Tracking and capture of constant and varying velocity stimuli: a cross-species comparison of pigeons and humans

The mechanisms underlying tracking and capture of moving objects in non-human animals are poorly understood. This set of experiments sought to further explore aspects of anticipatory tracking in pigeons and to conduct comparisons with human participants. In Experiment 1a, pigeons were presented with two types of varying velocities (fast-slow-fast or slow-fast-slow) in separate phases. They were readily able to track and anticipate both of these motion types. To examine the effects of predictability on anticipatory tracking, Experiment 1b presented the pigeons with the same two varying velocities randomly intermixed within a session. This resulted in reduced capture success, later capture, and errors that no longer anticipated ahead of the motion, suggesting that the anticipatory mechanism had been disrupted. This implies that the mechanisms involved in pigeon tracking are different from the predictive extrapolation mechanism proposed in humans. Experiment 2 tested this by presenting adult humans with a tracking task that was similar to tasks previously received by the pigeons. The capture behavior of humans was similar to the pigeons, but the errors revealed different processes underlying their tracking behavior.     

Equivalence classes in individuals with minimal verbal repertoires

Studies from two different laboratories tested for equivalence classes in individuals with severe mental retardation and minimal verbal repertoires. In the first study, 3 individuals learned several matching-to-sample performances: matching picture comparison stimuli to dictated-word sample stimuli (AB), matching those same pictures to printed letter samples (CB), and also matching the pictures to nonrepresentative forms (DB). On subsequent tests, all individuals immediately displayed Emergent Relations AC, AD, BC, BD, CD, and DC, together constituting a positive demonstration of equivalence (as defined by Sidman). The second study obtained a positive equivalence test outcome in 1 of 2 individuals with similarly minimal verbal repertoires. Taken together, these studies call into question previous assertions that equivalence classes are demonstrable only in individuals with well-developed language repertoires.     

Health-related quality of life in Parkinson's disease after pallidotomy and deep brain stimulation

This study explored the multidimensional outcome of three neurosurgical interventions for Parkinson's disease (PD): pallidotomy (N = 23), pallidal deep brain stimulation (DBS) (N = 9), and thalamic DBS (N = 7). All patients completed the Sickness Impact Profile (SIP) and the Beck Depression Inventory. Pallidotomy patients also completed the Profile of Mood States, the Beck Anxiety Inventory, and a disease-specific quality of life (QOL) measure, the Parkinson's Disease Questionnaire (PDQ-39). Three months after surgery, all neurosurgical groups showed significant improvements in mood and function, including physical, psychosocial, and overall functioning. Pallidal DBS and pallidotomy patients who completed additional QOL measures reported decreased anxiety and tension, increased vigor, improved mobility and ability to perform activities of daily living, and decreased perceived stigma. Psychosocial dysfunction scores from the SIP were related to depressed mood both at baseline (r = .42) and at followup (r = .45), but the physical dysfunction subscale was not related to mood at either time point, suggesting that disruption of social relationships due to PD may have more impact on affective distress than physical symptoms alone. Results suggest that neurosurgical interventions for PD improve disabling PD motor symptoms and also improve several domains of quality of life.     

The mind-brain relationship: the emergent self

This paper explores the mind-brain relationship, using insights from contemporary neuroscience. It seeks to investigate how our brains become who we are, how subjective experience arises. In order to do this some explanation is given of the basic concepts of how the brain produces our subjective mental life. Current neuropsychological and neurobiological understanding of early brain development, memory, emotion and consciousness are explored. There is also an attempt at mapping the mind-brain-self relationship from a uniquely Jungian perspective. Clinical material is included in order to show the relevance of these insights to our work in the consulting room, arguing the value of the affect-regulating, relational aspects of the analytic dyad that forge new neural pathways through emotional connection. Such experience forms the emotional scaffolding necessary for the emergence of reflective function.     

Undoing dissociation. Affective neuroscience: a contemporary Jungian clinical perspective

In the last ten years both analysts and neuroscientists have begun to challenge the analytic world to explore the analytic view of the mind in relation to knowledge emerging from the field of neuroscience. I find that 'in many ways it is Jung's understanding of the mind, the human condition, and the self, that is most compatible with the insights that are emerging from neuroscience today' (Wilkinson 2004, p. 84). In this paper I consider the insights that neuroscience has to offer us as we seek to work with those patients whose early experience has diminished their capacity to be 'in mind' and with it their capacity for reflective self-function, whose defences are dissociative, whose need has been to keep unbearable experience at bay, out of mind. I look first at dissociationist theory and its development, then focus on the insights to be gained from neuroscience with regard to early trauma and its effect on the encoding and recall of memory. Finally, I turn to the nature of cure and argue that hemispheric integration is the key to undoing dissociation and the prelude to individuation.     

The role of stimulus factors in making categorical and coordinate spatial judgments

We report three experiments which investigate the lateralization of categorical and coordinate processing. In all experiments, participants judged the position of a dot relative to a line. We manipulated display luminance (controlling for contrast), polarity (black-on-white versus white-on-black displays), and exposure duration (100, 150, and 200 ms). The results showed a left visual field-right hemisphere advantage for coordinate judgments, but only under highly prescribed conditions. We argue that stimulus and procedural factors are critical in determining the hemisphere by task interaction.     

Measurement of the texture-coherence limit for bandpass arrays

Casual observation suggests that when the elements of a visual array are packed at a sufficiently high density they cohere to generate the percept of a texture. This 'texture-coherence limit' has been quantified by using arrays composed of Gabor functions, sixth Gaussian derivatives, or differences of Gaussians. In all cases the texture-coherence limit was a power-law function of the size of the elements as quantified by their space constants with an exponent averaging 0.7. Furthermore, the texture-coherence limit was independent of both element spatial frequency and contrast over a considerable range. A quantitative fit to the data is provided by a model in which the texture-coherence limit is determined by activation of complex cells, which pool a spatial range of subunit inputs, throughout the stimulus region. Possible extensions to two dimensions are considered.     

Eye movements measured with a solid state photodiode matrix

The apparatus described uses the corneal reflex technique to measure horizontal and vertical eye movements with a metal oxide semiconductor matrix array of 64 by 64 photodiodes. A simple optical system forms a reflex image on the array and also determines the device range, which can vary from ±25 deg to ±3 deg; sensitivity is 50 arc min and 6 arc min, respectively. Mounted on a simple lightweight headband complete with universal mechanical adjusters, the instrument weighs less than 100 g, excluding connecting cable, and samples eye movements every 5 msec.     

Last rights: the ethics of research on the dead

People often have strong views about being the subjects of research after their deaths. Should these views be given any weight and, if so, how much? How could we find out what the views are and what should we do if we cannot? This paper defends the idea of posthumous interests and discusses the significance of those interests for research ethics. It argues that we can be guided by a symmetry between the interests of living and dead people and uses posthumous privacy as an example. It also claims that the weight of those interests might not decline even over long periods of time. The arguments have important implications for the ethics of (amongst others) biomedical, archaeological, anthropological, historical, and sociological research.