Early Australian neuroscientists and the tyranny of distance.

Australian neuroscientists at the turn of the twentieth century and in the succeeding decades faced formidable obstacles to communication and supply due to their geographical isolation from centers of learning in Europe and North America. Consequently, they had to spend significant periods of their lives overseas for training and experience. The careers of six pioneers-Laura Forster, James Wilson, Grafton Elliot Smith, Alfred Campbell, Raymond Dart, and John Eccles-are presented in the form of vignettes that address their lives and most enduring scientific contributions. All six were medically trained and, although they never collaborated directly with one another, they were linked by their neuroanatomical interests and by shared mentors, who included Nobelists Ramon y Cajal and Charles Sherrington. By the 1960s, as the so-called "tyranny of distance" was overcome by advances in communication and transport technology, local collaborative groups of neuroscientists emerged in several Australian university departments that built on the individual achievements of these pioneers. This in turn led to the establishment of the Australasian Neuroscience Society in 1981.

Medical school accreditation in China: a Sino-Australian collaboration.

In 2008, China established a medical school accreditation process based on international standards and guidelines. Twenty schools had been accredited by 2013 and it is intended to accredit all 137 schools by 2020. To achieve this ambitious aim, Chinese medical educators have entered into collaboration with their Australian counterparts, engendered by mutual membership of the Association for Medical Education in the Western Pacific Region, a regional division of the World Federation for Medical Education. The collaboration began in 2000 as informal discussions at regional meetings and has since developed three major components: workshops held throughout China for potential assessors and for medical schools undergoing accreditation; visits by Chinese accreditors to Australia to observe Australian Medical Council processes; and participation by Australian assessors in the accreditation of Chinese medical schools. The incremental steps that led to this unique bi-national venture are outlined in the context of other international developments in accreditation of medical education. Then, the preparation, piloting and implementation of accreditation standards and guidelines with Chinese specifications are described. Finally, the outcomes achieved thus far and the challenges remaining are discussed.

Memory systems involved in professional skills: a case of dense amnesia due to herpes simplex viral encephalitis.

JL, a 25-year-old physiotherapist, became densely amnesic following herpes simplex viral encephalitis (HSVE), causing bilateral damage to medial and ventral areas of her frontal and temporal lobes and their associated circuitry. Three years post-onset, her WAIS-R full scale IQ (Verbal 74, Performance 102) showed an estimated loss of +/- 50 points. She displayed severe global amnesia and markedly impaired social cognition. However, her immediate memory, perceptual priming, and cognitive problem-solving abilities were relatively spared. Her retention of professional skills was assessed using simulated physiotherapy scenarios. JL was able to demonstrate some procedural skills spontaneously, but was unable to apply them precisely and flexibly to individual patient needs. She showed no memory of theoretical or propositional physiotherapy knowledge, and could neither plan treatment nor reason clinically. Her performance was well below that of four other physiotherapists who had also not practised for 4 years. Thus, despite the relative sparing of her implicit memory, JL's performance lacked the co-ordinated operation of declarative and implicit long-term memory and the links to working memory that are necessary for the flexible performance of complex professional procedures.

Executive control of working memory in schizophrenia.

There is considerable evidence that working memory impairment is a common feature of schizophrenia. The present study assessed working memory and executive function in 54 participants with schizophrenia, and a group of 54 normal controls matched to the patients on age, gender and estimated premorbid IQ, using traditional and newer measures of executive function and two dual tasks-Telephone Search with Counting and the Memory Span and Tracking Task. Results indicated that participants with schizophrenia were significantly impaired on all standardised measures of executive function with the exception of a composite measure of the Trail Making Test. Results for the dual task measures demonstrated that while the participants with schizophrenia were unimpaired on immediate digit span recall over a 2-min period, they recalled fewer digit strings and performed more poorly on a tracking task (box-crossing task) compared with controls. In addition, participants with schizophrenia performed more poorly on the tracking task when they were required to simultaneously recall digits strings than when they performed this task alone. Contrary to expectation, results of the telephone search task under dual conditions were not significantly different between groups. These results may reflect the insufficient complexity of the tone-counting task as an interference task. Overall, the present study showed that participants with schizophrenia appear to have a restricted impairment of their working memory system that is evident in tasks in which the visuospatial sketchpad slave system requires central executive control.

Genetic and environmental sources of covariance between reading tests used in neuropsychological assessment and IQ subtests.

