There is experimental evidence suggesting that ethanol alters the activity of the endogenous opioid peptide systems in a dose and brain region dependent manner. These ethanol-induced alterations in opioid activity may influence the processes of ethanol reward and reinforcement. However, the precise nature of the link between ethanol-opioid interactions influencing reward and reinforcement is not clearly understood. Thus, it was the objective of the present study to investigate the response of the three major opioid peptide systems (endorphins, enkephalins, and dynorphins) to acute ethanol administration, at the level of the ventral tegmental area (VTA), a brain region important for drug, including ethanol, reinforcement. Using the in vivo microdialysis technique coupled with specific solid-phase radioimmunoassays for beta-endorphin, met-enkephalin, and dynorphin A1-8, changes of the extracellular concentration of theses peptides at the level of VTA were determined at distinct time points following the administration of 0.0 (saline), 0.8, 1.6, and 2.4 g ethanol/kg B/Wt. Results demonstrated a biphasic effect of ethanol on beta-endorphin release with 1.6, but not 0.8 or 2.4, g ethanol/kg B.Wt. enhancing beta-endorphin release. None of the ethanol doses used altered the extracellular levels of met-enkephalin, and dynorphin A1-8 peptides. In conclusion, the present findings suggest that at the level of VTA interactions of beta-endorphin with the mu and/or delta opioid receptors on GABA interneurons may contribute to the ethanol induced augmentation in the activity of the mesolimbic dopaminergic system, and influence ethanol reinforcement.

The aim of this randomized, controlled trial was to test whether sweet taste and chewing modify self-report of pain intensity and negative affect caused by blood-draws and vaccination in children. Subjects were recruited (age mean +/- SD; 9.82 +/- 0.8 years) from schools (n = 115) and a hospital (n = 101). Subjects were assigned to Control, Sweet, Chew or Sweet+chew interventions. Pain intensity was rated on the Coloured Analogue Scale (CAS) and affective quality on the Faces Pain Scale (FPS). / In school and hospital settings a Sex by Sweet by Chew interaction was seen on CAS (p = 0.29; p < 0.01) and FPS (p < 0.05; p < 0.05) respectively. A consistent pattern was seen in which chewing reduced and sweet taste increased pain ratings in boys. The opposite effect was seen in girls. When sex was not considered no significant differences between groups were seen. / Sweet taste and chewing appear not to have useful analgesic effects. Sex must be considered in future investigations.

Awareness of movement onset was studied in a series of three experiments. It was defined as the ability to detect computer-generated delays between the movement onset of the subject's hand and a visually displayed hand. This was accomplished by employing a Cyber Glove that rendered a computer-generated image of a hand on a computer screen. / In the pilot study, an estimate of the average detection threshold of movement onset delays was obtained in 17 normal control subjects (9 females, 8 males). Peripheral view of the hands was blocked. No significant differences in detection thresholds between men and women, between left and right hands, and across types of movement (all-fingers, index-finger, index-middle-finger extension) were found. / In the second study, data on detection thresholds in the absence of proprioceptive input was gathered from a patient diagnosed with sensory neuropathy of the left hand. No significant differences in detection thresholds between the affected and unaffected hand were recorded. Proprioception does not appear to be critical for awareness of movement onset delays. / In the third study, 33 normal control subjects (31 females and 2 males) performed four experimental movement conditions, two passive and two active. During the passive conditions, a lever device moved the subject's finger while their hand was either visible (PF) or hidden (PH) from view. In the active condition the subject moved their own finger while their hand was either visible (AF) or hidden (AH) from view. Detection thresholds were significantly lower during the active than the passive conditions (p < 0.01). No significant main effect of view was present. It appears that internal feedback loops, as opposed to visual feedback loops, may play a critical role in awareness of movement onset. / Taken together, data from all three studies suggest that the efferent copy plays an important role compared to visual or proprioceptive cues in the detection of movement onset delays.

