title: Murine auditory brainstem evoked response: putative two-channel differentiation of peripheral and central neural pathways.
abstract: Standard noninvasive recordings of the auditory brainstem evoked response (ABR) from a single pair of obliquely oriented electrodes (typically midline vertex referenced to mastoid) confound inherently distinct signals propagating over peripheral and central neural pathways differing in location and spatial orientation. We describe here a technique for recording short-latency auditory evoked potentials that putatively differentiates peripheral and central neural activity in the mouse and rat. The technique involves recording from two orthogonally oriented electrode pairs using fast sample rates (100 k/s) to accurately measure differences in neural timing and waveform morphology. Electrodes oriented in a transverse plane (mastoid-to-mastoid) register an initial positive-going ABR peak (P1T) earlier than a series of peaks recorded from electrodes oriented along the midline (anterior and posterior to the inter-aural line). The absolute P1T latency is consistent with an origin in the primary auditory nerve, while the delayed midline latencies implicate activity farther along central neural pathways. Differences between these latencies (midline minus transverse) provide new and precise measures of central conduction time (CCT), which in one case is as brief as 0.10 ms. Results in wild type (WT) and knockout (KO) mice, as well as rats, show significant differences in absolute latencies as well as CCT.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California at Los Angeles 90095-7332, USA. garyg@ucla.edu
authors.forename: Gary
authors.initials: G
authors.lastname: Galbraith
authors.forename: James
authors.initials: J
authors.lastname: Waschek
authors.forename: Brian
authors.initials: B
authors.lastname: Armstrong
authors.forename: John
authors.initials: J
authors.lastname: Edmond
authors.forename: Ivan
authors.initials: I
authors.lastname: Lopez
authors.forename: Weixin
authors.initials: W
authors.lastname: Liu
authors.forename: Ira
authors.initials: I
authors.lastname: Kurtz
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D000831:Animals, Newborn; D002490:Central Nervous System / Q000502:physiology*; D004566:Electrodes; D004569:Electroencephalography / Q000379:methods; D001330:Electronic Data Processing; D016057:Evoked Potentials, Auditory, Brain Stem / Q000235:genetics / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D018345:Mice, Knockout; D009434:Neural Pathways / Q000502:physiology* / Q000528:radiation effects; D010525:Peripheral Nerves / Q000502:physiology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000172:deficiency; D051381:Rats; D011930:Reaction Time / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000172:deficiency
chemical_list: C495402:Adcyap1 protein, mouse; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide