Cookies Policy

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here

Prenatal Development of Spontaneous and Evoked Activity in the Rat (Rattus Norvegicus Albinus)

No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.

Brill’s MyBook program is exclusively available on BrillOnline Books and Journals. Students and scholars affiliated with an institution that has purchased a Brill E-Book on the BrillOnline platform automatically have access to the MyBook option for the title(s) acquired by the Library. Brill MyBook is a print-on-demand paperback copy which is sold at a favorably uniform low price.

Access this article

+ Tax (if applicable)
Add to Favorites
You must be logged in to use this functionality

image of Behaviour

I. The characteristics of prenatal spontaneous activity of rat fetuses of 16 through 20 days of gestation, and the development of responses to cutaneous stimulation are discussed and tabulated. In early fetuses of 16 and 17 days, only few activity bursts occur between long intervals of inactivity. The frequency of activity bursts increases greatly at day 18 and attains a peak at this stage, whereupon it declines to a lower level from day 19 through term. 2. Qualitatively, the movements appear to be unintegrated. Three types of activity have been distinguished: Total, generalized or mass movements, when all parts that are capable of movements participate; regional when only one body region such as the head and forelimbs are in motion, and local movements of single parts. In the earliest stage, only head and forelimb movements are observed. There is a gradual extension of motility in rostro-caudal and proximodistal direction, but there are exceptions to this rule. The movements in the rat fetus seem to be more smooth compared with those of the chick embryo where the movements are more jerky. 3. Our recordings show that no clear, or one-to-one correlation exists between fetal activity and uterine contractions. Amnion contractions do not occur in the rat fetus. 4. The first evoked responses in the rat fetus are interpreted as an incipient total or regional pattern. In later stages of development, discrete, low-amplitude unintegrated local responses are identifiable. At 17 and 18 days the local responses are frequently combined with regional and total mass body movements, but by day 19, total movements are less frequently elicited, and the local responses are more complex, resembling mature and fully integrated action patterns. The conclusion is made that in the rat fetus local complex patterns are built up from less complex units. 5. Spontaneous motility in other mammalian embryos and the origin of integrated specialized local action patterns are discussed in relation to the development of the structure and organization of the spinal cord.

Affiliations: 1: Departments of Biology and Psychology, Washington University, St. Louis, Mo., U.S.A.


Full text loading...


Data & Media loading...

Article metrics loading...



Can't access your account?
  • Tools

  • Add to Favorites
  • Printable version
  • Email this page
  • Subscribe to ToC alert
  • Get permissions
  • Recommend to your library

    You must fill out fields marked with: *

    Librarian details
    Your details
    Why are you recommending this title?
    Select reason:
    Behaviour — Recommend this title to your library
  • Export citations
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation