Anxiety in youth at clinical high risk for psychosis: A case study and conceptual model.

Some individuals identified as being at clinical high risk (CHR) for developing psychosis may suffer substantial anxiety due to a fear of transitioning to psychosis. This can be associated with catastrophic misinterpretation of normal mental experiences, such as a momentary lapse in attention, as markers for psychosis, fueled by hypervigilance for mental experiences that may be perceived as signs of impending psychosis. This anxiety may only worsen due to the self-stigma triggered by admission to a psychiatric CHR clinic, independent of whether or not the individual transitions to psychosis. Based on a clinical case study, we propose a cognitive model for this anxiety, an extension of Clark's model of panic. Our model accounts for causal factors of this distress, such as self-stigma and maladaptive core beliefs. It also includes maintaining factors such as hypervigilance for mental experiences and catastrophic misinterpretation of normal mental experiences as anomalous and portending eventual psychosis. We outline assessment and treatment guidelines and offer suggestions for how this model could be empirically validated. We suggest that treatment with this model, under the neural diathesis-stress framework, may have the potential to lower the risk of transition to psychosis and that assessment for such anxiety should be part of standard CHR care.

Regional cerebellar volumes are related to early musical training and finger tapping performance.

The cerebellum has been associated with timing on the millisecond scale and with musical rhythm and beat processing. Early musical training (before age 7) is associated with enhanced rhythm synchronization performance and differences in cortical motor areas and the corpus callosum. In the present study, we examined the relationships between regional cerebellar volumes, early musical training, and timing performance. We tested adult musicians and non-musicians on a standard finger tapping task, and extracted cerebellar gray and white matter volumes using a novel multi-atlas automatic segmentation pipeline. We found that early-trained musicians had reduced volume in bilateral cerebellar white matter and right lobules IV, V and VI, compared to late-trained musicians. Strikingly, better timing performance, greater musical experience and an earlier age of start of musical training were associated with smaller cerebellar volumes. Better timing performance was specifically associated with smaller volumes of right lobule VI. Collectively, these findings support the sensitivity of the cerebellum to the age of initiation of musical training and suggest that lobule VI plays a role in timing. The smaller cerebellar volumes associated with musical training and timing performance may be a reflection of more efficiently implemented low-level timing and sensorimotor processes.

The role of musical training in emergent and event-based timing.

INTRODUCTION: Musical performance is thought to rely predominantly on event-based timing involving a clock-like neural process and an explicit internal representation of the time interval. Some aspects of musical performance may rely on emergent timing, which is established through the optimization of movement kinematics, and can be maintained without reference to any explicit representation of the time interval. We predicted that musical training would have its largest effect on event-based timing, supporting the dissociability of these timing processes and the dominance of event-based timing in musical performance. MATERIALS AND METHODS: We compared 22 musicians and 17 non-musicians on the prototypical event-based timing task of finger tapping and on the typically emergently timed task of circle drawing. For each task, participants first responded in synchrony with a metronome (Paced) and then responded at the same rate without the metronome (Unpaced). RESULTS: Analyses of the Unpaced phase revealed that non-musicians were more variable in their inter-response intervals for finger tapping compared to circle drawing. Musicians did not differ between the two tasks. Between groups, non-musicians were more variable than musicians for tapping but not for drawing. We were able to show that the differences were due to less timer variability in musicians on the tapping task. Correlational analyses of movement jerk and inter-response interval variability revealed a negative association for tapping and a positive association for drawing in non-musicians only. DISCUSSION: These results suggest that musical training affects temporal variability in tapping but not drawing. Additionally, musicians and non-musicians may be employing different movement strategies to maintain accurate timing in the two tasks. These findings add to our understanding of how musical training affects timing and support the dissociability of event-based and emergent timing modes.