title: Neurophysiologic markers in laryngeal muscles indicate functional anatomy of laryngeal primary motor cortex and premotor cortex in the caudal opercular part of inferior frontal gyrus.
abstract: OBJECTIVE
  The aim of this study was to identify neurophysiologic markers generated by primary motor and premotor cortex for laryngeal muscles, recorded from laryngeal muscle.
  
  
  METHODS
  Ten right-handed healthy subjects underwent navigated transcranial magnetic stimulation (nTMS) and 18 patients underwent direct cortical stimulation (DCS) over the left hemisphere, while recording neurophysiologic markers, short latency response (SLR) and long latency response (LLR) from cricothyroid muscle. Both healthy subjects and patients were engaged in the visual object-naming task. In healthy subjects, the stimulation was time-locked at 10-300 ms after picture presentation while in the patients it was at zero time.
  
  
  RESULTS
  The latency of SLR in healthy subjects was 12.66 ± 1.09 ms and in patients 12.67 ± 1.23 ms. The latency of LLR in healthy subjects was 58.5 ± 5.9 ms, while in patients 54.25 ± 3.69 ms. SLR elicited by the stimulation of M1 for laryngeal muscles corresponded to induced dysarthria, while LLR elicited by stimulation of the premotor cortex in the caudal opercular part of inferior frontal gyrus, recorded from laryngeal muscle, corresponded to speech arrest in patients and speech arrest and/or language disturbances in healthy subjects.
  
  
  CONCLUSIONS
  In both groups, SLR indicated location of M1 for laryngeal muscles, and LLR location of premotor cortex in the caudal opercular part of inferior frontal gyrus, recorded from laryngeal muscle, while stimulation of these areas in the dominant hemisphere induced transient speech disruptions.
  
  
  CONCLUSIONS
  Described methodology can be used in preoperative mapping, and it is expected to facilitate surgical planning and intraoperative mapping, preserving these areas from injuries.
authors.affiliation: Laboratory for Human and Experimental Neurophysiology (LAHEN), School of Medicine, University of Split, Split, Croatia; Department for Intraoperative Neurophysiology, Roosevelt Hospital, New York, NY, USA. Electronic address: vdeletis@chpnet.org.
authors.forename: Vedran
authors.initials: V
authors.lastname: Deletis
authors.affiliation: Laboratory for Human and Experimental Neurophysiology (LAHEN), School of Medicine, University of Split, Split, Croatia.
authors.forename: Maja
authors.initials: M
authors.lastname: Rogić
authors.affiliation: University Hospital Bellvitge, Barcelona, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Fernández-Conejero
authors.affiliation: University Hospital Bellvitge, Barcelona, Spain.
authors.forename: Andreu
authors.initials: A
authors.lastname: Gabarrós
authors.affiliation: Laboratory for Human and Experimental Neurophysiology (LAHEN), School of Medicine, University of Split, Split, Croatia; Department for Research in Biomedicine and Health, School of Medicine, University of Split, Split, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Jerončić
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology / Q000523:psychology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006801:Humans; D007821:Laryngeal Muscles / Q000294:innervation / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology; D011597:Psychomotor Performance; D013064:Speech Disorders / Q000473:pathology; D050781:Transcranial Magnetic Stimulation; D014796:Visual Perception; D055815:Young Adult
keywords: Broca area; Electrical stimulation of motor speech areas; Inferior frontal gyrus; Motor speech areas; Navigated transcranial magnetic stimulation; Neurophysiologic markers; Premotor cortex; Primary motor cortex for laryngeal muscles