Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway
<p>Abstract</p> <p>Background</p> <p>Short-term habituation of the startle response represents an elementary form of learning in mammals. The underlying mechanism is located within the primary startle pathway, presumably at sensory synapses on giant neurons in the cauda...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2006-05-01
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| Series: | BMC Neuroscience |
| Online Access: | http://www.biomedcentral.com/1471-2202/7/38 |
| _version_ | 1811295781411356672 |
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| author | Pilz Peter KD Plappert Claudia F Weber Maruschka Simons-Weidenmaier Nadine S Schmid Susanne |
| author_facet | Pilz Peter KD Plappert Claudia F Weber Maruschka Simons-Weidenmaier Nadine S Schmid Susanne |
| author_sort | Pilz Peter KD |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Short-term habituation of the startle response represents an elementary form of learning in mammals. The underlying mechanism is located within the primary startle pathway, presumably at sensory synapses on giant neurons in the caudal pontine reticular nucleus (PnC). Short trains of action potentials in sensory afferent fibers induce depression of synaptic responses in PnC giant neurons, a phenomenon that has been proposed to be the cellular correlate for short-term habituation. We address here the question whether both this synaptic depression and the short-term habituation of the startle response are localized at the presynaptic terminals of sensory afferents. If this is confirmed, it would imply that these processes take place prior to multimodal signal integration, rather than occurring at postsynaptic sites on PnC giant neurons that directly drive motor neurons.</p> <p>Results</p> <p>Patch-clamp recordings <it>in vitro </it>were combined with behavioral experiments; synaptic depression was specific for the input pathway stimulated and did not affect signals elicited by other sensory afferents. Concordant with this, short-term habituation of the acoustic startle response in behavioral experiments did not influence tactile startle response amplitudes and vice versa. Further electrophysiological analysis showed that the passive properties of the postsynaptic neuron were unchanged but revealed some alterations in short-term plasticity during depression. Moreover, depression was induced only by trains of presynaptic action potentials and not by single pulses. There was no evidence for transmitter receptor desensitization. In summary, the data indicates that the synaptic depression mechanism is located presynaptically.</p> <p>Conclusion</p> <p>Our electrophysiological and behavioral data strongly indicate that synaptic depression in the PnC as well as short-term habituation are located in the sensory part of the startle pathway, namely at the axon terminals of sensory afferents in the PnC. Our results further corroborate the link between synaptic depression and short-term habituation of the startle response.</p> |
| first_indexed | 2024-04-13T05:38:40Z |
| format | Article |
| id | doaj.art-9ae783eab600490fba6a59bf8fd4dd11 |
| institution | Directory Open Access Journal |
| issn | 1471-2202 |
| language | English |
| last_indexed | 2024-04-13T05:38:40Z |
| publishDate | 2006-05-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Neuroscience |
| spelling | doaj.art-9ae783eab600490fba6a59bf8fd4dd112022-12-22T03:00:11ZengBMCBMC Neuroscience1471-22022006-05-01713810.1186/1471-2202-7-38Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathwayPilz Peter KDPlappert Claudia FWeber MaruschkaSimons-Weidenmaier Nadine SSchmid Susanne<p>Abstract</p> <p>Background</p> <p>Short-term habituation of the startle response represents an elementary form of learning in mammals. The underlying mechanism is located within the primary startle pathway, presumably at sensory synapses on giant neurons in the caudal pontine reticular nucleus (PnC). Short trains of action potentials in sensory afferent fibers induce depression of synaptic responses in PnC giant neurons, a phenomenon that has been proposed to be the cellular correlate for short-term habituation. We address here the question whether both this synaptic depression and the short-term habituation of the startle response are localized at the presynaptic terminals of sensory afferents. If this is confirmed, it would imply that these processes take place prior to multimodal signal integration, rather than occurring at postsynaptic sites on PnC giant neurons that directly drive motor neurons.</p> <p>Results</p> <p>Patch-clamp recordings <it>in vitro </it>were combined with behavioral experiments; synaptic depression was specific for the input pathway stimulated and did not affect signals elicited by other sensory afferents. Concordant with this, short-term habituation of the acoustic startle response in behavioral experiments did not influence tactile startle response amplitudes and vice versa. Further electrophysiological analysis showed that the passive properties of the postsynaptic neuron were unchanged but revealed some alterations in short-term plasticity during depression. Moreover, depression was induced only by trains of presynaptic action potentials and not by single pulses. There was no evidence for transmitter receptor desensitization. In summary, the data indicates that the synaptic depression mechanism is located presynaptically.</p> <p>Conclusion</p> <p>Our electrophysiological and behavioral data strongly indicate that synaptic depression in the PnC as well as short-term habituation are located in the sensory part of the startle pathway, namely at the axon terminals of sensory afferents in the PnC. Our results further corroborate the link between synaptic depression and short-term habituation of the startle response.</p>http://www.biomedcentral.com/1471-2202/7/38 |
| spellingShingle | Pilz Peter KD Plappert Claudia F Weber Maruschka Simons-Weidenmaier Nadine S Schmid Susanne Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway BMC Neuroscience |
| title | Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway |
| title_full | Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway |
| title_fullStr | Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway |
| title_full_unstemmed | Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway |
| title_short | Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway |
| title_sort | synaptic depression and short term habituation are located in the sensory part of the mammalian startle pathway |
| url | http://www.biomedcentral.com/1471-2202/7/38 |
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