Renatus renatus: the Cartesian tradition in British neuroscience and the neurophilosophy of John Carew Eccles

J. C. Eccles (1903-1997) had a highly distinguished career in neurophysiology, being awarded the Nobel Prize for Medicine or Physiology in 1963. This paper sets him within the Cartesian tradition of British neurophysiology initiated by Thomas Henry Huxley in the mid-19th century. It shows how the mind-brain problematique of the Cartesian tradition troubled him throughout his career, leading him finally to a solution in terms of quantum microphysics and microphysiology. This position, which has subsequently become fashionable, is discussed and shown (at least in the form Eccles espoused) to provide no solution to the problem posed by Descartes in the early 17th century.     

Preserved implicit learning on both the serial reaction time task and artificial grammar in patients with Parkinson's disease

Thirteen nondemented patients with Parkinson's disease (PD) were compared with age-matched controls on two standard tests of implicit learning. A verbal version of the Serial Reaction Time (SRT) task was used to assess sequence learning and an artificial grammar (AG) task assessed perceptual learning. It was predicted that PD patients would show implicit learning on the AG task but not the SRT task, as motor sequence learning is thought to be reliant on the basal ganglia, which is damaged in PD. Patients with PD demonstrated implicit learning on both tasks. In light of these unexpected results the research on SRT learning in PD is reconsidered, and some possible explanations for the sometimes conflicting results of PD patient samples on the SRT task are considered. Four factors which merit further study in this regard are the degree to which the SRT task relies on overt motor responses, the effects of frontal lobe dysfunction upon implicit sequence learning, the effects of cerebellar degeneration, and the degree to which the illness itself has advanced.     

Sigmund Koch as critical humanist

Just as Sigmund Koch was a good scientist without succumbing to scientism, he was a good humanist without succumbing to the popular distortions trading on the name of humanism. When humanistic psychology was seduced by the touchy-feely encounter group movement, Koch derided its technology of authenticity as shamelessly meretricious. Later, when postmodern humanists of deconstruction and textual analysis began to be heard in psychology, Koch wryly expressed his preference for the old-fashioned kind of humanism. Koch's interests and his conception of the domain of psychology thus transcended scientific and humanistic labels and boundaries. To be good science, human psychological studies have to start with and be guided by openness to all aspects of being human. No less in the present and future than during his lifetime, the implications of Koch's vision of psychological inquiry warrant discerning and disciplined attention.     

The connubial crucible: newlywed years as predictors of marital delight, distress, and divorce

This study showed that couples' newlywed marriages and changes in their union over the first 2 years foreshadow their long-term marital fate after 13 years. Consistent with the enduring dynamics model, differences in the intensity of newlyweds' romance as well as the extent to which they expressed negative feelings toward each other predicted (a) whether or not they were happy 13 years later (among those who stayed married) and (b) how long their marriage lasted prior to separation (for those who divorced). The results provide little support for the idea that emergence of distress (e.g., increasing negativity) early in marriage leads to marital failure but instead show that disillusionment--as reflected in an abatement of love, a decline in overt affection, a lessening of the conviction that one's spouse is responsive, and an increase in ambivalence--distinguishes couples headed for divorce from those who establish a stable marital bond.     

Effects of LY354740, a novel glutamatergic metabotropic agonist, on nonhuman primate hypothalamic-pituitary-adrenal axis and noradrenergic function

The search for novel anxiolytics and antidepressants has focused on compounds with the potential to reduce excessive hypothalamic-pituitary-adrenal (HPA) axis activity. L-glutamate, an excitatory neurotransmitter ubiquitously present within the central nervous system, conceivably plays an important role in activating the neural sites involved in stress modulation. Deactivation of the HPA axis by glutamatergic neurotransmission modulation may represent a novel therapeutic approach. Accordingly, the acute intravenous effects of the novel metabotropic (mGlu2/3) agonist LY354740 were tested on bonnet macaques (Macaca radiata) undergoing acute infusions of yohimbine, a noradrenergic stimulant. Dependent measures were the magnitude of the increase of plasma cortisol and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) customarily elicited by yohimbine. Next, the effects of 6 weeks of chronic oral administration of LY354740 on baseline (postcapture) plasma cortisol and MHPG levels in comparison to the identical measure in untreated controls were assessed. Subjects chronically treated with LY354740 received yohimbine infusions which were compared to yohimbine infusions and saline infusions in non-LY354740-treated subjects. Preliminary evidence supports the view that acute LY354740 infusion resulted in a marked diminution of yohimbine-induced stress response, as manifest by a substantial attenuation of cortisol and MHPG response observed in comparison to the saline-treated yohimbine condition. Chronic oral administration of LY354740 led to postcapture baseline cortisol levels which were markedly reduced (approximately 50 percent) in comparison to untreated control subjects; however, there were no significant parallel differences in MHPG levels. Yohimbine infusions elicited an increase in cortisol and MHPG levels in both LY354740-treated and non-LY354740-treated subjects, in comparison to declines in cortisol values observed following vehicle infusions (group X time interaction; P<.0001). Chronic LY354740-treated subjects failed to achieve cortisol levels comparable in range to those of untreated subjects primarily because of their low baseline cortisol levels. In contrast, despite equivalent baselines, yohimbine-induced MHPG values were increased overall in the chronically treated group compared to the saline and yohimbine-alone groups. Thus, LY354740 markedly reduced the acute corticoid and noradrenergic response elicited by yohimbine infusion. Chronic administration of LY354740 appears to present a safe and effective mechanism to markedly down-modulate the HPA axis while retaining noradrenergic responsivity.     

