Harrer, MI; Travers, SP

    Section of Oral Biology and Department of Psychology, College of
    Dentistry, The Ohio State University, 305 W. 12th Avenue,
    Columbus, OH 43210, USA

    BRAIN RES., vol. 711, no. 1-2, pp. 125-137, 1996

    ELSEVIER SCIENCE B.V.

    ISSN 0006-8993

    Fos immunohistochemistry was used to elucidate the pattern of
    activation elicited by two qualitatively and hedonically distinct
    taste stimuli, sucrose and quinine, within the first-order
    gustatory relay, the rostral division of the nucleus of the
    solitary tract. Compared to unstimulated controls, both sucrose
    and quinine elicited significant increases in Fos-like
    immunoreactivity in the rostral central subnucleus, the region of
    the rostral solitary nucleus that receives the densest primary
    afferent input. Within the rostral central subnucleus, neurons
    that exhibited Fos-like immunoreactivity following quinine
    stimulation were concentrated medially, but neurons that exhibited
    Fos-like immunoreactivity following sucrose stimulation were
    distributed more evenly along the mediolateral axis. Despite their
    differential distribution, sucrose- and quinine-activated neurons
    also demonstrated notable intermingling. Further, the chemotopic
    arrangement was only partially consistent with what would be
    predicted if chemotopy was merely an outcome of orotopy. Our
    results suggest that a rough chemotopy characterizes the
    organization of taste responses in the nucleus of the solitary
    tract, and that the topographic pattern of taste afferent
    terminations in this nucleus is related to their chemosensitivity
    as well as to their peripheral spatial distribution.