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Mushtaq M, Marshall L, ul Haq R, Martinetz T. Possible mechanisms to improve sleep spindles via closed loop stimulation during slow wave sleep: A computational study. PLoS One 2024; 19:e0306218. [PMID: 38924001 PMCID: PMC11207127 DOI: 10.1371/journal.pone.0306218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Sleep spindles are one of the prominent EEG oscillatory rhythms of non-rapid eye movement sleep. In the memory consolidation, these oscillations have an important role in the processes of long-term potentiation and synaptic plasticity. Moreover, the activity (spindle density and/or sigma power) of spindles has a linear association with learning performance in different paradigms. According to the experimental observations, the sleep spindle activity can be improved by closed loop acoustic stimulations (CLAS) which eventually improve memory performance. To examine the effects of CLAS on spindles, we propose a biophysical thalamocortical model for slow oscillations (SOs) and sleep spindles. In addition, closed loop stimulation protocols are applied on a thalamic network. Our model results show that the power of spindles is increased when stimulation cues are applied at the commencing of an SO Down-to-Up-state transition, but that activity gradually decreases when cues are applied with an increased time delay from this SO phase. Conversely, stimulation is not effective when cues are applied during the transition of an Up-to-Down-state. Furthermore, our model suggests that a strong inhibitory input from the reticular (RE) layer to the thalamocortical (TC) layer in the thalamic network shifts leads to an emergence of spindle activity at the Up-to-Down-state transition (rather than at Down-to-Up-state transition), and the spindle frequency is also reduced (8-11 Hz) by thalamic inhibition.
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Affiliation(s)
| | - Lisa Marshall
- Institute of Experimental and Clinical Pharmacology, University of Lübeck, Lübeck, Germany
- Center of Brain, Behavior and Metabolism, Lübeck, Germany
- University Clinic Hospital Schleswig Holstein, Lübeck, Germany
| | - Rizwan ul Haq
- Department of Pharmacy, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Thomas Martinetz
- Institute for Neuro- and Bioinformatics, Lübeck, Germany
- Center of Brain, Behavior and Metabolism, Lübeck, Germany
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2
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Burchell A, Mansour Y, Kulesza R. Leveling up: a long-range olivary projection to the medial geniculate without collaterals to the central nucleus of the inferior colliculus in rats. Exp Brain Res 2022; 240:3217-3235. [PMID: 36271940 DOI: 10.1007/s00221-022-06489-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/17/2022] [Indexed: 11/04/2022]
Abstract
The medial nucleus of the trapezoid body (MNTB) is one of the monaural cell groups situated within the superior olivary complex (SOC), a constellation of brainstem nuclei with numerous roles in hearing. Principal MNTB neurons are glycinergic and express the calcium-binding protein, calbindin (CB). The MNTB receives its main glutamatergic, excitatory input from the contralateral cochlear nucleus via the calyx of Held and converts this into glycinergic inhibition directed toward nuclei in the SOC and the ventral and intermediate nuclei of the lateral lemniscus (VNLL and INLL). Through this inhibition, the MNTB plays essential roles in localization of sound sources and encoding spectral and temporal features of sound. In rats, very few MNTB neurons project to the inferior colliculus. However, our recent study of SOC projections to the auditory thalamus revealed a substantial number of retrogradely labeled MNTB neurons. This observation led us to examine whether the rat MNTB provides a long-range projection to the medial geniculate body (MGB). We examined this possible projection using retrograde and anterograde tract tracing and immunohistochemistry for CB and the glycine receptor. Our results demonstrate a significant projection to the MGB from the ipsilateral MNTB that does not involve a collateral projection to the inferior colliculus.
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Affiliation(s)
- Alyson Burchell
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, 1858 West Grandview Blvd, Erie, PA, 16509, USA
| | - Yusra Mansour
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, 1858 West Grandview Blvd, Erie, PA, 16509, USA.,Department of Otolaryngology, Henry Ford Macomb Hospital, Clinton Township, MI, USA
| | - Randy Kulesza
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, 1858 West Grandview Blvd, Erie, PA, 16509, USA.
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3
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Montes-Lourido P, Kar M, Pernia M, Parida S, Sadagopan S. Updates to the guinea pig animal model for in-vivo auditory neuroscience in the low-frequency hearing range. Hear Res 2022; 424:108603. [PMID: 36099806 PMCID: PMC9922531 DOI: 10.1016/j.heares.2022.108603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/29/2022] [Accepted: 09/03/2022] [Indexed: 02/08/2023]
Abstract
For gaining insight into general principles of auditory processing, it is critical to choose model organisms whose set of natural behaviors encompasses the processes being investigated. This reasoning has led to the development of a variety of animal models for auditory neuroscience research, such as guinea pigs, gerbils, chinchillas, rabbits, and ferrets; but in recent years, the availability of cutting-edge molecular tools and other methodologies in the mouse model have led to waning interest in these unique model species. As laboratories increasingly look to include in-vivo components in their research programs, a comprehensive description of procedures and techniques for applying some of these modern neuroscience tools to a non-mouse small animal model would enable researchers to leverage unique model species that may be best suited for testing their specific hypotheses. In this manuscript, we describe in detail the methods we have developed to apply these tools to the guinea pig animal model to answer questions regarding the neural processing of complex sounds, such as vocalizations. We describe techniques for vocalization acquisition, behavioral testing, recording of auditory brainstem responses and frequency-following responses, intracranial neural signals including local field potential and single unit activity, and the expression of transgenes allowing for optogenetic manipulation of neural activity, all in awake and head-fixed guinea pigs. We demonstrate the rich datasets at the behavioral and electrophysiological levels that can be obtained using these techniques, underscoring the guinea pig as a versatile animal model for studying complex auditory processing. More generally, the methods described here are applicable to a broad range of small mammals, enabling investigators to address specific auditory processing questions in model organisms that are best suited for answering them.
