Patrick J. Gannon

Cellular localization of the 5-HT1A receptor in primate brain neurons and glial cells

Activation of 5-HT1A receptors produces many different physiologic responses, which may be due to their localization on divers cells in the brain. A 5-HT1A receptor antipeptide (aa170-186) antibody was produced that showed both high titer for peptide binding and immunocytochemical staining. Studies performed in perfusion-fixed brain tissue showed immunoreactive neurons, glial, and ependymal cells in the rat, mouse, cat, and monkey. Results from our studies of Macaca fascicularis brains are presented. We observed two main neuronal labeling patterns in the primate brain: (1) A general, diffuse somatodendritic distribution of 5-HT1A receptor immunoreactivity is seen in the raphe nuclei where the dendritic shaft, its branches and spines, and the entire perikaryon are immunolabeled. This pattern is also observed in the nucleus locus coeruleus, in scattered large brainstem reticular neurons, and in dentate gyrus hilar interneurons. (2) A discrete localization of 5-HT1A receptor immunoreactivity on the initial axon segment (axon hillock) is noted in pyramidal neurons of layer III and V of cerebral cortex, Cornu Ammonus (1-4) of the hippocampus, and in most brainstem and cervical spinal cord motorneurons. In addition to neuronal labeling, 5-HT1A receptor immunoreactivity is seen in the cell body and processes of astrocytes, and other nonneuronal cells. This pattern is particularly evident in the white matter of cerebral cortex and spinal cord, the pontine nulcei, the brainstem tectum, and the hilus of the dentate gyrus. The clinical implications of 5-HT1A cellular localization are briefly discussed.

The anatomy, physiology, acoustics and perception of speech: essential elements in analysis of the evolution of human speech

Abstract Inferences on the evolution of human speech based on anatomical data must take into account its physiology, acoustics and perception. Human speech is generated by the supralaryngeal vocal tract (SVT) acting as an acoustic filter on noise sources generated by turbulent airflow and quasi-periodic phonation generated by the activity of the larynx. The formant frequencies, which are major determinants of phonetic quality, are the frequencies at which relative energy maxima will pass through the SVT filter. Neither the articulatory gestures of the tongue nor their acoustic consequences can be fractionated into oral and pharyngeal cavity components. Moreover, the acoustic cues that specify individual consonants and vowels are “encoded”, i.e., melded together. Formant frequency encoding makes human speech a vehicle for rapid vocal communication. Non-human primates lack the anatomy that enables modern humans to produce sounds that enhance this process, as well as the neural mechanisms necessary for the voluntary control of speech articulation. The specific claims of Duchin (1990) are discussed.

Pressure measurements in the normal and occluded rabbit maxillary sinus

Occlusion of the maxillary ostium is considered to be a key factor in the pathogenesis of maxillary sinusitis. In this study, the authors determined the effect of ostial occlusion on pressure in the rabbit maxillary sinus which, like most humans, has only one ostium. We compared pressures in the normal and occluded maxillary sinus and the nasal cavity during spontaneous breathing in anesthetized adult animals. Serial pressure measurements were obtained from sinuses with patent ostia in nasal‐breathing rabbits and with occluded ostia in both nasal‐breathing and tracheotomized animals.

Mechanisms of Middle ear aeration: Anatomic and physiologic evidence in primates

Proper aeration is a prerequisite for normal middle ear function in all terrestrial mammals. Our previous studies in primates provided anatomic evidence of neural circuits between the middle ear, brain, and eustachian tube by which central respiratory neurons can control middle ear aeration. Yet mechanisms that regulate middle ear aeration remain poorly understood. This study extends our research by examining maturation of these neural circuits, and investigating their underlying physiology. Ultrastructural examination of tympanic nerves, the afferent limb of the neural circuit, in an age‐graded series of cynomolgus monkeys (Macaca fascicularis) showed substantial differences between newborn, young, and adult animals. These included a twofold increase in average myelin thickness, and greater than threefold increase in the ratio of myelinated to un‐myelinated fibers from newborn to adult animals. These marked developmental changes may translate into functional differences in regulation of middle ear aeration in young animals, and possibly explain the extraordinarily high incidence of middle ear disease in early childhood. In physiologic experiments, bilateral electromyographic responses were recorded from eustachian tube muscles, the efferent limb of the neural circuit, in adult monkeys after ipsilateral stimulation of the tympanic nerve. Response latencies were 9 to 28 msec, similar to those of other multi‐synaptic bilateral brainstem reflexes. These physiologic data strongly suggest a concept of active control of middle ear aeration by respiratory neurons in the brain.

