Cell-specific activity-dependent fractionation of layer 2/3→5B excitatory signaling in mouse auditory cortex
Middleton, Jason W.
Anderson, Charles T.
Suter, Benjamin A.
Shepherd, Gordon M. G.
MetadataShow full item record
KeywordAuditory cortex; Cortical mechanisms; Intrinsic mechanisms; Short-term plasticity; Synaptic mechanisms
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 (Ih), 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 Ih 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.
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Neuroscience 35 (2015): 3112-3123, doi:10.1523/JNEUROSCI.0836-14.2015.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Ketten, Darlene R.; Cramer, Scott R.; Arruda, Julie (Woods Hole Oceanographic Institution, 2007-01)This chapter is intended as an instructional guide for the removal, fixation and preservation of auditory system tissues of marine mammals. Each section describes procedures for a major ear type for marine mammals. The ...
Dynamics of myosin, microtubules, and Kinesin-6 at the cortex during cytokinesis in Drosophila S2 cells Vale, Ronald D.; Spudich, James A.; Griffis, Eric R. (Rockefeller University Press, 2009-08)Signals from the mitotic spindle during anaphase specify the location of the actomyosin contractile ring during cytokinesis, but the detailed mechanism remains unresolved. Here, we have imaged the dynamics of green fluorescent ...
Golgi cells operate as state-specific temporal filters at the input stage of the cerebellar cortex Heine, Shane A.; Highstein, Stephen M.; Blazquez, Pablo M. (Society for Neuroscience, 2010-12-15)Cerebellar processing of incoming information begins at the synapse between mossy fibers and granule cells, a synapse that is strongly controlled through Golgi cell inhibition. Thus, Golgi cells are uniquely positioned to ...