Dissociation of explicit and implicit timing in repetitive tapping and drawing movements

Four experiments explored the hypothesis that temporal processes may be represented and controlled explicitly or implicitly. Tasks hypothesized to require explicit timing were duration discrimination, tapping, and intermittent circle drawing. In contrast, it was hypothesized that timing control during continuous circle drawing does not rely on an explicit temporal representation; rather, temporal control is an emergent property of other control processes (i.e., timing is controlled implicitly). Temporal consistency on the tapping and intermittent drawing tasks was related, and performance on both of these tasks was correlated with temporal acuity on an auditory duration discrimination task. However, timing variability of these 3 tasks was not correlated with timing variability of continuous circle drawing. These results support the hypothesized distinction between explicit and implicit temporal representations.     

Memory mechanisms in pigeons: evidence of base-rate neglect

In delayed matching to sample, once acquired, pigeons presumably choose comparisons according to their memory for (the strength of) the sample. When memory for the sample is sufficiently weak, comparison choice should depend on the history of reinforcement associated with each of the comparison stimuli. In the present research, pigeons acquired two matching tasks in which Sample S1 was associated with one comparison from each task, C1 and C3, whereas Sample S2 was associated with Comparison C2, and Sample S3 was associated with Comparison C4. As the retention interval increased, the pigeons showed a bias to choose the comparison (C1 or C3) associated with the more frequently occurring sample (S1). Thus, pigeons were sensitive also to the (irrelevant) likelihood that each of the samples was presented. The results suggest that pigeons may allow their reference memory for the overall sample frequency to influence comparison choice, independent of the comparison stimuli present.     

Relationship between the rorschach and the MMPI-2 in a Swedish population: a replication study of the effects of first-factor related test-interaction styles

A sizeable amount of research literature has failed to demonstrate a stable relationship between self-report and the Rorschach (Exner, 1993). However, principal component first-factor related test-interaction style has been shown to moderate convergence. In this study 78 psychiatric patients completed the Rorschach and the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Hathaway & McKinley, 1989). Practically no correlation was evident between the MMPI-2 and the Rorschach, measuring similar constructs, in all patients. Patients with similar test-interaction styles demonstrated positive intermethod correlations between both conceptually related and conceptually not directly related test indexes. The same scales were negatively correlated in patients with discordant test-interaction styles, and this difference between test-interaction style groups was significant. It is suggested that first-factor related test-interaction style moderates convergence. It is further suggested that test-interaction style moderates convergence between both conceptually related and conceptually not directly related measures of distress or psychopathology.     

Generation of bimanual trajectories of disparate eccentricity: levels of interference and spontaneous changes over practice

The authors examined intermanual interactions of 2 hands that were required to concurrently follow trajectories that differed in eccentricity. Ten healthy participants attempted to learn to trace 2 figures, a circle and an ellipse, with bilaterally isochronous (1:1) timing demands. Initial unimanual trials were followed by bilateral practice comprising 750 movement cycles. Two objectives were addressed: The authors' primary aim was to determine if kinematic interlimb interference is evident independent of spatial and temporal interference and to observe the potential practice-related changes in the nature of that interference. That test was afforded by participants' natural tendency to draw a circle with a relatively constant tangential velocity and an ellipse with a systematically varying velocity. A second aim was to observe the nature of spontaneous changes in the performance of each individual effector, and in the relationship between effectors, across practice. Those objectives were specifically addressed in a context in which augmented feedback was not available to direct the learners' attention to a particular feature of performance. The results suggested that interlimb assimilation of spatial features is the primary source of interference for that task and that apparent effects at the kinematic level are the secondary, indirect product of spatial coupling. Those results were found across blocks of practice. With respect to nondirected performance changes, substantially less improvement was evident in the performance of each individual effector than in the reduction of interlimb interference. Specifically, no practice-related changes in temporal variability or velocity bias, and minimal changes in trajectory smoothness, were evident in individual limbs. Conversely, significant reductions were observed in the variability of relative phase between limbs and in the magnitude of interlimb phase lag.     

Friedrich Albert Lange on neo-Kantianism,socialist Darwinism,and a psychology without a soul

Friedrich Albert Lange was a German philosopher, political theorist, educator, and psychologist who outlined an objective psychology in the 1860s. This article shows how some of the most important worldviews of the nineteenth century (Kantianism, Marxism, and Darwinism) were combined creatively in his thought system. He was crucial in the development of neo-Kantianism and incorporated psycho-physiological research on sensation and perception in order to defend Kant's epistemological idealism. Based on a critique of phrenology and philosophical psychology of his time, Lange developed a program of a psychology without a soul. He suggested that only those phenomena that can be observed and controlled should be studied, that psychology should focus on actions and speech, and that for each psychological event the corresponding physical or physiological processes should be identified. Lange opposed introspection and subjective accounts and promoted experiments and statistics. He also promoted Darwinism for psychology while developing a socialist progressive-democratic reading of Darwin in his social theory. The implications of socialist Darwinism on Lange's conceptualization of race are discussed and his prominence in nineteenth century philosophy and psychology is summarized.     

