0000000000022847

AUTHOR

Mimi Halpern

Organization of the ophidian amygdala: chemosensory pathways to the hypothalamus.

Although recent studies in squamate reptiles have importantly clarified how chemical information is processed in the reptilian brain, how the amygdala relays chemosensory inputs to the hypothalamus to influence chemically guided behaviors is still poorly documented. To identify these chemosensory pathways, the amygdalo-hypothalamic projections, intra-amygdaloid circuitry and afferents from the lateral cortex (LC) to the amygdala were investigated by injecting conjugated dextran-amines into the hypothalamus, amygdala, and LC of garter snakes. The amygdala was divided into olfactory recipient (ventral anterior and external amygdalae), vomeronasal recipient (nucleus sphericus, NS, and medial a…

research product

Chemoarchitecture and afferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes.

The olfactostriatum, a portion of the striatal complex of snakes, is the major tertiary vomeronasal structure in the ophidian brain, receiving substantial afferents from the nucleus sphericus, the primary target of accessory olfactory bulb efferents. In the present study, we have characterized the olfactostriatum of garter snakes (Thamnophis sirtalis) on the basis of chemoarchitecture (distribution of serotonin, neuropeptide Y and tyrosine hydroxylase) and hodology (afferent connections). The olfactostriatum is densely immunoreactive for serotonin and neuropeptide Y and shows moderate-to-weak immunoreactivity for tyrosine hydroxylase. In addition to afferents from the nucleus sphericus, the…

research product

Efferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes.

Abstract The olfactostriatum is a portion of the basal ganglia of snakes that receives substantial vomeronasal afferents through projections from the nucleus sphericus. In a preceding article, the olfactostriatum of garter snakes (Thamnophis sirtalis) was characterized on the basis of chemoarchitecture (distribution of serotonin, neuropeptide Y and tyrosine hydroxylase) and pattern of afferent connections [Martinez-Marcos, A., Ubeda-Banon, I., Lanuza, E., Halpern, M., 2005. Chemoarchitecture and afferent connections of the “olfactostriatum”: a specialized vomeronasal structure within the basal ganglia of snakes. J. Chem. Neuroanat. 29, 49–69]. In the present study, its efferent connections …

research product

The "olfactostriatum" of snakes: a basal ganglia vomeronasal structure in tetrapods.

The olfactostriatum is a portion of the basal ganglia of snakes situated ventromedially to the nucleus accumbens proper. It receives a major vomeronasal input from the nucleus sphericus, the primary target of accessory olfactory bulb efferents. Recently, the ophidian olfactostriatum has been characterized on the basis of chemoarchitecture (distribution of serotonin, neuropeptide Y and tyrosine hydroxylase) and hodology (afferent and efferent connections). In contrast to the nucleus accumbens proper, the olfactostriatum is densely immunoreactive for serotonin and neuropeptide Y and sparsely immunoreactive for tyrosine hydroxylase. The nucleus accumbens proper and the olfactostriatum share mo…

research product

Neural substrates for processing chemosensory information in snakes.

Snakes interact with their chemical environment through their olfactory and vomeronasal systems. The present report summarizes advances on neural substrates for processing chemosensory information. First, the efferent and centrifugal afferent connections of the main and accessory olfactory bulbs were reinvestigated. Second, the afferent and efferent connections of the nucleus sphericus, the main target of the accessory olfactory bulb, were characterized. The nucleus sphericus gives rise to a very small projection to the hypothalamus, but it does project to other telencephalic structures where olfactory and vomeronasal information could converge. Third, the intra-amygdaloid circuitry and the…

research product