Psychophysiological and behavioral differences as a function of age and Parkinson’s disease

Differences related to age and to specific neurological (Parkinsonian) damage were studied by contrasting, respectively, old (mean age 64 years) and young (27 years) subjects (N=15), and old-normal (N=15) and old-Parkinsonian (N=15) subjects. Both behavioral as well as psychophysiological dependent variables were employed. The behavioral measure was performance on a discrimination learning task, while the psychophysiological measures were based on habituation to a repeated tone stimulus and on a Pavlovian differential conditioning preparation. The behavioral task showed predominantly age-related differences, with the young learning faster. Another age-related difference was interpreted as showing a more insight-like learning process in the young. Response-bias (beta) values did not differ between groups. Age-related differences also emerged more clearly than specific-neurological-damage differences in the psychophysiological data. The older subjects manifested markedly less autonomic conditioning, which was probably due to a lowering of reactivity, as well as the emergence of habituation to the (loud-noise) unconditional stimulus. A correlational analysis of discrimination conditioning also yielded age-related differences. Most notably, reactivity played a greater role in conditioning in the old than in the young subjects. The results illustrated how psychophysiological measures can provide information that complements those provided by behavioral measures.     

Task-related factors in oral motor control: speech and oral diadochokinesis in dysarthria and apraxia of speech

This study was focused on the potential influence of task-related factors on oral motor performance in patients with speech disorders. Sentence production was compared with a nonspeech oral motor task, i.e., oral diadochokinesis. Perceptual and acoustic measures of speech impairment were used as dependent variables. Between-task comparisons were made for subsamples of a population of 140 patients with different motor speech syndromes, including apraxia of speech and cerebellar dysarthria. In a further analysis subgroups were matched for speaking rate. Overall, dysdiadochokinesis was correlated with the degree of speech impairment, but there was a strong interaction between task type and motor speech syndrome. In particular, cerebellar pathology affected DDK to a relatively greater extent than sentence production, while apraxic pathology spared the ability of repeating syllables at maximum speed.     

Neuro-cognitive mechanisms of decision making in joint action: a human-robot interaction study

In this paper we present a model for action preparation and decision making in cooperative tasks that is inspired by recent experimental findings about the neuro-cognitive mechanisms supporting joint action in humans. It implements the coordination of actions and goals among the partners as a dynamic process that integrates contextual cues, shared task knowledge and predicted outcome of others’ motor behavior. The control architecture is formalized by a system of coupled dynamic neural fields representing a distributed network of local but connected neural populations. Different pools of neurons encode task-relevant information about action means, task goals and context in the form of self-sustained activation patterns. These patterns are triggered by input from connected populations and evolve continuously in time under the influence of recurrent interactions. The dynamic model of joint action is evaluated in a task in which a robot and a human jointly construct a toy object. We show that the highly context sensitive mapping from action observation onto appropriate complementary actions allows coping with dynamically changing joint action situations.     

Getting a Grasp on Children’s Representational Capacities in Pantomime of Object Use

This study examined how 5- and 9-year-old children (N = 40) produce pantomimes of object use on verbal request. The task required participants to enact an action with an imagined object. Results showed that with age, children (a) proceeded from body part as object to imaginary object and (b) incorporated into their pantomimes more distinctive features of the object and its use. While the first result replicated previous findings with more items and a more sophisticated coding procedure, the latter result revealed new insights. Children’s selection of distinctive features in pantomime was related to their performance on a semantic odd-one-out task that requires the abstraction of specific features without situational support. The discussion focuses on the cognitive requirements of the task and the potential of pantomime being a reflection of children’s representational development. We suggest an explanation of the findings within the more general developmental model of Karmiloff-Smith.     

On the Metaphysics of Linguistics

Mind–body dualism has rarely been an issue in the generative study of mind; Chomsky himself has long claimed it to be incoherent and unformulable. We first present and defend this negative argument but then suggest that the generative enterprise may license a rather novel and internalist view of the mind and its place in nature, different from all of, (i) the commonly assumed functionalist metaphysics of generative linguistics, (ii) physicalism, and (iii) Chomsky’s negative stance. Our argument departs from the empirical observation that the linguistic mind gives rise to hierarchies of semantic complexity that we argue (only) follow from constraints of an essentially mathematical kind. We assume that the faculty of language tightly correlates with the mathematical capacity both formally and in evolution, the latter plausibly arising as an abstraction from the former, as a kind of specialized output. On this basis, and since the semantic hierarchies in question are mirrored in the syntactic complexity of the expression involved, we posit the existence of a higher-dimensional syntax structured on the model of the hierarchy of numbers, in order to explain the semantic facts in question. If so, syntax does not have a physicalist interpretation any more than the hierarchy of number-theoretic spaces does.     

Classical conditioning and information processing: Different mechanism for prepared and unprepared stimuli?

Although learning without awareness conflicts with recent theories of classical human Pavlovian conditioning, there is at least one type of conditioning in which CS-US contingency is processed without awareness—the so-called prepared conditioning. Therefore, presenting a secondary reaction time probe to measure the amount of information processing capacity required should produce interference with the secondary task in unprepared, but not in prepared conditioning, since in the latter information should be processed in parallel. In a previous study, the authors could not find differences between both types of conditioning, neither in reaction time nor in electrodermal indicators of information processing. The present study was conducted to replicate and extend these findings, using a differential autonomic conditioning paradigm. One half of 42 subjects received spider and snake slides as prepared stimuli, while the other half received flower slides as unprepared stimuli. Both kinds of stimuli were used as CS+ and as CS-. An electric shock served as unconditioned stimulus. During 24 acquisition and 24 extinction trials, electrodermal and heart rate responses, as well as reaction times to a probe stimulus, were recorded. The results revealed significant conditioning effects in terms of CS-/CS+ differences. However, no differences were found between prepared and unprepared stimuli, neither in autonomic measures nor in reaction time. Again, our results are in favor of serial information processing in both prepared and unprepared stimuli, suggesting that the so-called prepared conditioning may be treated as a subclass of classical autonomic conditioning instead of forming a specific class of learning.     

The course of restitution of learning and concentrating ability in chronic alcoholics in the 1st year of abstinence

Aim of our investigation was the analysis of the performances of chronic alcoholics under abstinence. 3 groups of 30 alcoholics were investigated after 3 weeks, 3 months and one year and compared with a group of control (n = 30). The most essential results: Strong increase in the first 3 month, after only slow increase. The level of healthy population has been attained nearly but not complete. The restitution is independent of the age and sex but significant dependent to the type of drinking (gamma- and deltadrinker). This results are important for the occupational rehabilitation of alcoholics after therapy.