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Affiliation(s)
- Pilar Montes-Lourido
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Manaswini Kar
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marianny Pernia
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Satyabrata Parida
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Srivatsun Sadagopan
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Communication Science and Disorders, University of Pittsburgh, Pittsburgh, PA, USA.
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4
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Anandakumar DB, Liu RC. More than the end: OFF response plasticity as a mnemonic signature of a sound’s behavioral salience. Front Comput Neurosci 2022; 16:974264. [PMID: 36148326 PMCID: PMC9485674 DOI: 10.3389/fncom.2022.974264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/17/2022] [Indexed: 11/29/2022] Open
Abstract
In studying how neural populations in sensory cortex code dynamically varying stimuli to guide behavior, the role of spiking after stimuli have ended has been underappreciated. This is despite growing evidence that such activity can be tuned, experience-and context-dependent and necessary for sensory decisions that play out on a slower timescale. Here we review recent studies, focusing on the auditory modality, demonstrating that this so-called OFF activity can have a more complex temporal structure than the purely phasic firing that has often been interpreted as just marking the end of stimuli. While diverse and still incompletely understood mechanisms are likely involved in generating phasic and tonic OFF firing, more studies point to the continuing post-stimulus activity serving a short-term, stimulus-specific mnemonic function that is enhanced when the stimuli are particularly salient. We summarize these results with a conceptual model highlighting how more neurons within the auditory cortical population fire for longer duration after a sound’s termination during an active behavior and can continue to do so even while passively listening to behaviorally salient stimuli. Overall, these studies increasingly suggest that tonic auditory cortical OFF activity holds an echoic memory of specific, salient sounds to guide behavioral decisions.
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Affiliation(s)
- Dakshitha B Anandakumar
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
- Department of Biology, Emory University, Atlanta, GA, United States
| | - Robert C Liu
- Department of Biology, Emory University, Atlanta, GA, United States
- Center for Translational Social Neuroscience, Emory University, Atlanta, GA, United States
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5
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Solyga M, Barkat TR. Emergence and function of cortical offset responses in sound termination detection. eLife 2021; 10:e72240. [PMID: 34910627 PMCID: PMC8673837 DOI: 10.7554/elife.72240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/28/2021] [Indexed: 11/20/2022] Open
Abstract
Offset responses in auditory processing appear after a sound terminates. They arise in neuronal circuits within the peripheral auditory system, but their role in the central auditory system remains unknown. Here, we ask what the behavioral relevance of cortical offset responses is and what circuit mechanisms drive them. At the perceptual level, our results reveal that experimentally minimizing auditory cortical offset responses decreases the mouse performance to detect sound termination, assigning a behavioral role to offset responses. By combining in vivo electrophysiology in the auditory cortex and thalamus of awake mice, we also demonstrate that cortical offset responses are not only inherited from the periphery but also amplified and generated de novo. Finally, we show that offset responses code more than silence, including relevant changes in sound trajectories. Together, our results reveal the importance of cortical offset responses in encoding sound termination and detecting changes within temporally discontinuous sounds crucial for speech and vocalization.
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6
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Jia G, Li X, Liu C, He J, Gao L. Stimulus-Specific Adaptation in Auditory Thalamus Is Modulated by the Thalamic Reticular Nucleus. ACS Chem Neurosci 2021; 12:1688-1697. [PMID: 33900722 DOI: 10.1021/acschemneuro.1c00137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A striking property of the auditory system is its capacity for the stimulus-specific adaptation (SSA), which is the reduction of neural response to repeated stimuli but a recuperative response to novel stimuli. SSA is found in both the medial geniculate body (MGB) and thalamic reticular nucleus (TRN). However, it remains unknown whether the SSA of MGB neurons is modulated by inhibitory inputs from the TRN, as it is difficult to investigate using the extracellular recording method. In the present study, we performed intracellular recordings in the MGB of anesthetized guinea pigs and examined whether and how the TRN modulates the SSA of MGB neurons with inhibitory inputs. This was accomplished by using microinjection of lidocaine to inactivate the neural activity of the TRN. We found that (1) MGB neurons with hyperpolarized membrane potentials exhibited SSA at both the spiking and subthreshold levels; (2) SSA of MGB neurons depends on the interstimulus interval (ISI), where a shorter ISI results in stronger SSA; and (3) the long-lasting hyperpolarization of MGB neurons decreased after the burst firing of the TRN was inactivated. As a result, SSA of these MGB neurons was diminished after inactivation of the TRN. Taken together, our results revealed that the SSA of the MGB is strongly modulated by the neural activity of the TRN, which suggests an alternative circuit mechanism underlying the SSA of the auditory thalamus.
