Acute systemic fibroblast growth factor-2 enhances long-term memory in developing rats

Recent findings have provided much insight into the mechanisms underlying long-term memory formation, and it is now known that long-term memory depends on the activation of a molecular cascade that culminates with structural changes in the brain. However, little is known about the signals that give rise to or regulate these structural changes. In this article we propose that fibroblast growth factor-2 (FGF2), a mitogen for several cell types, may be one of the molecular signals critically involved in the structural changes underlying long-term memory. If FGF2 is part of the signalling cascade involved in long-term memory, then increasing the activation of FGF2 should facilitate memory. In Experiments 1 and 2, we demonstrated that systemic injection of FGF2 (20 ng/g of body weight) facilitated memory for contextual fear in 16, 19, and 22 day old male Sprague Dawley rats. Experiment 3 demonstrated that the observed facilitation of memory was not due to FGF2 increasing rats’ sensitivity to footshock. These results implicate FGF2 as a possible molecular signal in long-term memory, and further, illustrate a novel means of enhancing memory.     

Skill theory v2.0: dispositions,emulation, and spatial perception

An attempt is made to defend a general approach to the spatial content of perception, an approach according to which perception is imbued with spatial content in virtue of certain kinds of connections between perceiving organism’s sensory input and its behavioral output. The most important aspect of the defense involves clearly distinguishing two kinds of perceptuo-behavioral skills—the formation of dispositions, and a capacity for emulation. The former, the formation of dispositions, is argued to by the central pivot of spatial content. I provide a neural information processing interpretation of what these dispositions amount to, and describe how dispositions, so understood, are an obvious implementation of Gareth Evans’ proposal on the topic. Furthermore, I describe what sorts of contribution are made by emulation mechanisms, and I also describe exactly how the emulation framework differs from similar but distinct notions with which it is often unhelpfully confused, such as sensorimotor contingencies and forward models.     

Graded motor responses in the time course of categorizing atypical exemplars

The time course of categorization was investigated in four experiments, which revealed graded competitive effects in a categorization task. Participants clicked one of two categories (e.g., mammal or fish) in response to atypical or typical exemplars (e.g., whale or cat) in the form of words (Experiments 1 and 2) or pictures (Experiments 3 and 4). Streaming x, y coordinates of mouse movement trajectories were recorded. Normalized mean trajectories revealed a graded competitive process: Atypical exemplars produced trajectories with greater curvature toward the competing category than did typical exemplars. The experiments contribute to recent examination of the time course of categorization and carry implications for theories of representation in cognitive science.     

Use of a virtual reality car-driving stressor in cardiovascular reactivity research

Eighteen subjects (11 males, 7 females) completed a virtual reality car-driving stressor on two occasions several weeks apart. Immediately before and throughout task performance, blood pressure, cardiac output, and total peripheral resistance were assessed. Reactivity scores were calculated for each parameter for each subject as the arithmetic difference between task level and baseline level. The task elicited considerable hemodynamic activation on each occasion of testing, as well as high levels of self-reported task realism, engagement, excitement, and nervousness. Correlation analyses of both absolute and reactivity scores revealed evidence of test-retest reliability. Males were found to exhibit greater absolute levels of and greater increases in systolic blood pressure. The development of tasks suitable for inclusion in a battery of behavioral stressors, responses to which may help identify those at risk for later disease, is of considerable interest in cardiovascular behavioral medicine. The present findings suggest that the virtual reality car-driving task may be useful in this context.     

A meta-analysis of bibliotherapy studies

Used meta-analysis to examine the efficacy of bibliotherapy. Bibliotherapy treatments were compared to control groups and therapist-administered treatments. The mean estimated effect size (d) of the 70 samples analyzed was +0.565. There was no significant differences between the effects of bibliotherapy and therapist-administered treatments, as well as no significant erosion of effect sizes at follow-up. Bibliotherapy did appear more effective for certain problem types (assertion training, anxiety, and sexual dysfunction) than for others (weight loss, impulse control, and studying problems). Overall, the amount of therapist contact during bibliotherapy did not seem to relate to effectiveness, but there was evidence that certain problem types (weight loss and anxiety reduction) responded better with increased therapist contact. Recommendations for future research were given, especially for more research on the commonly purchased books and moderator analyses by personality type and reading ability. This article is based on a doctoral dissertation by Rick W. Marrs under the direction of Steven D. Brown at Loyola University of Chicago. I gratefully acknowledge the assistance of Dr. Brown as well as of my other committee members, Joseph Durlak and Gloria Lewis. I also gratefully acknowledge the assistance in coding done by Laura Marrs and John Gibson and helpful editorial comments made by Wayne Lucht.     

Endogenous Ketamine-Like Compounds and the NDE: If So, So What?

This commentary on Karl Jansen's ketamine model for the near-death experience expands upon and raises additional questions about several issues and hypotheses: self-experimentation as a source of data; ketamine's similarities to and differences from classical hallucinogens; the need for quantification of unusual subjective states; clinical research and toxicological implications of this model; drugs as gateways to religious states; and evolutionary versus religious significance of naturally occurring compounds released in the near-death state. I suggest future research that could help explicate several of these areas.Formerly Associate Professor of Psychiatry at the University of New Mexico School of Medicine     

Table of criterion values (β) used in signal detection theory

A table of criterion values for use with the theory of signal detection (TSD) is presented. Criterion values (β) are presented for varying proportions of hits and false alarms. A brief explanation of signal detection theory is given, and the measures for sensory sensitivity (d′) and response criterion (β) are described.     

Tilt from ahead-inverted position produces displacement of visual subjective vertical in the opposite direction

Observers who lie supine with their heads inverted report large (up to 60°) tilt of a light line in an otherwise dark room when their heads and/or bodies are tilted. Most observers report that visual subjective vertical is tilted in the direction opposite to the head/body tilt. The results can be interpreted by employing a model developed by Mittelstaedt (1983), which suggests that visual subjective vertical is derived from a gravity vector transduced by vestibular and somesthetic receptors combined with “idiotropic vectors” that represent the orientation of the observer’s own head and body axes.     

Acquisition, extinction and reacquisition of a conditioned response in the cockroach: The effects of orotic acid

Cockroaches can be trained to keep their metathoracic leg out of a saline solution. Isolated metathoracic ganglia learnt faster than headless animals, which in turn learnt faster than intact animals. Extinction took longer in the isolated ganglion than in the other two preparations. Extinction times increased with increasing dose of orotic acid, a precursor of RNA. Orotic acid did not systematically affect the times for acquisition and reacquisition of the learnt response.