Phylogenetic threats such as spiders evoke our deepest primitive fears. When close or looming, such threats engage evolutionarily conserved monitoring systems and defense reactions that promote self-preservation. With the use of a modified behavioral approach task within functional MRI, we show that, as a tarantula was placed closer to a subject's foot, increased experiences of fear coincided w...

Anatomic descriptions of amygdaloid lesions resulting in hyperphagia and obesity in rats, cats, and dogs have been inconsistent and often contradictory, frequently resulting in failures to replicate. The present study attempted to reconcile these differences by examining common areas of overlap among differently placed lesions in female rats. Small bilateral lesions of the most posterodorsal as...

The hamster intergeniculate leaflet (IGL), part of the circadian rhythm regulatory system, has very extensive interconnections with subcortical visual nuclei. The present investigation describes IGL connections with the hamster diencephalon and telencephalon and compares them with ventral lateral geniculate nucleus (VLG) connections and retinal projections. Connections of the geniculate nuclei ...

A collection of 125 PHAL experiments in the rat has been analyzed to characterize the organization of projections from each amygdalar cell group (except the nucleus of the lateral olfactory tract) to the bed nuclei of the stria terminalis, which surround the crossing of the anterior commissure. The results suggest three organizing principles of these connections. First, the central nucleus, and...

The amygdaloid neurons of origin and the trajectory of amygdaloid fibers to the medial preoptic area of the adult male Syrian hamster were identified by using horseradish peroxidase (HRP) histochemistry. After iontophoresis of HRP into the medial preoptic area, retrogradely labeled amygdaloid neurons were located in the dorsal and caudal parts of the medial amygdaloid nucleus and throughout the...

BNST Bed nucleus of the stria terminalis CCK Cholecystokinin cGMP Cyclic guanosine monophosphate DCN Dorsal central autonomic nucleus fMRI Functional magnetic resonance imaging IML Intermediolateral cell column LCTF Lateral central tegmental field LSt cells Lumbar spinothalamic cells MEA Medial amygdala MPOA Medial preoptic area NO Nitric oxide nPGi Nucleus paragigantocellularis NPY Neuropeptid...

The present study reports for the first time the distribution of androgen receptor immunoreactivity (AR-ir) in the human hypothalamus of ten human subjects (five men and five women) ranging in age between 20 years and 39 years using the antibody PG21. Prolonged postmortem delay (72:00 hours) or fixation time (100 days) did not influence the AR-ir. In men, intense nuclear AR-ir was found in neur...