Knowledge of the literature pertaining to patterns of performance in normal individuals is essential if we are to understand intraindividual variability in neurocognitive test performance in neuropsychiatric disorders. Twenty-five healthy individuals with a high-level of education were evaluated on a short neuropsychological battery which spanned several cognitive domains. ---Results indicated that cognitive abilities are not equally distributed within a sample of healthy, high-level functioning individuals. This may be of interest to neuropsychologists who might base clinical inference about the presence of cerebral dysfunction, at least in part, on marked variation in a patient’s level of cognitive test performance. The practice of deductive reasoning in clinical neuropsychology may be prone to false-positive conclusions about cognitive functioning in neuropsychiatric disorders where base-rates of cognitive impairments are low and pre-existing educational achievements are high.

While neuropsychological deficits have been reported in healthy individuals who use cannabis, data in patients with multiple sclerosis (MS) are lacking. Given that MS is associated with cognitive deterioration, the aim of this study was to determine the cognitive effects of inhaled or ingested cannabis in this population. Fifty MS patients (25 cannabis users and 25 non-users) completed the Minimal Assessment of Cognitive Function in MS battery of neuropsychological tests. Cannabis users had significantly poorer performance on measures of information processing speed, executive functions, and visuospatial perception, and were twice as likely to be classified as globally cognitively impaired. Similar results were found after controlling for potential confounding variables. This study provides evidence that prolonged cannabis use in MS patients is associated with poorer performance on cognitive domains commonly affected in this population. The therapeutic benefits patients may derive from using cannabis should be weighed against the associated cognitive side-effects.

Behavioral deficits caused by fetal-alcohol are well expressed in juvenile subjects but usually ameliorate with maturation. It suggests some kind of postnatal regeneration. The aim of the present study was to examine the potential correlation between behavioral recovery and the postnatal hippocampal development in the fetal-alcohol rats. This study included behavioral tests applied to juvenile and adult subjects, unbiased stereology to investigate changes in neuron numbers and hippocampal volumes, the postnatal tracing and analysis of the hippocampal principal neuron&rsquo / s morphology, investigation of age-dependent changes in the distribution of doublecortin-expressing neurons, and evaluation of synaptic development by assessing age-dependent changes in the regional immunoreactivity/expression of synaptophysin and PSD95. Rats have been exposed to ethanol throughout 7-21 gestation days with daily ethanol dose of 6g/kg delivered by intragastric intubation to the pregnant dams. The morphological characteristics were examined on postnatal days P1, P10, P30, P60, in hippocampal CA1, CA3, and DG subregions, in fetal-alcohol and control rats. Both, stereological and doublecortin-immunoreactivity data pointed towards a possibility of limited neurogenesis taking place during a protracted postnatal period not only in the germinal zones (SGZ and SVZ) but also in the hippocampal CA regions. Ethanol effect on postnatal hippocampal development was limited to marginally lower number of granular cells in DG on P30. It correlated with poorer cognitive performance in the fetal-alcohol group. The treatment effect on the morphology of hippocampal neurons was observed mainly in CA region at P1 and seemed to be attributed more to the intubation stress than the ethanol itself.

This body of research investigates the effects of sex and estrogen on higher brain functions, in general, and on working memory, in particular. A female advantage for object-location and verbal working memory has been reported, and estrogen supplementation facilitates performance of the same. Less is known about whether the female advantage is due to the verbalizability of the stimuli, and whether estrogen-suppression adversely affects performance on working memory and other neuropsychological domains sensitive to estrogen. Study 1 examined sex-related differences in young adults on an object-location working memory measure that varied in verbalizability of stimuli and task presentation (i.e., manual or computer); as expected, females performed better than males regardless of the verbalizability of the stimuli or task presentation. Study 2 examined sex-related differences in young adults on the n-back working memory task across verbal, spatial, and object conditions. Contrary to the hypotheses, there was no sex effect for the verbal version of the n-back task, and males actually performed better than females on the object version; as expected, males performed better than females on the spatial version. Study 3 investigated the effect of estrogen suppression in middle-aged and older adult females undergoing treatment for estrogenic breast cancer using the experimental working memory measures from Studies 1 and 2, and a comprehensive neuropsychological battery that included measures considered to be either sensitive (e.g., letter fluency) or insensitive (e.g., spatial ability) to the female advantage and the effects of estrogen. The estrogen suppression group performed more poorly than healthy age-matched controls on certain estrogen-sensitive measures (i.e., speeded visuomotor attention, speeded manual dexterity, and letter fluency), but unexpectedly, the groups did not differ on any of the memory measures presumed to be estrogen-sensitive. This body of research suggests that although certain working memory measures are sensitive to sex effects, the direction depends on the domain, and that estrogen suppression does not impact working memory in postmenopausal women but does adversely impact speeded performance measures.

