Identification of the reptilian basolateral amygdala: an anatomical investigation of the afferents to the posterior dorsal ventricular ridge of the lizard Podarcis hispanica
Article first published online: 25 DEC 2001
European Journal of Neuroscience
Volume 10, Issue 11, pages 3517–3534, November 1998
How to Cite
Lanuza, E., Belekhova, M., Martínez-Marcos, A., Font, C. and Martínez-García, F. (1998), Identification of the reptilian basolateral amygdala: an anatomical investigation of the afferents to the posterior dorsal ventricular ridge of the lizard Podarcis hispanica. European Journal of Neuroscience, 10: 3517–3534. doi: 10.1046/j.1460-9568.1998.00363.x
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- Received 20 October 1997, revised 10 May 1998, accepted 25 June 1998
- brain evolution;
- emotional behaviour;
- limbic system;
- multimodal association;
The presence of multimodal association in the telencephalon of reptiles has been investigated by tracing the afferent connections to the posterior dorsal ventricular ridge (PDVR) of the lizard Podarcis hispanica. The PDVR receives telencephalic afferents from the lateral (olfactory) and dorsal cortices, and from the three unimodal areas of the anterior dorsal ventricular ridge, in a convergent manner. From the diencephalon, it receives afferents from the dorsomedial anterior and medial posterior thalamic nuclei, and from several hypothalamic nuclei. Brainstem afferents to the PDVR originate in the dorsal interpeduncular nucleus, the nucleus of the lateral lemniscus and parabrachial nucleus.
The afferents to the thalamic nuclei that project to the PDVR have also been studied. The dorsomedial anterior thalamic nucleus receives projections mainly from limbic structures, whereas the medial posterior thalamic nucleus is the target of projections from structures with a clear sensory significance (optic tectum, torus semicircularis, nuclei of the lateral and spinal lemniscus, superior olive and trigeminal complex).
As a result, the PDVR appears as an associative centre that receives visual, auditory, somatosensory and olfactory information from several telencephalic and non-telencephalic centres, and a multimodal projection from the medial posterior thalamic nucleus. This pattern of afferents of the PDVR is similar to that of the caudal neostriatum in birds and the basolateral division of the mammalian amygdala. These results indicate that a multimodal amygdala is already present in reptiles, and has probably played a key role in the evolution of the vertebrate brain.