Steven M. Smith - US grants

The dissociation of memory has important clinical relevance for a number of concerns such as repression, dissociative disorders, post-hypnotic amnesia, and drug dependence. Dissociation, also known as context-dependent memory or state-dependent memory, refers to the idea that memory for events suffers if background changes in environmental context or internal states occur. A wide variety of studies throughout the century have demonstrated context- and state-dependent memory, and major models of memory employ contextual processing as one of memory's fundamental concern. Many studies, however, have failed to detect memory dissociation, and one of the most consistent characteristics of reported failures is the use of recognition tests rather than recall tests. The implication is that contextual reinstatement does not activate memory for events which occurred in that context (i.e., it does not increase their strength or familiarity), but rather reinstatement of contest acts by facilitating retrieval. The 14 proposed experiments are designed to test the idea that the typical failure to detect context-dependent recognition does not necessarily deny the existence of contextually activated event memory. One set of proposed experiments will test a number of alternative methods for observing contextual activation. Another set of studies will test the theory that context-dependent recognition occurs only when enough material additional to the target information is learned. A third set of experiments will test the idea that context-dependent recognition will be more detectable when better, more specific memory cues, such as interitem associations or physical characteristics of test items, are restricted.

Thinking can become "stuck" on inappropriate ideas or information such that even a well-learned target or a simple solution to a problem may become temporarily irretrievable. Whereas memory is generally considered to be a positive or adaptive ability, in cases of "stuck thinking" memory of inappropriate information impedes successful cognitive processing. A variety of cognitive phenomena, including fixation in problem solving, output interference in free recall, the tip-of-the-tongue (TOT) phenomenon, and blocks to creative design may occur in cases when initial information processing causes fixation. Fixation is herein defined as inaccessibility of appropriate information and/or strategies caused by heightened accessibility of inappropriate information. Appropriate information becomes relatively more accessible as the fixation dissipates, a heretofore elusive laboratory effect called incubation. Based upon positive results from preliminary studies, it is proposed that an effective method for studying incubation is to first induce fixation, and then examine methods of subsequently reducing it. Induction of fixation will be accomplished via a set of priming techniques designed to elicit inappropriate responses to test stimuli. Methods to be tested for reducing fixation focus upon techniques which cause forgetting, ideally, forgetting of fixated information, which should make appropriate target information relatively more accessible. Forgetting techniques include decay (i.e., time passage), displacement, interference, habituation/saturation, and context shifts. Other potentially useful techniques for reducing induced fixation may include awareness of one's fixated state, and relaxation techniques intended to broaden the focus of attention. Experiments are proposed to study methods for inducing and reducing fixation across a broad spectrum of cognitive domains. Latency measures will be used to supplement the traditional accuracy measures used for problem solving and memory studies. Development of theoretical accounts of the general phenomena of fixation and incubation are also proposed. The range of potential applications of this knowledge is great, including treatment of maladaptive perseverative behaviors, enhancing recall performance by increasing reminiscence, and training of creative thinking.

Funds are being used to purchase a high quality microscope with bright-field, fluorescent, and photographic capabilities. This instrument is to be the focus of lab exercises in the introductory genetics course, a cytogenetics course, and an immunology course. It is to be used to a lesser degree in bacteriology, embryology, and histology courses, and will also be used in independent research projects. In the genetics courses, attention is focused on chromosomes. Several laboratory exercises and student research projects have been designed to involve students in cytogenetics and immunological techniques which require photo- and fluorescent microscopy. This provides students, many of whom are members of minority groups, with technical knowledge and expertise in the use of an instrument fundamental to biological investigations. The university will contribute an amount equal to the award.

Poisonous snakes use venom for immobilizing and digesting prey. Crotalid and viperid venoms are complex mixtures of toxins and enzymes which are extremely effective in destroying tissue and causing hemorrhage. Physical, chemical, and immunological properties of venom suggest that a number of hemorrhagic factors are present in a single venom sample. Even though many hemorrhagic factors are common to several species of snakes and some of the amino acid sequences are similar, geographical variation in hemorrhagic factors have been demonstrated within certain species. Although envenomation is an effective way to capture prey, we were among the first to show that a number of mammals, such as the opossum and the grey woodrat, exhibit resistance to lethal toxicity, proteolytic and hemorrhagic activities os snake venoms. We have isolated antihemorrhagic factors that are not antibodies in the sera of resistant mammal. The nature of the resistance is significant, since it is broad-spectrum and neutralizes all hemorrhagic toxins tested thus far. The proposed research will expand and correlated the hemorrhagic variation found in rattlesnake venoms (Crotalus sp.) with the antihemorrhagic variation found in resistant animals. The goal of the RIMI proposal is to examine, using recombinant DNA techniques, a hypothesis of correlation between a venomous predator and venom- resistant prey. The information derived from this study will also be crucial to understanding the mechanism of venom detoxification in resistant species and in developing potential uses of snake toxins in medical science such as the production of immunotoxins. The RIMI proposal will expand our present venom research program and more students and faculty will be involved. Both students and the University will benefit by such an expansion. The teaching load is heavy and undergraduate students require intensive training before they are capable of doing meaningful research. Many of our undergraduate and masters' students working under the direction of Dr. John C. Perez have published in professional journals before going on to major universities for doctoral research. With the RIMI program, three additional faculty would be working with minority students in a very active research program.