Limits...
An Overrepresentation of High Frequencies in the Mouse Inferior Colliculus Supports the Processing of Ultrasonic Vocalizations.

Garcia-Lazaro JA, Shepard KN, Miranda JA, Liu RC, Lesica NA - PLoS ONE (2015)

Bottom Line: Auditory brainstem response measurements suggested stronger responses in the midbrain relative to the periphery for frequencies higher than 32 kHz.This result was confirmed by single- and multi-unit recordings showing that high ultrasonic frequency tones and vocalizations elicited responses from only a small fraction of cells in the periphery, while a much larger fraction of cells responded in the inferior colliculus.These results suggest that the processing of communication calls in mice is supported by a specialization of the auditory system for high frequencies that emerges at central stations of the auditory pathway.

View Article: PubMed Central - PubMed

Affiliation: Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, United Kingdom.

ABSTRACT
Mice are of paramount importance in biomedical research and their vocalizations are a subject of interest for researchers across a wide range of health-related disciplines due to their increasingly important value as a phenotyping tool in models of neural, speech and language disorders. However, the mechanisms underlying the auditory processing of vocalizations in mice are not well understood. The mouse audiogram shows a peak in sensitivity at frequencies between 15-25 kHz, but weaker sensitivity for the higher ultrasonic frequencies at which they typically vocalize. To investigate the auditory processing of vocalizations in mice, we measured evoked potential, single-unit, and multi-unit responses to tones and vocalizations at three different stages along the auditory pathway: the auditory nerve and the cochlear nucleus in the periphery, and the inferior colliculus in the midbrain. Auditory brainstem response measurements suggested stronger responses in the midbrain relative to the periphery for frequencies higher than 32 kHz. This result was confirmed by single- and multi-unit recordings showing that high ultrasonic frequency tones and vocalizations elicited responses from only a small fraction of cells in the periphery, while a much larger fraction of cells responded in the inferior colliculus. These results suggest that the processing of communication calls in mice is supported by a specialization of the auditory system for high frequencies that emerges at central stations of the auditory pathway.

No MeSH data available.


Related in: MedlinePlus

Multi-unit responses in the dorsal cochlear nucleus to tones and vocalizations.(A) Each panel shows FRAs for each of the 32 recording sites across one electrode penetration in the DCN. Two different penetrations are shown with the most rostral location at the top and the most caudal at the bottom. (B) FRAs estimated from multi-unit activity at three different recording sites along the medial-lateral axis in the DCN. The location of each site is indicated by the corresponding white rectangle in Fig 3A. (C) Histogram showing the distribution of CFs across the sites we recorded from in a population of 8 animals. (D) PSTHs of the responses to the vocalization stimuli for the two electrode penetrations for which FRAs were shown in (A). For each recording site, the x-axis (time) covers the range from 0 to 130 msec and the y-axis (SDs above spontaneous) covers the range from 0 to 5. (E) SNR for each recording site as a function of its Fmax. For each site, SNR values were averaged across the 9 different vocalizations tested.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526676&req=5

pone.0133251.g003: Multi-unit responses in the dorsal cochlear nucleus to tones and vocalizations.(A) Each panel shows FRAs for each of the 32 recording sites across one electrode penetration in the DCN. Two different penetrations are shown with the most rostral location at the top and the most caudal at the bottom. (B) FRAs estimated from multi-unit activity at three different recording sites along the medial-lateral axis in the DCN. The location of each site is indicated by the corresponding white rectangle in Fig 3A. (C) Histogram showing the distribution of CFs across the sites we recorded from in a population of 8 animals. (D) PSTHs of the responses to the vocalization stimuli for the two electrode penetrations for which FRAs were shown in (A). For each recording site, the x-axis (time) covers the range from 0 to 130 msec and the y-axis (SDs above spontaneous) covers the range from 0 to 5. (E) SNR for each recording site as a function of its Fmax. For each site, SNR values were averaged across the 9 different vocalizations tested.

Mentions: We next investigated the representation of high ultrasonic frequencies in the dorsal cochlear nucleus by recording multi-unit activity using a large multi-electrode array. To sample the entire DCN, we performed multiple electrode penetrations oriented along the rostral-caudal axis (see Fig 3A for FRAs estimated from multi-unit activity for two example penetrations, and Fig 3B for FRAs estimated for three example sites). The distribution of CFs across all recordings sites in the DCN was centered around 20–30 kHz (Fig 3C), consistent with previous studies [35, 36]. As in the AN, only a small number of sites with sensitivity to high frequencies responded significantly to the vocalizations (118 recoding sites out of a total of 1248 ≈ 9%, 95% CI [5% 15%], see Fig 3D and 3E). The results from the AN and DCN are therefore consistent in suggesting that vocalizations evoke responses in only the small fraction of cells that are sensitive to high ultrasonic frequencies and, thus, are not well represented in the auditory periphery.