Comparative Neuropathology of Brain Aging in Primates

aKastor Neurobiology of Aging Laboratories and Fishberg Research Center for Neurobiology, Departments of bGeriatrics and Adult Development, cRadiology, dOtolaryngology and ePathology, Mount Sinai School of Medicine, fDepartment of Anthropology, Columbia University, gNew York Consortium in Evolutionary Primatology, New York, N.Y., hDivision of Neurobiology, Behavior, and Genetics, Bioqual Inc., Rockville, Md., and iFoundation for Comparative and Conservation Biology, Rockville, Md., USA; jDepartment of Anatomical Sciences, University of the Witwatersrand, Parktown, South Africa

Characterizing the antigenic profile of the human trachea: Implications for tracheal transplantation

Tracheal transplantation may be a viable alternative in select situations of long‐segment tracheal stenosis. Issues concerning human tracheal antigenicity and the requirement for systemic immunosuppression need to be addressed. This study examined the distribution of the major transplantation antigens on fresh human trachea.

Neuroanatomical basis of facial expression in monkeys, apes, and humans.

CHET C. SHERWOOD,a,b,c RALPH L. HOLLOWAY,a,c PATRICK J. GANNON,c,d KATERINA SEMENDEFERI,e JOSEPH M. ERWIN,f KARL ZILLES,g AND PATRICK R. HOFb,c,f aDepartment of Anthropology, Columbia University, New York, New York 10027, USA bKastor Neurobiology of Aging Laboratory and Fishberg Research Center for Neurobiology, and dDepartment of Otolaryngology, Mount Sinai School of Medicine, New York, New York 10029, USA cNew York Consortium in Evolutionary Primatology, New York, New York eDepartment of Anthropology, University of California, San Diego, La Jolla, California 92093-0532, USA fFoundation for Comparative and Conservation Biology, Needmore, Pennsylvania 17238, USA gInstitut fur Medizin, Forschungszentrum Julich und C.& O. Vogt-Institut fur Hirnforschung, Heinrich-Heine-Universitat, Dusseldorf, Germany

A specialized innervation of the tensor tympani muscle inMacaca fascicularis

The innervation of the tensor tympani muscle of the middle ear in Macaca fascicularis (cynomolgus monkey) was studied using the horseradish peroxidase (HRP) neural tracing technique. A compact column of small trigeminal motoneurons was labeled ipsilaterally following intramuscular application of HRP to the tensor tympani muscle. This column is located ventral and lateral to the dorsolateral division of the trigeminal motor nucleus, and just medial to the descending trigeminal nerve rootlets. No labeled neurons were present in the trigeminal mesencephalic nucleus or any other brainstem nucleus. Results are compared with those previously reported in several non-primate mammalian species, and in detail with that of the cat. A possible differential role of the tensor tympani muscle in acoustic modulation/middle ear aeration between primate and non-primate mammals is discussed.

Microvascular Transfer of Long Tracheal Autograft Segments in the Canine Model

Objective The reconstruction of long segment tracheal defects represents an unsolved clinical dilemma. Prior attempts to directly revascularize tracheal segments have been unsuccessful. The objective of this study was to evaluate orthotopic autotransplantation of revascularized long tracheal segments in the canine model.

Motor innervation of the eustachian tube muscles in the guinea pig.

The brainstem location of motoneurons innervating eustachian tube‐associated muscles in the adult guinea pig was determined using intramuscular injections of the neural tracer horseradish peroxidase (HRP). Following HRP injections into the tensor veli palatini and the eustachian tube belly of the medial pterygoid muscle, an ipsilateral column of HRP‐labeled motoneurons was present medial to the dorsolateral division of the trigeminal motor nucleus. Following HRP injection into the levator veli palatini, labeled motoneurons were present in the ipsilateral dorsal division of nucleus ambiguus. The locations of the tensor veli palatini and levator veli palatini motoneurons are similar to those found in studies of other animals. A distinct eustachian tube belly of the medial pterygoid muscle was also identified. This sub‐belly had a motoneuron pool distinct from the main medial pterygoid muscle group. The authors have provided the gross anatomical and neuroanatomical substrates upon which future studies of eustachian tube function in the guinea pig may be based.