Abstract # 237:

Scheduled for Monday, September 19, 2011 03:15 PM-03:30 PM: Session 33 (Meeting Room 410) Oral Presentation


A COMPARATIVE EXAMINATION OF VIBRISSA MUSCULATURE AMONG PRIMATES

M. N. Muchlinski1, E. L. Durham2, T. D. Smith3,4 and A. M. Burrows2,4
1University of Kentucky, Department of Anatomy and Neurobiology, 800 Rose Street, MN 210, Lexington, Kentucky 40536, USA, 2Duquesne University, Department of Physical Therapy, Pittsburgh, PA, 15282 USA, 3Slippery Rock University, School of Physical Therapy, Slippery Rock, PA US, 4University of Pittsburgh, Department of Anthropology, Pittsburgh, PA, 15260 USA
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Vibrissae (whiskers) are specialized sensory hairs that respond to mechanical stimuli such as tension, pressure, and displacement. Unlike regular hair/fur, vibrissae are thick and are associated with “touch” receptors (mechanoreceptors). The vibrissae of some mammals (e.g., rodents) are organized into discrete rows and have special intrinsic vibrissa muscles that facilitate vibrissa movement (i.e., whisking). All non- human primates have vibrissae and vibrissa count does not differ between primates and most other mammals. However, primate vibrissae are generally not organized into discrete rows, tend to be thinner than the vibrissae of most other mammals, and it is unknown if primates posses intrinsic vibrissa musculature. Here we hypothesize that external vibrissa morphology documented in primates may indicate a lack of intrinsic musculature, which would suggest the vibrissae of primates serve a different function (i.e., vibrissae assist in facial object recognition versus spatial orientation/navigation). We examined histologically (hematoxylin and eosin stains) the facial skin of seven prosimians and four anthropoids for the presence/absence of intrinsic muscles. Intrinsic muscles are small, attach directly to the vibrissa shaft, and lack a bony attachment. Extrinsic muscles are primarily facial muscles. All prosimians, excluding lorisids, have intrinsic vibrissa musculature. Conversely, anthropoids lack intrinsic muscles. These findings mirror external vibrissa morphology, indicating that external vibrissa morphology may be a good indicator of intrinsic vibrissa musculature. Thus, external vibrissa morphology may indicate vibrissa function.