Phylogenetic reorganization of the basal ganglia: A necessary, but not the only, bridge over a primate Rubicon of acoustic communication

Ackermann, Hermann; Hage, Steffen R. and Ziegler, Wolfram (2014): Phylogenetic reorganization of the basal ganglia: A necessary, but not the only, bridge over a primate Rubicon of acoustic communication. In: Behavioral and Brain Sciences, Vol. 37, No. 6: pp. 577-604

Abstract

In this response to commentaries, we revisit the two main arguments of our target article. Based on data drawn from a variety of research areas – vocal behavior in nonhuman primates, speech physiology and pathology, neurobiology of basal ganglia functions, motor skill learning, paleoanthropological concepts – the target article, first, suggests a two-stage model of the evolution of the crucial motor prerequisites of spoken language within the hominin lineage: (1) monosynaptic refinement of the projections of motor cortex to brainstem nuclei steering laryngeal muscles, and (2) subsequent “vocal-laryngeal elaboration” of cortico-basal ganglia circuits, driven by human-specific FOXP2 mutations. Second, as concerns the ontogenetic development of verbal communication, age-dependent interactions between the basal ganglia and their cortical targets are assumed to contribute to the time course of the acquisition of articulate speech. Whereas such a phylogenetic reorganization of cortico-striatal circuits must be considered a necessary prerequisite for ontogenetic speech acquisition, the 30 commentaries – addressing the whole range of data sources referred to – point at several further aspects of acoustic communication which have to be added to or integrated with the presented model. For example, the relationships between vocal tract movement sequencing – the focus of the target article – and rhythmical structures of movement organization, the connections between speech motor control and the central-auditory and central-visual systems, the impact of social factors upon the development of vocal behavior (in nonhuman primates and in our species), and the interactions of ontogenetic speech acquisition – based upon FOXP2-driven structural changes at the level of the basal ganglia – with preceding subvocal stages of acoustic communication as well as higher-order (cognitive) dimensions of phonological development. Most importantly, thus, several promising future research directions unfold from these contributions – accessible to clinical studies and functional imaging in our species as well as experimental investigations in nonhuman primates.

• Item Type: Journal article
• Form of publication: Postprint
• Faculties: Languages and Literatures > Department 2 > Speech Science
• Subjects: 100 Philosophy and Psychology > 150 Psychology; 400 Language > 400 Language; 600 Technology > 610 Medicine and health
• ISSN: 1469-1825
• Alliance/National Licence: This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
• Language: English