Establishing a Rodent Model of Mild Cognitive Impairment in Aging
Age-related cognitive decline is a substantial societal problem, particularly based on the growing population of elderly in the United States and in other developed nations. The number of people over 65 living in the US is expected to increase from 35 million in 2000 to 71.5 million by the year 2030, comprising almost 20% of the US population (Federal Interagency Forum on Aging-Related Statistics, 2005). It has further been estimated that 7-8% of elderly individuals in the US will develop cognitive impairment resulting from severe dementia associated with pathological diseases such as Alzheimer’s disease (AD; Freedman et al., 2002). Many more, however, will experience cognitive decline independent of age-related disease, which can be equally devastating to one’s life quality and the ability to live independently. The term mild cognitive impairment (MCI) is used to describe cognitive impairment at advanced ages prior to, or independent of, dementia associated with pathological diseases such as AD. It is estimated that up to 20% of people over age 65 suffer from MCI (Mayo Foundation, 2004). MCI is characterized by loss of a range of cognitive abilities including those associated with declarative/spatial memory (dependent on the medial temporal lobe system) and higher-order/executive functions (associated with prefrontal cortex).
Examination of the Role of Drug Administration in the Neural and Behavioral Mechanisms of Tolerance
Nicotine tolerance has been shown to play an important role in the development and maintenance of smoking behavior. Research has shown that the development of nicotine tolerance is likely the result of desensitization of nicotine cholinergic receptors (nAChRs), that occurs during the first few minutes of exposure. This rapid desensitization is a decrease in receptor efficacy and occurs following sub-cellular signaling by neighboring receptors following activation. Additionally, it has been shown that the activation of sub-cellular mechanisms responsible for desensitization of nAChRs can lead to immediate early gene expression, responsible for the development of long-term receptor inactivation. Upregulation of receptors is a phenomenon that has also been shown to occur with repeated drug administration, as a compensatory response to receptor desensitization. Upregulation has also been shown to occur rapidly, however unlike desensitization, upregulation returns to baseline after a few days.
The Effects of Post-training d-Amphetamine on a Learned Stimulus-Reward Association
The memory consolidation hypothesis posits that memories require a fixed amount of time to stabilize following learning. During this stabilization period, these labile memories are highly sensitive to disruption or enhancement. Previous research has suggested that psychostimulant drugs (such as cocaine and amphetamine) can enhance memory for previously learned information through actions on memory consolidation. It is feasible that these memory-enhancing effects of stimulant drugs may indirectly facilitate their addictive potential, by strengthening memories linking the drugs with a particular cue or context, thus increasing the likelihood of drug craving or drug-seeking behavior upon re-experiencing that cue or context.
Parental Influences on Academic Performance and Attitudes Toward Achievement
Parenting styles (Baumrind, 1967) have consistently been shown to relate to various child behaviors and academic achievement. In general, an authoritative parenting style emphasizing both responsiveness and demandingness appears superior in fostering high academic achievement (Reitman, Rhode, Hupp, & Altobello, 2002). Most notably, parenting styles and academic achievement have been studied in children and adolescents, but have been examined in college students over the past few years. In the present study, the relations among parenting style, academic achievement, and attitudes toward achievement were examined in a sample of college students (n=213). Results indicated a relation between authoritative parenting and academic achievement such that after a student enters college parents continue to influence a students' academic motivation and behavior.
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