Monaural and binaural response properties of single neurons in the rat's dorsal nucleus of the lateral lemniscus.
Extracellular recordings were made with microelectrodes from single neurons in the rat's dorsal nucleus of the lateral lemniscus (DNLL) and response characteristics were determined for monaural and binaural acoustic stimulation. The vast majority of DNLL neurons were narrowly tuned to sound frequency and their temporal responses to contralateral tone pulses fell into one of three broad categories: onset (57%), sustained (21%) or onset-pause-sustained (22%). Most DNLL neurons fired multiple action potentials to a single click delivered to the contralateral ear. The majority (77%) of DNLL neurons showed a monotonic increase in the number of spikes elicited by contralateral tone pulses of increasing sound pressure level; the remaining cells were weakly non-monotonic. No obvious tonotopic pattern was found in the distribution of characteristic frequency of neurons in DNLL. Most DNLL neurons exhibited either excitatory/inhibitory (74%) or excitatory/excitatory (9%) binaural response patterns. The remaining cells (17%) were monaural and driven exclusively by stimulation of the contralateral ear. The binaural neurons in DNLL were sensitive to both interaural intensity and interaural time differences as determined by presentation of dichotic tone bursts and clicks respectively. The responses of DNLL neurons could be distinguished on the basis of monaural and binaural response characteristics from those in surrounding areas including the sagulum, paralemniscal zone and the intermediate nucleus of the lateral lemniscus.
Institute of Neuroscience and Department of Psychology, Carleton University, Ottawa, Ont., Canada. jkelly@ccs.carleton.ca
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JB
Kelly
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Buckthought
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Kidd
D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D017626:Cochlear Nucleus / Q000033:anatomy & histology / Q000502:physiology*; D004567:Electrodes, Implanted; D005829:Geniculate Bodies / Q000502:physiology; D007245:Inferior Colliculi / Q000033:anatomy & histology / Q000502:physiology; D008297:Male; D009412:Nerve Fibers / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D000159:Vestibulocochlear Nerve / Q000033:anatomy & histology / Q000502:physiology*