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Ackermann H.,University of Tubingen | Hage S.R.,University of Tubingen | Ziegler W.,Clinical Neuropsychology Research Group | Ziegler W.,Ludwig Maximilians University of Munich
Behavioral and Brain Sciences | Year: 2014

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. Copyright © Cambridge University Press 2014. Source


Ackermann H.,University of Tubingen | Hage S.R.,University of Tubingen | Ziegler W.,Clinical Neuropsychology Research Group
Behavioral and Brain Sciences | Year: 2014

Any account of what is special about the human brain (Passingham 2008) must specify the neural basis of our unique ability to produce speech and delineate how these remarkable motor capabilities could have emerged in our hominin ancestors. Clinical data suggest the basal ganglia provide a platform for the integration of primate-general mechanisms of acoustic communication with the faculty of articulate speech in humans. Furthermore, neurobiological and paleoanthropological data point at a two-stage model of the phylogenetic evolution of this crucial prerequisite of spoken language: (i) monosynaptic refinement of the projections of motor cortex to the brainstem nuclei that steer laryngeal muscles, presumably, as part of a phylogenetic trend associated with increasing brain size during hominin evolution, (ii) subsequent vocal-laryngeal elaboration of cortico-basal ganglia circuitries, driven by human-specific FOXP2 mutations. This concept implies vocal continuity of spoken language evolution at the motor level, elucidating the deep entrenchment of articulate speech into a "nonverbal matrix" (Ingold 1994) which is not accounted for by gestural-origin theories. Moreover, it provides a solution to the question for the adaptive value of the "first word" (Bickerton 2009) since even the earliest and most simple verbal utterances must have increased the versatility of vocal displays afforded by the preceding elaboration of monosynaptic corticobulbar tracts, giving rise to enhanced social cooperation and prestige. At the ontogenetic level, the proposed model assumes age-dependent interactions between the basal ganglia and their cortical targets, similar to vocal learning in some songbirds. In this view, the emergence of articulate speech builds on the "renaissance" of an ancient organizational principle and, hence, may represent an example of evolutionary tinkering (Jacob 1977). © 2014 Cambridge University Press. Source


Ziegler W.,Clinical Neuropsychology Research Group | Ackermann H.,University of Tubingen
Folia Phoniatrica et Logopaedica | Year: 2014

The aim of this article is to explicate the uniqueness of the motor activity implied in spoken language production and to emphasize how important it is, from a theoretical and a clinical perspective, to consider the motor events associated with speaking as domain-specific, i.e., as pertaining to the domain of linguistic expression. First, phylogenetic data are reviewed demonstrating the specificity of the human vocal tract motor network regarding (i) the entrenchment of laryngeal motor skills within the organization of vocal tract movements, (ii) the evolution of a neural basis for skill acquisition within this system, and (iii) the integration of this system into an auditory-motor network. Second, ontogenetic evidence and existing knowledge about the experience-dependent plasticity of the brain are reported to explicate that during speech acquisition the vocal tract motor system is constrained by universal properties of speech production and by the specific phonological properties of the speaker's ambient language. Third, clinical data from dysarthria and apraxia of speech provide the background for a discussion about the theoretical underpinnings of domain-general versus domain-specific views of speech motor control. The article ends with a brief sketch of a holistic neurophonetic approach in experimental inquiries, assessment, and treatment of neuromotor speech impairment. Copyright © 2013 S. Karger AG, Basel. Source


Marien P.,Vrije Universiteit Brussel | Marien P.,Advanced Studies Institute of the Royal Flemish Academy of Belgium for science and the Arts | Ackermann H.,University of Tubingen | Adamaszek M.,University of Leipzig | And 19 more authors.
Cerebellum | Year: 2014

In less than three decades, the concept "cerebellar neurocognition" has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the "linguistic cerebellum" in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper. © Springer Science+Business Media 2013. Source


Edmed S.L.,Clinical Neuropsychology Research Group | Edmed S.L.,Queensland University of Technology | Sullivan K.A.,Clinical Neuropsychology Research Group | Sullivan K.A.,Queensland University of Technology
Brain Injury | Year: 2015

Primary objective: To investigate the influence of the diagnostic terms 'concussion' and 'mild traumatic brain injury' (mTBI) on contact-sport players' injury perceptions and expected symptoms from a sport-related mTBI. It was hypothesized that contact-sport players would hold more negative injury perceptions and expect greater symptom disturbance from a sport-related injury that was diagnosed as an 'mTBI' compared to 'concussion' or an undiagnosed injury. Methods and procedures: One hundred and twenty-two contact-sport players were randomly allocated to one of three conditions in which they read a sport-related mTBI vignette that varied only according to whether the person depicted in the vignette was diagnosed with concussion (n=40), mTBI (n=41) or received no diagnosis (control condition; n=41). After reading the vignette, participants rated their injury perceptions (perceived undesirability, chronicity and consequences) and expectations of post-concussion syndrome (PCS) and post-traumatic stress disorder (PTSD) symptoms 6 months post-injury. Main outcomes: There were no significant differences in contact-sport players' injury perceptions or symptom expectations from a sport-related mTBI when it was diagnosed as an mTBI, concussion or when no diagnosis was given. Conclusions: Diagnostic terminology does not appear to have a potent influence on symptom expectation and injury perceptions in contact-sport players. © 2015 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted. Source

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