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Affiliation(s)
- Guoqiang Jia
- Department of Neurology of the Second Affiliated Hospital and Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou 310029, China
| | - Xinjian Li
- Department of Neurology of the Second Affiliated Hospital and Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou 310029, China
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chunhua Liu
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Guangzhou Regenerative Medicine and Health Guang Dong Laboratory, Guangzhou 510005, China
| | - Jufang He
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Departments of Neuroscience and Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Lixia Gao
- Department of Neurology of the Second Affiliated Hospital and Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou 310029, China
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China
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7
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Bondanelli G, Deneux T, Bathellier B, Ostojic S. Network dynamics underlying OFF responses in the auditory cortex. eLife 2021; 10:e53151. [PMID: 33759763 PMCID: PMC8057817 DOI: 10.7554/elife.53151] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Across sensory systems, complex spatio-temporal patterns of neural activity arise following the onset (ON) and offset (OFF) of stimuli. While ON responses have been widely studied, the mechanisms generating OFF responses in cortical areas have so far not been fully elucidated. We examine here the hypothesis that OFF responses are single-cell signatures of recurrent interactions at the network level. To test this hypothesis, we performed population analyses of two-photon calcium recordings in the auditory cortex of awake mice listening to auditory stimuli, and compared them to linear single-cell and network models. While the single-cell model explained some prominent features of the data, it could not capture the structure across stimuli and trials. In contrast, the network model accounted for the low-dimensional organization of population responses and their global structure across stimuli, where distinct stimuli activated mostly orthogonal dimensions in the neural state-space.
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Affiliation(s)
- Giulio Bondanelli
- Laboratoire de Neurosciences Cognitives et Computationelles, Département d’études cognitives, ENS, PSL University, INSERMParisFrance
- Neural Computation Laboratory, Center for Human Technologies, Istituto Italiano di Tecnologia (IIT)GenoaItaly
| | - Thomas Deneux
- Départment de Neurosciences Intégratives et Computationelles (ICN), Institut des Neurosciences Paris-Saclay (NeuroPSI), UMR 9197 CNRS, Université Paris SudGif-sur-YvetteFrance
| | - Brice Bathellier
- Départment de Neurosciences Intégratives et Computationelles (ICN), Institut des Neurosciences Paris-Saclay (NeuroPSI), UMR 9197 CNRS, Université Paris SudGif-sur-YvetteFrance
- Institut Pasteur, INSERM, Institut de l’AuditionParisFrance
| | - Srdjan Ostojic
- Laboratoire de Neurosciences Cognitives et Computationelles, Département d’études cognitives, ENS, PSL University, INSERMParisFrance
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8
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Kopp-Scheinpflug C, Sinclair JL, Linden JF. When Sound Stops: Offset Responses in the Auditory System. Trends Neurosci 2018; 41:712-728. [DOI: 10.1016/j.tins.2018.08.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/30/2018] [Accepted: 08/10/2018] [Indexed: 11/17/2022]
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9
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Kimura A, Imbe H. Robust Subthreshold Cross-modal Modulation of Auditory Response by Cutaneous Electrical Stimulation in First- and Higher-order Auditory Thalamic Nuclei. Neuroscience 2018; 372:161-180. [PMID: 29309880 DOI: 10.1016/j.neuroscience.2017.12.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/14/2017] [Accepted: 12/27/2017] [Indexed: 12/14/2022]
Abstract
Conventional extracellular recording has revealed cross-modal alterations of auditory cell activities by cutaneous electrical stimulation of the hindpaw in first- and higher-order auditory thalamic nuclei (Donishi et al., 2011). Juxta-cellular recording and labeling techniques were used in the present study to examine the cross-modal alterations in detail, focusing on possible nucleus and/or cell type-related distinctions in modulation. Recordings were obtained from 80 cells of anesthetized rats. Cutaneous electrical stimulation, which did not elicit unit discharges, i.e., subthreshold effects, modulated early (onset) and/or late auditory responses of first- (64%) and higher-order nucleus cells (77%) with regard to response magnitude, latency and/or burst spiking. Attenuation predominated in the modulation of response magnitude and burst spiking, and delay predominated in the modulation of response time. Striking alterations of burst spiking took place in higher-order nucleus cells, which had the potential to exhibit higher propensities for burst spiking as compared to first-order nucleus cells. A subpopulation of first-order nucleus cells showing modulation in early response magnitude in the caudal domain of the nucleus had larger cell bodies and higher propensities for burst spiking as compared to cells showing no modulation. These findings suggest that somatosensory influence is incorporated into parallel channels in auditory thalamic nuclei to impose distinct impacts on cortical and subcortical sensory processing. Further, cutaneous electrical stimulation given after early auditory responses modulated late responses. Somatosensory influence is likely to affect ongoing auditory processing at any time without being coincident with sound onset in a narrow temporal window.
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Affiliation(s)
- Akihisa Kimura
- Department of Physiology, Wakayama Medical University, Wakayama Kimiidera 811-1, 641-8509, Japan.
| | - Hiroki Imbe
- Department of Physiology, Wakayama Medical University, Wakayama Kimiidera 811-1, 641-8509, Japan
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10
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Weigenand A, Mölle M, Werner F, Martinetz T, Marshall L. Timing matters: open-loop stimulation does not improve overnight consolidation of word pairs in humans. Eur J Neurosci 2016; 44:2357-68. [PMID: 27422437 PMCID: PMC5113809 DOI: 10.1111/ejn.13334] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 06/13/2016] [Accepted: 07/06/2016] [Indexed: 11/29/2022]
Abstract
The application of auditory clicks during non‐rapid eye movement (NREM) sleep phase‐locked to the up state of the slow oscillation (closed‐loop stimulation) has previously been shown to enhance the consolidation of declarative memories. We designed and applied sequences of three clicks during deep NREM sleep to achieve a quasi‐phase‐dependent open‐loop stimulation. This stimulation was successful in eliciting slow oscillation power in the stimulation period. Although fast and slow spindle power were markedly decreased during the stimulation period, memory consolidation did not differ from control. During putative up states fast spindle power remained, however, at control levels. We conclude that concurrence of slow oscillations and fast spindles suffices to maintain memory consolidation at control levels despite an overall decreased spindle activity.
