The roles of the cerebellum and basal ganglia in timing and error prediction

Recent evidence that the cerebellum and the basal ganglia are activated during the performance of cognitive and attention tasks challenges the prevailing view of their primary function in motor control. The specific roles of the basal ganglia and the cerebellum in cognition, however, have been difficult to identify. At least three functional hypotheses regarding their roles have been proposed. The first hypothesis suggests that their main function is to switch attentional set. The second hypothesis states that they provide error signals regarding stimuli or rewards. The third hypothesis is that they operate as an internal timing system, providing a precise representation of temporal information. Using functional magnetic resonance imaging, we tested these three hypotheses using a task-switching experiment with a 2 x 2 factorial design varying timing (random relative to fixed) and task order (unpredictable relative to predictable). This design allowed us to test whether switching between tasks, timing irregularity and/or task order unpredictability activate the basal ganglia and/or the cerebellum. We show that the cerebellum is primarily activated with timing irregularity while the anterior striatum is activated with task order unpredictability, supporting their distinctive roles in two forms of readjustment. Task order unpredictability alone, independent of reward delivery, is sufficient to induce striatal activation. In addition, activation of the cerebellum and basal ganglia were not specific to switching attention because these regions were both activated during switching between tasks and during the simultaneous maintenance of two tasks without switching between them.     

Pseudoaneurysm of the Internal Carotid Artery: Treatment with a Covered Stent

Dissection of the cervical segment of the internal carotid artery may occur spontaneously or after trauma. We report the management of a 53-year-old right-handed man with progressive dizziness and neck pain 6 weeks after a motor vehicle collision. The clinical and neurologic examinations were normal. The CT scan led to the diagnosis of a pseudoaneurysm of the right internal carotid artery near the skull base. We successfully treated this post-traumatic lesion with a covered stent. The patient underwent the endovascular procedure under general anesthesia and transcranial Doppler monitoring. No neurologic event was observed. Obliteration of the pseudoaneurysm with preservation of the carotid artery was achieved. The patient was discharged from the hospital 72 hr later with no complications. Clinical and imaging follow-up at 6 months was unremarkable.     

Self-esteem and social adjustment in young women with Turner syndrome--influence of pubertal management and sexuality: population-based cohort study

CONTEXT: Pediatric management of patients with Turner syndrome focuses on height, frequently resulting in a delay of pubertal induction. The influence of pubertal management on psychosocial adjustment and sex life has not been evaluated in Turner syndrome patients. OBJECTIVE: The objective of the study was to identify the determinants of self-esteem, social adjustment, and initiation of sex life in patients with Turner syndrome, particularly those related to pubertal management. DESIGN: This was a prospective evaluation, the StaTur study. SETTING: The study was conducted with a population-based registry of GH-treated patients. PARTICIPANTS: Participants included 566 young adult women with Turner syndrome, aged 22.6 +/- 2.6 yr (range, 18.3-31.2). MAIN OUTCOME MEASURES: Measures used in the study were Coopersmith's Self-Esteem Inventory, Social Adjustment Scale Self-Report, questions on sexual experience, and extensive data on pediatric management. RESULTS: Low self-esteem was associated with otological involvement and limited sexual experience. Low social adjustment was associated with lower paternal socioeconomic class and an absence of sexual experience. Late age at first kiss or date was associated with cardiac involvement and a lack of spontaneous pubertal development. Age at first sexual intercourse was related to age at puberty and paternal socioeconomic class. Delayed induction of puberty had a long-lasting effect on sex life. Height and height gain due to GH treatment had no effect on outcomes. CONCLUSIONS: Puberty should be induced at a physiologically appropriate age in patients with Turner syndrome to optimize self-esteem, social adjustment, and initiation of the patient's sex life. Therapeutic interventions altering normal pubertal development in other groups of patients should be reconsidered in light of these findings.