Elsevier

Developmental Brain Research

Volume 44, Issue 2, 1 December 1988, Pages 189-196
Developmental Brain Research

Research report
Feeding behavior in mammals: corticobulbar projection is reorganized during conversion from sucking to chewing

https://doi.org/10.1016/0165-3806(88)90217-9Get rights and content

Abstract

It is known that repetitive stimulation of the frontal cortex (cortical masticatory area, CMA) induces rhythmical jaw movements similar to chewing in adult mammals. In the present study we were able to induce rhythmical jaw movements similar to sucking by repetitive stimulation of the frontal cortex in neonatal guinea pigs. This area, which we named the cortical sucking area (CSA), was located rostral to the CMA which was later formed upon maturation. Neurons of the CSA were shown electrophysiologically and morphologically to project primarily to the dorsal part of the paragigantocellular reticular nucleus of the contralateral side. This was the site which the CMA neurons, later, projected to induce chewing. It is generally thought that tooth eruption triggers the conversion from sucking to chewing. However, guinea pigs are born with a complete permanent dentition and therefore devoid of this peripheral trigger for the conversion to chewing. Accordingly we propose that shift of the cortical projection area from the CSA to the CMA during the maturation causes the conversion of the mammalian feeding behavior. It is discussed that this transition involves extensive reorganization of the cortical efferent system including the pyramidal tract during early postnatal development.

References (14)

  • K.E. Byrd et al.

    Cerebellar ablation and mastication in the guinea pig (Cavia porcellus)

    Brain Res.

    (1980)
  • J. Ainamo

    Prenatal occlusal wear in guinea pig molars

    Scand. J. Dent. Res.

    (1971)
  • J.F. Bosma

    Human infant oral function

  • W.M. Cowan et al.

    Regressive events in neurogenesis

    Science

    (1984)
  • R. Dubner et al.
  • E.S. Luschei et al.

    Neural mechanisms of mandibular control: mastication and voluntary biting

  • M.-M. Mesulam et al.

    Additional factors influencing sensitivity in the tetramethyl benzidine method for horseradish peroxidase neurohistochemistry

    J. Histochem. Cytochem.

    (1980)
There are more references available in the full text version of this article.

Cited by (63)

  • Unilateral nasal obstruction affects development of cortical orofacial motor representation in the cortical masticatory area of growing rats

    2022, Neuroscience Letters
    Citation Excerpt :

    Projection from the cortical sucking area is lost during postnatal development and replaced by projection from the CMA [12]. The reorganization of corticobulbar projection found by Nakamura et al. is consistent with a general reorganization of the corticospinal centrifugal system during development, an adaptive control based on feedback information from the mouth [12]. Rats begin masticatory activity at 3 weeks of age [13], and mastication after weaning has been reported to result in abundant afferent stimulation and to promote brain development [14].

  • Postnatal Maturation of Glutamatergic Inputs onto Rat Jaw-closing and Jaw-opening Motoneurons

    2022, Neuroscience
    Citation Excerpt :

    The jaw-closing muscle activity dramatically changes during the period in which feeding behavior changes from suckling to chewing. Suckling is a simple and patterned motor behavior consisting of jaw closing and opening because milk keeps its physical state unchanged throughout suckling (Iriki et al., 1988; Westneat and Hal, 1992). In rat pups, their incisal teeth first erupt at around P7 (Asahito et al., 1999), and then immature chewing starts approximately at P12 (Westneat and Hal, 1992).

View all citing articles on Scopus
View full text