Regional cerebral blood flow characteristics and variations with age in resting normal subjects

Regional cerebral blood flow (rCBF) was measured during resting in 97 normal subjects, 19-68 years old. The results showed that the mean CBF level decreased progressively with age. The decrease was more prominent in frontotemporal and inferior Rolandic areas bilaterally. Frontal areas showed the highest values in all age groups. This hyperfrontality weakened somewhat with age. Mean CBF in the right hemisphere was significantly higher than in the left, as was flow in superior frontal, inferior frontal, and parietal areas. These asymmetries were age invariant. The age-related decrease of rCBF is interpreted as reflecting aging of the brain per se, although the influence of asymptomatic brain disease can not be ruled out. The flow asymmetries are interpreted as being related to functional lateralization of some aspects of attentional activation.     

Cerebral blood flow and anxiety in older men: an analysis of resting anterior asymmetry and prefrontal regions

Asymmetric resting blood flow in prefrontal and hemispheric regions, assessed by single photon emission computed tomography (SPECT), was examined as a potential biological marker for enhanced trait and state anxiety in 30 older men (ages 55-81). Average and asymmetric perfusion in dorsolateral, medial, and orbital regions of the prefrontal lobes was also assessed. Results indicated a significant association between lower levels of resting dorsolateral blood flow and greater state anxiety responses to a series of stressful provocations (measured on a separate occasion). A significant curvilinear (U-shaped) relation between asymmetric dorsolateral perfusion and state anxiety was also identified; increased asymmetric blood flow favoring either the right or the left dorsolateral region related to higher levels of state anxiety. However, this association was attenuated by age and systolic blood pressure. Resting perfusion in the dorsolateral region may represent a more reliable biological marker for state anxiety than trait anxiety in older men.     

A theory of magnitude: common cortical metrics of time, space and quantity

Research into the perception of space, time and quantity has generated three separate literatures. That number can be represented spatially is, of course, well accepted and forms a basis for research into spatial aspects of numerical processing. Links between number and time or between space and time, on the other hand, are rarely discussed and the shared properties of all three systems have not been considered. I propose here that time, space and quantity are part of a generalized magnitude system. I outline A Theory Of Magnitude (ATOM) as a conceptually new framework within which to re-interpret the cortical processing of these elements of the environment.     

Running memory span: A comparison of behavioral capacity limits with those of an attractor neural network

We studied a computational model of short term memory capacity that performs a simulated running memory span task using Hebbian learning and rapid decay of connection strengths to keep recent items active for later recall. This model demonstrates recall performance similar to humans performing the same task, with a capacity limit of approximately three items and a prominent recency effect. The model also shows that this capacity depends on decay to release the model from accumulating interference. Model findings are compared with data from two behavioral experiments that used varying task demands to tax memory capacity limits. Following additional theoretical predictions from the computational model, behavioral data support that when task demands require attention to be spread too thin to keep items available for later recall, capacity limits suffer. These findings are important both for understanding the mechanisms underlying short term memory capacity, and also to memory researchers interested in the role of attention in capacity limitations.     

Anxious personality and functional efficiency of the insular-opercular network: A graph-analytic approach to resting-state fMRI

The brain is an intricate network, not only structurally but also functionally. On the functional level, connectivity in the brain is organized in separable yet interacting networks that support information processing by maintaining a ready state, even in the absence of external stimulation. It has been hypothesized that an insular-opercular network underlies the processing of emotionally salient information and that individual differences in functional connectivity within this network correspond to individual differences in trait anxiety. Here, we tested this relationship by applying graph analysis to multiple regions of interests delineating the insular-opercular network to estimate the characteristic path length that quantifies the overall information exchange efficiency within a given network. We found that people scoring high on the anxiety-related temperament-dimension harm avoidance had decreased insular-opercular network efficiency in the resting state, as indicated by a higher characteristic path length. Furthermore, people scoring high on harm avoidance showed generally reduced functional connectivity between brain regions; the relationship between harm avoidance and insular-opercular network efficiency remained significant when controlling for mean connectivity within this network. No such results were found for other resting-state networks. The results provide insights into how personality is organized in the human brain and point toward clinically relevant endophenotypes for affective and mood disorders.     

