Intrinsic Electrophysiology of Mouse Corticospinal Neurons: a Class-Specific Triad of Spike-Related Properties

Suter, Benjamin A.; Migliore, Michele; Shepherd, Gordon M.

doi:10.1093/cercor/bhs184

Cited by 86 publications

(111 citation statements)

References 63 publications

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“…The corticocollicular projection from auditory cortex (AC) to the inferior colliculus (IC) plays crucial modulatory roles in auditory processing (Winer, 2006;Suga, 2012;Stebbings et al, 2014). The functional properties of the corticocollicular projection have been studied by electrically stimulating AC while measuring IC responses (Yan and Ehret, 2002;Yan et al, 2005;Suga, 2012).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The functional properties of the corticocollicular projection have been studied by electrically stimulating AC while measuring IC responses (Yan and Ehret, 2002;Yan et al, 2005;Suga, 2012). For example, AC stimulation enhances the responses of IC neurons that are matched in best-frequency to the AC-stimulated neuron, but suppresses IC responses that are unmatched (Suga, 2012). AC stimulation shifts the frequency tuning of IC neurons (Yan and Ehret, 2002), and modulates the gain of IC neurons' responses by elevating thresholds and reducing dynamic ranges (Yan and Ehret, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…AC stimulation shifts the frequency tuning of IC neurons (Yan and Ehret, 2002), and modulates the gain of IC neurons' responses by elevating thresholds and reducing dynamic ranges (Yan and Ehret, 2002). Behavioral studies show that corticocollicular projections mediate learning-induced plasticity (Suga et al, 2002;Bajo et al, 2010). Whereas progress has been made toward characterizing AC¡IC projections at the level of the IC (Doucet et al, 2003;Suga and Ma, 2003;Bajo et al, 2010), the intracortical circuits and cellular mechanisms shaping the activity of corticocollicular neurons remain incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

“…Behavioral studies show that corticocollicular projections mediate learning-induced plasticity (Suga et al, 2002;Bajo et al, 2010). Whereas progress has been made toward characterizing AC¡IC projections at the level of the IC (Doucet et al, 2003;Suga and Ma, 2003;Bajo et al, 2010), the intracortical circuits and cellular mechanisms shaping the activity of corticocollicular neurons remain incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

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Cell-Specific Activity-Dependent Fractionation of Layer 2/3→5B Excitatory Signaling in Mouse Auditory Cortex

et al. 2015

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Auditory cortex (AC) layer 5B (L5B) contains both corticocollicular neurons, a type of pyramidal-tract neuron projecting to the inferior colliculus, and corticocallosal neurons, a type of intratelencephalic neuron projecting to contralateral AC. Although it is known that these neuronal types have distinct roles in auditory processing and different response properties to sound, the synaptic and intrinsic mechanisms shaping their input-output functions remain less understood. Here, we recorded in brain slices of mouse AC from retrogradely labeled corticocollicular and neighboring corticocallosal neurons in L5B. Corticocollicular neurons had, on average, lower input resistance, greater hyperpolarization-activated current (I h ), depolarized resting membrane potential, faster action potentials, initial spike doublets, and less spike-frequency adaptation. In paired recordings between single L2/3 and labeled L5B neurons, the probabilities of connection, amplitude, latency, rise time, and decay time constant of the unitary EPSC were not different for L2/3¡corticocollicular and L2/3¡corticocallosal connections. However, short trains of unitary EPSCs showed no synaptic depression in L2/3¡corticocollicular connections, but substantial depression in L2/3¡corticocallosal connections. Synaptic potentials in L2/3¡corticocollicular connections decayed faster and showed less temporal summation, consistent with increased I h in corticocollicular neurons, whereas synaptic potentials in L2/3¡corticocallosal connections showed more temporal summation. Extracellular L2/3 stimulation at two different rates resulted in spiking in L5B neurons; for corticocallosal neurons the spike rate was frequency dependent, but for corticocollicular neurons it was not. Together, these findings identify cell-specific intrinsic and synaptic mechanisms that divide intracortical synaptic excitation from L2/3 to L5B into two functionally distinct pathways with different input-output functions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cell-Specific Activity-Dependent Fractionation of Layer 2/3→5B Excitatory Signaling in Mouse Auditory Cortex

et al. 2015

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Fezf2 expression in layer 5 projection neurons of mature mouse motor cortex

