Ontogenetic differences in mandibular morphology of two related macaque species and its adaptive implications.

Mandibular morphology is determined not only by dietary habits, but also by sexual selection and allometry in primates. It is well-known that African papionins show intra- and interspecific variations through varied extensions of a common ontogenetic allometric trajectory in the face. Here, we used geometric morphometrics to compare the ontogenetic trajectories of large-bodied Japanese macaques and small-bodied long-tailed macaques in the sister clade of African papionins. The two species showed a major common allometric trend that was comparable to that of African papionins, but the allometric trajectory was transposed parallel to each other with few interspecies differences in mandibular shape. A minor allometric trend occurred before the eruption of the first molar. During extensino of this allometric trend in Japanese macaques, mandibular shape becomes mechanically suitable for processing tough food items in their dietary repertoire in winter. The decoupling of size and shape in the major allometric trend can allow for adaptive modifications in mandibular shape, which in turn may play a central role in speciation in macaques. Compared to other African papionins, macaques are widely distributed in temperate areas and have survived in fluctuating climates and habitats. Thus, evolutionary modifications that occur in different ontogenetic bases can result in variations in size and shape that are uniquely adaptive for a given clade.

Clinical Outcome and Intraoperative Neurophysiology of the Lance-Adams Syndrome Treated with Bilateral Deep Brain Stimulation of the Globus Pallidus Internus: A Case Report and Review of the Literature.

BACKGROUND: The Lance-Adams syndrome (LAS) is a myoclonus syndrome caused by hypoxic-ischemic encephalopathy. LAS cases could be refractory to first-line medications, and the neuronal mechanism underlying LAS pathology remains unknown. OBJECTIVES: To describe a patient with LAS who underwent bilateral globus pallidus internus (GPi) stimulation and discuss the pathophysiology of LAS with intraoperative electrophysiological findings. PATIENTS: A 79-year-old woman presented with a history of cardiopulmonary arrest due to internal carotid artery rupture following carotid endarterectomy after successful cardiopulmonary resuscitation. However, within 1 month, the patient developed sensory stimulation-induced myoclonus in her face and extremities. Because her myoclonic symptoms were refractory to pharmacotherapy, deep brain stimulation of the GPi was performed 1 year after the hypoxic attack. RESULTS: Continuous bilateral GPi stimulation with optimal parameter settings remarkably improved the patient's myoclonic symptoms. At the 2-year follow-up, her Unified Myoclonus Rating Scale score decreased from 90 to 24. In addition, we observed burst firing and interburst pause patterns on intraoperative microelectrode recordings of the bilateral GPi and stimulated this area as the therapeutic target. CONCLUSION: Our results show that impairment in the basal ganglion circuitry might be involved in the pathogenesis of myoclonus in patients with LAS.