Johannes G. M. Thewissen

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Anecdotal evidence suggests that the foramina of the cribriform plate which transmit cranial nerve I decrease in size with age, but this finding has never been supported with quantitative data. It has also been observed that olfactory function declines with increasing age. It has been hypothesized that the cribriform plate foramina closure may be(More)
Leptin is the primary hormone in mammals that regulates adipose stores. Arctic adapted cetaceans maintain enormous adipose depots, suggesting possible modifications of leptin or receptor function. Determining expression of these genes is the first step to understanding the extreme physiology of these animals, and the uniqueness of these animals presents(More)
During development and evolution, the morphology of ectodermal organs can be modulated so that an organism can adapt to different environments. We have proposed that morphoregulation can be achieved by simply tilting the balance of molecular activity. We test the principles by analyzing the effects of partial downregulation of Bmp signaling in oral and(More)
The myology of the fore-limb of the Aardvark, Orycteropus afer (Pallas 1766) (Tubulidentata, Mammalia) is redescribed on the basis of the dissection of two specimens. The results were complemented with data derived from X-ray pictures and a motion picture. Some remarks are made on the digging techniques in the Aardvark and other fossorial mammals. In(More)
Von Economo neurons (VENs) are specialized projection neurons with a characteristic spindle-shaped soma and thick basal and apical dendrites. VENs have been described in restricted cortical regions, with their most frequent appearance in layers III and V of the anterior cingulate cortex, anterior insula, and frontopolar cortex of humans, great apes, macaque(More)
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