Corticofugal Modulation on Both <scp>on</scp> and<scp>off</scp> Responses in the Nonlemniscal Auditory Thalamus of the Guinea Pig

He, Jufang

doi:10.1152/jn.00593.2002

Cited by 53 publications

(78 citation statements)

References 94 publications

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“…We performed several mapping studies of the auditory cortex before the present study and found that the stimulation site only made a quantitative difference to the corticofugal modulation of the thalamic neurons (He et al, 2002;He, 2003a). In the present study, we omitted the mapping procedure to save time for the intracellular recordings.…”

Section: Methodsmentioning

confidence: 89%

“…The subject was mounted in a stereotaxic device after the induction of anesthesia. A midline incision was made in the scalp, and craniotomy was performed to enable us to implant stimulation electrodes into the auditory cortex and vertically access the MGB in the right hemisphere (He et al, 2002;He, 2003a;Xiong et al, 2003). The head was fixed with two stainless steel bolts to an extended arm from the stereotaxic frame using acrylic resin.…”

Section: Methodsmentioning

confidence: 99%

“…Electrical currents of 50 -200 A were applied to the auditory cortex, ipsilateral to the recording thalamus through either a monopolar or bipolar low-impedance electrode array. After a delay interval of 100 msec, a sound stimulus was delivered to the contralateral ear of the recording hemisphere after the end of the cortical stimulation (He, 1997(He, , 2003a.…”

Section: Methodsmentioning

confidence: 99%

“…In previous studies, we discussed other stimulation parameters, such as the stimulation frequency, stimulation intensity, the interval between the electrical pulses, and the delivery of the acoustic stimulus with an extracellular preparation (He et al, 2002;He, 2003a). The number of electrical stimulation pulses is thought to have determinative effects on thalamic neurons (McCormick and von Krosigk, 1992).…”

Section: Number Of Cortical Stimulation Pulsesmentioning

confidence: 99%

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Corticofugal Gating of Auditory Information in the Thalamus: AnIn VivoIntracellular Recording Study

Yu¹,

Xiong²,

Chan³

et al. 2004

J. Neurosci.

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In the present study, we investigated the auditory responses of the medial geniculate (MGB) neurons, through in vivo intracellular recordings of anesthetized guinea pigs, while the auditory cortex was electrically activated. Of the 63 neurons that received corticofugal modulation of the membrane potential, 30 received potentiation and 33 received hyperpolarization. The corticofugal potentiation of the membrane potential (amplitude, mean Ϯ SD, 8.6 Ϯ 5.5 mV; duration, 125.5 Ϯ 75.4 msec) facilitated the auditory responses and spontaneous firing of the MGB neurons. The hyperpolarization of Ϫ11.3 Ϯ 4.9 mV in amplitude and 210.0 Ϯ 210.1 msec in duration suppressed the auditory responses and spontaneous firing of the MGB neurons. Four of the five neurons that were histologically confirmed to be located in the lemniscal MGB received corticofugal facilitatory modulation, and all of the four neurons that were confirmed to be located in the non-lemniscal MGB received corticofugal inhibitory modulation. The present intracellular recording provides novel results on how the corticofugal projection gates the sensory information in the thalamus: via the spatially selective depolarization of lemniscal MGB neurons and hyperpolarization of non-lemniscal MGB neurons. It is speculated that the systematic selectivity of facilitation and inhibition over the lemniscal and non-lemniscal MGB is related to the attention shift within the auditory modality and across the sensory modalities.

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Section: Methodsmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Number Of Cortical Stimulation Pulsesmentioning

confidence: 99%

See 2 more Smart Citations

Corticofugal Gating of Auditory Information in the Thalamus: AnIn VivoIntracellular Recording Study

Yu¹,

Xiong²,

Chan³

et al. 2004

J. Neurosci.

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“…He and his colleagues (He, 2003;He et al, 2002) used focal electrical stimulation of the auditory cortex and showed that it was possible to both facilitate (mainly in the ventral division of the medial geniculate body) and suppress (in nonlemniscal parts of the medial geniculate body) different thalamic neurons. They suggested that such modulation of the ascending information could play a role in attentional processes by selectively gating the information passing through the lemniscal pathways, while switching off other unwanted sensory signals.…”

Section: Corticofugal Modulation Of Auditory Processingmentioning

confidence: 99%

Some investigations into non-passive listening

et al. 2007

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Our knowledge of the function of the auditory nervous system is based upon a wealth of data obtained, for the most part, in anaesthetised animals. More recently, it has been generally acknowledged that factors such as attention profoundly modulate the activity of sensory systems and this can take place at many levels of processing. Imaging studies, in particular, have revealed the greater activation of auditory areas and areas outside of sensory processing areas when attending to a stimulus. We present here a brief review of the consequences of such non-passive listening and go on to describe some of the experiments we are conducting to investigate them. In imaging studies, using fMRI, we can demonstrate the activation of attention networks that are non-specific to the sensory modality as well as greater and different activation of the areas of the supra-temporal plane that includes primary and secondary auditory areas. The profuse descending connections of the auditory system seem likely to be part of the mechanisms subserving attention to sound. These are generally thought to be largely inactivated by anaesthesia. However, we have been able to demonstrate that even in an anaesthetised preparation, removing the descending control from the cortex leads to quite profound changes in the temporal patterns of activation by sounds in thalamus and inferior colliculus. Some of these effects seem to be specific to the ear of stimulation and affect interaural processing. To bridge these observations we are developing an awake behaving preparation involving freely moving animals in which it will be possible to investigate the effects of consciousness (by contrasting awake and anaesthetized), passive and active listening.

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Corticofugal modulation of acoustically induced Fos expression in the rat auditory pathway

Sun

Xia

Lai

et al. 2007

J of Comparative Neurology

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To investigate the corticofugal modulation of acoustic information ascending through the auditory pathway of the rat, immunohistochemical techniques were used to study the functional expression of Fos protein in neurons. With auditory stimulation at different frequencies, Fos expression in the medial geniculate body (MGB), inferior colliculus (IC), superior olivary complex, and cochlear nucleus was examined, and the extent of Fos expression on the two sides was compared. Strikingly, we found densely Fos-labeled neurons in all divisions of the MGB after both presentation of an auditory stimulus and administration of a gamma-aminobutyric acid type A (GABA(A)) antagonist (bicuculline methobromide; BIM) to the auditory cortex. The location of Fos-labeled neurons in the ventral division (MGv) after acoustic stimulation at different frequencies was in agreement with the known tonotopic organization. That no Fos-labeled neurons were found in the MGv with acoustic stimuli alone suggests that the transmission of ascending thalamocortical information is critically governed by corticofugal modulation. The dorsal (DCIC) and external cortices (ECIC) of the IC ipsilateral to the BIM-injected cortex showed a significantly higher number of Fos-labeled neurons than the contralateral IC. However, no difference in the number of Fos-labeled neurons was found between the central nucleus of the IC on either side, indicating that direct corticofugal modulation occurs only in the ECIC and DCIC. Further investigations are needed to assess the functional implications of the morphological differences observed between the descending corticofugal projections to the thalamus and the IC.

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Corticofugal Modulation on Both on andoff Responses in the Nonlemniscal Auditory Thalamus of the Guinea Pig

Cited by 53 publications

References 94 publications

Corticofugal Gating of Auditory Information in the Thalamus: AnIn VivoIntracellular Recording Study

Corticofugal Gating of Auditory Information in the Thalamus: AnIn VivoIntracellular Recording Study

Some investigations into non-passive listening

Corticofugal modulation of acoustically induced Fos expression in the rat auditory pathway

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