[Surgical treatment of intracerebral frontal lobe tumors. Part II: speech functional system]

Complexity of neurosurgery for intracerebral frontal lobe tumors is determined by adjacent cortical and subcortical functional zones and white matter fibers connecting these areas and responsible for various neurocognitive functions. When removing frontal lobe gliomas in dominant hemisphere, neurosurgeons are forced to interact with speech functional system. Recent studies have shown that neuroanatomical basis of speech is more complex, multicomponent and integrated system than previously thought. Postulates of classical model of speech analyzer organization do not coincide with results of modern researches in speech physiology and pathophysiology. According to modern neuroscience, cognitive functions of the brain are realized by distributed groups of connected and synchronized networks of neurons rather separate neural centers as previously assumed. To understand such a complex cognitive system as speech, it is necessary to recognize not only elementary components of this system, but also their interaction and appropriate new properties. This review systematizes modern ideas about organization of speech functional system from the perspective of neurosurgery for glial frontal lobe tumors.