In this study, we examined genetic and environmental influences on covariation among two reading tests used in neuropsychological assessment (Cambridge Contextual Reading Test [CCRT], [Beardsall, L., and Huppert, F. A. (1994). J. Clin. Exp. Neuropsychol. 16:232-242], Schonell Graded Word Reading Test [SGWRT], [Schonell, F. J., and Schonell, P. E. (1960). Diagnostic and attainment testing. Edinburgh: Oliver and Boyd.]) and among a selection of IQ subtests from the Multidimensional Aptitude Battery (MAB), [Jackson, D. N. (1984). Multidimensional aptitude battery, Ontario: Research Psychologists Press.] and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) [Wechsler, D. (1981). Manual for the Wechsler Adult Intelligence Scale-Revised (WAIS-R). San Antonio: The Psychological Corporation]. Participants were 225 monozygotic and 275 dizygotic twin pairs aged from 15 years to 18 years (mean, 16 years). For Verbal IQ subtests, phenotypic correlations with the reading tests ranged from 0.44 to 0.65. For Performance IQ subtests, phenotypic correlations with the reading tests ranged from 0.23 to 0.34. Results of Structural Equation Modeling (SEM) supported a model with one genetic General factor and three genetic group factors (Verbal, Performance, Reading). Reading performance was influenced by the genetic General factor (accounting for 13% and 20% of the variance for the CCRT and SGWRT, respectively), the genetic Verbal factor (explaining 17% and 19% of variance for the CCRT and SGWRT), and the genetic Reading factor (explaining 21% of the variance for both the CCRT and SGWRT). A common environment factor accounted for 25% and 14% of the CCRT and SGWRT variance, respectively. Genetic influences accounted for more than half of the phenotypic covariance between the reading tests and each of the IQ subtests. The heritabilities of the CCRT and SGWRT were 0.54 and 0.65, respectively. Observable covariance between reading assessments used by neuropsychologists to estimate IQ and IQ subtests appears to be largely due to genetic effects.

A genetic investigation of the covariation among inspection time, choice reaction time, and IQ subtest scores.

Information processing speed, as measured by elementary cognitive tasks, is correlated with higher order cognitive ability so that increased speed relates to improved cognitive performance. The question of whether the genetic variation in Inspection Time (IT) and Choice Reaction Time (CRT) is associated with IQ through a unitary factor was addressed in this multivariate genetic study of IT, CRT, and IQ subtest scores. The sample included 184 MZ and 206 DZ twin pairs with a mean age of 16.2 years (range 15-18 years). They were administered a visual (pi-figure) IT task, a two-choice RT task, five computerized subtests of the Multidimensional Aptitude Battery, and the digit symbol substitution subtest from the WAIS-R. The data supported a factor model comprising a general, three group (verbal ability, visuospatial ability, broad speediness), and specific genetic factor structure, a shared environmental factor influencing all tests but IT, plus unique environmental factors that were largely specific to individual measures. The general genetic factor displayed factor loadings ranging between 0.35 and 0.66 for the IQ subtests, with IT and CRT loadings of -0.47 and -0.24, respectively. Results indicate that a unitary factor is insufficient to describe the entire relationship between cognitive speed measures and all IQ subtests, with independent genetic effects explaining further covariation between processing speed (especially CRT) and Digit Symbol.

Event-related potential correlates of impaired visuospatial working memory in schizophrenia.

Previous studies have reported that patients with schizophrenia demonstrate impaired performance during working memory (WM) tasks. The current study aimed to determine whether WM impairments in schizophrenia are accompanied by reduced slow wave (SW) activity during on-line maintenance of mnemonic information. Event-related potentials were obtained from patients with schizophrenia and well controls as they performed a visuospatial delayed response task. On 50% of trials, a distractor stimulus was introduced during the delay. Compared with controls, patients with schizophrenia produced less SW memory negativity, particularly over the right hemisphere, together with reduced frontal enhancement of SW memory negativity in response to distraction. The results indicate that patients with schizophrenia generate less maintenance phase neuronal activity during WM performance, especially under conditions of distraction.

Genetic sources of covariation among P3(00) and online performance variables in a delayed-response working memory task.

Genetic and environmental sources of covariation among the P3(00) and online performance elicited in a delayed-response working memory task, and psychometric IQ assessed by the multidimensional aptitude battery, were examined in an adolescent twin sample. An association between frontal P3 latency and task performance (phenotypic r=-0.33; genotypic r=-0.49) was indicated, with genes (i.e. twin status) accounting for a large part of the covariation (>70%). In contrast, genes influencing P3 amplitude mediated only a small part (2%) of the total genetic variation in task performance. While task performance mediated 15% of the total genetic variation in IQ (phenotypic r=0.22; genotypic r=0.39) there was no association between P3 latency and IQ or P3 amplitude with IQ. The findings provide some insight into the inter-relationships among psychophysiological, performance and psychometric measures of cognitive ability, and provide support for a levels-of-processing genetic model of cognition where genes act on specific sub-components of cognitive processes.

Working memory correlates of three symptom clusters in schizophrenia.

This study was designed to examine whether discrete working memory deficits underlie positive, negative and disorganised symptoms of schizophrenia. Symptom dimension ratings were assigned to 52 outpatients with schizophrenia (ICD-10 criteria), using items drawn from the Positive and Negative Syndrome Scale (PANSS). Linear regression and correlational analyses were conducted to examine whether symptom dimension scores were related to performance on several tests of working memory function. Severity of negative symptoms correlated with reduced production of words during a verbal fluency task, impaired ability to hold letter and number sequences on-line and manipulate them simultaneously, reduced performance during a dual task, and compromised visuospatial working memory under distraction-free conditions. Severity of disorganisation symptoms correlated with impaired visuospatial working memory under conditions of distraction, failure of inhibition during a verbal fluency task, perseverative responding on a test of set-shifting ability, and impaired ability to judge the veracity of simple declarative statements. Severity of positive symptoms was uncorrelated with performance on any of the measures examined. The present study provides evidence that the positive, negative and disorganised symptom dimensions of the PANSS constitute independent clusters, associated with unique patterns of working memory impairment.