Quantitative analysis of neuronal response properties in primary and higher-order auditory cortical fields of awake house mice (Mus musculus).
Bottom Line: Field similarities were noted as significant correlations between CFs and BFs, V-shaped frequency tuning curves, similar minimum response thresholds and non-monotonic rate-level functions in approximately two-thirds of the neurons.Comparative and quantitative analyses showed that the measured response characteristics were, to various degrees, susceptible to influences of anesthetics.Therefore, studies of neuronal responses in the awake AC are important in order to establish adequate relationships between neuronal data and auditory perception and acoustic response behavior.
Affiliation: Institute of Neurobiology, University of Ulm, Institute of Neurobiology 89081 Ulm, Germany; Systems Neurophysiology, Department of Cognitive Neurology, Werner Reichardt Centre for Integrative Neuroscience, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.Show MeSH
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Mentions: The relationships between BFs and CFs of the neurons are shown in Fig.8 separately for each field. Despite variability between CF and BF values, the indicated regression lines were all statistically significant (AI, AAF, DP, P < 0.001; AII, P < 0.01). The slope values for the AI, AAF and DP were all very close to 1.0, and the regression lines showed that, on average, BFs and CFs were almost the same in these fields. AII differed in this respect from the AAF and DP, because both the slope and the y-axis intercept of the AII regression line differed significantly from those of the AAF and DP (AII vs. AAF, P < 0.05 in each case; AII vs. DP, P < 0.01 in each case). Differences between the AII and AI occurred as a trend (P < 0.1). In order to further analyse the relationship between the BF and CF in the fields, we analysed the cases in which the largest differences between the CF and BF occurred. Figure8 shows units with differences of less than ± 0.5 octaves (black dots), units with differences of ± 0.5–1.5 octaves (green dots), and units with larger differences. For most units in the AI and AAF, differences between the CF and BF were within ± 0.5 octaves (red dots). In the AII and DP, these differences reached > 1.5 octaves for a considerable number of units, favoring much higher BFs in the AII and lower BFs in the DP with regard to a given CF. In summary, the frequency range of the highest activity of a unit could deviate more from the unit’s CF in the higher-order fields (AII and DP) than in the primary fields (AI and AAF).
Affiliation: Institute of Neurobiology, University of Ulm, Institute of Neurobiology 89081 Ulm, Germany; Systems Neurophysiology, Department of Cognitive Neurology, Werner Reichardt Centre for Integrative Neuroscience, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.