Neuron Location Of Direct Cerebellar Projections From Hippocampal Formation In Poultry By Applying Retrograde Transport Of Horseradish Peroxidase

To determine the existence and the topographic territories of direct hippo-cerebellar projections in chicken.Solution of 50% HRP(horseradish peroxidase ) were injected into the foliaⅣthroughⅨof the cerebellum in youth chickens, and injected into the foliaⅥ,ⅦandⅧof the cerebellum in adult chickens and pigeons and ducks,respectively, for retrograde tracing the origins of the cerebrum projection to the cerebellum. Carried out the frozen sections for cerebrum and brain stem and cerebellum,stained with TMB,we observed the location of the labelled cells. The results indicated that:(1)A lot of labeled cells were observed in the parahippocampal area(APHm) of the bilateral hippocampal formation after injected in foliumⅣ～Ⅸexcept foliumⅨin youth chickens. In other areas the labeled cells weren't observed.The density of labeled cells was centered and large,the length was 5～12㎜.The labeled area accounted more than 40% of the length.The cells in the dorsomedial hippocampus were labeled heavily and their average size was 18.78±2.79μm。(2)In addition, afterⅣthroughⅥfolium injection small number of labelled cells were also found in the lateral septal nucleus .The cells in the in the septal nucleus were labeled lightly and their average size was 12.84±1.54μm.(3)With the injection site shifted from foliumⅣtoⅨ, the possibility of the APHm being labeled gradually declined ,but that of the pre-cerebellar nuclei ,including Nuc. magnocellular reticular, Nuc. parvocellular reticular , Nuc.vestibularis descendens, Nuc. inferior olivary, Nuc. inferiorin trigeminal, Nuc.pontine and Nuc. spiriformis medialis increased respectively.(4)We observed the labelled cells in APHm, Nuc. septal, Nuc. magnocellular reticular, Nuc. parvocellular reticular , Nuc.vestibularis descendens, Nuc. inferior olivary, Nuc. inferiorin trigeminal, Nuc.pontine and Nuc. spiriformis medialis after injected from foliumⅥtoⅧof adult chickens.(5)We observed the labelled cells in Nuc. septal, Nuc. magnocellular reticular, Nuc. parvocellular reticular , Nuc.vestibularis descendens, Nuc. inferior olivary, Nuc. inferiorin trigeminal, Nuc.pontine, Nuc. cuneate lateral , Nuc. spinal of trigeminal and Nuc. spiriformis medialis after injected from foliumⅥtoⅧof pigeons,but didn't found labeled cells in hippocampus.(6)We observed the labelled cells in Nuc. lentiform and Nuc. spiriformis medialis after injected from foliumⅥtoⅧof ducks.But didn't found labeled cells in hippocampus and Nuc. septal.In a word,to determine the existence and the topographic territories of direct hippo-cerebellar projections in poultry. These results indicated that there are direct projections from the hippocampal formation to the rostral and intermedial folia of the cerebellum in chicken and aren't in pigeon and duck.As in mammal,the septal nucleus have tight connections with hippocampal formation in chicken.About this question will be further studied.