Posttraining Electrical Stimulation of Vagal Afferents with Concomitant Vagal Efferent Inactivation Enhances Memory Storage Processes in the Rat

Peripherally administered or released substances that modulate memory storage, but do not freely enter the brain, may produce their effects on memory by activating peripheral receptors that send messages centrally through the vagus nerve. Indeed, vagus nerve stimulation enhances memory performance, although it is unclear whether this effect is due to the activation of vagal afferents or efferents. To eliminate the possible influence of descending fibers on memory storage processes, rats were implanted with cuff electrode/catheter systems along the left cervical vagus. Forty-eight hours following surgery, each animal received a 3.0-μl infusion (1.0 μl/min) of either lidocaine hydrochloride (75.0 mM) or isotonic saline below the point of stimulation. Animals were then trained 10 min later on an inhibitory-avoidance task with a 0.75-mA, 1.0-s foot shock. Sham stimulation or vagus nerve stimulation (0.5-ms biphasic pulses; 20.0 Hz; 30 s; 0.2, 0.4, or 0.8 mA) was administered immediately after training. Memory, tested 24 h later, was enhanced by stimulation whether descending vagus nerve fibers were inactivated or not. Both lidocaine- and saline-infused groups showed an intensity-dependent, inverted-U-shaped pattern of retention performance, with the greatest effect observed for 0.4 mA (U= 9,p< .05, andU= 7,p< .01, respectively). Additionally, animals that received lidocaine infusions, but no vagus nerve stimulation, showed impaired memory compared to the performance of saline-infused control animals (U= 11,p< .05). Together, these findings suggest that vagal afferents carry messages about peripheral states that lead to the modulation of memory storage and that the memory-enhancing effect produced by vagus nerve stimulation is not mediated via the activation of vagal efferents.     

Different Training Procedures Recruit Either One or Two Critical Periods for Contextual Memory Consolidation, Each of Which Requires Protein Synthesis and PKA

We have used a combined genetic and pharmacological approach to define the time course of the requirement for protein kinase A (PKA) and protein synthesis in long-term memory for contextual fear conditioning in mice. The time course of amnesia in transgenic mice that express R(AB) and have genetically reduced PKA activity in the hippocampus parallels that observed both in mice treated with inhibitors of PKA and mice treated with inhibitors of protein synthesis. This PKA- and protein synthesis-dependent memory develops between 1 hr and 3 hr after training. By injecting the protein synthesis inhibitor anisomycin or the PKA inhibitor Rp-cAMPs at various times after training, we find that depending on the nature of training, contextual memory has either one or two brief consolidation periods requiring synthesis of new proteins, and each of these also requires PKA. Weak training shows two time periods of sensitivity to inhibitors of protein synthesis and PKA, whereas stronger training exhibits only one. These studies underscore the parallel dependence of long-term contextual memory on protein synthesis and PKA and suggest that different training protocols may recruit a common signaling pathway in distinct ways.     

From individual to group impressions: Availability heuristics in stereotype formation

When subjects are presented with information about the attributes of individuals and are then asked to make judgments about the characteristics of the group composed of those individuals, the group impression may depend on the way in which data on individuals are organized in memory. Experiment 1 demonstrated that under conditions of low memory load (16 instances of person-trait pairings), subjects organize their perceptions of a group around the characteristics of its individual members, whereas under high memory load (64 instances of person-trait pairings), subjects organize trait information in an undifferentiated way around the group as a whole. Under low memory load, subjects distinguish between repeated occurrences of a trait in the same individual and comparable repeated occurrences of that trait in different individuals; under high memory load, subjects do not make such a differentiation. Subjects' judgments about the frequency of categories of traits were related to the ease of recall of category instances, as predicted by an availability heuristic. Experiments 2 and 3 demonstrated that group members who are most available in memory will be disproportionately represented in the group impression. Specifically, the proportion of extreme individuals in a group was retro-spectively overestimated; this was true for both physical stimuli (height) and social stimuli (criminal acts).     

