The hippocampus and delayed recall: bigger is not necessarily better?

Healthy young female participants were tested on a measure of delayed verbal recall and then received volumetric Magnetic Resonance Imaging (MRI) scans. The analysis of the MRI scans focused on the volume of the hippocampus. Left hippocampal volume was negatively associated with the level of delayed verbal recall performance. This relationship was confirmed in further testing. This finding is consistent with a previous report of a similar relationship in healthy elderly individuals, but not in patients with Alzheimer's disease, in whom the opposite relationship was observed. An explanation of these findings in terms of impaired neural pruning of the hippocampus is advanced, whereby insufficient pruning of the hippocampus during childhood and adolescence (following adequate growth) may lead to reduced mnemonic efficiency.     

Quantitative and Qualitative Integration of Lurian Procedures

This article reviews contemporary Russian research aimed at integrating and combining qualitative and quantitative evaluation approaches using Luria's procedures of neuropsychological assessment. A scoring system for rating and evaluating cognitive disturbances in different functional areas is described. The advantages of application of this system are discussed, using as examples the neuropsychological follow-up of neurosurgical patients, as well as neuropsychological research into the cognitive disturbances in patients with Parkinsonism and in children who are mentally retarded. The effectiveness of these updates to Luria's approach is demonstrated.     

The movement-activated recording monitor: A third-generation motor-activity monitoring system

The movement-activated recording monitor (MARM) is a small noninvasive device that continuously detects, accumulates, and stores the amount of motor activity produced during sequential time intervals of designed duration. If motor activity totals are recorded every 15 min, the MARM is capable of calculating and storing 96 data points/day for 5.33 days. The MARM employs large-scale-integrated complementary-metal-oxide integrated circuits. To date, application has been primarily limited to psychiatric investigations, but the MARM is readily applicable for other time-motion studies of human or animal subjects.     

A computer-compatible multichannel event counting and digital recording system

An inexpensive multichannel event counting digital recording system has been designed for compatibility with automated data analysis equipment. For as many as 16 channels, events are simultaneously summed over preselected repetitive time intervals and recorded. Each data entry is marked with the time of day and a code identifying each channel’s data. The data is formated to be computer compatible and is logged on inexpensive readily available digital magnetic tape cassettes.     

Effects of cycle length on performance on a temporally defined avoidance schedule

Three rats were trained on a temporally defined avoidance schedule logically similar to a fixed-interval, limited-hold positive reinforcement schedule. This avoidance schedule was composed of time periods during which responses had no scheduled consequences alternating with time periods during which a response precluded shock. As with fixed-interval length and response rate on positive reinforcement schedules, an inverse relationship was obtained between the length of the no-consequence interval and response rate during the no-consequence interval. An inverse relationship was also obtained between the length of the no-consequence interval and the per cent of shocks avoided. A rate increase within the no-consequence interval, similar to that typically produced by fixed-interval positive reinforcement procedures, was displayed by one of the rats where the no-consequence interval was at intermediate values and frequency of shock was relatively high. The introduction of a discriminative stimulus correlated with the avoidance interval produced typical discriminated avoidance behavior as well as alterations in temporal patterning of responses during the no-consequence interval in the two rats exposed to this procedure. These alterations in temporal patterning disappeared when the discriminative stimulus was removed. The results were consonant with those reported in the literature involving food reinforcement and fixed-interval, limited-hold schedules.     

Some deleterious consequences of the act of recollection

Two experiments investigated the impact of responding to recognition test items that do not include a correct alternative. In Experiment 1, subjects who were given exclusively incorrect response alternatives were less likely than control subjects to favor the correct alternatives on a second recognition test. Analysis of subjects’ responses indicated that commitments, rather than distractor familiarity, was the main source of this effect. In Experiment 2, an impairing effect of committing to an incorrect alternative was observed even when the initial distractors were excluded from the final test. Thus, this decreased performance cannot simply be attributed to a bias toward remaining consistent. One interpretation of these results is that committing to a distractor causes subjects to remember a false detail that can interfere with their later ability to access the original information. Other potential theoretical and applied implications of these results are explored.     

Birth order and intelligence: an immunological interpretation.

The literature indicates that the IQs and school performance of children tend to decline with increasing order of birth. A hypothesis is here presented that the effect of birth order upon intellectual performance may result from an increasing probability of maternal immune attack upon the fetal brain in utero with order of parity. In support of this hypothesis, evidence is adduced from the literature that the fetal brain is antigenic, that fetal antigens may reach the immune system of the mother, that the incidence of maternal sensitization to fetal antigens increases with parity, that antibodies may readily cross the placenta and reach the fetal brain, that antibodies can be highly teratogenic, and that certain antibodies may damage, in a lasting way, the structure, function, and learning capacity of brains in experimental animals and human infants.     

Racial discrimination-induced anger and alcohol use among black adolescents

This study explored whether a relationship exists between anger among Black adolescents that has been provoked by racial discrimination, and alcohol consumption. Participants consisted of 134 Black adolescents from 14 to 18 years of age, residing in northeast Texas. All participants were administered a questionnaire measuring whether and the extent to which they might be dependent upon alcohol, a background information questionnaire which included questions about their drinking pattern, and a measure designed to assess the extent to which they feel angry either because they had been discriminated against or observed other Blacks being discriminated against or observed other Blacks being discriminated against in various situations. Only gender was found to be predictive of scores on the dependency scale. However gender, age, and racial discrimination anger scores were found to be predictive of the amount of alcohol consumed by the participants. Some implications for theory, research, and intervention are suggested.     

Information limits on identification of natural surfaces by apparent colour

By adaptational and other mechanisms, the visual system can compensate for moderate changes in the colour of the illumination on a scene. Although the colours of most surfaces are perceived to be constant ('colour constancy'), some are not. The effect of these residual colour changes on the ability of observers to identify surfaces by their apparent colour was determined theoretically from high-resolution hyperspectral images of natural scenes under different daylights with correlated colour temperatures 4,300 K, 6,500 K, and 25,000 K. Perceived differences between colours were estimated with an approximately uniform colour-distance measure. The information preserved under illuminant changes increased with the number of surfaces in the sample, but was limited to a relatively low asymptotic value, indicating the importance of physical factors in constraining identification by apparent colour.     

Men’s Decision-Making About Predictive <Emphasis Type="Italic">BRCA1/2</Emphasis> Testing: The Role of Family

Men who have a family history of breast and/or ovarian cancer may be offered a predictive genetic test to determine whether or not they carry the family specific BRCA1/2 mutation. Male carriers may be at increased risk of breast and prostate cancers. Relatively little is known about at-risk men’s decision-making about BRCA1/2 testing. This qualitative study explores the influences on male patients’ genetic test decisions. Twenty-nine in-depth interviews were undertaken with both carrier and noncarrier men and immediate family members (17 male patients, 8 female partners, and 4 adult children). These explored family members’ experiences of cancer and genetic testing, decision-making about testing, family support, communication of test results within the family, risk perception and risk management. Implicit influences on men’s testing decisions such as familial obligations are examined. The extent to which other family members—partners and adult children—were involved in testing decisions is also described. It is demonstrated that mothers of potential mutation carriers not only perceive themselves as having a right to be involved in making this decision, but also were perceived by their male partners as having a legitimate role to play in decision-making. There was evidence that (adult) children were excluded from the decision-making, and some expressed resentment about this. The implications of these findings for the practice of genetic counseling are discussed.