Semantic priming in Alzheimer's dementia: evidence for dissociation of automatic and attentional processes

The nature of the semantic memory deficit in dementia of the Alzheimer's type (DAT) was investigated in a semantic priming task which was designed to assess both automatic and attention-induced priming effects. Ten DAT patients and 10 age-matched control subjects completed a word naming semantic priming task in which both relatedness proportion (RP) and stimulus-onset asynchrony (SOA) were varied. A clear dissociation between automatic and attentional priming effects in both groups was demonstrated; however, the DAT subjects' pattern of priming deviated significantly from that of the normal controls. The DAT patients failed to produce any priming under conditions which encouraged automatic semantic processing and produced facilitation only when the RP was high. In addition, the DAT group produced hyperpriming, with significantly larger facilitation effects than the control group. These results suggest an impairment of automatic spreading activation in DAT and have implications for theories of semantic memory impairment in DAT as well as models of normal priming.     

A prospective test of the dual-pathway model of bulimic pathology: mediating effects of dieting and negative affect

Because there have been few longitudinal investigations of integrative etiological theories of bulimia nervosa, this study prospectively tested the dual-pathway model using random regression growth curve models and data from a 3-wave community sample of adolescent girls (N = 231). Initial pressure to be thin and thin-ideal internalization predicted subsequent growth in body dissatisfaction, initial body dissatisfaction predicted growth in dieting and negative affect, and initial dieting and negative affect predicted growth in bulimic symptoms. There was prospective evidence for most of the hypothesized mediational effects. Results are consistent with the assertion that pressure to be thin, thin-ideal internalization, body dissatisfaction, dieting, and negative affect are risk factors for bulimic pathology and provide support for the dual-pathway model.     

The midstream order deficit

The relative order of an auditory sequence can be more difficult to apprehend when it is presented repeatedly without pause (i.e., cycling) than when it is presented only once (Warren, Obusek, Farmer, & Warren, 1969). We find that this phenomenon, referred to as the midstream order deficit (MOD), can also occur with visual stimuli. The stimuli need not form separate perceptual "streams," and the effect can occur with presentation rates as slow as five items per second, even though the identification of individual letters is very accurate at this rate. However, if the first item of the sequence is visually very distinct from the preceding items, relative order reports can be as accurate in the cycling condition as in the single-presentation condition. Our results suggest that the MOD is not due to masking, attentional blink, repetition blindness, Reeves and Sperling's (1986) order illusion, memory limitations, or decision criteria. The MOD may reflect an attentional cost to the initiation of order encoding, which is distinct from the allocation of attention is required in order to detect and identify individual items. To initiate order encoding successfully, one's attention must be set for, or captured by, an initial salient event.     

Quality of life before and after lung transplantation in patients with emphysema versus other indications

Whether lung transplantation improves Health-related Quality of Life in patients with emphysema and other end-stage lung diseases before and after lung transplantation was examined. Between 1992 and 1999, 23 patients with emphysema and 19 patients with other indications completed self-administered questionnaires before lung transplantation, and at 4, 7, 13, and 25 mo. after transplantation. The questionnaire included the Nottingham Health Profile, the State-Trait Anxiety Inventory, the Self-rating Depression Scale, the Index of Well-being, the self-report Karnofsky Index, and four respiratory-specific questions. Neither before nor after transplantation were significant differences found on most dimensions of Health-related Quality of Life between patients with emphysema and other indications. Before transplantation, both groups report major restrictions on the dimensions Energy and Mobility of the Nottingham Health Profile, low experienced well-being, depressive symptoms, and high dyspnea. About 4 mo. after transplantation, most Health-related Quality of Life measures improved significantly in both groups. These improvements were maintained in the following 21 mo.     

How much observational data is enough? An empirical test using marital interaction coding

Using three different samples of couples (clinic, nondistressed community, and engaged), we found that 15 minutes was sufficient to witness enough behavior to make reliable (i.e., internally consistent) estimations of most Rapid Marital Interaction Coding System (Heyman & Vivian, 1993) code frequencies. Ten minutes is sufficient for many codes of interest. The ease in which "how much time is necessary" calculations can be made should entice behavioral investigators from a variety of content areas to publish such figures. By empirically investigating a factor that in most fields becomes reified through convention, investigators can conduct observational research that is both maximally efficient and maximally scientifically defensible.     

Evidence of Impaired Glucose Tolerance and Insulin Resistance in Patients With Alzheimer’s Disease

Alzheimer’s disease (AD) and diabetes rarely occur together, a finding that provides a possible clue as to the development of AD. Abnormal glucose metabolism is not limited to diabetes, but also can include impaired glucose tolerance, insulin resistance, and hyperinsulinemia. AD patients have significantly varying insulin levels after drinking sugared sodas and thus may be classified as insulin resistant. After reviewing the literature on impaired glucose tolerance and insulin production in AD, we present several hypotheses as possible explanations for the relationship between insulin resistance and AD. Finally, we suggest future studies, including studies on use of thiazolidinediones (currently used in the treatment of diabetes) in AD.     

Crossing the Line: Case Studies of Identity Development in First-Generation College Women

In this paper we present four case studies of adult women from working class backgrounds who attended Hillside College (a pseudonym for one of the seven-sister colleges) during the early 1990s. Although research on women has led, over the past few decades, to a more complex picture of the contexts in which women develop their identities, one important context that has been underexplored is social class. Drawing on data from three lengthy interviews with each of our four participants, our purpose was to explore the identity concerns of adult women from working class backgrounds in their experience getting to and attending Hillside College, which has historically been home to the middle and upper social classes. Implications for college retention are discussed.     

Parallel neural systems for classical conditioning: Support from computational modeling

Classical conditioning has been explained by two main types of theories that postulate different learning mechanisms. Rescorla and Wagner (1972) put forth a theory in which conditioning is based on the ability of the US to drive learning through error correction. Alternatively, Mackintosh (1973) put forth a theory in which the ability of the CS to be associated with the unconditioned stimulus is modulated. We have proposed a reconciliation of these two mechanisms as working in parallel within different neural systems: a cerebellar system for US modulation and a hippocampal system for CS modulation. We developed a computational model of cerebellar function in eyeblink conditioning based on the error correction mechanism of the Rescorla-Wagner rule in which learningrelated activity from the cerebellum inhibits the inferior olive, which is the US input pathway to the cerebellum (Gluck et al., 1994). We developed a computational model of the hippocampal region that forms altered representations of conditioned stimuli based on their behavioral outcomes (Gluck & Myers, 1993; Myers et al., 1995). Overall, computational modeling and empirical findings support the idea that, at least in the case of eyeblink conditioning, there may be two different neural systems: the cerebellum which mediates US-based error correction and hippocampus which alters representations of CSs.