Connections of the sheep basolateral amygdala: A diffusion tensor imaging study

Abstract

Background: A large amount of anatomic data published over the past decade has provided novel insight into the connections of the basolateral amygdala (BLA) in the rat, cat, and monkey. The mammalian (rat, cat, and monkey) BLA has strong connections with the cortex (especially piriform, and frontal cortices), the hippocampal region (especially perirhinal cortex, entorhinal cortex, and subiculum), the thalamus (in particular, the posterior internuclear nucleus and medial geniculate nucleus) and, to some extent, the hypothalamus. An important question remains as to how well the data obtained in rodents and primates can be extrapolated to ruminants.

New method: To address this issue the connections of the sheep BLA has been determined by Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI, Tractography).

Results: Tractography showed ipsilateral connections between the BLA and several areas.

Comparison with existing method(s): Reviews based mainly on description of the results obtained using anterograde and retrograde neuronal tracers. In the present research, we prefer to use a non-invasive technique (DTI).

Conclusions: This report shows the existence of specific amygdaloid connections in the sheep.

Keywords: Amygdala; Basolateral complex; Connections; Sheep; Tractography.