Japanese quail (Coturnix coturnix japonica) were selected over 8 generations for long or short duration of tonic immobility (TI) weighted for independence from social reinstatement (SR) behavior (as measured in a treadmill) and for high or low levels of SR behavior weighted for independence from duration of TI. Divergent selection for long or short duration of TI and for high or low levels of SR behavior resulted in immediate and significant responses that continued throughout the 8 generations. There was no evidence of a plateau in the response to selection in any of the lines. SR responses did not vary in lines selected for duration of TI and vice versa. Selection for short duration of TI led to in an increase in the number of inductions required to induce TI. Selection for low levels of SR behavior led to a decrease in the tendency to move toward conspecifics but not to an increase in the tendency to move away from conspecifics.
Objectives The aim of this study was to describe a novel three-dimensional (3D) ultrasound rendering technique to examine the normal fetal posterior palate and to assess its correspondence with the real fetal anatomy.
Methods
We examined effects of environmental enrichment and regular handling on fear-related responses in chicks of Japanese quail (Coturnix coturnix japonica) selected over several generations for short or long tonic immobility (STI and LTI, respectively). STI chicks froze less, vocalized and walked sooner and more in an open field, emerged sooner from a hole-in-the-wall box, and showed shorter TI reactions than did chicks of the LTI line. Similarly, environmental enrichment reduced silence and inactivity in the open field, accelerated emergence, and attenuated TI. Regular handling promoted open-field vocalization and reduced the duration of TI but exerted no other significant effects. Principal component analysis showed that the responses in the 3 tests were not independent, which implies that they measured the same underlying factor. The genetic and experiential manipulation of stimulus-specific fears and of general fearfulness is discussed.
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