Auditory response properties of neurons in the tectal longitudinal column of the rat.
The newly-discovered tectal longitudinal column (TLC) spans the paramedian region of the mammalian tectum. It has connections with several nuclei of the auditory system. In this report, we provide the first detailed description of the responses of TLC neurons to auditory stimuli, including monaural and binaural tones and amplitude modulated tones. For comparison, responses in the inferior colliculus (IC) were also recorded. Neurons in the TLC were sensitive to similar ranges of frequency as IC neurons, could have comparably low thresholds, and showed primarily excitatory responses to stimulation of the contralateral ear with either phasic or sustained response patterns. Differences of TLC compared to IC neurons included broader frequency tuning, higher average threshold, longer response latencies, little synchronization or rate tuning to amplitude modulation frequency and a smaller degree of inhibition evoked by stimulation of the ipsilateral ear. These features of TLC neurons suggest a role for the TLC in descending auditory pathways.
Marshall
Allen F
AF
Department of Otolaryngology, Head and Neck Surgery, CB#7070, G0412 Neurosciences Hospital, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7070, United States.
Pearson
James M
JM
Falk
Stephanie E
SE
Skaggs
John D
JD
Crocker
William D
WD
Saldaña
Enrique
E
Fitzpatrick
Douglas C
DC
D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D004566:Electrodes; D005072:Evoked Potentials, Auditory / Q000502:physiology; D007245:Inferior Colliculi / Q000502:physiology*; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology