Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex
In the primary motor cortex (M1), layer 5 projection neurons signal directly to distant motor structures to drive movement. Despite their pivotal position and acknowledged diversity these neurons are traditionally separated into broad commissural and corticofugal types, and until now no attempt has...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-10-01
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| Series: | Frontiers in Cellular Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncel.2013.00174/full |
| _version_ | 1818595696772644864 |
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| author | Manfred J Oswald Malinda LS Tantirigama Ivo eSonntag Stephanie M Hughes Ruth M Empson |
| author_facet | Manfred J Oswald Malinda LS Tantirigama Ivo eSonntag Stephanie M Hughes Ruth M Empson |
| author_sort | Manfred J Oswald |
| collection | DOAJ |
| description | In the primary motor cortex (M1), layer 5 projection neurons signal directly to distant motor structures to drive movement. Despite their pivotal position and acknowledged diversity these neurons are traditionally separated into broad commissural and corticofugal types, and until now no attempt has been made at resolving the basis for their diversity. We therefore probed the electrophysiological and morphological properties of retrogradely labelled M1 corticospinal (CSp), corticothalamic (CTh), and commissural projecting corticostriatal (CStr) and corticocortical (CC) neurons. An unsupervised cluster analysis established at least four phenotypes with additional differences between lumbar and cervical projecting CSp neurons. Distinguishing parameters included the action potential (AP) waveform, firing behaviour, the hyperpolarisation-activated sag potential, sublayer position, and soma and dendrite size. CTh neurons differed from CSp neurons in showing spike frequency acceleration and a greater sag potential. CStr neurons had the lowest AP amplitude and maximum rise rate of all neurons. Temperature influenced spike train behaviour in corticofugal neurons. At 26 ºC CTh neurons fired bursts of APs more often than CSp neurons, but at 36 ºC both groups fired regular APs. Our findings provide reliable phenotypic fingerprints to identify distinct M1 projection neuron classes as a tool to understand their unique contributions to motor function. |
| first_indexed | 2024-12-16T11:20:07Z |
| format | Article |
| id | doaj.art-69759b204f3340c4a5ddf9a8ed1b02be |
| institution | Directory Open Access Journal |
| issn | 1662-5102 |
| language | English |
| last_indexed | 2024-12-16T11:20:07Z |
| publishDate | 2013-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cellular Neuroscience |
| spelling | doaj.art-69759b204f3340c4a5ddf9a8ed1b02be2022-12-21T22:33:29ZengFrontiers Media S.A.Frontiers in Cellular Neuroscience1662-51022013-10-01710.3389/fncel.2013.0017462984Diversity of Layer 5 Projection Neurons in the Mouse Motor CortexManfred J Oswald0Malinda LS Tantirigama1Ivo eSonntag2Stephanie M Hughes3Ruth M Empson4University of OtagoUniversity of OtagoUniversity of OtagoUniversity of OtagoUniversity of OtagoIn the primary motor cortex (M1), layer 5 projection neurons signal directly to distant motor structures to drive movement. Despite their pivotal position and acknowledged diversity these neurons are traditionally separated into broad commissural and corticofugal types, and until now no attempt has been made at resolving the basis for their diversity. We therefore probed the electrophysiological and morphological properties of retrogradely labelled M1 corticospinal (CSp), corticothalamic (CTh), and commissural projecting corticostriatal (CStr) and corticocortical (CC) neurons. An unsupervised cluster analysis established at least four phenotypes with additional differences between lumbar and cervical projecting CSp neurons. Distinguishing parameters included the action potential (AP) waveform, firing behaviour, the hyperpolarisation-activated sag potential, sublayer position, and soma and dendrite size. CTh neurons differed from CSp neurons in showing spike frequency acceleration and a greater sag potential. CStr neurons had the lowest AP amplitude and maximum rise rate of all neurons. Temperature influenced spike train behaviour in corticofugal neurons. At 26 ºC CTh neurons fired bursts of APs more often than CSp neurons, but at 36 ºC both groups fired regular APs. Our findings provide reliable phenotypic fingerprints to identify distinct M1 projection neuron classes as a tool to understand their unique contributions to motor function.http://journal.frontiersin.org/Journal/10.3389/fncel.2013.00174/fullElectrophysiologycorticothalamicmorphologyCluster analysiscorticostriatalcorticocortical |
| spellingShingle | Manfred J Oswald Malinda LS Tantirigama Ivo eSonntag Stephanie M Hughes Ruth M Empson Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex Frontiers in Cellular Neuroscience Electrophysiology corticothalamic morphology Cluster analysis corticostriatal corticocortical |
| title | Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex |
| title_full | Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex |
| title_fullStr | Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex |
| title_full_unstemmed | Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex |
| title_short | Diversity of Layer 5 Projection Neurons in the Mouse Motor Cortex |
| title_sort | diversity of layer 5 projection neurons in the mouse motor cortex |
| topic | Electrophysiology corticothalamic morphology Cluster analysis corticostriatal corticocortical |
| url | http://journal.frontiersin.org/Journal/10.3389/fncel.2013.00174/full |
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