Shared Brain Lateralization Patterns in Language and Acheulean Stone Tool Production: A Functional Transcranial Doppler Ultrasound Study

• Published in: PloS one Vol. 8; no. 8; p. e72693
• Main Authors: Uomini, Natalie Thaïs, Meyer, Georg Friedrich
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.08.2013; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Archaeology; Biology; Blood; Blood flow; Blood Volume - physiology; Brain; Brain - blood supply; Brain - physiology; Brain Mapping; Cerebral blood flow; Cerebrovascular Circulation - physiology; Cognition & reasoning; Cognitive ability; Cues; Doppler effect; Echoencephalography; Evolution; Female; Flow velocity; Functional Laterality - physiology; Hemispheric laterality; Hemodynamics; Humans; Language; Male; Medical imaging; Medicine; Middle Aged; Neural networks; Neuroimaging; Neurology; Planning; Prehistoric; Prehistoric era; Regional Blood Flow - physiology; Skills; Social and Behavioral Sciences; Speech - physiology; Stone; Studies; Substrates; Task Performance and Analysis; Time Factors; Tool Use Behavior - physiology; Ultrasonic imaging; Ultrasonography, Doppler, Transcranial - methods; Ultrasound; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0072693

The popular theory that complex tool-making and language co-evolved in the human lineage rests on the hypothesis that both skills share underlying brain processes and systems. However, language and stone tool-making have so far only been studied separately using a range of neuroimaging techniques and diverse paradigms. We present the first-ever study of brain activation that directly compares active Acheulean tool-making and language. Using functional transcranial Doppler ultrasonography (fTCD), we measured brain blood flow lateralization patterns (hemodynamics) in subjects who performed two tasks designed to isolate the planning component of Acheulean stone tool-making and cued word generation as a language task. We show highly correlated hemodynamics in the initial 10 seconds of task execution. Stone tool-making and cued word generation cause common cerebral blood flow lateralization signatures in our participants. This is consistent with a shared neural substrate for prehistoric stone tool-making and language, and is compatible with language evolution theories that posit a co-evolution of language and manual praxis. In turn, our results support the hypothesis that aspects of language might have emerged as early as 1.75 million years ago, with the start of Acheulean technology.