You may be interested in some measurements obtained by Brad May and Murray Sachs to VCN units in awake behaving cats. The response properties of these units
in anaesthetised animals are similar to those of the AN, so this may be as close as you’ll get to how the AN might respond in the awake animal:
DYNAMIC-RANGE OF NEURAL RATE RESPONSES IN THE VENTRAL COCHLEAR NUCLEUS OF
MAY, BJ (MAY, BJ);
SACHS, MB (SACHS, MB)
Source: JOURNAL OF NEUROPHYSIOLOGY Volume: 68 Issue: 5 Pages: 1589-1602 Published: NOV
37 (from Web of Science)
41 [ view
related records ] Citation
Abstract: 1. Response thresholds and dynamic range properties of neurons in the ventral cochlear nucleus (VCN) of
awake cats were measured by fitting a computational model to rate-level functions for best frequency (BF) tone bursts and for bursts of broad-band noise. Dynamic range measurements were performed in quiet and in the presence of
continuous background noise.
2. The sample of neurons obtained in the VCN of awake cats exhibited a variety of peristimulus histograms (PSTHs) and thresholds. All PSTH response types previously described in the VCN of anesthetized cats were found in
awake cats. The lowest thresholds for neural responses were observed at sound pressure levels that were equivalent to behavioral thresholds of absolute auditory sensitivity.
3. When responses to BF tones or bursts of broad-band noise were recorded in quiet backgrounds, the dynamic range properties of most units in the VCN of
awake cats were not significantly different from dynamic range properties of auditory nerve fibers (ANFs) in anesthetized cats or VCN units in decerebrate cats. All auditory units showed a larger dynamic range for noise bursts
than for tone bursts, but VCN units with primary-like and onset PSTHs showed larger dynamic ranges for responses to noise bursts than that of ANFs and VCN chopper units.
4. When tests were performed in the presence of continuous noise, rate-level functions for BF tone bursts shifted to higher tone levels and showed a more compressed range of driven rates in comparison with data obtained in quiet. Compression of the rate-level
function in noise resulted from an increase in driven rate at low tone levels and a decrease in rate at high tone levels. These changes in the rate-level function suggest that noise may reduce the range of BF tone levels that are potentially encoded by a unit's
rate responses. By exhibiting larger shifts and less compression in background noise, VCN units in
awake cats better preserved the dynamic range of their rate responses to BF tones than ANFs in anesthetized cats or VCN units in decerebrate cats.
5. Rate-level functions were obtained from a small sample of VCN units not only with the cat performing the behavioral task but also with the cat
awake and sitting quietly in the testing apparatus. No differences in noise-induced shift or compression were noted between the two testing conditions.
6. The dynamic range adjustments to noise exhibited by VCN units in
awake cats are similar to changes in the rate responses of ANFs that are elicited in anesthetized cats by electrical stimulation of the crossed olivocochlear bundle.
Dr. Bob Carlyon
MRC Cognition & Brain Sciences Unit
15 Chaucer Rd.
Cambridge CB2 7EF
Tel: +44 (0)1223 355294
Fax: +44 (0)1223 355294
MRC Centenary 1913-2013 | 100 years of life-changing discoveries
From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx]
On Behalf Of Derek Burton
Sent: 13 September 2013 07:27
Subject: Unanesthetized measurements
Has anyone made auditory nerve and/or basilar membrane motion measurements in awake, behaving (non-decerebrate) animals?
Thanks for any input,