The evolutionary origin of the mammalian isocortex: Towards an integrated developmental and functional approach
Behavioral and Brain Sciences 26 (5):535-552 (2003)
|Abstract||The isocortex is a distinctive feature of mammalian brains, which has no clear counterpart in the cerebral hemispheres of other amniotes. This paper speculates on the evolutionary processes giving rise to the isocortex. As a first step, we intend to identify what structure may be ancestral to the isocortex in the reptilian brain. Then, it is necessary to account for the transformations (developmental, connectional, and functional) of this ancestral structure, which resulted in the origin of the isocortex. One long-held perspective argues that part of the isocortex derives from the ventral pallium of reptiles, whereas another view proposes that the isocortex originated mostly from the dorsal pallium. We consider that, at this point, evidence tends to favor correspondence of the isocortex with the dorsal cortex of reptiles. In any case, the isocortex may have originated partly as a consequence of an overall “dorsalizing” effect (that is, an expansion of the territories expressing dorsal-specific genes) during pallial development. Furthermore, expansion of the dorsal pallium may have been driven by selective pressures favoring the development of associative networks between the dorsal cortex, the olfactory cortex, and the hippocampus, which participated in spatial or episodic memory in the early mammals. In this context, sensory projections that in reptiles end in the ventral pallium, are observed to terminate in the isocortex (dorsal pallium) of mammals, perhaps owing to their participation in these associative networks. Key Words: basolateral amygdala; claustrum; Emx-1; endopiriform nucleus; dorsal cortex; dorsal ventricular ridge; hippocampus; homology; olfactory cortex; Pax-6; ventral pallium.|
|Keywords||No keywords specified (fix it)|
|Through your library||Configure|
Similar books and articles
Alessandro Treves (2003). More Dorsal Cortex, Yes, but What Flavor? Behavioral and Brain Sciences 26 (5):571-572.
Miguel Marín-Padilla (2003). Reptilian Cortex and Mammalian Neocortex Early Developmental Homologies. Behavioral and Brain Sciences 26 (5):560-561.
Alice Schade Powers (2003). Relevance of Medial and Dorsal Cortex Function to the Dorsalization Hypothesis. Behavioral and Brain Sciences 26 (5):566-567.
Loreta Medina (2003). Histogenetic Divisions, Developmental Mechanisms, and Cortical Evolution. Behavioral and Brain Sciences 26 (5):563-564.
Michael Colombo (2003). Avian and Mammalian Hippocampus: No Degrees of Freedom in Evolution of Function. Behavioral and Brain Sciences 26 (5):554-555.
Fernando Martinez-Garcia (2003). The Origin of the Amniote Sensory and Motor Cortices. Behavioral and Brain Sciences 26 (5):561-563.
Toru Shimizu (2003). Toward the Answer, but Still Far to Go. Behavioral and Brain Sciences 26 (5):569-570.
Hans Supèr (2003). Cortical Evolution: No Expansion Without Organization. Behavioral and Brain Sciences 26 (5):570-571.
Salvador Guirado (2003). The Dorsal Thalamic Connection in the Origin of the Isocortex. Behavioral and Brain Sciences 26 (5):557-558.
Francisco Aboitiz, Daniver Morales & Juan Montiel (2003). An Interdisciplinary Approach to Brain Evolution: A Long Due Debate. Behavioral and Brain Sciences 26 (5):572-576.
Added to index2009-01-28
Total downloads3 ( #202,008 of 549,117 )
Recent downloads (6 months)0
How can I increase my downloads?