[Diencephalic afferents of the rat hippocampus]

The diencephalohippocampal connections in rats were studied using the horseradish peroxidase (HRP) retrograde axonal transport technique. After HRP injections into the CA1 hippocampal field labelled cells were found both in the thalamic and hypothalamic nuclei. It is found that both specific (anterodorsal, anteroventral, lateral anterior, lateral) and nonspecific (reuniens, central lateral, central medial) nuclei of thalamus are the sources of the hippocampal afferents. The cells of the paraventricular and perifornical hypothalamic nuclei also send their axons to the hippocamp. The data obtained show that the hippocamp receives direct thalamic connections from the thalamic structures which have sensory inputs.