Effect of sound pressure level on contralateral inhibition underlying duration-tuned neurons in the mammalian inferior colliculus
Bibliographic record
Abstract
Duration tuning in the mammalian inferior colliculus (IC) is created by the interaction of excitatory and inhibitory synaptic inputs. We used extracellular recordings and paired tone stimulation to measure the strength and time course of the contralateral inhibition underlying duration-tuned neurons (DTNs) in the IC of the awake bat. The onset time of a short, best duration (BD), excitatory probe tone set to +10 dB (re threshold) was varied relative to the onset of a longer-duration, nonexcitatory (NE) suppressor tone whose sound pressure level (SPL) was varied. Spikes evoked by the roving BD tone were suppressed when the stationary NE tone amplitude was at or above the BD tone threshold. When the NE tone was increased from 0 to +10 dB, the inhibitory latency became shorter than the excitatory first-spike latency and the duration of inhibition increased, but no further changes occurred at +20 dB (re BD tone threshold). We used the effective duration of inhibition as a function of the NE tone amplitude to obtain suppression-level functions that were used to estimate the inhibitory half-maximum SPL (ISPL 50 ). We also measured rate-level functions of DTNs with single BD tones varied in SPL and modeled the excitatory half-maximum SPL (ESPL 50 ). There was a correlation between the ESPL 50 and ISPL 50 , and the dynamic range of excitation and inhibition were similar. We conclude that the strength of inhibition changes in proportion to excitation as a function of SPL, and this feature likely contributes to the amplitude tolerance of the responses of DTNs. NEW & NOTEWORTHY Duration-tuned neurons arise from excitatory and inhibitory synaptic inputs offset in time. We measured the strength and time course of inhibition to changes in sound level. The onset of inhibition shortened while its duration lengthened as the stimulus level increased from 0 to +10 dB re threshold; however, no further changes were observed at +20 dB. Excitatory rate-level and inhibitory suppression-level response functions were strongly correlated, suggesting a mechanism for level tolerance in duration tuning.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".