Cerebral White Matter Integrity and Cognitive Aging: Contributions from Diffusion Tensor Imaging

The integrity of cerebral white matter is critical for efficient cognitive functioning, but little is known regarding the role of white matter integrity in age-related differences in cognition. Diffusion tensor imaging (DTI) measures the directional displacement of molecular water and as a result can characterize the properties of white matter that combine to restrict diffusivity in a spatially coherent manner. This review considers DTI studies of aging and their implications for understanding adult age differences in cognitive performance. Decline in white matter integrity contributes to a disconnection among distributed neural systems, with a consistent effect on perceptual speed and executive functioning. The relation between white matter integrity and cognition varies across brain regions, with some evidence suggesting that age-related effects exhibit an anterior–posterior gradient. With continued improvements in spatial resolution and integration with functional brain imaging, DTI holds considerable promise, both for theories of cognitive aging and for translational application.     

Age-related differences in idea generation and selection for propositional language

Conceptual preparation mechanisms such as novel idea generation and selection from amongst competing alternatives are critical for language production and may contribute to age-related language deficits. This study investigated whether older adults show diminished idea generation and selection abilities, compared to younger adults. Twenty younger (18–35 years) and 20 older (60–80 years) adults completed two novel experimental tasks, an idea generation task and a selection task. Older participants were slower than younger participants overall on both tasks. Importantly, this difference was more pronounced for task conditions with greater demands on generation and selection. Older adults were also significantly reduced on a semantic, but not phonemic, word fluency task. Overall, the older group showed evidence of age-related decline specific to idea generation and selection ability. This has implications for the message formulation stage of propositional language decline in normal aging.     

The role of age and perceptual symbols in language comprehension

Older and younger participants read sentences about objects and were then shown a picture of an object that either matched or mismatched the implied shape of the object in the sentence. Participants' response times were recorded when they judged whether the object had been mentioned in the sentence. Responses were faster in the shape-matching condition for all participants, but the mismatch effect was stronger for older than for younger adults, even when the larger variability of the older group's response times was controlled for. These results suggest that older adults may construct stronger situation models than younger adults.     

A solution-focused approach to working with clients who are suicidal

Self-harm and suicide are amongst the most challenging and frightening problems that therapists and counsellors can encounter in the course of their work. The risk of clients harming themselves in the course of treatment can debilitate the therapists from acting creatively and collaboratively, and make their actions defensive, focused solely on risk assessment rather than therapeutic change.Yet it is precisely a creative and collaborative response, such as that engendered by solution-focused therapy and other models, that is the most likely to facilitate change and re-empower clients to take back charge of their lives. This article describes a solution-focused approach to working with suicidal clients that can be used in conjunction with traditional approaches and which focus on establishing safety as well as assessing risk.Working from this model the clinician shifts to identifying client strengths and coping skills, to collaborating with the client to establish meaningful goals and to helping the client envision a positive future. Arguably, such an approach can increase collaboration between therapist and client and lead to a more client-centred safety plan.     

Human group choice: discrete-trial and free-operant tests of the ideal free distribution

Ideal free distribution theory predicts that foragers will form groups proportional in number to the resources available in alternative resource sites or patches, a phenomenon termed habitat matching. Three experiments tested this prediction with college students in discrete-trial simulations and a free-operant simulation. Sensitivity to differences in programmed reinforcement rates was quantified by using the sensitivity parameter of the generalized matching law (s). The first experiment, replicating prior published experiments, produced a greater degree of undermatching for the initial choice (s = 0.59) compared to final choices (s = 0.86). The second experiment, which extended prior findings by allowing only one choice per trial, produced comparable undermatching (s = 0.82). The third experiment used free-operant procedures more typical of laboratory studies of habitat matching with other species and produced the most undermatching (s = 0.71). The results of these experiments replicated previous results with human groups, supported predictions of the ideal free distribution, and suggested that undermatching represents a systematic deviation from the ideal free distribution. These results are consistent with a melioration account of individual behavior as the basis for group choice.     

Aging and Visual Attention

ABSTRACT— Older adults are often slower and less accurate than are younger adults in performing visual-search tasks, suggesting an age-related decline in attentional functioning. Age-related decline in attention, however, is not entirely pervasive. Visual search that is based on the observer's expectations (i.e., top-down attention) is relatively preserved as a function of adult age. Neuroimaging research suggests that age-related decline occurs in the structure and function of brain regions mediating the visual sensory input, whereas activation of regions in the frontal and parietal lobes is often greater for older adults than for younger adults. This increased activation may represent an age-related increase in the role of top-down attention during visual tasks. To obtain a more complete account of age-related decline and preservation of visual attention, current research is beginning to explore the relation of neuroimaging measures of brain structure and function to behavioral measures of visual attention.     

2004 DIVISION 35 PRESIDENTIAL ADDRESS: GENDER AND LEADERSHIP IN HIGHER EDUCATION

Literature on gender, higher education administration, and leadership is reviewed using the framework of five principles derived from feminist psychology ( Worell & Johnson, 1997 ): (a) sociocultural context influences leadership situations, (b) power dynamics impact sociocultural structures, (c) people are active agents of coping and environmental change, (d) multiple perspectives are useful, and (e) collaboration is an important technique for changing organizations. Within this framework are discussions of the effects of historical context, gender discrimination and stereotyping, hierarchical organization, masculinized context, the interconnection between gender and status, and leadership as empowerment. Examples of administrative strategies that may promote feminist leadership behavior by college administrators are given, such as understanding behavior in context, promoting structural change, using active survival strategies, changing behavioral incentives, striving for activism and social justice, fostering interdisciplinary perspectives, and encouraging collaboration. Difficulties encountered by women attempting to change the higher education context and assume feminist leadership styles are discussed.