Science Times: Brain Freeze: Focal Cooling Reveals Distinct Cortical Sites Underlying Speech

Speech is a fundamental human function undergirding much of our daily interaction with the world. However, it is a remarkably complex process drawing on the interaction of many regions of the brain.1,2 Although methods including direct electric stimulation, transcranial magnetic stimulation, and lesion studies have identified several involved regions, including the Broca area in the left inferior frontal gyrus and speech motor cortex in the inferior precentral gyrus, the exact functions of these regions remain incompletely understood. The development of new techniques to test hypotheses of regional function may enable a more precise understanding of these interacting brain regions and their relative contributions to speech production.In a recent article in Neuron, Long et al3 from the University of Iowa described using focal cooling to examine the roles of individual brain regions in human speech production in neurosurgical patients. They used custom focal cooling instruments incorporating either infusion of chilled saline or Peltier cooling, both of which they tested in a sheep model. The authors then used these probes in 16 patients undergoing awake craniotomy with language mapping for intractable epilepsy or brain tumor resection. The authors cooled 42 total regions within the inferior frontal exposures while patients produced easily generated overlearned vocal sequences (eg, days of the week or number sequences).

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