The structure of mood: A comparison between sleep deprivation and normal wakefulness conditions

The stability of the factor structure of mood was examined under two different experimental conditions, sleep deprivation and normal wakefulness In the first phase of the study, two different forms of a mood scale were administered to several college classes, and the ratings for each scale were intercorrelated and factored Eight interpretable factors emerged from each analysis, and the two sets of factors were highly congruent. In the second phase of the study subjects completed the mood ratings after staying awake all night or after getting a good night's rest Comparisons between the means for the two groups showed significant differences on 26 of the 44 variables included in the scale The scores for the sleep-deprived group were then intercorrelated and factored, and the factor structure was compared with the relevant factor structure obtained in the first phase of the study The results of the comparison showed that six of the eight factors appeared under both conditions of sleep deprivation and normal wakefulness Additional analysis indicated that a seventh factor appeared, but in the guise of different variables The only factor which failed to appear under sleep deprivation was elation. It was concluded that although variable ratings showed high sensitivity to the experimental operations, the basic structure of the underlying mood states remained remarkably stable The results indicate that the search for a list of basic mood states may be quite fruitful An important methodological implication was that a variable may be selected to measure a mood under various experimental operations with the assurance that the nature of the mood to be measured does not change as a result of those operations     

Shape correlates of visual and tactual size judgments: A contrast with complexity

Pattern correlates of perceived size were studied by obtaining category judgments of the size of 100 random forms from 40 Ss who explored the forms visually and 40 Ss who explored them factually. Comparison of the modalities and contrasts with perceived complexity were made via intercorrelations of judgments and latencies, multiple regression analyses using factored form dimensions, and correlations with original form measures. By holding area of the forms constant, it was shown that perceived size can be related to characteristics of shape.     

Widowhood and illness: a comparison of social network characteristics in France, Germany, Japan, and the United States.

This study examined social network characteristics of adults aged 70 to 90 years in relation to widowhood and illness in France, Germany, Japan, and the United States. Participants were drawn from representative samples from each of the 4 countries (total N = 1,331). Resource deficit profiles based on whether respondents were widowed, ill, both, or neither were directly related to social network characteristics for German and Japanese adults, were differentially related by gender and age for French adults, and were not related to social networks of Americans. Country, gender, and age differences in total network size, proportion of close network members, and frequency of contact with network members are reported. Similarities and differences found in the associations between normative late-life deficits and social network characteristics in the 4 countries point to the importance of investigating sociocultural factors that mediate the impact of resource loss and afford life quality in very old age.     

Laterality of cerebral function: relations with anxiety, repression, and perception

Based on two factor analyses of data from 67 right-handed undergraduates, a laterality quotient based on forward memory spans, spatial minus digit, divided by their sum, was devised. The hemispheric balance factor for which this quotient served as the principal marker had significant positive loadings by the laterality quotient for the Edinburgh Handedness Questionnaire and by a measure of repressive tendencies, the Marlowe-Crowne Social Desirability Scale. Scores from this factor were positively related to global as opposed to analytic perception as measured by the Navon tachistoscopic task. This factor was unrelated to the trait anxiety and working short-term memory factors which also emerged. Trait anxiety was negatively related to global perception. The results raise the possibility that greater degrees of right-handedness may be related to the release of the nondominant right hemisphere from inhibition and that working short-term memory may not be lateralized.     

Intellectual, mnemonic, and frontal functions in dementia with Lewy bodies: A comparison with early and advanced Parkinson's disease

Both Parkinson's disease (PD) and dementia with Lewy bodies (DLB) share a common neuropathological marker, the presence of Lewy bodies in brain stem and basal forebrain nuclei. DLB, in addition, is associated with Lewy bodies in the neocortex, and, in it's more common form, with Alzheimer-type pathological markers, particularly amyloid plaques. Published neuropsychological studies have focused on the differential profiles of DLB and Alzheimer's disease (AD). However, it is presently unclear whether DLB should be classified as a variant of AD or PD. In the present study we compare a healthy age-matched control group with three groups of patients, one with DLB, and two with PD. One of the PD groups was early in the course (PD-E) and the second, more advanced group (PD-A), was matched on severity of cognitive impairment with the DLB group. The results show that DLB was associated with a different pattern of neuropsychological impairment than the PD-A group, particularly in tests believed to be mediated by prefrontal cortical regions.     

A comparison of the marriage-role expectations of college women enrolled in a functional marriage course in 1961, 1972, and 1978

The Dunn Marriage Role Expectation Inventory was used to compare the marriage-role expectations of female university students enrolled in an introductory marriage and family course in 1961 (N=72), 1972 (N=58), and 1978 (N=115). The 1978 group was significantly more egalitarian than the 1961 group in overall marriage-role expectations and on each of the seven subcategories of authority, homemaking, child care, personal characteristics, social participation, education, and employment and support. The 1972 group was also found to be significantly more egalitarian than the 1961 group in overall marriage-role expectations and on all subcategories except authority. The 1978 group was significantly more egalitarian than the 1972 group only on authority and homemaking, with no significant differences on overall marriage-role expectations or on the other five subscales. The significant move toward more egalitarian attitudes toward authority and homemaking is accentuated by the fact that only 6 years separate the 1972 and 1978 groups, while there is an 11-year difference between the 1961 and 1972 groups.The data were collected in February 1961, January 1972, and September 1978. Special acknowledgment and appreciation are expressed to Jessie Ringo (retired) for making the 1961 data available for this study and to William F. Kenkel, Department of Sociology, University of Kentucky, for his helpful comments.     