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Affiliation(s)
- Arne Weigenand
- Institute for Neuro- and Bioinformatics, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany. .,Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany.
| | - Matthias Mölle
- Center for Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany.,Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Friederike Werner
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Thomas Martinetz
- Institute for Neuro- and Bioinformatics, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.,Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
| | - Lisa Marshall
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany. .,Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.
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11
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Characterization of Rebound Depolarization in Neurons of the Rat Medial Geniculate Body In Vitro. Neurosci Bull 2016; 32:16-26. [PMID: 26781877 DOI: 10.1007/s12264-015-0006-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/11/2015] [Indexed: 10/22/2022] Open
Abstract
Rebound depolarization (RD) is a response to the offset from hyperpolarization of the neuronal membrane potential and is an important mechanism for the synaptic processing of inhibitory signals. In the present study, we characterized RD in neurons of the rat medial geniculate body (MGB), a nucleus of the auditory thalamus, using whole-cell patch-clamp and brain slices. RD was proportional in strength to the duration and magnitude of the hyperpolarization; was effectively blocked by Ni(2+) or Mibefradil; and was depressed when the resting membrane potential was hyperpolarized by blocking hyperpolarization-activated cyclic nucleotide-gated (HCN) channels with ZD7288 or by activating G-protein-gated inwardly-rectifying K(+) (GIRK) channels with baclofen. Our results demonstrated that RD in MGB neurons, which is carried by T-type Ca(2+) channels, is critically regulated by HCN channels and likely by GIRK channels.
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12
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Kim N, Kong MS, Jo KI, Kim EJ, Choi JS. Increased tone-offset response in the lateral nucleus of the amygdala underlies trace fear conditioning. Neurobiol Learn Mem 2015; 126:7-17. [PMID: 26524504 DOI: 10.1016/j.nlm.2015.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 10/19/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022]
Abstract
Accumulating evidence suggests that the lateral nucleus of the amygdala (LA) stores associative memory in the form of enhanced neural response to the sensory input following classical fear conditioning in which the conditioned stimulus (CS) and the unconditioned stimulus (US) are presented in a temporally continuous manner. However, little is known about the role of the LA in trace fear conditioning where the CS and the US are separated by a temporal gap. Single-unit recordings of LA neurons before and after trace fear conditioning revealed that the short-latency activity to the CS offset, but not that to the onset, increased significantly and accompanied the conditioned fear response. The increased short-latency activity was evident in two aspects: the number of offset-responsive neurons was increased and the latency of the neuronal response to the CS offset was shortened. On the contrary, changes in the firing rate to either the onset or the offset were negligible following unpaired presentations of the CS and US. In sum, our results suggest that increased synaptic efficacy in the CS offset pathway in the LA might underlie the association between temporally distant stimuli in trace fear conditioning.
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Affiliation(s)
- Namsoo Kim
- Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Mi-Seon Kong
- Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology, University of Washington, Seattle, WA, USA
| | - Kyeong Im Jo
- Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea
| | - Eun Joo Kim
- Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology, University of Washington, Seattle, WA, USA
| | - June-Seek Choi
- Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea.
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13
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Mellott JG, Bickford ME, Schofield BR. Descending projections from auditory cortex to excitatory and inhibitory cells in the nucleus of the brachium of the inferior colliculus. Front Syst Neurosci 2014; 8:188. [PMID: 25339870 PMCID: PMC4186273 DOI: 10.3389/fnsys.2014.00188] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 09/16/2014] [Indexed: 01/13/2023] Open
Abstract
Descending projections from the auditory cortex (AC) terminate in subcortical auditory centers from the medial geniculate nucleus (MG) to the cochlear nucleus, allowing the AC to modulate the processing of acoustic information at many levels of the auditory system. The nucleus of the brachium of the inferior colliculus (NBIC) is a large midbrain auditory nucleus that is a target of these descending cortical projections. The NBIC is a source of several auditory projections, including an ascending projection to the MG. This ascending projection appears to originate from both excitatory and inhibitory NBIC cells, but whether the cortical projections contact either of these cell groups is unknown. In this study, we first combined retrograde tracing and immunochemistry for glutamic acid decarboxylase (GAD, a marker of GABAergic cells) to identify GABAergic and non-GABAergic NBIC projections to the MG. Our first result is that GAD-immunopositive cells constitute ~17% of the NBIC to MG projection. We then used anterograde labeling and electron microscopy to examine the AC projection to the NBIC. Our second result is that cortical boutons in the NBIC form synapses with round vesicles and asymmetric synapses, consistent with excitatory effects. Finally, we combined fluorescent anterograde labeling of corticofugal axons with immunochemistry and retrograde labeling of NBIC cells that project to the MG. These final results suggest first that AC axons contact both GAD-negative and GAD-positive NBIC cells and, second, that some of cortically-contacted cells project to the MG. Overall, the results imply that corticofugal projections can modulate both excitatory and inhibitory ascending projections from the NBIC to the auditory thalamus.
