A computational model of mechanisms controlling experience-dependent reorganization of representational maps in auditory cortex

Cortical representations of sound can be modified by repeatedly pairing presentation of a pure tone with electrical stimulation of neuromodulatory neurons located in the basal forebrain (Bakin & Weinberger, 1996; Kilgard & Merzenich, 1998a). We developed a computational model to investigate the possible effects of basal forebrain modulation on map reorganization in the auditory cortex. The model is a self-organizing map with acoustic response characteristics mimicking those observed in the mammalian auditory cortex. We simulated the effects of basal forebrain modulation, using parameters intrinsic to the self-organizing map, such as the learning rate (controlling the adaptability of map nodes) and the neighborhood function (controlling the excitability of map nodes). Previous research has suggested that both parameters can be useful for characterizing the effects of neuromodulation on plasticity (Kohonen, 1993; Myers et al., 1996; Myers, Ermita, Hasselmo, & Gluck, 1998). The model successfully accounts for experimentally observed effects of pairing basal forebrain stimulation with the presentation of a single tone, but not of two tones, suggesting that auditory cortical plasticity is constrained in ways not accounted for by current theories. Despite this limitation, the model provides a useful framework for describing experience-induced changes in auditory representations and for relating such changes to variations in the excitability and adaptability of cortical neurons produced by neuromodulation.     

Juvenile onset Huntington's disease--clinical and research perspectives

Huntington's disease (HD) is an inherited neurodegenerative disorder. The mutation which causes the disease is an expansion in the number of repetitions of three nucleotides, C, A, and G in exon 1 of the huntingtin gene. The gene normally has 15 to 30 repeats and an expansion to 40 or more is associated with HD. HD usually has a mid-life onset, but a juvenile form, defined by onset of symptoms before the age of 21 years, is present in about 7% of HD cases. Juvenile HD is characterized by (1) transmission from an HD affected father, (2) an unusually large repeat size, usually of 60 or more units, and (3) unique clinical features, including rigidity and seizure disorder. Although juvenile onset is associated with a more severe neuropathological involvement, the neuropathological characteristics of juvenile HD are similar to those seen in the adult form in that the striatum bears the brunt of the illness. Clumps of protein, termed inclusion bodies, which stain positive for huntingtin and ubiquitin, are found primarily in the nucleus but also in the cytoplasm and axons in HD neurons. Research suggests that these inclusion bodies sequester a deleterious protein fragment and prolong cell life during the degenerative process of the disease.     

Counseling Women in Midlife: An Integrative Approach to Menopause

Menopause is a normative life transition that is experienced by virtually all women, yet remains poorly understood. The dominance of the biomedical model results in a unidimensional definition of menopause as a biological event, ignoring the influence of cultural and psychosocial factors. Counselors who use an integrative approach can not only provide accurate biomedical information but also conceptualize menopause as a normative midlife transition. The purpose of this article is to provide a foundation in biomedical issues and to consider how these independently, and in interaction with cultural and psychosocial factors, influence the experience of menopause.     

Relations of Parenting and Negative Life Events to Cognitive Diatheses for Depression in Children

In a sample of 299 children (grades 2, 4, and 6), we examined parenting and negative life events as predictors of depressive cognitions, specifically low self-perceived competence, depressive cognitive schemas, and depressogenic attributional style. We also examined developmental trends in these relations. Children completed measures of parenting, negative life events, and depressive cognitions. Parents also completed measures of parenting and negative life events. Consistent with our hypotheses, negative parenting and negative life events corresponded with higher levels of depressive cognitions, whereas positive parenting corresponded with lower levels of depressive cognitions. The relations between negative parenting and negative automatic thoughts were stronger for older children. Theoretical and practical implications are discussed.     

Geometric orientation by humans: angles weigh in

Human participants were trained to navigate to two geometrically equivalent corners of a parallelogram-shaped virtual environment. The unique shape of the environment combined three distinct types of geometric information that could be used in combination or in isolation to orient and locate the goals: the angular amplitudes of the corners, the relative wall length relationships, and the principal axis of symmetry. In testing, participants were placed in manipulated versions of the training environment that tested which types of geometry they had encoded and how angular information weighed in against the other two geometric properties. The test environments were (a) a rectangular environment that removed the angular information, (b) a rhombic environment that removed wall length information and drastically reduced the principal axis, and (c) a reverse-parallelogram-shaped environment that placed angular information against both wall length and principal axis information. Participants chose accurately in the rectangular and rhombus environments, despite the removal of one of the cues. In the conflict test, participants preferred corners with the correct angular amplitudes over corners that were correct according to both wall length relationships and the principal axis. These results are comparable to recent findings with pigeons and suggest that angles are a salient orientation cue for humans.     

Origins of the human pointing gesture: a training study

Despite its importance in the development of children’s skills of social cognition and communication, very little is known about the ontogenetic origins of the pointing gesture. We report a training study in which mothers gave children one month of extra daily experience with pointing as compared with a control group who had extra experience with musical activities. One hundred and two infants of 9, 10, or 11 months of age were seen at the beginning, middle, and end of this one‐month period and tested for declarative pointing and gaze following. Infants’ability to point with the index finger at the end of the study was not affected by the training but was instead predicted by infants’ prior ability to follow the gaze direction of an adult. The frequency with which infants pointed indexically was also affected by infant gaze following ability and, in addition, by maternal pointing frequency in free play, but not by training. In contrast, infants’ ability to monitor their partner’s gaze when pointing, and the frequency with which they did so, was affected by both training and maternal pointing frequency in free play. These results suggest that prior social cognitive advances, rather than adult socialization of pointing per se, determine the developmental onset of indexical pointing, but socialization processes such as imitation and adult shaping subsequently affect both infants’ ability to monitor their interlocutor’s gaze while they point and how frequently infants choose to point.     

Videoconferencing psychotherapy: a systematic review

Individuals with mental health problems may face barriers to accessing effective psychotherapies. Videoconferencing technology, which allows audio and video information to be shared concurrently across geographical distances, offers an alternative that may improve access. We conducted a systematic literature review of the use of videoconferencing psychotherapy (VCP), designed to address 10 specific questions, including therapeutic types/formats that have been implemented, the populations with which VCP is being used, the number and types of publications related to VCP, and available satisfaction, feasibility, and outcome data related to VCP. After electronic searches and reviews of reference lists, 821 potential articles were identified, and 65 were selected for inclusion. The results indicate that VCP is feasible, has been used in a variety of therapeutic formats and with diverse populations, is generally associated with good user satisfaction, and is found to have similar clinical outcomes to traditional face-to-face psychotherapy. Although the number of articles being published on VCP has increased in recent years, there remains a need for additional large-scale clinical trials to further assess the efficacy and effectiveness of VCP.