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Nasal chemosensory-stimulation evoked activity patterns in the rat trigeminal ganglion visualized by in vivo voltage-sensitive dye imaging.

Rothermel M, Ng BS, Grabska-Barwińska A, Hatt H, Jancke D - PLoS ONE (2011)

Bottom Line: Mammalian nasal chemosensation is predominantly mediated by two independent neuronal pathways, the olfactory and the trigeminal system.Within the early olfactory system, spatiotemporal responses of the olfactory bulb to various odorants have been mapped in great detail.Application of different chemical stimuli to the nasal cavity elicited distinct, stimulus-category specific, spatiotemporal activation patterns that comprised activated as well as suppressed areas.

View Article: PubMed Central - PubMed

Affiliation: Lehrstuhl für Zellphysiologie, Ruhr-Universität, Bochum, Germany.

ABSTRACT
Mammalian nasal chemosensation is predominantly mediated by two independent neuronal pathways, the olfactory and the trigeminal system. Within the early olfactory system, spatiotemporal responses of the olfactory bulb to various odorants have been mapped in great detail. In contrast, far less is known about the representation of volatile chemical stimuli at an early stage in the trigeminal system, the trigeminal ganglion (TG), which contains neurons directly projecting to the nasal cavity. We have established an in vivo preparation that allows high-resolution imaging of neuronal population activity from a large region of the rat TG using voltage-sensitive dyes (VSDs). Application of different chemical stimuli to the nasal cavity elicited distinct, stimulus-category specific, spatiotemporal activation patterns that comprised activated as well as suppressed areas. Thus, our results provide the first direct insights into the spatial representation of nasal chemosensory information within the trigeminal ganglion imaged at high temporal resolution.

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Related in: MedlinePlus

Suppression of ganglionic activity.Raster plots and corresponding Peri-Stimulus-Time-Histogram of spike responses to ethanol (A) CO2 (B) or citral (C) application (insert: electrode penetration site) (4 trials; bin factor 100 ms); blue = spontaneous activity; black = stimulus evoked activity; note the rhythmic spontaneous activity found in this region. This spontaneous spiking activity is suppressed by CO2 and ethanol application. Recovery from suppression is observed after several seconds. Spontaneous activity is not influenced by citral. Recording duration = 20 s; red lines = stimulus on- and offset.
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pone-0026158-g005: Suppression of ganglionic activity.Raster plots and corresponding Peri-Stimulus-Time-Histogram of spike responses to ethanol (A) CO2 (B) or citral (C) application (insert: electrode penetration site) (4 trials; bin factor 100 ms); blue = spontaneous activity; black = stimulus evoked activity; note the rhythmic spontaneous activity found in this region. This spontaneous spiking activity is suppressed by CO2 and ethanol application. Recovery from suppression is observed after several seconds. Spontaneous activity is not influenced by citral. Recording duration = 20 s; red lines = stimulus on- and offset.

Mentions: Interestingly, the strong trigeminal agonists also evoked prominent suppression (as compared to baseline) of the dye signal around near-posterior medial parts of the TG (blue areas Figure 3A/B). Electrode penetrations within these areas revealed rhythmic spontaneous spike activity (Figure 5, blue) uncorrelated with neither heartbeat nor artificial respiration (switching off the respirator cycles for 30 s did not affect the activity). This spontaneous spiking activity was selectively suppressed when the strong trigeminal agonists were applied (Figure 5A/B; black bars) with a mean stimulus induced spike rate reduction of 55.2%±12.9, n = 5. No reduction of spontaneous activity at the same area was observed after citral application (Figure 5C).


Nasal chemosensory-stimulation evoked activity patterns in the rat trigeminal ganglion visualized by in vivo voltage-sensitive dye imaging.

Rothermel M, Ng BS, Grabska-Barwińska A, Hatt H, Jancke D - PLoS ONE (2011)

Suppression of ganglionic activity.Raster plots and corresponding Peri-Stimulus-Time-Histogram of spike responses to ethanol (A) CO2 (B) or citral (C) application (insert: electrode penetration site) (4 trials; bin factor 100 ms); blue = spontaneous activity; black = stimulus evoked activity; note the rhythmic spontaneous activity found in this region. This spontaneous spiking activity is suppressed by CO2 and ethanol application. Recovery from suppression is observed after several seconds. Spontaneous activity is not influenced by citral. Recording duration = 20 s; red lines = stimulus on- and offset.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198387&req=5

pone-0026158-g005: Suppression of ganglionic activity.Raster plots and corresponding Peri-Stimulus-Time-Histogram of spike responses to ethanol (A) CO2 (B) or citral (C) application (insert: electrode penetration site) (4 trials; bin factor 100 ms); blue = spontaneous activity; black = stimulus evoked activity; note the rhythmic spontaneous activity found in this region. This spontaneous spiking activity is suppressed by CO2 and ethanol application. Recovery from suppression is observed after several seconds. Spontaneous activity is not influenced by citral. Recording duration = 20 s; red lines = stimulus on- and offset.
Mentions: Interestingly, the strong trigeminal agonists also evoked prominent suppression (as compared to baseline) of the dye signal around near-posterior medial parts of the TG (blue areas Figure 3A/B). Electrode penetrations within these areas revealed rhythmic spontaneous spike activity (Figure 5, blue) uncorrelated with neither heartbeat nor artificial respiration (switching off the respirator cycles for 30 s did not affect the activity). This spontaneous spiking activity was selectively suppressed when the strong trigeminal agonists were applied (Figure 5A/B; black bars) with a mean stimulus induced spike rate reduction of 55.2%±12.9, n = 5. No reduction of spontaneous activity at the same area was observed after citral application (Figure 5C).

Bottom Line: Mammalian nasal chemosensation is predominantly mediated by two independent neuronal pathways, the olfactory and the trigeminal system.Within the early olfactory system, spatiotemporal responses of the olfactory bulb to various odorants have been mapped in great detail.Application of different chemical stimuli to the nasal cavity elicited distinct, stimulus-category specific, spatiotemporal activation patterns that comprised activated as well as suppressed areas.

View Article: PubMed Central - PubMed

Affiliation: Lehrstuhl für Zellphysiologie, Ruhr-Universität, Bochum, Germany.

ABSTRACT
Mammalian nasal chemosensation is predominantly mediated by two independent neuronal pathways, the olfactory and the trigeminal system. Within the early olfactory system, spatiotemporal responses of the olfactory bulb to various odorants have been mapped in great detail. In contrast, far less is known about the representation of volatile chemical stimuli at an early stage in the trigeminal system, the trigeminal ganglion (TG), which contains neurons directly projecting to the nasal cavity. We have established an in vivo preparation that allows high-resolution imaging of neuronal population activity from a large region of the rat TG using voltage-sensitive dyes (VSDs). Application of different chemical stimuli to the nasal cavity elicited distinct, stimulus-category specific, spatiotemporal activation patterns that comprised activated as well as suppressed areas. Thus, our results provide the first direct insights into the spatial representation of nasal chemosensory information within the trigeminal ganglion imaged at high temporal resolution.

Show MeSH
Related in: MedlinePlus