Ten-year follow-up of a successful treatment of self-injurious behavior

Ten years ago, self-injurious behavior that produced blindness in a man with profound mental retardation was treated through behavioral intervention. This person's behavioral history was reviewed for 12 years prior to the intervention through examination of his clinical record and for 10 years following the intervention through examination of his clinical record, direct observation, and interviews with staff. Physical injury occurred only once in the last 46 months; physical restraint has not been used in 10 years; and for the past 9 years, no more than one medication has been prescribed for the control of behavior or seizures. Suggestions are presented for designing behavioral interventions at the beginning of treatment to maintain reductions in behavior.     

The effects of family structure on the sexual behavior of adolescents.

The effects of two family structures, single- and two-parent homes, on adolescent sexual behavior were studied. The variables of race, age, and gender were controlled. The analysis compared the age at first intercourse, frequency of intercourse in the last four weeks, and virgin/nonvirgin status of adolescents from black single-parent families, white single-parent families, black two-parent families, and white two-parent families. For males, the two-parent family was related to less sexual activity and older age at first intercourse. For females, the two-parent family was not as important as race in influencing sexual behavior. The white females from two-parent families were more likely to be virgins, but once having had sexual intercourse, tended to have a higher level of sexual activity than did black females from two-parent homes.     

Adolescent sexuality and public policy

In recent decades, various attempts have been made to determine the level of sexual activity among adolescents. This information has been used in the planning and evaluation of sex-related programs. However, there is a flaw in using only the initial estimates of the behavior--that a sexually active person is defined as one who has had sexual intercourse. This narrow definition distorts the perception of adolescent sexual behavior. Sexual activity can more accurately be designated by focusing on the actual frequency with which teenagers have sex. In this research report, adolescents were considered sexually active if they had had sex within the last four weeks. Using this definition, adolescents were found to be substantially less sexually active than has been previously reported. This finding was then used to look at various policy decisions in the areas of sex education, family planning, and sexually transmitted disease prevention.     

Attachment style and self-handicapping: the mediating role of the imposter phenomenon

Social Psychology of Education - Many students pursuing post-secondary education will experience the imposter phenomenon at some point in their academic career. The imposter phenomenon can lead to...     

Reducing risk of head injury in youth soccer: An extension of behavioral skills training for heading

Recently, concerns regarding sport-related concussions have increased within the research literature, the media, and popular culture. One potential source of soccer-related concussions involves the purposeful striking of the ball with one's head (i.e., heading). There is currently limited research on an effective teaching method to improve safe heading technique. In the current study, Behavior Skills Training (BST) was evaluated as a method to teach correct heading techniques to youth soccer players. BST increased the percentage of correct steps for each player based on a task analysis of heading. Based on social validity questionnaires administered to players and the coach, BST was rated as an acceptable form of training. After the final training session, experienced coaches rated each player as having improved from baseline to training.     

Analgesic effects of posthypnotic suggestions and virtual reality distraction on thermal pain

The individual and combined effects of posthypnotic suggestion (PHS) and virtual reality distraction (VRD) on experimentally induced thermal pain were examined using a 2 x 2, between-groups design. After receiving baseline thermal pain, each participant received hypnosis or no hypnosis, followed by VRD or no VRD during another pain stimulus. Consistent with the hypothesis that hypnosis and VRD work via different mechanisms, results show that posthypnotic analgesia was moderated by hypnotizability but VRD analgesia was not. The impact of PHSs for analgesia was specific to high hypnotizables, whereas VRD was effective independent of hypnotizability. Results also show a nonsignificant but predicted pattern for high hypnotizables: Audio hypnosis combined with VRD reduced worst pain 22% more and pain unpleasantness 25% more than did VRD alone. Theoretical and clinical implications are discussed.     

The role of segmental mass and moment of inertia in dynamic-contact task construction

The authors examined whether differences between children and adults in the application of muscle forces during a dynamic-contact task (cycling) can be attributed to children's relatively lower segmental mass and moment of inertia. They examined pedal-force construction as adults and younger and older children (n = 7 in each group), with and without mass added to their limbs, pedaled an appropriately scaled bicycle ergometer. When mass was added to their limbs, children adjusted muscular forces on the pedal in a way that began to approach the pattern demonstrated by adults. Because age, neuromotor maturation, and motor experience were held constant, it seems plausible that by 6 to 8 years of age, and perhaps younger, physical size and growth limit children's production of adult-like muscle forces on the pedal.