Olfaction impaired

Cyptosmia. Impairment of olfaction by obstmction of the nasal passages. 

The gravitational field affects olfaction as it does vision, audition, or vestibular function. It could impair detection of dangerous fumes or burning electrical equipment in airplanes or space vehicles. Astronauts also report altered perception of food flavors under weightless conditions. Men and women tested with four scratch-and-sniff odor samples of the University of Pennsylvania Smell Identification Test identified odors more poorly when in an upside-down position (Mester eta/., 1988). 

Land tortoises Testudo hermannt), especially males, caught in the wild and displaced 500-1000 m returned to the point of their capture. However, if their olfaction was impaired by washing the nasal cavity with zinc sulfate, their... 

H. M. clearly understands how to discriminate chemical stimuli. His impairment limits only his recognition of odors, but no other aspect of his sense of smell. He is "odor deaf," by analogy to stroke victims who can read and write and retain an intact sense of hearing but cannot recognize words aurally (and are said to be "word deaf ) (Takahashi et al., 1992). Based on the evidence discussed so far, H. M. s behavior does not satisfy the fourth of the guidelines for olfaction. 

Postnatally, offspring were tested for olfaction, neuromuscular ability, exploratory and circadian activity, aversive and appetitive learning." There was evidence of impaired neuromuscular ability." Offspring from dams exposed on days 7-13 were poorer than controls in ascent of a wire mesh screen during the second week of life and were poorer than controls on a rotorod test on one of the 3 days tested in the fourth week of life." Offspring from dams exposed on days 14-20 performed less well in ascent of a wire mesh screen. 

Although LPAj was originally believed to be involved in the myelination process, no significant abnormality in locomotion was evident in LPAj knockout mice, indicating that the myelination process was relatively normal (Yang et al, 2002). However, LPAj mice have a reduced survival rate, decreased size, impaired olfaction and altered craniofacial stmcture. LPA knockout mice have no obvious phenotype, whereas a knockout mouse for LPAj has not been reported to date (Yang et al., 2002). The LPA receptor subtypes are not redundant since LPAj present in the embryonic brain fails to rescue LPAj mice from their observed abnormalities. 

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