Tantirigama

Oswald

Clare

et al. 2015

J of Comparative Neurology

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The mature cerebral cortex contains a wide diversity of neuron phenotypes. This diversity is specified during development by neuron-specific expression of key transcription factors, some of which are retained for the life of the animal. One of these key developmental transcription factors that is also retained in the adult is Fezf2, but the neuron types expressing it in the mature cortex are unknown. With a validated Fezf2-Gfp reporter mouse, whole-cell electrophysiology with morphology reconstruction, cluster analysis, in vivo retrograde labeling, and immunohistochemistry, we identify a heterogeneous population of Fezf2(+) neurons in both layer 5A and layer 5B of the mature motor cortex. Functional electrophysiology identified two distinct subtypes of Fezf2(+) neurons that resembled pyramidal tract projection neurons (PT-PNs) and intratelencephalic projection neurons (IT-PNs). Retrograde labeling confirmed the former type to include corticospinal projection neurons (CSpPNs) and corticothalamic projection neurons (CThPNs), whereas the latter type included crossed corticostriatal projection neurons (cCStrPNs) and crossed-corticocortical projection neurons (cCCPNs). The two Fezf2(+) subtypes expressed either CTIP2 or SATB2 to distinguish their physiological identity and confirmed that specific expression combinations of key transcription factors persist in the mature motor cortex. Our findings indicate a wider role for Fezf2 within gene expression networks that underpin the diversity of layer 5 cortical projection neurons.

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Expression of Kv3.1b potassium channel is widespread in macaque motor cortex pyramidal cells: A histological comparison between rat and macaque

Soares

Goldrick

Lemon

et al. 2017

J of Comparative Neurology

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There are substantial differences across species in the organization and function of the motor pathways. These differences extend to basic electrophysiological properties. Thus, in rat motor cortex, pyramidal cells have long duration action potentials, while in the macaque, some pyramidal neurons exhibit short duration “thin” spikes. These differences may be related to the expression of the fast potassium channel Kv3.1b, which in rat interneurons is associated with generation of thin spikes. Rat pyramidal cells typically lack these channels, while there are reports that they are present in macaque pyramids. Here we made a systematic, quantitative comparison of the Kv3.1b expression in sections from macaque and rat motor cortex, using two different antibodies (NeuroMab, Millipore). As our standard reference, we examined, in the same sections, Kv3.1b staining in parvalbumin‐positive interneurons, which show strong Kv3.1b immunoreactivity. In macaque motor cortex, a large sample of pyramidal neurons were nearly all found to express Kv3.1b in their soma membranes. These labeled neurons were identified as pyramidal based either by expression of SMI32 (a pyramidal marker), or by their shape and size, and lack of expression of parvalbumin (a marker for some classes of interneuron). Large (Betz cells), medium, and small pyramidal neurons all expressed Kv3.1b. In rat motor cortex, SMI32‐postive pyramidal neurons expressing Kv3.1b were very rare and weakly stained. Thus, there is a marked species difference in the immunoreactivity of Kv3.1b in pyramidal neurons, and this may be one of the factors explaining the pronounced electrophysiological differences between rat and macaque pyramidal neurons.

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Intrinsic Electrophysiology of Mouse Corticospinal Neurons: a Class-Specific Triad of Spike-Related Properties

Cited by 86 publications

References 63 publications

Cell-Specific Activity-Dependent Fractionation of Layer 2/3→5B Excitatory Signaling in Mouse Auditory Cortex

Cell-Specific Activity-Dependent Fractionation of Layer 2/3→5B Excitatory Signaling in Mouse Auditory Cortex

Fezf2 expression in layer 5 projection neurons of mature mouse motor cortex

Expression of Kv3.1b potassium channel is widespread in macaque motor cortex pyramidal cells: A histological comparison between rat and macaque

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