A stereotaxic method for small animals using experimentally determined reference profiles

Schuller, Gerd; Radtke‐Schuller, Susanne; Betz, M

doi:10.1016/0165-0270(86)90022-1

Cited by 116 publications

(90 citation statements)

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“…The bat was then transferred to a heated recording chamber, where it was placed in a restraining cushion constructed of foam molded to the animal's body. The restraining cushion was attached to a platform mounted on a custom-made stereotaxic instrument (Schuller et al, 1986). A small metal rod was cemented to the foundation layer on the skull and then attached to a bar mounted on the stereotaxic instrument to ensure a uniform positioning of the head.…”

Section: Methodsmentioning

confidence: 99%

Reversible Inactivation of the Dorsal Nucleus of the Lateral Lemniscus Reveals Its Role in the Processing of Multiple Sound Sources in the Inferior Colliculus of Bats

2001

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Neurons in the inferior colliculus (IC) that are excited by one ear and inhibited by the other [excitatory-inhibitory (EI) neurons] can code interaural intensity disparities (IIDs), the cues animals use to localize high frequencies. Although EI properties are first formed in a lower nucleus and imposed on some IC cells via an excitatory projection, many other EI neurons are formed de novo in the IC. By reversibly inactivating the dorsal nucleus of the lateral lemniscus (DNLL) in Mexican free-tailed bats with kynurenic acid, we show that the EI properties of many IC cells are formed de novo via an inhibitory projection from the DNLL on the opposite side. We also show that signals excitatory to the IC evoke an inhibition in the opposite DNLL that persists for tens of milliseconds after the signal has ended. During that period, strongly suppressed EI cells in the IC are deprived of inhibition from the DNLL and respond to binaural signals as weakly inhibited or monaural cells. By relieving inhibition at the IC, we show that an initial binaural signal essentially reconfigures the circuit and thereby allows IC cells to respond to trailing binaural signals that were inhibitory when presented alone. Thus, DNLL innervation creates a property in the IC that is not possessed by lower neurons or by collicular EI neurons that are not innervated by the DNLL. That property is a change in responsiveness to binaural signals, a change dependent on the reception of an earlier sound. These features suggest that the circuitry linking the DNLL with the opposite central nucleus of the IC is important for the processing of IIDs that change over time, such as the IIDs generated by moving stimuli or by multiple sound sources that emanate from different regions of space. Key words: GABA; persistent inhibition; precedence effect; inferior colliculus; sound localization; dorsal nucleus of lateral lemniscusThe projections from the vast majority of lower auditory nuclei converge at a common destination in the central nucleus of the inferior colliculus (ICc) (for review, see Aitkin, 1986;Oliver and Huerta, 1992). This large convergence of inputs suggests that substantial transformations occur in the ICc; yet the response properties of ICc neurons appear to be similar to those of the lower nuclei from which they receive their innervation. An example is excitatory-inhibitory (EI) neurons in the ICc, neurons that are excited by one ear and inhibited by the other ear. These neurons are sensitive to interaural intensity disparities (IIDs), the cues animals use to localize high-frequency sounds (Erulkar, 1972;Mills, 1972). EI neurons are initially formed in the lateral superior olive (LSO) (Boudreau and Tsuchitani, 1968;Finlayson and Caspary, 1991). They are also the dominant type in the dorsal nucleus of the lateral lemniscus (DNLL), a nucleus the neurons of which are almost exclusively GABAergic (Brugge et al., 1970;Adams and Mugniani, 1984;Covey, 1993; Yang and Pollak, 1994a,b,c;Winer et al., 1995). The DNLL, like the ICc, is one of the principa...

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Section: Methodsmentioning

confidence: 99%

Reversible Inactivation of the Dorsal Nucleus of the Lateral Lemniscus Reveals Its Role in the Processing of Multiple Sound Sources in the Inferior Colliculus of Bats

2001

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“…For the experiments, awake bats were administered a low dose of an opioid agonist (butorphanol tartrate, 0.7 mg/kg i.p. ; Abbot Laboratories, North Chicago, IL), and restrained painlessly in a stereotactic frame (Schuller et al, 1986). Single unit recordings were made in the IC on the left side exclusively, using sharpened 1 M Na + acetate-filled glass micropipettes with tip impedances ranging from 9 to 12 MX.…”

Section: Preparationmentioning

confidence: 99%

On the prediction of sweep rate and directional selectivity for FM sounds from two-tone interactions in the inferior colliculus