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Affiliation(s)
- Jeffrey G Mellott
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University Rootstown, OH USA
| | - Martha E Bickford
- Department of Anatomical Sciences and Neurobiology, University of Louisville Louisville, KY USA
| | - Brett R Schofield
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University Rootstown, OH USA
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14
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Lou Y, Luo W, Zhang G, Tao C, Chen P, Zhou Y, Xiong Y. Ventral tegmental area activation promotes firing precision and strength through circuit inhibition in the primary auditory cortex. Front Neural Circuits 2014; 8:25. [PMID: 24688459 PMCID: PMC3960576 DOI: 10.3389/fncir.2014.00025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 03/03/2014] [Indexed: 01/27/2023] Open
Abstract
The activation of the ventral tegmental area (VTA) can rebuild the tonotopic representation in the primary auditory cortex (A1), but the cellular mechanisms remain largely unknown. Here, we investigated the firing patterns and membrane potential dynamics of neurons in A1 under the influence of VTA activation using in vivo intracellular recording. We found that VTA activation can significantly reduce the variability of sound evoked responses and promote the firing precision and strength of A1 neurons. Furthermore, the compressed response window was caused by an early hyperpolarization as a result of enhanced circuit inhibition. Our study suggested a possible mechanism of how the reward system affects information processing in sensory cortex: VTA activation strengthens cortical inhibition, which shortens the response window of post-synaptic cortical neurons and further promotes the precision and strength of neuronal activity.
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Affiliation(s)
- Yunxiao Lou
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
| | - Wenzhi Luo
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
- Battalion Cadet Brigade 7, Third Military Medical UniversityChongqing, China
| | - Guangwei Zhang
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
| | - Can Tao
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
| | - Penghui Chen
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
| | - Yi Zhou
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
| | - Ying Xiong
- Chongqing Key Laboratory of Neurobiology, Department of Neurobiology, Third Military Medical UniversityChongqing, China
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15
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Antunes FM, Malmierca MS. An Overview of Stimulus-Specific Adaptation in the Auditory Thalamus. Brain Topogr 2013; 27:480-99. [DOI: 10.1007/s10548-013-0342-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/05/2013] [Indexed: 12/30/2022]
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16
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Bartlett EL. The organization and physiology of the auditory thalamus and its role in processing acoustic features important for speech perception. BRAIN AND LANGUAGE 2013; 126:29-48. [PMID: 23725661 PMCID: PMC3707394 DOI: 10.1016/j.bandl.2013.03.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 02/28/2013] [Accepted: 03/19/2013] [Indexed: 05/17/2023]
Abstract
The auditory thalamus, or medial geniculate body (MGB), is the primary sensory input to auditory cortex. Therefore, it plays a critical role in the complex auditory processing necessary for robust speech perception. This review will describe the functional organization of the thalamus as it relates to processing acoustic features important for speech perception, focusing on thalamic nuclei that relate to auditory representations of language sounds. The MGB can be divided into three main subdivisions, the ventral, dorsal, and medial subdivisions, each with different connectivity, auditory response properties, neuronal properties, and synaptic properties. Together, the MGB subdivisions actively and dynamically shape complex auditory processing and form ongoing communication loops with auditory cortex and subcortical structures.
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17
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Geis HRA, Borst JGG. Large GABAergic neurons form a distinct subclass within the mouse dorsal cortex of the inferior colliculus with respect to intrinsic properties, synaptic inputs, sound responses, and projections. J Comp Neurol 2012; 521:189-202. [DOI: 10.1002/cne.23170] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/18/2012] [Accepted: 06/07/2012] [Indexed: 11/10/2022]
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18
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Ji W, Suga N. Histaminergic modulation of nonspecific plasticity of the auditory system and differential gating. J Neurophysiol 2012; 109:792-802. [PMID: 23136340 DOI: 10.1152/jn.00930.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the auditory system of the big brown bat (Eptesicus fuscus), paired conditioned tonal (CS) and unconditioned leg stimuli (US) for auditory fear conditioning elicit tone-specific plasticity represented by best-frequency (BF) shifts that are augmented by acetylcholine, whereas unpaired CS and US for pseudoconditioning elicit a small BF shift and prominent nonspecific plasticity at the same time. The latter represents the nonspecific augmentations of auditory responses accompanied by the broadening of frequency tuning and decrease in threshold. It is unknown which neuromodulators are important in evoking the nonspecific plasticity. We found that histamine (HA) and an HA3 receptor (HA3R) agonist (α-methyl-HA) decreased, but an HA3R antagonist (thioperamide) increased, cortical auditory responses; that the HA3R agonist applied to the primary auditory cortex before pseudoconditioning abolished the nonspecific augmentation in the cortex without affecting the small cortical BF shift; and that antagonists of acetylcholine, norepinephrine, dopamine, and serotonin receptors did not abolish the nonspecific augmentation elicited by pseudoconditioning. The histaminergic system plays an important role in eliciting the arousal and defensive behavior, possibly through nonspecific augmentation. Thus HA modulates the nonspecific augmentation, whereas acetylcholine amplifies the BF shifts. These two neuromodulators may mediate differential gating of cortical plasticity.