<p> The association between stress and illness is well recognized. One recently proposed pathway between these constructs is the Allostatic Load framework, which is a biological-process model in which chronic stress is linked to physiological dysregulation. The current study tested one part of the Allostatic Load process model by looking at a spectrum of chronic stressors experienced in everyday life by healthy, typically&macr;-developing children during middle childhood, to find out whether their exposures are associated with the development of Allostatic Load at age 15. This was done by utilizing the National Institute of Child Health and Development Study of Early Child Care and Youth Development (NICHD SECCYD) data and drawing on the Allostatic Load model. The level of chronic stress experienced during middle childhood is associated positively with Allostatic Load in adolescence. The Home/Family context is more predictive of Allostatic Load in adolescence than stress experienced in the Extrafamilial context. However, this relationship is moderated by the sex of the research participant: the relationship between Home/Family stress and Allostatic Load was only significant for males. In contrast, the relationship between Extrafamilial stress and Allostatic Load was only significant for females.</p>

Stress plays a significant role in the initiation and continuation of drinking. Furthermore, epidemiological studies have shown a higher incidence of alcoholism in males than females. Objective. The current studies aimed to investigate the presence of gender differences in the interactions of ethanol and stress with the Hypothalamic-Pituitary-Adrenal (HPA) axis. Methods. Participants included 12 males and 10 females with no previous personal or familial history of alcoholism. Plasma levels of ACTH and cortisol were estimated following a placebo drink, a low and a high dose of alcohol and a psychological stress task performed 30 minutes after the ingestion of the placebo, the low and the high alcohol drinks. Results. Male participants presented a more pronounced response of the HPA-axis to both alcohol and psychological stress. Prior ingestion of the low and to a lesser extent of the high dose of alcohol induced a more pronounced and longer lasting attenuation of the HPA-axis response to stress in males than females. Conclusions. There are gender differences in the interactions of ethanol and stress with the HPA-axis, which may contribute to the gender differences in alcohol consumption.

This thesis describes two studies that were performed to explore how the gustatory code is influenced by ingestive and motivational variables. To examine the possibility of a dissociation between gustatory sensation and perception that may be accounted for by integration of the gustatory code with limbic aspects of feeding, I first compared citric acid detection and recognition thresholds in two groups of patients, and a group of healthy control subjects. Patients had undergone resections from either a right or left anterior temporal lobe for the treatment of intractable epilepsy. A Positron Emission Tomography (PET) activation study was then performed on a separate group of healthy subjects to ascertain brain regions involved in the perception of citric acid. A role for the right anterior temporal lobe in taste quality recognition was elucidated in that experiment. / As taste perception generally occurs with olfactory perception, in the context of feeding, I designed a second study to explore cerebral processing of flavor. This study used PET to determine if unimodal taste and smell processing differs from bimodal flavor processing. Evidence for a flavor specific neural network was found.

The design of a high performance tactile stimulator with six degrees of freedom for psychometric investigations is the subject of this thesis. / In order to design this device, a new mechanism is put forward, which is fully parallel and string driven. It achieves kinematic and dynamic isotropy. From the kinematic and dynamic analysis, the conditions for obtaining the best performance results are derived. These form the basis for the design and lead to a high performance device, which has wide bandwidth, low friction and which is free from backlash. The input and output is fully decoupled, which lead to simple control.

Emotion can exert a modulatory role on declarative memory. Several studies have shown that emotional stimuli (e.g., words, pictures) are better remembered than neutral ones. Although facial expressions are powerful emotional stimuli and have been shown to influence perception and attention processes, little is known about their effect on memory. We conducted an event-related fMRI study in 18 healthy individuals (9 men) to investigate the effects of expression on recognition memory for faces. During the encoding phase, participants viewed 84 faces of different individuals, depicting happy, fearful or neutral expressions. Subjects were asked to perform a gender discrimination task and remember the faces for later. In the recognition part subjects performed an old/new decision task on 168 faces (84 new). Both runs were scanned. Our findings highlight the importance of the amygdala, hippocampus and prefrontal cortex on the formation and retrieval of memories with emotional content.

Thesis (Ph.D.)--Pacific Graduate School of Psychology, 1995. / Source: Dissertation Abstracts International, Volume: 56-10, Section: B, page: 5820.

Thesis (Ph.D.)--Pacific Graduate School of Psychology, 1995. / Source: Dissertation Abstracts International, Volume: 57-04, Section: B, page: 2930.