The golden mean: A systems biology approach to language disorders

Abstract

Current clinical typologies of language disorders are mostly based on symptomatic criteria. Nonetheless, they often fail to categorize and characterize patients unambiguously, essentially because of the widespread problems of comorbidity and heterogeneity. Likewise, they usually fail to incorporate etiological factors in a distinctive way, particularly, what we have learnt in the last decades about the genetic causes of neurodevelopmental conditions. Ultimately, these shortcomings are expected to impact negatively on therapies and the recovery of patient’s abilities. This paper argues in favour of a systems biology approach to language disorders, which pays attention to the way in which the myriad of the biological factors involved (at the bottom) interact complexly to regulate language development and processing (at the surface). In particular, it argues for a classification of disorders based on intermediate-level components, like brain oscillations. This fresh approach to the etiopathogenesis of language disorders, which is more biologically motivated and more theoretically grounded, should allow identify robust endophenotypes of language disorders that can be used as reliable hallmarks for an earlier and more accurate diagnosis.

Why brain oscillations are improving our understanding of language

“…Importantly, these candidate genes map on to specific aspects of brain function, particularly on to neurotransmitter function, and particularly through dopaminergic, GABAergic and glutamatergic synapses. A systems biology approach to language, focused on the dynamics of cellular and organismal function and on the (emergent) properties of the whole system, is compulsory if one wants to understand how language emerges from these complex interactions (Benítez-Burraco, 2019). It seems that the biological specificity of language may emerge at the oscillomic level (reproduced from Murphy and Benítez-Burraco, 2017;Figure 8)…”

“…Moreover, these deficits are only indirectly related to (broad) cognitive deficits at the bottom. Finally, although most of these conditions have a genetic basis, the same gene can contribute to more than one cognitive disorder (see Benítez-Burraco, 2019 for an ample discussion of these problems for clinical linguistics). This circumstance seemingly explains why the divide between the genetics and pathophysiology of prevalent cognitive/language disorders like autism spectrum disorder (ASD), schizophrenia (SZ) or developmental dyslexia (DD) remains open.…”