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Affiliation(s)
- Weiqing Ji
- Dept. of Biology, Washington Univ, St. Louis, MO 63130, USA.
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19
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Rabang CF, Bartlett EL. A computational model of cellular mechanisms of temporal coding in the medial geniculate body (MGB). PLoS One 2011; 6:e29375. [PMID: 22195049 PMCID: PMC3241713 DOI: 10.1371/journal.pone.0029375] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 11/28/2011] [Indexed: 12/04/2022] Open
Abstract
Acoustic stimuli are often represented in the early auditory pathway as patterns of neural activity synchronized to time-varying features. This phase-locking predominates until the level of the medial geniculate body (MGB), where previous studies have identified two main, largely segregated response types: Stimulus-synchronized responses faithfully preserve the temporal coding from its afferent inputs, and Non-synchronized responses, which are not phase locked to the inputs, represent changes in temporal modulation by a rate code. The cellular mechanisms underlying this transformation from phase-locked to rate code are not well understood. We use a computational model of a MGB thalamocortical neuron to test the hypothesis that these response classes arise from inferior colliculus (IC) excitatory afferents with divergent properties similar to those observed in brain slice studies. Large-conductance inputs exhibiting synaptic depression preserved input synchrony as short as 12.5 ms interclick intervals, while maintaining low firing rates and low-pass filtering responses. By contrast, small-conductance inputs with Mixed plasticity (depression of AMPA-receptor component and facilitation of NMDA-receptor component) desynchronized afferent inputs, generated a click-rate dependent increase in firing rate, and high-pass filtered the inputs. Synaptic inputs with facilitation often permitted band-pass synchrony along with band-pass rate tuning. These responses could be tuned by changes in membrane potential, strength of the NMDA component, and characteristics of synaptic plasticity. These results demonstrate how the same synchronized input spike trains from the inferior colliculus can be transformed into different representations of temporal modulation by divergent synaptic properties.
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Affiliation(s)
- Cal F. Rabang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Edward L. Bartlett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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20
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Neural substrate of sound duration discrimination during an auditory sequence in the guinea pig primary auditory cortex. Hear Res 2010; 259:107-16. [DOI: 10.1016/j.heares.2009.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 10/19/2009] [Accepted: 10/21/2009] [Indexed: 11/21/2022]
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21
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Sun X, Guo YP, Shum DKY, Chan YS, He J. Time course of cortically induced fos expression in auditory thalamus and midbrain after bilateral cochlear ablation. Neuroscience 2009; 160:186-97. [PMID: 19232381 DOI: 10.1016/j.neuroscience.2009.02.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 01/18/2009] [Accepted: 02/10/2009] [Indexed: 11/18/2022]
Abstract
Expression of c-fos in the medial geniculate body (MGB) and the inferior colliculus (IC) in response to bicuculline-induced corticofugal activation was examined in rats at different time points after bilateral cochlear ablation (4 h-30 days). Corticofugal activation was crucial in eliciting Fos expression in the MGB after cochlear ablation. The pars ovoidea (OV) of the medial geniculate body ventral division (MGv) showed dense Fos expression 4 h after cochlear ablation; the expression declined to very low levels at 24 h and thereafter. In turn, strong Fos expression was found in the pars lateralis (LV) of the MGv 24 h after cochlear ablation and dropped dramatically at 14 days. The dorsal division of the MGB (MGd) showed high Fos expression 7 days after cochlear ablation, which persisted for a period of time. Using multi-electrode recordings, neuronal activity of different MGB subnuclei was found to correlate well with Fos expressions. The temporal changes in cortically activated Fos expression in different MGB subnuclei after bilateral cochlear ablation indicate differential denervation hypersensitivities of these MGB neurons and likely point to differential dependence of these nuclei on both auditory ascending and corticofugal descending inputs. After bilateral cochlear ablation, significant increases in Fos-positive neurons were detected unilaterally in all IC subnuclei, ipsilateral to the bicuculline injection.
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Affiliation(s)
- X Sun
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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22
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Ji W, Suga N. Tone-specific and nonspecific plasticity of the auditory cortex elicited by pseudoconditioning: role of acetylcholine receptors and the somatosensory cortex. J Neurophysiol 2008; 100:1384-96. [PMID: 18596186 DOI: 10.1152/jn.90340.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Experience-dependent plastic changes in the central sensory systems are due to activation of both the sensory and neuromodulatory systems. Nonspecific changes of cortical auditory neurons elicited by pseudoconditioning are quite different from tone-specific changes of the neurons elicited by auditory fear conditioning. Therefore the neural circuit evoking the nonspecific changes must also be different from that evoking the tone-specific changes. We first examined changes in the response properties of cortical auditory neurons of the big brown bat elicited by pseudoconditioning with unpaired tonal (CS(u)) and electric leg (US(u)) stimuli and found that it elicited nonspecific changes to CS(u) (a heart-rate decrease, an auditory response increase, a broadening of frequency tuning, and a decrease in threshold) and, in addition, a small tone-specific change to CS(u) (a small short-lasting best-frequency shift) only when CS(u) frequency was 5 kHz lower than the best frequency of a recorded neuron. We then examined the effects of drugs on the cortical changes elicited by the pseudoconditioning. The development of the nonspecific changes was scarcely affected by atropine (a muscarinic cholinergic receptor antagonist) and mecamylamine (a nicotinic cholinergic receptor antagonist) applied to the auditory cortex and by muscimol (a GABAA-receptor agonist) applied to the somatosensory cortex. However, these drugs abolished the small short-lasting tone-specific change as they abolished the large long-lasting tone-specific change elicited by auditory fear conditioning. Our current results indicate that, different from the tone-specific change, the nonspecific changes depend on neither the cholinergic neuromodulator nor the somatosensory cortex.
