, broader inferences can be made about the neural circuits that influence maternal behavior in other mammals, including humans. Maternal behavior of rats includes nest building, pup grooming, nursing, and pup retrieval. The projections from the medial preoptic area of the hypothalamus (MPOA) to the ventral tegmental area (VTA) of the mesolimbic dopamine system are known to regulate maternal behavior in post-partum rats. The aim of the present study was to examine how inhibition of the basolateral amygdala (BLA), an area that projects to the nucleus accumbens-ventral palldium (NA-VP) circuit of the mesolimbic dopamine system, bilaterally with muscimol (a GABA-A agonist) might interrupt the retrieval of pups by post-partum rats. Females injected with muscimol, but not those injected with saline, displayed significant deficits in retrieval behavior, suggesting that the BLA is a region important for the promotion of maternal behavior. The effects were also reversible, as all females displayed normal maternal behavior 24-hours post-injection. Follow-up studies should use asymmetric neuron-specific lesions of the BLA and the VP to show that the projections from the BLA to the VP are essential for maternal behavior. / Thesis (BA) — Boston College, 2010. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Psychology Honors Program. / Discipline: Psychology.

Heavy episodic drinking is linked with poorer academic performance, injury, and risk behaviors among college students. Understanding the cognitive and motivational factors that influence self-control of alcohol use is critical to identifying students' risk factors and developing interventions. Dual process models characterize alcohol use patterns as a function of automatic appetitive responses to alcohol-related stimuli and executive control functions. These processes may be influenced by contextual cues such as mood. The present research sought to better understand the cognitive-motivational mechanisms through which an established contextual cue for drinking - positive mood - influences alcohol use. Two studies examined the influence of positive mood induction on undergraduate drinkers' approach biases for alcohol cues and executive functioning using established and modified Stimulus Response Compatibility Tasks (SRC). Undergraduates who used alcohol at least once in the past month were recruited from the introductory psychology subject pool and randomized to positive or neutral mood induction conditions to determine whether positive mood: (1) increased approach bias or (2) impaired efforts to control alcohol cue responses. Prior to mood induction, participants completed individual difference measures related to alcohol use to evaluate potential moderators. Experiment 1 (N=93) examined post-induction alcohol approach bias and approach response inhibition using a stop-signal task within SRCs. Those in the positive mood condition did not exhibit greater approach bias or less inhibition, and mood effects were not moderated by individual differences as hypothesized. Experiment 2 (N=141) examined the influence of mood on approach bias and the ability to reverse established SRC responses to alcohol cues, with a pre-induction SRC to control for baseline approach biases. Again, positive mood did not significantly influence alcohol approach bias or executive control. Discussion: Results did not support positive mood influences on cognitive-motivational processes associated with drinking. The absence of mood effects may be a function of the type of positive mood induced or sensitivity of the SRC to detect alcohol-specific approach bias in this population. Future studies should explore these processes using alternate measures of alcohol-specific approach bias, response inhibition, and mood states that may be more specific to drinking.

During the past few decades, obesity has risen significantly in the United States with recent estimates showing that 65% of Americans are overweight and 30% are obese. This increase is a major cause for concern because obesity is linked to many secondary health consequences that include type II diabetes, heart disease, and cancer. Current approaches to the obesity problem primarily have focused on controls of food intake and have been largely unsuccessful. Food, however, almost always has to be acquired (foraging) and frequently is stored for later consumption (hoarding). Therefore, a more comprehensive approach that includes studying the underlying mechanisms in human foraging and food hoarding behaviors could provide an additional target for pharmaceutical or behavioral manipulations in the treatment and possibly prevention of obesity. Neuropeptide Y (NPY) is a particular peptide that provides a potent orexigenic drive to alter foraging, food hoarding (appetitive ingestive behaviors) and food intake (consummatory ingestive behaviors) in variety of species. NPY is predominantly produced in the arcuate nucleus of the hypothalamus (ARC) and has extensive efferent projections throughout the brain. Two target nuclei of ARC-NPY, the paraventricular nucleus of the hypothalamus (PVH) and perifornical area (PFA), have been shown to mediate the effect of NPY on food intake in laboratory rats and mice, but nothing is known about the effect of ARC-NPY on foraging and food hoarding. In addition, the action of specific NPY receptor subtypes within these two nuclei for these behaviors is unknown. Even though ARC-NPY is one of the main sources of input into the PVH and PFA, it is not known if this NPY fiber projection mediates alterations in appetitive and consummatory ingestive behaviors. Therefore, the purpose of this dissertation is to test 1) if NPY within the PVH or PFA controls appetitive, as well as, consummatory ingestive behaviors, 2) if NPY Y1 receptors within the PVH or PFA differentially control appetitive or consummatory ingestive behaviors, and 3) if NPY from the ARC is necessary for the control of appetitive and consummatory ingestive behaviors.