Brimijoin

O’Neill

2005

Hearing Research

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Two-tone stimuli have traditionally been used to reveal regions of inhibition in auditory spectral receptive fields, particularly for neurons with low spontaneous rates. These techniques reveal how different frequencies excite or suppress the response to an excitatory frequency of a cell, but have often been assessed at a fixed masker-probe time interval. We used a variation of this methodology determine whether two-tone spectrotemporal interactions can account for ratedependent directional selectivity for frequency modulations (FM) in the mustached bat inferior colliculus (IC). First, we quantified the response to upward and downward sweeping, linear, fixedbandwidth FM tones centered at a unit's characteristic frequency (CF) at 6 sweep durations ranging from 2 to 64 ms. Then, to examine how responses to instantaneous frequencies contained within the sweeps might interact in time, we varied the frequency and relative onset of a brief (4 ms) "conditioner" tone paired with a fixed 4-ms CF probe tone. We constructed "conditioned response areas" (CRA) depicting regions of suppression and facilitation of the probe tone caused by the conditioning tone. We classified the CRAs as predominantly excitatory (40.9%), inhibitory (22.7%), or mixed (36.4%). To generate FM response predictions, the CRAs were multiplied with spectrograms of the same sweeps used to assess response to FM. The predictions of FM rate and directionality were accurate by our criteria in approximately 20% of units. Conversely, the CRAs from the remaining units failed to predict FM responses as accurately, suggesting that most IC units respond differently to FM sweeps than they do to tone-pairs matched to the instantaneous frequencies contained in those sweeps. The implications of these results for models of FM directionality are discussed.

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“…We focused on the area ventral to the inferior colliculus and medial to the nuclei of the lateral lemniscus, which included the paralemniscal tegmentum at its anterior end and the parabrachial nuclei (PB) at its posterior end. For this purpose, we systematically mapped this region using a stereotaxic approach (modified after Schuller et al, 1986) and iontophoretically injected various GABA and L-glutamate agonists and antagonists, respectively, while monitoring the effects on both RF and DSC behavior. Although we did not find any specific effects in the paralemniscal tegmentum, we found that we could dramatically alter RF and block DSC within the lateral portions of PB.…”

Section: Introductionmentioning

confidence: 99%

A Neural Basis for Auditory Feedback Control of Vocal Pitch

2003

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Hearing one's own voice is essential for the production of correct vocalization patterns in many birds and mammals, including humans. Bats, for instance, adjust temporal, spectral, and intensity parameters of their echolocation calls by precisely monitoring the characteristics of the returning echo signals. However, neuronal substrates and mechanisms for auditory feedback control of vocalizations are still mostly unknown in any vertebrate. We used echolocating horseshoe bats to investigate the role of the midbrain and hindbrain tegmentum for the control of call frequencies in response to changing auditory feedback. These bats accurately control the frequency of their echolocation calls through auditory feedback both when the bat is at rest [resting frequency (RF)] and when it is flying and compensating for changes in echo frequency caused by flight-induced Doppler shifts [Doppler shift compensation (DSC)]. We iontophoretically injected various GABAergic and glutamatergic transmitter agonists and antagonists into the brainstem tegmentum. We found that within the parabrachial nuclei and the immediately adjacent tegmentum, excitatory effects caused by application of the glutamate agonist AMPA or the GABA A antagonist bicuculline raised RF and the frequency of calls emitted during DSC. Bicuculline application routinely blocked DSC altogether. Alternately, inhibitory effects caused by application of either the GABA A agonist muscimol or the AMPA antagonist CNQX lowered call frequencies emitted at rest and during DSC. Such an audio-vocal feedback mechanism might share basic aspects with audio-vocal feedback controlling the pitch of vocalizations in other mammals, including the involuntary response to "pitch-shifted feedback" in humans.

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A stereotaxic method for small animals using experimentally determined reference profiles

Cited by 116 publications

References 1 publication

Reversible Inactivation of the Dorsal Nucleus of the Lateral Lemniscus Reveals Its Role in the Processing of Multiple Sound Sources in the Inferior Colliculus of Bats

Reversible Inactivation of the Dorsal Nucleus of the Lateral Lemniscus Reveals Its Role in the Processing of Multiple Sound Sources in the Inferior Colliculus of Bats

On the prediction of sweep rate and directional selectivity for FM sounds from two-tone interactions in the inferior colliculus

A Neural Basis for Auditory Feedback Control of Vocal Pitch

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