Effects of right and left hemisphere damage on performance of the "Right Hemisphere Communication Battery"

A Hebrew adaptation of Gardner and Brownell's (1986) "Right Hemisphere Communication Battery" (HRHCB) was administered to 27 right brain-damaged (RBD) patients, 31 left brain-damaged (LBD) patients, and 21 age-matched normal controls. Both patient groups showed deficits relative to controls and overall there was no difference between the two patient groups. A factor analysis of patients' scores on the HRHCB yielded two interpretable factors, a verbal and a nonverbal one. These factors were not lateralized. Performance of patients on the HRHCB correlated significantly and positively with performance on most tests of basic language functions, measured with a Hebrew adaptation of the "Western Aphasia Battery" (HWAB) and with other cognitive functions measured with standardized neuropsychological tests. There were stronger correlations of HRHCB with subtests of the HWAB in LBD patients and with nonlanguage cognitive tests in RBD patients. In the LBD group, HRHCB subtests' scores correlated negatively with lesion extent in frontal and temporal perisylvian regions. Such localization was not observed in RBD patients. The results argue against selective right hemisphere (RH) involvement in the RHCB, alleged to measure pragmatic aspects of language use, and show, instead, bilateral involvement. The results also argue against a modular organization of these functions of language use, especially in the RH.     

Decreased levels of N-acetylaspartate in dorsolateral prefrontal cortex in a case of intractable severe sympathetically mediated chronic pain (complex regional pain syndrome,type I)

In our previous in vivo proton magnetic resonance spectroscopy ((1)H MRS) study we found reduced levels of N-acetylaspartate in dorsolateral prefrontal cortex of chronic back pain patients. This study tests whether these chemical abnormalities can be detected in other pain states. Using (1)H MRS, we measured levels for N-acetylaspartate and other identifiable chemicals relative to creatine in four bilateral brain regions, including dorsolateral prefrontal cortex, orbitofrontal cortex, cingulate, and thalamus, in a case of intractable severe sympathetically mediated chronic pain [complex regional pain syndrome (CRPS) type I]. The subject's chemical variations in the brain were compared to the same regional chemicals in 10 normal subjects (age- and sex-matched). Univariate statistics showed reduced levels of N-acetylaspartate in bilateral dorsolateral prefrontal cortex and increased levels of myo-inositol in left orbitofrontal cortex of the patient with intractable severe CRPS type I. These data support our original hypothesis that depletion of N-acetylaspartate in dorsolateral prefrontal cortex is a chemical marker of chronic pain, indicating for neuronal degeneration. Unpredicted changes of orbitofrontal myo-inositol may be related to the specific mood/affective state in an extreme pain perception. This is the first report, which identifies chemical markers in the prefrontal cortex for objective measurement and monitoring of CRPS type I. This information might lead to valuable insights into diagnosis and future effective interventions of CRPS type I (e.g., prefrontal brain stimulation).     

Experiments on the role of painted cues in Hughes's reverspectives

The English artist Patrick Hughes has created an extraordinary class of painted artpieces, most commonly referred to as 'reverspectives'. They consist of truncated pyramids and prisms with their smaller faces closer to the viewer, in such a way as to allow a realistic scene to be painted on them. The works of art contain rich perspective and other painted cues that conspire to elicit an illusory depth percept that is the reverse of the physical depth arrangement. This reverse depth is obtained under a wide range of viewing conditions, and competes with the veridical depth percept in a classical bistable paradigm that was found to exhibit a high degree of hysteresis. Under the illusory depth percept, reverspectives appear to move vividly as the viewer moves in front of them. This paper reports two experiments that were designed to assess the effectiveness of the painted cues in eliciting the illusory depth percept by using three different measures for the strength of the illusion. As expected, the illusion was favored by monocular viewing and large viewing distances. The results from these two experiments are in close agreement with each other, and they indicate that the painted cues are powerful in influencing the ultimate percept.     

Processing of temporal duration information in working memory after frontodorsal tumour excisions

This study aimed to test the hypothesis that impairments of temporal duration processing after frontal lobe lesions reflect deficits in executive monitoring functions rather than a domain-specific deficit in the maintenance of duration information in working memory. Patients with frontodorsal lesions, clinical controls with post-central lesions, and healthy controls performed recognition and classification tasks, which should allow for testing maintenance and monitoring functions, respectively. Results showed mild non-selective impairments of the frontal patients on both temporal and spatial recognition tasks, but a marked selective degradation on temporal classification while performance on spatial classification was unimpaired. This suggests that maintenance of duration information in working memory after frontal lesions is basically preserved but that, depending on executive task characteristics, there is a specific deficit in the strategic organization of this type of information.     

Ethical and practical considerations in managing incidental findings in functional magnetic resonance imaging

Functional magnetic resonance imaging has emerged as a powerful tool for mapping the neurologic underpinnings of sensory, motor and cognitive function. Much of this evolution carries assumptions about the subject population under study and, in particular, the neurologic status of subjects entered into studies either as healthy controls or as belonging to a specific disease group. Recent reports of incidental MRI abnormalities in normal volunteers for fMRI studies have brought to attention a variety of practical challenges and ethical dilemmas for researchers, many of whom are not physicians and most of whom have no formal radiological training. We propose a minimum standard for consenting subjects in fMRI protocols, and consider strategies over the longer term that call for expert physician participation, archiving of incidental findings including false positives, and the adoption of guidelines for handling variation in neural activations or performance that appear outside expected norms.