Maternal Behaviour

Re: symposium 822

alison Fleming
fleming@psych.utoronto.ca

Just to continue my thoughts on the first point...and on rereading your paper....I guess one might predict a reduction in vmh activation with exposure to pups (assuming its inhibitory) but not in meamyg or ls activation-unless, as you point out, different cell groups within these latter two structures are activated by novel stimulation as opposed to by sensory inputs normally associated with maternal responding. It is certainly the case that medial/cortical amyg lesions results in both facilitation of expression of maternal behavior in virgins AND in reduced licking when virgin animals become maternal or during the postpartum period, in dams...suggesting these nuclei have multiple functions.
Bye for now, Af

On Mon Dec 7, alison Fleming wrote
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>>1. These are lovely data. It would be really interesting to follow the pattern of change in the density and pattern of c-fos exression in vmh, me and ls from a condition of total inexperience (as in nulliaprous virgin) to partially induced (as a virgin) to completely induced (maternal virgin). The prediction is that as the animal becomes more experienced, there would occur progressively reduced activation in these 'inhibitory' areas---something that is accomplished in the postpartum animal by hormones.

>2. Have you thought about also employing a measure of 'fear' or timidity to correlate with c-fos expression?

>3. Do you think vmh is acting through the mpoa...? inwhich case one would expect that vmh lesions would not enhance mat behav if the mpoa is simultaneously lesioned.
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>4. I looked at our medial amygdala Fos results in maternally experienced, vs inexperienced animals (in Fleming & Korsmit,1996)and noticed that for some groups at least, inexperienced animals had higher numbers of c-fos cells in ,medial and in cortical amygdala than did the experienced animals. Other areas where we found elevated c-fos expression in experienced, over inexperienced animals (but only under some conditions) were the nucleus accmbens, the prefrontal cortex and the habenula. Did you look at any of these sites?

>5. Further thoughts are forthcoming
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Mon Dec 7