Thalamic Activation Modulates the Responses of Neurons in Rat Primary Auditory Cortex: An In Vivo Intracellular Recording Study

Cortical sensory representation is highly adaptive to the environment, and prevalent or behaviorally important stimuli are often overrepresented. One class of such stimuli is species-specific vocalizations. Rats vocalize in the ultrasonic range >30 kHz, but cortical representation of this frequency range has not been systematically examined. We recorded in vivo cortical electrophysiological responses to ultrasonic pure-tone pips, natural ultrasonic vocalizations, and pitch-shifted vocalizations to assess how rats represent this ethologically relevant frequency range. We find that nearly 40% of the primary auditory cortex (AI) represents an octave-wide band of ultrasonic vocalization frequencies (UVFs; 32–64 kHz) compared with <20% for other octave bands <32 kHz. These UVF neurons respond preferentially and reliably to ultrasonic vocalizations. The UVF overrepresentation matures in the cortex before it develops in the central nucleus of inferior colliculus, suggesting a cortical origin and corticofugal influences. Furthermore, the development of cortical UVF overrepresentation depends on early acoustic experience. These results indicate that natural sensory experience causes large-scale cortical map reorganization and improves representations of species-specific vocalizations.

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Local Homogeneity of Tonotopic Organization in the Primary Auditory Cortex of Marmosets

10.1101/398677 ◽

2018 ◽

Author(s):

Huan-huan Zeng ◽

Jun-feng Huang ◽

Ming Chen ◽

Yun-qing Wen ◽

Zhi-ming Shen ◽

...

Keyword(s):

Auditory Cortex ◽

Large Scale ◽

Frequency Tuning ◽

Primary Auditory Cortex ◽

Primate Species ◽

Tonotopic Organization ◽

Brain Structure And Function ◽

A1 Neurons ◽

Cortical Regions

AbstractMarmoset has emerged as a useful non-human primate species for studying the brain structure and function. Previous studies on the mouse primary auditory cortex (A1) showed that neurons with preferential frequency tuning responses are mixed within local cortical regions, despite a large-scale tonotopic organization. Here we found that frequency tuning properties of marmoset A1 neurons are highly uniform within local cortical regions. We first defined tonotopic map of A1 using intrinsic optical imaging, and then used in vivo two-photon calcium imaging of large neuronal populations to examine the tonotopic preference at the single-cell level. We found that tuning preferences of layer 2/3 neurons were highly homogeneous over hundreds of micrometers in both horizontal and vertical directions. Thus, marmoset A1 neurons are distributed in a tonotopic manner at both macro- and microscopic levels. Such organization is likely to be important for the organization of auditory circuits in the primate brain.

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Functional Organization of Mouse Primary Auditory Cortex in adult C57BL/6 and F1 (CBAxC57) mice

10.1101/843300 ◽

2019 ◽

Author(s):

Zac Bowen ◽

Daniel E. Winkowski ◽

Patrick O. Kanold

Keyword(s):

Auditory Cortex ◽

Functional Organization ◽

Strain Differences ◽

Primary Auditory Cortex ◽

Cellular Level ◽

Optimal Choice ◽

Sound Level ◽

Sound Perception ◽

Cba Mice

AbstractThe primary auditory cortex (A1) plays a key role for sound perception since it represents one of the first cortical processing stations for sounds. Recent studies have shown that on the cellular level the frequency organization of A1 is more heterogeneous than previously appreciated. However, many of these studies were performed in mice on the C57BL/6 background which develop high frequency hearing loss with age making them a less optimal choice for auditory research. In contrast, mice on the CBA background retain better hearing sensitivity in old age. Since potential strain differences could exist in A1 organization between strains, we performed comparative analysis of neuronal populations in A1 of adult (~10 weeks) C57BL/6 mice and CBAxC57 F1 mice. We used in vivo 2-photon imaging of pyramidal neurons in cortical layers L4 and L2/3 of awake mouse primary auditory cortex (A1) to characterize the populations of neurons that were active to tonal stimuli. Pure tones recruited neurons of widely ranging frequency preference in both layers and strains with neurons in CBA mice exhibiting a wider range of frequency preference particularly to higher frequencies. Frequency selectivity was slightly higher in C57BL/6 mice while neurons in CBA mice showed a greater sound-level sensitivity. The spatial heterogeneity of frequency preference was present in both strains with CBA mice exhibiting higher tuning diversity across all measured length scales. Our results demonstrate that the tone evoked responses and frequency representation in A1 of adult C57BL/6 and CBAxC57 F1 mice is largely similar.

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Tone-Evoked Excitatory and Inhibitory Synaptic Conductances of Primary Auditory Cortex Neurons

Journal of Neurophysiology ◽

10.1152/jn.01020.2003 ◽

2004 ◽

Vol 92 (1) ◽

pp. 630-643 ◽

Cited By ~ 175

Author(s):

Andrew Y. Y. Tan ◽

Li I. Zhang ◽

Michael M. Merzenich ◽

Christoph E. Schreiner

Keyword(s):

Auditory Cortex ◽

Time Course ◽

Frequency Tuning ◽

Primary Auditory Cortex ◽

Cell Voltage ◽

Synaptic Conductance ◽

Synaptic Excitation ◽

Tone Intensity ◽

Synaptic Conductances

In primary auditory cortex (AI) neurons, tones typically evoke a brief depolarization, which can lead to spiking, followed by a long-lasting hyperpolarization. The extent to which the hyperpolarization is due to synaptic inhibition has remained unclear. Here we report in vivo whole cell voltage-clamp measurements of tone-evoked excitatory and inhibitory synaptic conductances of AI neurons of the pentobarbital-anesthetized rat. Tones evoke an increase of excitatory synaptic conductance, followed by an increase of inhibitory synaptic conductance. The synaptic conductances can account for the gross time course of the typical membrane potential response. Synaptic excitation and inhibition have the same frequency tuning. As tone intensity increases, the amplitudes of synaptic excitation and inhibition increase, and the latency of synaptic excitation decreases. Our data indicate that the interaction of synaptic excitation and inhibition shapes the time course and frequency tuning of the spike responses of AI neurons.

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Characterization of thalamocortical responses of regular-spiking and fast-spiking neurons of the mouse auditory cortex in vitro and in silico

Journal of Neurophysiology ◽

10.1152/jn.00208.2011 ◽

2012 ◽

Vol 107 (5) ◽

pp. 1476-1488 ◽

Cited By ~ 22

Author(s):

Max L. Schiff ◽

Alex D. Reyes

Keyword(s):

Auditory Cortex ◽

Pyramidal Neurons ◽

Modulation Frequency ◽

Primary Auditory Cortex ◽

Cortical Inhibition ◽

Membrane Properties ◽

Thalamic Stimulation ◽

Fast Spiking

We use a combination of in vitro whole cell recordings and computer simulations to characterize the cellular and synaptic properties that contribute to processing of auditory stimuli. Using a mouse thalamocortical slice preparation, we record the intrinsic membrane properties and synaptic properties of layer 3/4 regular-spiking (RS) pyramidal neurons and fast-spiking (FS) interneurons in primary auditory cortex (AI). We find that postsynaptic potentials (PSPs) evoked in FS cells are significantly larger and depress more than those evoked in RS cells after thalamic stimulation. We use these data to construct a simple computational model of the auditory thalamocortical circuit and find that the differences between FS and RS cells observed in vitro generate model behavior similar to that observed in vivo. We examine how feedforward inhibition and synaptic depression affect cortical responses to time-varying inputs that mimic sinusoidal amplitude-modulated tones. In the model, the balance of cortical inhibition and thalamic excitation evolves in a manner that depends on modulation frequency (MF) of the stimulus and determines cortical response tuning.

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