Archery can be described as a static sport requiring strength and endurance of the upper body, in particular the shoulder girdle (Mann, 1984 / Mann &amp / Littke, 1989). To get a good record in an archery competition, one requires well-balanced and highly reproducible movements during the shooting (Nishizono, 1987). The bowstring is released when audible impetus is received from a device called &ldquo / clicker&rdquo / . As the fall of the clicker is an acoustic stimulus, it may evoke a sequence of potentials that can be recorded from the scalp of an archer. Auditory Evoked Potentials (AEPs) occur at different latencies and with various relations to the auditory stimuli. Therefore, the present study aims at investigating the Long-latency Auditory Evoked Potentials in Recurve Archery. Research questions can be stated briefly as follows: (1) What kind of Brain Potentials are Evoked by the Event (Fall of Clicker) during Archery Shooting? (2) Is there any significant difference between the characteristics of the potentials measured in laboratory conditions and during archery shooting? (3) Is there any significant difference between the successful and unsuccessful shots in terms of Auditory Evoked Brain Potentials? (4) Does Archery Shooting session have any effect on Auditory Evoked Brain Potentials? The subjects of the present study were 10 non-archers (N=6 males / N=4 females) for control trials and 15 archers (N=9 males / N=6 females) for archery shooting experiments. All subjects reported normal hearing, had medical histories free of significant neurological problems, and were not taking medication known to affect brain activity. Six different control paradigms have been created. Archery shootings were performed from 18 m that is official competition distance with target face.AEBPs were recorded 200 ms before and 800 ms after the trigger (fall of the clicker) over the vertex during the shots of each subject. Paradigm 1 and 5 was conducted just before and after the archery shooting to test the effect of archery shooting on AEBPs. The hit-area is defined as the rectangle between (x1, y1), (x1, y2), (x2, y1), (x2, y2) and the miss-area is the outer part of the hit-area on the target face. The preliminary analysis has shown that fall of the clicker evokes long latency auditory brain potentials with the latency of 100 msec and 200 msec. These responses are called as N1-P2 components. The means and standard deviations of both N100 and P200 amplitudes were as follows: N100 = 27,73 &plusmn / 16,82, P200 = -21,89 &plusmn / 20,46. The latencies of given brain responses were also summarized as: N100 = 141,93 &plusmn / 41,46 / P200 = 211,8 &plusmn / 43,97. N1 amplitude was significantly different in archery shooting than that of control conditions (p&lt / 0.05) except for trial 3, N1 latency was significantly different than that of trial 2 &ndash / 5 (p&lt / 0.05). P2 amplitude is significantly different in archery shooting than that of trial 6 (p&lt / 0.05). However, there was no significant difference in terms of P2 latency between archery shooting and control conditions (p&gt / 0.05). There was no significant difference between successful and unsuccessful shots in terms of N1-P2 components (p&gt / 0.05). An archery shooting session did not create any difference between these components recorded before and after the shot (p&gt / 0.05). Having higher N1 amplitudes during archery shooting can be explained by the known multi-component structure of this wave. Different lobes and regions of the brain can be active during the time of the scalp-recorded N1 and simultaneous involvement of several of these areas may be contributing to the electrical field recorded at scalp in the archery shooting paradigm.

Evidence suggests that emotion affects memory often yielding enhanced recall and recognition of stimuli with emotional content. The nature of the relationship between emotion and memory for words has been particularly difficult to parse in part because of the stimulus characteristics. For example, emotional words tend to engender greater levels of physiological and psychological arousal, which have also been shown to enhance memory. Inter item relatedness has also been suggested as playing a part in the observed effects (i.e., emotional words belong to a closed semantic category compared to neutral words and are therefore easier to remember). While the enhancement of memory for emotional material has been demonstrated across a variety of stimuli and experimental conditions, the neural underpinnings of these effects remain unclear. The Old/New effect is an event related potential finding where electrophysiologic waveforms elicited by previously presented stimuli (i.e., old) are more positive going than those elicited by stimuli that were not previously presented (i.e., new). A few prior studies have investigated Old/New effects for emotional words, mostly comparing negative to neutral words and failing to equate their stimuli for the crucial confounding effects of arousal and inter item relatedness. The present study employed event related potentials to investigate recognition memory for words of positive, negative, and neutral valences in a sample of thirty healthy college undergraduates. It was predicted that positive and negative words would yield greater participant accuracy, response bias and Old/New effects in comparison to neutral words. The observed results yielded some variability in support for all of the hypotheses and predictions that were made a priori. Possible explanations for these results are discussed and directions for future research recommended.

