Univocal or orthogonal estimators of orthogonal factors

The defects of the least-squares or multiple-regression equation approach to estimating orthogonal factors are discussed and transformations of the beta weights are derived which remove these defects with minimum loss in correlations between estimators and true factor scores.The opinions expressed in this paper are those of the author and do not necessarily reflect official Department of the Army policy.     

Too close for comfort: the challenges of engaging with sexuality in work with adolescents

This paper explores some of the ways in which sexuality can intrude into the psychotherapeutic relationship and present both opportunities and risks to our work with adolescents. It highlights some of the complexities of this area of the clinical encounter, exploring the particular difficulties encountered by both patient and therapist when sexuality emerges in the transference and countertransference. While we are well aware of the centrality of sexual development during adolescence, far less has been written about the way in which sexuality and the erotic transference emerges and impacts on both patient and therapist. Given the profoundly unsettling nature of this area of work and its capacity to disrupt our thinking and psychic equilibrium, it is easy to underestimate how much we are drawn to avoid, negate and defend ourselves against registering such experiences. Through the discussion of clinical material with two adolescent patients, this paper explores some of these dynamics, addressing some of the technical dilemmas that frequently challenge us in this area of work. These include questions about whether and when it is therapeutically important and effective to take up and interpret the emergence of sexuality more directly in the transference and some of the risks to our patients when we ‘play safe’ and fail to do so. Most importantly, this paper aims to facilitate further thinking and discussion about an important but uncomfortable and easily neglected area of our work.     

In vitro hippocampal gamma oscillation power as an index of in vivo CA3 gamma oscillation strength and spatial reference memory

Neuronal synchronisation at gamma frequencies (30-100 Hz) has been implicated in cognition and memory. Gamma oscillations can be studied in various in vitro models, but their in vivo validity and their relationship with reference memory remains to be proven. By using the natural variation of wild type C57bl/6J mice, we assessed the relationships between reference memory and gamma oscillations recorded in hippocampal area CA3 in vivo and in vitro. Local field potentials (LFPs) were recorded from area CA3 in behaviourally-characterised freely moving mice, after which hippocampal slices were prepared for recordings in vitro of spontaneous gamma oscillations and kainate-induced gamma oscillations in CA3. The gamma-band power of spontaneous oscillations in vitro correlated with that of CA3 LFP oscillations during inactive behavioural states. The gamma-band power of kainate-induced oscillations correlated with the activity-dependent increase in CA3 LFP gamma-band power in vivo. Kainate-induced gamma-band power correlated with Barnes circular platform performance and object location recognition, but not with object novelty recognition. Kainate-induced gamma-band power was larger in mice that recognised the aversive context, but did not correlate with passive avoidance delay. The correlations between behavioural and electrophysiological measures obtained from the same animals show that the gamma-generating capacity of the CA3 network in vitro is a useful index of in vivo gamma strength and supports an important role of CA3 gamma oscillations in spatial reference memory.