An Overrepresentation of High Frequencies in the Mouse Inferior Colliculus Supports the Processing of Ultrasonic Vocalizations.

Garcia-Lazaro JA, Shepard KN, Miranda JA, Liu RC, Lesica NA - PLoS ONE (2015)

Multi-unit responses in the dorsal cochlear nucleus to tones and vocalizations.(A) Each panel shows FRAs for each of the 32 recording sites across one electrode penetration in the DCN. Two different penetrations are shown with the most rostral location at the top and the most caudal at the bottom. (B) FRAs estimated from multi-unit activity at three different recording sites along the medial-lateral axis in the DCN. The location of each site is indicated by the corresponding white rectangle in Fig 3A. (C) Histogram showing the distribution of CFs across the sites we recorded from in a population of 8 animals. (D) PSTHs of the responses to the vocalization stimuli for the two electrode penetrations for which FRAs were shown in (A). For each recording site, the x-axis (time) covers the range from 0 to 130 msec and the y-axis (SDs above spontaneous) covers the range from 0 to 5. (E) SNR for each recording site as a function of its Fmax. For each site, SNR values were averaged across the 9 different vocalizations tested.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526676&req=5

pone.0133251.g003: Multi-unit responses in the dorsal cochlear nucleus to tones and vocalizations.(A) Each panel shows FRAs for each of the 32 recording sites across one electrode penetration in the DCN. Two different penetrations are shown with the most rostral location at the top and the most caudal at the bottom. (B) FRAs estimated from multi-unit activity at three different recording sites along the medial-lateral axis in the DCN. The location of each site is indicated by the corresponding white rectangle in Fig 3A. (C) Histogram showing the distribution of CFs across the sites we recorded from in a population of 8 animals. (D) PSTHs of the responses to the vocalization stimuli for the two electrode penetrations for which FRAs were shown in (A). For each recording site, the x-axis (time) covers the range from 0 to 130 msec and the y-axis (SDs above spontaneous) covers the range from 0 to 5. (E) SNR for each recording site as a function of its Fmax. For each site, SNR values were averaged across the 9 different vocalizations tested.
Mentions: We next investigated the representation of high ultrasonic frequencies in the dorsal cochlear nucleus by recording multi-unit activity using a large multi-electrode array. To sample the entire DCN, we performed multiple electrode penetrations oriented along the rostral-caudal axis (see Fig 3A for FRAs estimated from multi-unit activity for two example penetrations, and Fig 3B for FRAs estimated for three example sites). The distribution of CFs across all recordings sites in the DCN was centered around 20–30 kHz (Fig 3C), consistent with previous studies [35, 36]. As in the AN, only a small number of sites with sensitivity to high frequencies responded significantly to the vocalizations (118 recoding sites out of a total of 1248 ≈ 9%, 95% CI [5% 15%], see Fig 3D and 3E). The results from the AN and DCN are therefore consistent in suggesting that vocalizations evoke responses in only the small fraction of cells that are sensitive to high ultrasonic frequencies and, thus, are not well represented in the auditory periphery.

Bottom Line: Auditory brainstem response measurements suggested stronger responses in the midbrain relative to the periphery for frequencies higher than 32 kHz.This result was confirmed by single- and multi-unit recordings showing that high ultrasonic frequency tones and vocalizations elicited responses from only a small fraction of cells in the periphery, while a much larger fraction of cells responded in the inferior colliculus.These results suggest that the processing of communication calls in mice is supported by a specialization of the auditory system for high frequencies that emerges at central stations of the auditory pathway.

View Article: PubMed Central - PubMed

Affiliation: Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, United Kingdom.

ABSTRACT
Mice are of paramount importance in biomedical research and their vocalizations are a subject of interest for researchers across a wide range of health-related disciplines due to their increasingly important value as a phenotyping tool in models of neural, speech and language disorders. However, the mechanisms underlying the auditory processing of vocalizations in mice are not well understood. The mouse audiogram shows a peak in sensitivity at frequencies between 15-25 kHz, but weaker sensitivity for the higher ultrasonic frequencies at which they typically vocalize. To investigate the auditory processing of vocalizations in mice, we measured evoked potential, single-unit, and multi-unit responses to tones and vocalizations at three different stages along the auditory pathway: the auditory nerve and the cochlear nucleus in the periphery, and the inferior colliculus in the midbrain. Auditory brainstem response measurements suggested stronger responses in the midbrain relative to the periphery for frequencies higher than 32 kHz. This result was confirmed by single- and multi-unit recordings showing that high ultrasonic frequency tones and vocalizations elicited responses from only a small fraction of cells in the periphery, while a much larger fraction of cells responded in the inferior colliculus. These results suggest that the processing of communication calls in mice is supported by a specialization of the auditory system for high frequencies that emerges at central stations of the auditory pathway.

No MeSH data available.


Related in: MedlinePlus