Intellectual, mnemonic, and frontal functions in dementia with Lewy bodies: A comparison with early and advanced Parkinson's disease

Both Parkinson's disease (PD) and dementia with Lewy bodies (DLB) share a common neuropathological marker, the presence of Lewy bodies in brain stem and basal forebrain nuclei. DLB, in addition, is associated with Lewy bodies in the neocortex, and, in it's more common form, with Alzheimer-type pathological markers, particularly amyloid plaques. Published neuropsychological studies have focused on the differential profiles of DLB and Alzheimer's disease (AD). However, it is presently unclear whether DLB should be classified as a variant of AD or PD. In the present study we compare a healthy age-matched control group with three groups of patients, one with DLB, and two with PD. One of the PD groups was early in the course (PD-E) and the second, more advanced group (PD-A), was matched on severity of cognitive impairment with the DLB group. The results show that DLB was associated with a different pattern of neuropsychological impairment than the PD-A group, particularly in tests believed to be mediated by prefrontal cortical regions.     

Nature, nurture, and the development of functional specializations: A computational approach

The roles assigned to nature and nurture in the acquisition of functional specializations have been modified in recent years due to increasing evidence that experience-dependent processes are more influential in determining a brain region’s functional properties than was previously supposed. Consequently, one may study the developmental principles that play a role in the acquisition of functional specializations. This article studies the hypothesis that a combination of structure-function correspondences plus the use of competition between modules leads to functional specializations. This principle has been instantiated in a family of neural network architectures referred to as “mixtures-ofexperts” architectures. These architectures are sensitive to structure-function relationships in the sense that they often learn to allocate to each task a network whose structure is well matched to that task. The viewpoint advocated here represents a middle ground between nativist and constructivist views of modularity.     

Love preferences and ideals: A comparison of homosexual,bisexual, and heterosexual groups

Homosexuals, bisexuals, and heterosexuals were compared on self-reported love preferences and ideals. In general, the three groups tended to agree on ideal characteristics of love objects, love relationships, and love related beliefs. Nevertheless, the groups differed significantly on preferences and beliefs related to love-object sex, residential proximity, ethnic background, physical intimacy, freedom from feelings of jealousy, sexual fidelity, emotional intimacy, and the importance of religious or legal acknowledgment.An early version of this paper was presented at the Annual Meeting of the National Council on Family Relations, in San Francisco, October 1984, Journal Series No. 2973 of the Hawaii Institute of Tropical Agriculture and Human Resources.     

Organization-, supervisor-, and workgroup-directed commitments and citizenship behaviours: A comparison of models

The purpose of this study was to test two competing theoretical models explaining the relationships between affective commitment to the organization, the supervisor, and the workgroup, and organizational citizenship behaviours (OCB) specifically directed toward these foci. Drawing on cohesion theory, the first model stated that commitment to the organization is a key mediating variable intervening between “local” commitments and OCB (Hunt & Morgan, 1994). Building on Lewin's (1943) field theory and the notion of psychological proximity, the second model proposed that commitment to the most proximal focus should mediate the effect of commitment to more distal entities on OCB. Data drawn from a sample of blue-collar workers and their supervisors in an iron and steel company indicated that the model of a proximal mediation best represented the relationships between commitments and OCB.     

Response rate,speed, and completeness: A comparison of Internet-based and mail surveys

Because of their speed and accessibility, the use of on-line research tools has grown considerably in recent years. The present study compared two ways of delivering surveys: Internet-based and mail delivery methods. Although Internet-basedand mail surveys achieved a similar response rate, Internet-based surveys may be more effective than mail surveys in a setting such as when the target population has both e-mail and Internet access.     

A matched-subject comparison of underachievers with normals on intellectual,behavioral, and emotional variables

Children labeled as under achievers are compared to a matched group functioning normally within the classroom. Factor analyses of the data from several tests reveal that the normal children not only have achieved higher academic performance but also have better learning aptitude. The inference may be made that many underachievers actually have a low general aptitude when carefully measured.This study was supported from funds from the Holden Foundation at the Children's Hospital of Michigan. The authors extend their thanks to Mrs. Barrie Lowy, Mrs. Sheila Kempler, and Ms. Enid Braun.