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Affiliation(s)
- Weiqing Ji
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
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23
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Reprint of “frequency tuning and firing pattern properties of auditory thalamic neurons: An in vivo intracellular recording from the guinea pig” [Neuroscience 151 (2008) 293–302]☆. Neuroscience 2008; 154:273-82. [DOI: 10.1016/s0306-4522(08)00741-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2007] [Indexed: 11/21/2022]
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24
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Zhang Z, Liu CH, Yu YQ, Fujimoto K, Chan YS, He J. Corticofugal Projection Inhibits the Auditory Thalamus Through the Thalamic Reticular Nucleus. J Neurophysiol 2008; 99:2938-45. [DOI: 10.1152/jn.00002.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrical stimulation of the auditory cortex (AC) causes both facilitatory and inhibitory effects on the medial geniculate body (MGB). The purpose of this study was to identify the corticofugal inhibitory pathway to the MGB. We assessed two potential circuits: 1) the cortico-colliculo-thalamic circuit and 2) cortico-reticulo-thalamic one. We compared intracellular responses of MGB neurons to electrical stimulation of the AC following bilateral ablation of the inferior colliculi (IC) or thalamic reticular nucleus (TRN) in anesthetized guinea pigs. Cortical stimulation with intact TRN could cause strong inhibitory effects on the MGB neurons. The corticofugal inhibition remained effective after bilateral IC ablation, but it was minimized after the TRN was lesioned with kainic acid. Synchronized TRN neuronal activity and MGB inhibitory postsynaptic potentials (IPSPs) were observed with multiple recordings. The results suggest that corticofugal inhibition traverses the corticoreticulothalamic pathway, indicating that the colliculi-geniculate inhibitory pathway is probably only for feedforward inhibition.
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25
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Cotillon-Williams N, Huetz C, Hennevin E, Edeline JM. Tonotopic Control of Auditory Thalamus Frequency Tuning by Reticular Thalamic Neurons. J Neurophysiol 2008; 99:1137-51. [DOI: 10.1152/jn.01159.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
GABAergic cells of the thalamic reticular nucleus (TRN) can potentially exert strong control over transmission of information through thalamus to the cerebral cortex. Anatomical studies have shown that the reticulo-thalamic connections are spatially organized in the visual, somatosensory, and auditory systems. However, the issue of how inhibitory input from TRN controls the functional properties of thalamic relay cells and whether this control follows topographic rules remains largely unknown. Here we assessed the consequences of increasing or decreasing the activity of small ensembles of TRN neurons on the receptive field properties of medial geniculate (MG) neurons. For each MG cell, the frequency tuning curve and the rate-level function were tested before, during, and after microiontophoretic applications of GABA, or of glutamate, in the auditory sector of the TRN. For 66 MG cells tested during potent pharmacological control of TRN activity, group data did not reveal any significant effects. However, for a population of 20/66 cells (all but 1 recorded in the ventral, tonotopic, division), the breadth of tuning, the frequency selectivity and the acoustic threshold were significantly modified in the directions expected from removing, or reinforcing, a dominant inhibitory input onto MG cells. Such effects occurred only when the distance between the characteristic frequency of the recorded ventral MG cell and that of the TRN cells at the ejection site was <0.25 octaves; they never occurred for larger distances. This relationship indicates that the functional interactions between TRN cells and ventral MG cells rely on precise topographic connections.
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26
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Frequency tuning and firing pattern properties of auditory thalamic neurons: An in vivo intracellular recording from the guinea pig. Neuroscience 2008; 151:293-302. [DOI: 10.1016/j.neuroscience.2007.09.082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2007] [Revised: 08/30/2007] [Accepted: 11/07/2007] [Indexed: 11/18/2022]
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27
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Smith PH, Bartlett EL, Kowalkowski A. Cortical and collicular inputs to cells in the rat paralaminar thalamic nuclei adjacent to the medial geniculate body. J Neurophysiol 2007; 98:681-95. [PMID: 17537907 DOI: 10.1152/jn.00235.2007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The paralaminar nuclei, including the medial division of the medial geniculate nucleus, surround the auditory thalamus medially and ventrally. This multimodal area receives convergent inputs from auditory, visual, and somatosensory structures and sends divergent outputs to cortical layer 1, amygdala, basal ganglia, and elsewhere. Studies implicate this region in the modulation of cortical 40-Hz oscillations, cortical information binding, and the conditioned fear response. We recently showed that the basic anatomy and intrinsic physiology of paralaminar cells are unlike that of neurons elsewhere in sensory thalamus. Here we evaluate the synaptic inputs to paralaminar cells from the inferior and superior colliculi and the cortex. Combined physiological and anatomical evidence indicates that paralaminar cells receive both excitatory and inhibitory inputs from both colliculi and excitatory cortical inputs. Excitatory inputs from all three sources typically generate small summating EPSPs composed of AMPA and NMDA components and terminate primarily on smaller dendrites and occasionally on dendritic spines. The cortical input shows strong paired-pulse facilitation (PPF), whereas both collicular inputs show weak PPF or paired-pulse depression (PPD). EPSPs of cells with no low-threshold calcium conductance do not evoke a burst response when the cell is hyperpolarized. Longer-latency EPSPs were seen and our evidence indicates that these arise from axon collateral inputs of other synaptically activated paralaminar cells. The inhibitory collicular inputs are GABAergic, activate GABA(A) receptors, and terminate on dendrites. Their activation can greatly alter EPSP-generated spike number and timing.
