Cortical maps for hearing and egocentric selection for self-organization

The auditory cortex of the mustached bat shows complex multiple frequency maps, because cortical neurons in several areas are tuned to particular combinations of signal elements. Different types of combination-sensitive neurons form computational maps in which information-bearing parameters for echolocation (biosonar) are represented systematically. Neuronal response properties and multiple-frequency and computational maps were considered to be created solely by divergent-convergent interactions of neurons in the 'ascending' system. However, we have found that the 'corticofugal' system also plays an important role. Neurons in an iso-best frequency (or echo delay) 'minicolumn' of the auditory cortex augment the auditory responses of subcortical neurons tuned to that frequency (or echo delay) and sharpen their tuning. At the same time, they reduce the response and shift the tuning of subcortical neurons tuned to other frequencies (or echo delays) away from the best frequency (or delay) of the cortical neurons. Cortical neurons mediate a highly focused positive feedback, incorporated with widespread lateral inhibition, via corticofugal projections. This 'egocentric selection' is expected to play an important role in self-organizing the central auditory system.     

Zhuangzi and relativistic scepticism

Chad Hansen is one of the strongest proponents of the view that the important second chapter of Zhuangzi's Inner Chapters (The Qi Wu Lun) reveals Zhuangzi to be a relativistic sceptidst. Hansen argues that Zhuangzi is a sceptic because he is first and foremost a relativist. Hansen's argument is essentially that Zhuangzi's perspectivism, his belief that one's linguistic and conceptual perspective determines what one claims to know, makes him a thorough going relativist and sceptic. I agree that Zhuangzi is a perspectivist, but disagree with Hansen's portrayal of him as a relativistic sceptic. I first show that there is an important ambiguity in Hansen's argument. I then proceed to argue that important passages in the Qi Wu Lun (in particular the butterfly dream passage,) reveal serious problems with Hansen's interpretation of Zhuangzi's philosophical stance, I maintain that Zhuangzi is neither a sceptic nor a perspectival relativist. He is rather a perspectival realist.     

Towards an Interactive Acculturation Model: A Social Psychological Approach

The first part of this paper proposes a continuum of ideological premises that seeks to account for the broad range of immigrant integration policies adopted by Western democratic states. In the second part, a review of Social Psychological models of immigrant acculturation strategies demonstrates the need to explain more clearly the interactive nature of immigrant and host community relations. The Interactive Acculturation Model (IAM) presented next proposes that relational outcomes are the product of the acculturation orientations of both the host majority and immigrant groups as influenced by state integration policies. The model makes predictions regarding the acculturation combinations most likely to produce consensual, problematic, and conflictual relational outcomes between immigrants and members of the host community. Social psychological research is needed to test the validity of the IAM model empirically.     

Motor skill acquisition and retention as a function of average feedback, summary feedback, and performance variability

Summary feedback involves withholding feedback from subjects until the last trial in a block is completed, and then presenting feedback about each trial. A variation of this method, called average feedback (Young & Schmidt, 1992), presents subjects with only the mean of the trial block. We investigated whether these methods have similar effects on acquisition and retention of a simple motor skill. Five groups of subjects (n = 16 per group) performed 60 acquisition trials of an aiming task involving both spatial and temporal accuracy. We presented average and summary feedback based on either 5-trial blocks or 15-trial blocks and compared these schedules with every-trial feedback. During acquisition, all groups improved with practice, with a slight tendency for the every-trial condition to have less absolute error than the longer summary and average conditions. Analysis of delayed no-feedback retention tests, however, revealed a strong advantage for the 5-trial summary and average conditions compared with the every-trial condition. In addition, we found that for long blocks of acquisition trials without augmented feedback, the performance variability of those trials was associated with retention performance. Results are discussed in terms of how these different manipulations may make feedback less useful during acquisition, but foster the use of certain information processing activities that enhance overall learning.     

How (not) to evaluate the comparability of MMPI and MMPI-2 profile configurations: a reply to Humphrey and Dahlstrom

Humphrey and Dahlstrom (1995) presented a study on the comparability of MMPI/MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) profiles in which they concluded that "the bases for clinical interpretation derived from the MMPI and MMPI-2 profiles were sufficiently at variance to require different conclusions" [sic] (p. 2). In this brief critique, we identify procedural and data-analytical deficiencies that invalidate Humphrey and Dahlstrom's argument. Their blanket recommendation based on this argument, namely, that clinicians routinely plot both MMPI and MMPI-2 profiles, is unwarranted.     

Prepulse inhibition of the startle eyeblink as an indicator of temporal summation

The inhibition of the human startle eyeblink response was assessed in three experiments in which the duration of the prepulse was manipulated. In all cases, inhibition of startle was more pronounced as prepulse duration increased from 6 to 50 msec. Inhibition of startle amplitude for single prepulses was not significantly different from that for paired prepulses (Experiment 1), but inhibition was more pronounced as prepulse intensity increased (Experiment 3). Varying the interval between prepulse offset and startle-stimulus onset had no significant effect on inhibition (Experiment 2). These data demonstrate the sensitivity of startle inhibition to prepulse duration, and suggest that this response system can be used to evaluate early temporal summation in the auditory system.     

Spiritual journeys in aging: A buddhist view

The spiritual journey of a Buddhist devotee is a continual exploration of the truth of interdependence which Siddhartha Gautama realized to become the Buddha, “the Enlightened One.” On the morning of the enlightenment, the Buddha apprehended the truth that all things and all beings are interconnected and mutually dependent in time and space. One measure of the spiritual maturity of the Buddhist devotee is his or her appreciation for the profound responsibilities and gratitude we share for all things. To illustrate the significance of interdependence in our lives, the author turns to the wisdom contained inVital Involvement in Old Age by Erik and Joan Erikson and Helen Q. Kivnick.