In certain species, puberty is thought to be a period of susceptibility to various stressors, resulting in pathological behavioral and physiological changes subsequent to exposure during this period. However, juvenile male golden hamsters appear to be fairly resilient to pubertal stress, as compared to adult hamsters and many other species. In these experiments, repeatedly stressed juvenile male hamsters were found to be avoidant of aggressive adult male social stimuli, but did not display anxious behavior outside of a social context. In addition, several long-term changes in neural activity were associated with social stress during early puberty. The medial preoptic area and medial preoptic nucleus, and ventral tegmental area showed decreased neural activity in subjugated juveniles than in naïve individuals. Since these brain areas are involved in the expression of motivated behaviors, specifically sexual behavior, and reward pathways, we next investigated sexual behavior in virgin juveniles. When placed in a confined space with receptive females, consummatory behavior in subjugated juveniles was similar to those observed in naive juveniles. Appetitive aspects of sexual behavior were also tested in a Y-maze to allow subjects to choose whether to approach a social stimulus. When given a choice between a sexually receptive and non-receptive female social stimulus, socially stressed individuals showed anxiety related behaviors and did not show a preference. However, naïve hamsters preferred the non-receptive female. Interestingly, this effect was less significant in naïve animals tested during late puberty and early adulthood, and a preference for sexually receptive females was not observed. In addition, stressed hamsters tested with harnessed females at mid-puberty were slower to approach females, indicating altered motivation to approach adult conspecifics. This research is unique in that it is the first to suggest the disconnect between the development of consummatory and appetitive aspects of sexual behavior. Together, these data examine the effects of stress on the development of pubertal social behaviors. / text

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Eating behaviors, notably eating behaviors conceptualized as appetitive traits, have been suggested as important determinants of individual differences in body weight and thus overweight and obesity. Such appetitive traits include emotional overeating, food responsiveness, enjoyment of food, satiety responsiveness and slowness in eating. Yet little is known about the factors that influence the development of these appetitive traits. Therefore, the current study prospectively investigated a range of predictors of appetitive traits related to both individual child characteristics and parent factors in a large population-based sample of children followed from age 6 to 8 years (N = 689). When adjusting for the initial levels of the specific appetitive trait in question at age 6 and the other predictors, the results showed that instrumental feeding and low levels of effortful control predicted emotional overeating at age 8, whereas instrumental feeding and parental restrained eating predicted food responsiveness at age 8. Enjoyment of food, satiety responsiveness and slowness in eating were not affected by any of the predictors investigated in this study. In conclusion, these findings support low effortful control and instrumental feeding as predictors of emotional overeating, and instrumental feeding and parental restrained eating as predictors of food responsiveness. These findings are relevant in providing a better understanding of the development of children’s eating behaviors, in addition to informing prevention and treatment strategies for childhood obesity.

Recent developments in emotion and EI research have introduced new ways of measuring emotional abilities, including performance based tests. The current study aimed to examine the associations of three emotional abilities, using three objective measures. The study consisted of a survey and an experiment, where 89 participants completed performance based multimodal emotion recognition and emotion understanding tests, and a conditioning task using social aversive and appetitive stimuli. The results showed that individuals who are more proficient in emotion understanding were more accurate in emotion recognition and more effective in extinguishing fear-evoking responses. In addition, individuals proficient in emotion recognition were shown to have stronger general responding during fear acquisition. Furthermore, various findings related to emotion understanding and emotion recognition modalities, including item difficulty and specific emotions. Implications of current findings support the notion of separate but related emotional abilities while also highlighting a potentially underlying mechanism or core emotional competence.

Newborn rats were injected SC during the first week of life with 80 μ/kg Met-enkephalin, DSIP, MIF-I, or diluent. When tested 3 months later in a 12-choice maze for a reward of food, hungry rats injected neonatally with Met-enkephalin were found to run the maze faster and with fewer errors than the controls. DSIP and MIF-I did not improve performance in the maze, indicating some specificity to the findings. Tyrosine hydroxylase and choline acetyltransferase activity in several parts of the brain were not significantly different among the groups. Radioimmunoassay of brain parts from a small number of adult rats indicated slightly more DSIP-like material in the thalamus and striatum of females injected neonatally with DSIP as compared with those injected with diluent. The results extend our previous observations of the persistence of central effects of peripherally injected Met-enkephalin from several minutes to three months when administration occurs early in life. The findings further suggest an effect of peptides on the organization of the developing brain.

A multitude of research supports that fluctuations in fertility and hormonal shifts in normally cycling females influence changes in female sexual strategies, preferences, and desires across the menstrual cycle. Evolutionary theory posits that in order to maximize reproductive benefits, near ovulation female responses to sexual stimuli alter and cues of sex are more appealing. The post-auricular reflex (PAR) is a psychophysiological reaction that has been linked to motivation and reward, emotion, and appetitive responding. The PAR responds to pleasant stimuli, including stimuli that are relevant to evolutionary themes. The purpose of the current study was to explore the nature of the post-auricular reflex, and in particular, to examine potential shifts in motivation and reward processing of sexual and emotional stimuli across the female menstrual cycle. Ovulation blunted PAR responses to non-erotic categories in normally cycling females, while responses to erotica did not significantly decrease across phases of the menstrual cycle. Ovulation was also found to affect female self-report of sexual desire. These shifts were not seen in females using hormonal birth control. The study results suggest that ovulation shifts female priorities towards reproduction by increasing desire and also decreasing motivations for non-mate-relevant activities. The study also demonstrates the need for greater investigation of the PAR and the appetitive responding system. / Psychology