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Affiliation(s)
- Philip H Smith
- Department of Anatomy, University of Wisconsin Medical School-Madison, Madison, Wisconsin 53706, USA.
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28
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Sun X, Xia Q, Lai CH, Shum DKY, Chan YS, He J. Corticofugal modulation of acoustically induced Fos expression in the rat auditory pathway. J Comp Neurol 2007; 501:509-25. [PMID: 17278128 DOI: 10.1002/cne.21249] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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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Affiliation(s)
- Xia Sun
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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29
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Smith PH, Bartlett EL, Kowalkowski A. Unique combination of anatomy and physiology in cells of the rat paralaminar thalamic nuclei adjacent to the medial geniculate body. J Comp Neurol 2006; 496:314-34. [PMID: 16566009 PMCID: PMC2943380 DOI: 10.1002/cne.20913] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The medial geniculate body (MGB) has three major subdivisions, ventral (MGV), dorsal (MGD), and medial (MGM). MGM is linked with paralaminar nuclei that are situated medial and ventral to MGV/MGD. Paralaminar nuclei have unique inputs and outputs compared with MGV and MGD and have been linked to circuitry underlying some important functional roles. We recorded intracellularly from cells in the paralaminar nuclei in vitro. We found that they possess an unusual combination of anatomical and physiological features compared with those reported for "standard" thalamic neurons seen in the MGV/MGD and elsewhere in the thalamus. Compared with MGV/MGD neurons, anatomically, 1) paralaminar cell dendrites can be long, branch sparingly, and encompass a much larger area; 2) their dendrites may be smooth but can have well defined spines; and 3) their axons can have collaterals that branch locally within the same or nearby paralaminar nuclei. When compared with MGV/MGD neurons, physiologically, 1) their spikes are larger in amplitude and can be shorter in duration; 2) their spikes can have dual afterhyperpolarizations with fast and slow components; and 3) they can have a reduction or complete absence of the low-threshold, voltage-sensitive calcium conductance that reduces or eliminates the voltage-dependent burst response. We also recorded from cells in the parafascicular nucleus, a nucleus of the posterior intralaminar nuclear group, because they have unusual anatomical features that are similar to those of some of our paralaminar cells. As with the labeled paralaminar cells, parafascicular cells had physiological features distinguishing them from typical thalamic neurons.
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Affiliation(s)
- Philip H Smith
- Department of Anatomy, University of Wisconsin, Medical School-Madison, 53706, USA.
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30
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Xiong Y, Yu YQ, Chan YS, He J. Effects of cortical stimulation on auditory-responsive thalamic neurones in anaesthetized guinea pigs. J Physiol 2004; 560:207-17. [PMID: 15272037 PMCID: PMC1665194 DOI: 10.1113/jphysiol.2004.067686] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In the present study, we investigated neuronal responses to acoustic stimuli and cortical stimulation in the medial geniculate body (MGB) through in vivo intracellular recordings in anaesthetized guinea pigs. Of the 54 neurones examined with acoustic stimuli, 36 showed excitatory postsynaptic potential (EPSP) responses and 19 showed inhibitory postsynaptic potential (IPSP) responses to acoustic stimuli. Of the 36 EPSP neurones examined with corticofugal modulation, 29 received corticofugal depolarization, 3 corticofugal inhibition, and 4 showed no effect. Of the 19 IPSP neurones, 17 received corticofugal inhibition and 2 were not affected. The mean amplitude of the EPSPs evoked by acoustic stimuli was similar to that evoked by the electrical cortical stimulation (9.19 +/- 5.55 mV versus 9.22 +/- 5.16 mV). There was a significant correlation between the parameters of the EPSPs evoked by an acoustic stimulus and those evoked by cortical stimulation. The mean amplitude of the IPSP evoked by electrical cortical stimulation was significantly greater than that evoked by acoustic stimuli (11.6 +/- 3.8 mV versus 9.1 +/- 3.7 ms, P < 0.05). Seven auditory EPSP and 7 IPSP neurones were examined with corticofugal modulation and labelled with Neurobiotin. Of the 7 EPSP neurones, 5 showed excitatory responses to cortical stimulation and 2 demonstrated no effects. Four of the 5 neurones that received corticofugal depolarization were located in the lemniscal MGB and 1 in the non-lemniscal MGB; of the remaining 2, 1 was located in the lemniscal and the other in the non-lemniscal MGB. Of the 7 IPSP neurones, 1 received an excitatory corticofugal input followed by an inhibitory input and 4 received only an inhibitory corticofugal input, while the remainder demonstrated no corticofugal effects. All 7 neurones were located in the non-lemniscal MGB. The result that both ascending and descending inputs caused similarly shaped EPSPs reflects a neuronal endogenous characteristic irrespective of the physical locations of the synapses. The IPSP responses to both acoustic stimuli and electrical cortical stimulation are likely to be caused by feedback from the thalamic reticular nucleus.
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Affiliation(s)
- Ying Xiong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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