Resilience concepts and findings: implications for family therapy

Resilience is a term used to describe relative resistance to psychosocial risk experiences. There is abundant evidence that there is enormous variation in children's responses to such experiences but research to determine the processes underlying the variations needs to take account of several crucial methodological issues. The findings emphasize that multiple risk and protective factors are involved; that children vary in their vulnerability to psychosocial stress and adversity as a result of both genetic and environmental influences; that family-wide experiences tend to impinge on individual children in quite different ways; that the reduction of negative, and increase of positive, chain reactions influences the extent to which the effects of adversity persist over time; that new experiences which open up opportunities can provide beneficial 'turning- point' effects; that although positive experiences in themselves do not exert much of a protective effect, they can be helpful if they serve to neutralize some risk factors; and that the cognitive and affective processing of experiences is likely to influence whether or not resilience develops. The implications of these findings for family therapy are considered in terms of the need for therapists to look carefully at the ways in which different risk factors interact; to assess and take account of individual differences in susceptibility; to consider the extent to which risk factors impinge on the individual and, in that connection, to note the importance of patterns of social interaction outside as well as inside the family; to appreciate the role of both the peer group and individual characteristics in the development of negative and positive chain reactions; and to pay attention to the ways in which individuals process their experiences.     

Development and phonetic differentiation of speech movement patterns.

It is often hypothesized that speech production units are less distinctive in young children and that generalized movement primitives, or templates, serve as a base on which distinctive, mature templates are later elaborated. This hypothesis was examined by analyzing the shape and stability of single close-open speech movements of the lower lip recorded in 4-year-old, 7-year-old, and adult speakers during production of utterances that varied in only a single phoneme. To assess the presence of a generalized template, lower lip movement sequences were time and amplitude normalized, and a pattern recognition procedure was implemented. The findings indicate that speech movements of children already converged on phonetically distinctive patterns by 4 years of age. In contrast, an index of spatiotemporal stability demonstrated that the stability of underlying patterning of the movement sequence improves with maturation.     

Health and educational outcomes of children who experienced severe neonatal medical complications.

To determine the long-term developmental and educational outcomes of a sample of low birthweight infants with intraventricular hemorrhage (IVH), the authors conducted developmental assessments and interviews 8 years after the initiation of an early intervention project. At the time of the follow-up, 62% of the children were experiencing some developmental or behavior problems, with visual impairments, cerebral palsy, and attention deficits occurring most frequently. Grade of IVH and the number of days spent in the neonatal intensive care unit were the best predictors of later developmental delays. The sample also scored below average on school achievement; approximately 30% of those in school were eligible for special education services. These findings corroborate results from investigations with similar populations whose birth characteristics put them at risk for subsequent developmental delay.     

Do self-fulfilling prophecies accumulate, dissipate, or remain stable over time?

The authors examined whether self-fulfilling prophecies accumulate, dissipate, or remain stable over time by using data from more than 500 6th- through 12th-grade students in public school math classes. The authors used multiple regression analyses to assess the extent to which teacher perceptions predicted students' final math marks and standardized math-test scores from 6th through 12th grade. Control variables included 5 measures of student motivation and 2 measures of previous achievement. The results were consistent with both the dissipation and stability hypotheses. Implications for understanding the extent to which social perception creates social reality and the role of expectations in social problems are discussed.     

Knowledge level learning and the power law: A soar model of skill acquisition in scheduling

Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning.