Single neuron recordings in dorsal cochlear nucleus (DCN) of awake gerbil

Navawongse, Rapeechai; Voigt, Herbert

doi:10.1016/j.heares.2009.05.004

Cited by 8 publications

(5 citation statements)

References 74 publications

(116 reference statements)

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“…Within the pyramidal cell population, only 13% (17 out of 129) of cells were intensity-selective. This relatively small percentage of intensity-selective neurons was also reported in other rodents (Davis et al, 1996; Navawongse and Voigt, 2009; Ma and Brenowitz, 2011).…”

Section: Resultssupporting

confidence: 80%

Generation of Intensity Selectivity by Differential Synaptic Tuning: Fast-Saturating Excitation But Slow-Saturating Inhibition

2012

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Intensity defines one fundamental aspect of sensory information, and is specifically represented in each sensory modality. Interestingly, only in the central auditory system are intensity-selective neurons evolved. These neurons are characterized by nonmonotonic response-level functions. The synaptic circuitry mechanisms underlying the generation of intensity selectivity from nonselective auditory nerve inputs remain largely unclear. Here, we carried out in vivo whole-cell recordings from pyramidal neurons in the rat dorsal cochlear nucleus (DCN), where intensity selectivity first emerges along the auditory neuraxis. Our results revealed that intensity-selective cells received fast-saturating excitation but slow-saturating inhibition with intensity increments, whereas in intensity-nonselective cells excitation and inhibition were similarly slow-saturating. The differential intensity tuning profiles of the monotonic excitation and inhibition qualitatively determined the intensity selectivity of output responses. In addition, the selectivity was further strengthened by significantly lower excitation/inhibition ratios at high intensity levels compared to intensity-nonselective neurons. Our results demonstrate that intensity selectivity in the DCN is generated by extracting the difference between tuning profiles of nonselective excitatory and inhibitory inputs, which we propose can be achieved through a differential circuit mediated by feedforward inhibition.

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Section: Resultssupporting

confidence: 80%

Generation of Intensity Selectivity by Differential Synaptic Tuning: Fast-Saturating Excitation But Slow-Saturating Inhibition

2012

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“…Effects of ketamine/xylazine on subcortical auditory processing are typically mild (Smith and Mills, 1989; Ter-Mikaelian et al, 2007), and both bushy cells (Kuenzel et al, 2011) and primary neurons of the MNTB (Hermann et al, 2007; Kopp-Scheinpflug et al, 2008) in gerbil show considerable spontaneous activity even under ketamine/xylazine anesthesia. Decreased inhibition has been reported in the dorsal cochlear nucleus (Navawongse and Voigt, 2009). However, the original evidence favoring well-timed inhibition was also obtained under ketamine/xylazine anesthesia (Brand et al, 2002; Pecka et al, 2008).…”

Section: Discussionmentioning

confidence: 94%

Directional Hearing by Linear Summation of Binaural Inputs at the Medial Superior Olive

Heijden

Lorteije

Plauška

et al. 2013

Neuron

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SUMMARY Neurons in the medial superior olive (MSO) enable sound localization by their remarkable sensitivity to submillisecond interaural time differences (ITDs). Each MSO neuron has its own “best ITD” to which it responds optimally. A difference in physical path length of the excitatory inputs from both ears cannot fully account for the ITD tuning of MSO neurons. As a result, it is still debated how these inputs interact and whether the segregation of inputs to opposite dendrites, well-timed synaptic inhibition, or asymmetries in synaptic potentials or cellular morphology further optimize coincidence detection or ITD tuning. Using in vivo whole-cell and juxtacellular recordings, we show here that ITD tuning of MSO neurons is determined by the timing of their excitatory inputs. The inputs from both ears sum linearly, whereas spike probability depends nonlinearly on the size of synaptic inputs. This simple coincidence detection scheme thus makes accurate sound localization possible.

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“…Giant Cells in the DCN likely receive inputs of broad frequency range and has a relatively broadband frequency tuning (Ryugo and Willard 1985;Zhang and Oertel 1993;Kemmer and Vater 2001;Davis and Young 2000;Navawongse and Voigt 2009). These features of Giant Cells are compatible with the features of the IC offset neurons and could be a candidate for the source of ascending synaptic inputs (Figures 7A and 2A(a)-D(a); Chen 1998).…”

Section: Distinct Mechanisms To Generate Offset Responses In the Icmentioning

confidence: 71%

Distinct neural firing mechanisms to tonal stimuli offset in the inferior colliculus of mice in vivo

Kasai

Ono

Ohmori

2012

Neuroscience Research

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Offset neurons, which fire at the termination of sound, likely encode sound duration and serve to process temporal information. Offset neurons are found in most ascending auditory nuclei; however, the neural mechanisms that evoke offset responses are not well understood. In this study, we examined offset neural responses to tonal stimuli in the inferior colliculus (IC) in vivo with extracellular and intracellular recording techniques in mice. Based on peristimulus time histogram (PSTH) patterns, we classified extracellular offset responses into four types: Offset, Onset-Offset, Onset-Sustained-Offset and Inhibition-Offset types. Moreover, using in vivo whole-cell recording techniques, we found that offset responses were generated in most cells through the excitatory and inhibitory synaptic inputs. However, in a small number of cells, the offset responses were generated as a rebound to hyperpolarization during tonal stimulation. Many offset neurons fired robustly at a preferred duration of tonal stimulus, which corresponded with the timing of rich excitatory synaptic inputs. We concluded that most IC offset neurons encode the termination of the tone stimulus by responding to inherited ascending synaptic information, which is tuned to sound duration. The remainder generates offset spikes de novo through a post-inhibitory rebound mechanism.

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Single neuron recordings in dorsal cochlear nucleus (DCN) of awake gerbil

Cited by 8 publications

References 74 publications

Generation of Intensity Selectivity by Differential Synaptic Tuning: Fast-Saturating Excitation But Slow-Saturating Inhibition

Generation of Intensity Selectivity by Differential Synaptic Tuning: Fast-Saturating Excitation But Slow-Saturating Inhibition

Directional Hearing by Linear Summation of Binaural Inputs at the Medial Superior Olive

Distinct neural firing mechanisms to tonal stimuli offset in the inferior colliculus of mice in vivo

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