Not available / text

Behavioral studies have documented impaired working memory in childhood brain tumor survivors; however, neural mechanisms have yet to be identified using fMRI. The current study investigated BOLD response differences between twenty survivors (Mean age=23.1(4.14), 55% female) and twenty age- and gender-matched controls from the start to the end of a twenty minute 3-back task. There were no differences in task performance between groups or over time. Effects of practice were present in left prefrontal regions, with both groups showing decreases in activation as the task progressed. There were qualitative and quantitative differences in the brain regions that survivors recruited relative to controls in bilateral prefrontal (including the dorsolateral prefrontal cortex) and parietal cortices. Findings suggest that areas under top-down control of the dorsolateral prefrontal cortex become less activated with practice, and that survivors may require more top-down processing and attentional control to perform at similar levels to healthy controls.

The aim of this study was to come to a better understanding of possible neuropsychological mechanisms underlying psychosocial well-being and therefore to determine whether a relationship between neuropsychological executive functions and psychosocial well-being does indeed exist. Research was conducted in the domains of neuropsychology and positive psychology. This thesis consists of three articles, namely I ) Neuropsychological executive functions and psychosocial well-being: A review, 2) Attentional switching and psychosocial! well-being, and 3) The relationship between generativity as neuropsychological process and psychosocial well-being. The first article argued the possibility of a relationship between neuropsychological and psychosocial aspects, with reference to a pluralistic ecosystems perspective, neuropsychological and other positive psychological theories, such as Miller's neuropsychodynamic model and Frederickson's broaden-and-build theory, as well as existing empirical studies. Numerous neuropsychological studies have indicated that the prefrontal cortex is involved in executive functions, with its main function to regulate both cognitive and affective functioning. Analyses of existing empirical studies indicated an established relationship between prefrontal lobe / executive / regulatory dysfunction and psychopathology, but also that the relationship between normal or optimal prefrontal executive functions and psychosocial well-being is still unclear. The first article concluded that evidence correlating neuropsychological functioning with human flourishing, or indicating possible neuropsychological mechanisms involved in psychosocial well-being, is sparse, presenting a serious lacuna in scientific knowledge. The following two articles focused on contributing to filling this lacuna. "Attentional switching and psychosocial well-being" and "The relationship between generativity, as neuropsychological process and psychosocial well-being" focused on attentional switching and generativity, as part of neuropsychological executive functions, as potential mechanisms associated with psychosocial well-being. These studies aimed to determine whether the capacity to switch attention, as measured by the Color Trails Test (CTT) and Wisconsin Card Sorting Test (WCST), and the capacity to generate novelty, as measured by the Controlled Verbal Fluency Task (CVFT) (Benton, 1967) and Uses of Objects Test (UOT) (Getzels & Jackson, 1962), are related to the degree of psychosocial well-being experienced. As part of the interdisciplinary POWIRS (Profiles of Obese Women with Insulin Resistance Syndrome) project, black African women (article 2 n=66; article 3 n=72) completed the above mentioned neuropsychological measures, as well as indices of psychosocial wellbeing, in a cross-sectional design. The psychosocial measures included the Affectometer (AFM) 2 (Kammann & Flett, 1983); Constructive Thinking Inventory (CTI) abbreviated version (Epstein & Meier, 1989); Sense of Coherence Scale (SOC- 29) (Antonovsky, 1987, 1993); The Fortitude Questionnaire (FORQ) (Pretorius, 1998); JAREL Spiritual Well-being Scale (SWS-H) (Hungelman et al., 1989); Psychological Well-being Scales (SPW-B) (Ryff & Singer, 1998); and the Cognitive Appraisal Questionnaire (CAQ) (Botha & Wissing, 2003). The main findings of these studies were hat the ease of attentional switching and generativity correlates statistically (p<0.5) and practically significantly with higher levels of psychosocial well-being. From a micro-deterministic perspective it can be concluded that frontal lobe executive functions may play a role in the regulation higher-order adjusting psychosocial functions related to quality of life. From a micro-deterministic perspective it can be concluded that psychosocial well-being, while being influenced by executive functions, may also influence the continuous development of neuropsychological executive functions. / Thesis (Ph.D. (Psychology))--North-West University, Potchefstroom Campus, 2005.

Repetitive presentation of any non-significant stimulus to an animal results in a decrement in the animal's response to that stimulus. This phenomenon, termed habituation, is distinguishable from fatigue and receptor adaptation in that it is long-lasting and in that the habituation is fairly specific to the repeated stimulus. The prevailing view of habituation is that it, like learning in general, results from an increase in the efficacy of neural transmission, but, unlike learning, this increased efficacy primarily affects inhibitory interneurons (e.g., Soko1ov, 1960; Hernandez-Peon, 1960; Jouvet, 1961). Within this broad framework, disagreements exist regarding the source of the inhibitory influences. [...]