Amphibian Brains

Abstract

Amphibians mark the transition from an aquatic to a terrestrial lifestyle. From a phylogenetic point of view, amphibians are, therefore, considered of particular interest for a better understanding of evolutionary processes in brain organization of vertebrates.

Keywords: evolution; nervous system; adaptation; vocal behaviour; motor behaviour

Figure 1.

Lateral views and transverse sections from rostral (a) to caudal (d) through the brain of the frog Rana perezi (left) and the urodele Pleurodeles waltl (right). The levels of the transverse sections are indicated and are taken through the telencephalon (a) diencephalon (b), mesencephalon (c) and rhombencephalon (d). They illustrate the major differences in shape and distribution of cell bodies, as noted for the different amphibian orders. They also show the position of important structures such as the striatum, posterior tubercle, torus semicircularis and midbrain tectum. Acc, nucleus accumbens; aol, area octavolateralis; C, central thalamic nucleus; DTh, dorsal thalamic nuclei; DB, diagonal band nucleus; Dp, dorsal pallidum; Ep, entopeduncular nucleus; Ip, interpeduncular nucleus; La, lateral thalamic nucleus, anterior division; Lp, lateral pallium; Ls, lateral septum; Mp, medial pallium; Ms, medial septum; Ols, oliva superior; P, posterior thalamic nucleus; PT, pretectal region; Ra, raphe nuclei; Rm, nucleus reticularis medius; Str, striatum; T, tectum mesencephali; tegm, tegmentum mesencephali; Tor, torus semicircularis; VH, ventral hypothalamic nucleus; VM, ventromedial thalamic nucleus; VTh, ventral thalamus; IV, nucleus nervi trochlearis; VIIm, nucleus motorius nervi facialis; VIIId, nucleus dorsalis nervi vestibulocochlearis; VIIIv, nucleus ventralis nervi vestibulocochlearis.

Figure 2.

Basal ganglia connections in ancestral tetrapods. The putative connections of the dorsal (a) and ventral (b) striatopallidal systems in ancestral tetrapods can be inferred from a comparative analysis of the basal ganglia organization in extant tetrapods. A9, substantia nigra, pars compacta; A10, ventral tegmental area; Acc, nucleus accumbens; Amy, amygdala; cDTh, caudal dorsal thalamic nuclei; DP, dorsal pallidum; Hb, habenula; HYP, hypothalamus; Ilm, intralaminar midline nuclei; LC, locus coeruleus; LDT, laterodorsal tegmental nucleus; Mp, medial pallium; PPN, pedunculopontine nucleus; PT, pretectal region; rDTh, rostral dorsal thalamic nucleus; RF, reticular formation; SNr, substantia nigra, pars reticulata; STh, subthalamus; Str, striatum; T, tectum mesencephali; Tor, torus semicircularis; VP, ventral pallidum; VTh, ventral thalamus.

close

References

Brahic, CJ and Kelley, DB (2003) Vocal circuitry in Xenopus laevis; Telencephalon to laryngeal motor neurons. Journal of Comparative Neurology 464: 115–130.

Duellman, WE and Trueb L (1986) Biology of Amphibians. New York: McGraw‐Hill.

Ewert, J‐P (1984) Tectal mechanisms that underlie prey‐catching and avoidance behaviors in toads. In: Vanegas H (ed.) Comparative Neurology of the Tectum pp. 247–416. New York: Plenum.

Ewert J‐P (1997) Neural correlates of key stimulus and releasing mechanism: a case study and two concepts. Trends in Neurosciences 20: 332–39.

Fritzsch B (1990) The evolution of metamorphosis in amphibians. Journal of Neurobiology 21: 1011–021.

González A López JM Sánchez‐Camacho, C and Marín O (2002) Regional expression of the homeobox gene NKX2‐1 defines pallidal and interneuronal populations in the basal ganglia of amphibians. Neuroscience 114: 567–75.

Jarvik E (1980) Basic Structure and Evolution of Vertebrates vols 1, 2. London: Academic Press.

Marín O González A and Smeets WJAJ (1997) Anatomical substrate of amphibian basal ganglia involvement in visuomotor behaviour. European Journal of Neuroscience 9: 2100–109.

Marín O Smeets WJAJ and González A (1998) Evolution of the basal ganglia in tetrapods: a new perspective based on recent studies in amphibians. Trends in Neurosciences 21: 487–94.

Roth G Nishikawa KC Naujoks‐Manteuffel C Schmidt A and Wake DB (1993) Paedomorphosis and simplification in the nervous system of salamanders. Brain, Behavior and Evolution 42: 137–70.

Smeets WJAJ and González A (2000) Catecholamine systems in the brain of vertebrates: new perspectives through a comparative approach. Brain Research Reviews 33: 308–79.

Smeets WJAJ and Reiner A (eds) (1994) Phylogeny and Development of Catecholaminergic Systems in the CNS of Vertebrates Cambridge: Cambridge University Press.

Smeets WJAJ Marín O and González A (2000) Evolution of the basal ganglia: new perspectives through a comparative approach. Journal of Anatomy 196: 501–17.

Wilczynski W (1988) Brainstem auditory pathways in anuran amphibians. In: Fritzsch B (ed.) The Evolution of the Amphibian Auditory System pp. 209–231. New York: Wiley.

Further Reading

Bachy I Berthon J and Rétaux S (2002) Defining pallial and subpallial divisions in the developing Xenopus forebrain. Mechanisms of Development. 117: 163–172.

Ewert J‐P (1989) The release of visual behavior in toads. Stages of parallel/hierarchical information processing. In: Ewert J‐P and Arbib MA (eds) Visuomotor Coordination, Amphibians, Comparisons, Models and Robots, pp 39–120. New York: Plenum.

Feng AS Hall JC and Gooler DM (1990) Neural basis of sound pattern recognition in anurans. Progress in Neurobiology. 34: 313–329.

Kay JN Hannigan P and Kelley DB (1999) Trophic effects of androgen: development and hormonal regulation of neuron number in a sexually dimorphic vocal motor nucleus. Journal of Neurobiology. 40: 375–385.

Kelley DB (1997) Generating sexually differentiated songs. Current Opinion in Neurobiology. 7: 839–843.

Lin W‐Y and Feng AS (2003) GABA is involved in spatial unmasking in the frog auditory midbrain. The Journal of Neuroscience. 23: 8143–8151.

Marín O Smeets WJAJ and González A (1998) Basal ganglia organization in amphibians: evidence for a common pattern in tetrapods. Progress in Neurobiology. 55: 363–397.

Ten Donkelaar HJ (1998) Urodeles. In: Nieuwenhuys R (ed.) The central nervous system of Vertebrates, vol 2, pp. 1045–1150. Berlin: Springer.

Ten Donkelaar HJ (1998) Anurans. In: Nieuwenhuys R (ed.) The central nervous system of Vertebrates, vol. 2, pp. 1051–1314. Berlin: Springer.

Yamaguchi A and Kelley DB (2000) Generating sexually differentiated vocal patterns: laryngeal nerve and EMG recordings from vocalizing male and female African clawed frogs (Xenopus laevis). Journal of Neuroscience. 20: 1559–1567.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Smeets, Wilhelmus JAJ, and González, Agustín(Jan 2006) Amphibian Brains. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0004095]