Adult attention-deficit/hyperactivity disorder: neuropsychological correlates and clinical presentation

We compared the neuropsychological test performance of adult ADHD patients to the neurocognitive profiles of control subjects recruited from the general population. We administered a neuropsychological test battery consisting of measures considered sensitive to either orbitofrontal or dorsolateral-prefrontal (DLPF) dysfunction. Orbitofrontal hypoarousal is associated with behavioral disinhibition and a relative indifference to punishment. The DLPF region may function as a central executive system. Indeed, DLPF dysfunction may underlie many of the cardinal symptoms associated with ADHD. We tested the following hypotheses: (1) adult subjects meeting DSM-IV criteria for ADHD, predominantly hyperactive-impulsive type, would display neuropsychological deficits on tasks sensitive to orbitofrontal dysfunction; (2) adult subjects meeting DSM-IV criteria for ADHD, predominantly inattentive type, would perform poorly on measures sensitive to DLPF dysfunction; and (3) adult subjects meeting DSM-IV criteria for ADHD, combined type, would exhibit performance deficits on orbitofrontal measures and on DLPF tasks. Results partially confirmed our hypotheses. Subtyping ADHD patients revealed important group differences. Distinct neurocognitive and clinical profiles were observed.     

Interaction of the Dopaminergic System With Mechanisms of Associative Learning and Cognition:Implications for Drug Abuse

The possible role of mechanisms of associative learning in drug abuse and addiction is considered with respect to psychomotor stimulant drugs such as cocaine and amphetamine. Although the initial sites of the reinforcing effects of these drugs are associated with the mesolimbic dopamine projection to the nucleus accumbens, other important neuromodulatory influences are identified. These include the amygdala, which appears to mediate the associative processes by which environmental stimuli come to control drug-seeking behavior. Possible parallel mechanisms by which stimulant drugs enhance effects of aversive as well as rewarding stimuli are discussed. The importance of attribution and context in determining relative rewarding and aversive effects is pointed out. These attributional and contextual factors may be a function of cortical regions that may themselves be impaired by chronic drug abuse, leading to further dysexecutive control over cognition and behavior.     

The adaptive significance of destructiveness in primitive personalities

Destructiveness in primitive personalities is not restricted to a segment of the person as it is in the case of neurotics, but is global and pervasive. This destructiveness is meaningfully configured in a manner which cannot fully be accounted for by constitutional factors or be comprehended from the individual, intrapsychic, conflictual viewpoint of classical psychoanalysis. It follows an interpersonally meaningful pattern and therefore has adaptive significance in the contemporary life of the individual. The adaptive model I propose does not violate essential canons of psychoanalytic theory, for it can simultaneously be conceptualized in terms of intrapsychic structure and dynamics. This model holds out the possibility for a therapeutic approach to primitive personality organization which differs in some but by no means all respects from classical analysis.     

Natural variation in Drosophila larval reward learning and memory due to a cGMP-dependent protein kinase

Animals must be able to find and evaluate food to ensure survival. The ability to associate a cue with the presence of food is advantageous because it allows an animal to quickly identify a situation associated with a good, bad, or even harmful food. Identifying genes underlying these natural learned responses is essential to understanding this ability. Here, we investigate whether natural variation in the foraging (for) gene in Drosophila melanogaster larvae is important in mediating associations between either an odor or a light stimulus and food reward. We found that for influences olfactory conditioning and that the mushroom bodies play a role in this for-mediated olfactory learning. Genotypes associated with high activity of the product of for, cGMP-dependent protein kinase (PKG), showed greater memory acquisition and retention compared with genotypes associated with low activity of PKG when trained with three conditioning trials. Interestingly, increasing the number of training trials resulted in decreased memory retention only in genotypes associated with high PKG activity. The difference in the dynamics of memory acquisition and retention between variants of for suggests that the ability to learn and retain an association may be linked to the foraging strategies of the two variants.     

Heroin Addicts' Views of Commonly Abused Drugs: A Semantic Differential Approach

52 heroin addicts were given a form of the Semantic Differential asking for their perceptions of heroin, methadone, LSD, amphetamines and marijuana. Marijuana was viewed most favorably, heroin least favorably. Views of heroin and marijuana were positively correlated; but not so heroin and methadone. There was a positive relationship between length of time on methadone maintenance and the potency score for heroin.     

Characterization and sociocultural predictors of neuropsychological test performance in HIV+ Hispanic individuals

Hispanic individuals in the U.S. have been disproportionately impacted by HIV/AIDS, yet little is known regarding the neuropsychological sequelae of HIV within the Hispanic population. This study characterized neuropsychological (NP) test performance of HIV+ English-speaking Hispanic participants (n = 51) and investigated the combined roles of sociocultural factors (e.g., ethnicity, socioeconomic status [SES] proxy, and reading level) on NP test performance among our HIV+ Hispanic and non-Hispanic White participants (n = 49). Results revealed that the pattern of NP impairment in HIV+ Hispanic participants is consistent with the frontal-striatal pattern observed in HIV-associated CNS sequelae, and the overall prevalence of global NP impairment was high compared to previous reports with more ethnically homogeneous, non-Hispanic White cohorts. Multivariate prediction models that considered both sociocultural factors and CD4 count revealed that reading level was the only unique predictor of global NP functioning, learning, and attention/working memory. In contrast, ethnicity was the only unique predictor of abstraction/executive functioning. This study provides support for the use of neuropsychological evaluation in detecting HIV-associated NP impairment among HIV+ Hispanic participants and adds to the growing literature regarding the importance of considering sociocultural factors in the interpretation of NP test performance.     

You’re looking for what? Comparing search for familiar,nameable objects to search for unfamiliar,novel objects

Searching for items in one’s environment often includes considerable reliance on semantic knowledge. The present study examines the importance of semantic information in visual and memory search, especially with respect to whether the items reside in long-term or working memory. In Experiment 1, participants engaged in hybrid visual memory search for items that were either highly familiar or novel. Importantly, the relatively large number of targets in this hybrid search task necessitated that targets be stored in some form of long-term memory. We found that search for familiar objects was more efficient than search for novel objects. In Experiment 2, we investigated search for familiar versus novel objects when the number of targets was low enough to be stored in working memory. We also manipulated how often participants in Experiment 2 were required to update their target (every trial vs. every block) in order to control for target templates that were stored in long-term memory as a result of repeated exposure over trials. We found no differences in search efficiency for familiar versus novel objects when templates were stored in working memory. Our results suggest that while semantic information may provide additional individuating features that are useful for object recognition in hybrid search, this information could be irrelevant or even distracting when searching for targets stored in working memory.