A horseradish peroxidase study of parallel thalamocortical projections responsible for the generation of mid-latency auditory-evoked potentials

Brett, Barbara; Di, Shi; Watkins, Linda R.; Barth, Daniel S.

doi:10.1016/0006-8993(94)91399-4

Cited by 19 publications

(23 citation statements)

References 34 publications

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“…The average latency shift of the P1 in AII relative to AI was 2.4 Ϯ 0.52 (SE) msec (n ϭ 5; P Ͻ 0.01; t test). This latency shift was consistent with that found in previous studies where longer latency responses posterior and dorsal to AI were associated with cortex receiving parallel input from the dorsal division of the medial geniculate body (MGd; Brett et al, 1994). Here, a normalized isopotential map computed at 11.0-msec poststimulus, before AII responded, indicates that the short latency AI response covered approximately 2.5 mm 2 at the lateral border of the array (Fig.…”

Section: Extracellular Recordingsupporting

confidence: 89%

“…However, a definitive distinction between AI and the anterior auditory field based on thalamocortical projection is not available in the rat. In addition, MZ injections labeled the MGd, MGm, and Sg, which have been shown by others (Niimi and Naito, 1974;Ryugo and Killackey, 1974;Raczkowski et al, 1975;Patterson, 1977;Winer and Morest, 1983;Winer and Larue, 1987;Arnault and Roger, 1990;Brett et al, 1994;Huang and Winer, 2000) to project to AII in the rat.…”

Section: Mz and Secondary Sensory Areasmentioning

confidence: 88%

“…However, it is noteworthy that evoked responses in secondary sensory cortex and in MZ have the same positive/negative morphology as those in primary sensory cortex, characterizing thalamocortical activation of the middle cortical layers. The regions of AII abutting AI receive projections from the MGd and MGm as well as the Sg in the rat and cat (Niimi and Naito, 1974;Ryugo and Killackey, 1974;Raczkowski et al, 1975;Patterson, 1977;Winer and Morest, 1983;Winer and Larue, 1987;Arnault and Roger, 1990;Brett et al, 1994;Huang and Winer, 2000). There are also parallel thalamocortical projections to SII from the Vpm, Vpl, and Po (Tracey and Waite, 1995).…”

Section: Sequential and Parallel Activation Of Mzmentioning

confidence: 95%

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A multisensory zone in rat parietotemporal cortex: Intra‐ and extracellular physiology and thalamocortical connections

Brett-Green

Fifková

Larue

et al. 2003

J of Comparative Neurology

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Multisensory integration is essential for the expression of complex behaviors in humans and animals. However, few studies have investigated the neural sites where multisensory integration may occur. Therefore, we used electrophysiology and retrograde labeling to study a region of the rat parietotemporal cortex that responds uniquely to auditory and somatosensory multisensory stimulation. This multisensory responsiveness suggests a functional organization resembling multisensory association cortex in cats and primates. Extracellular multielectrode surface mapping defined a region between auditory and somatosensory cortex where responses to combined auditory/somatosensory stimulation were larger in amplitude and earlier in latency than responses to either stimulus alone. Moreover, multisensory responses were nonlinear and differed from the summed unimodal responses. Intracellular recording found almost exclusively multisensory cells that responded to both unisensory and multisensory stimulation with excitatory postsynaptic potentials (EPSPs) and/or action potentials, conclusively defining a multisensory zone (MZ). In addition, intracellular responses were similar to extracellular recordings, with larger and earlier EPSPs evoked by multisensory stimulation, and interactions suggesting nonlinear postsynaptic summation to combined stimuli. Thalamic input to MZ from unimodal auditory and somatosensory thalamic relay nuclei and from multisensory thalamic regions support the idea that parallel thalamocortical projections may drive multisensory functions as strongly as corticocortical projections. Whereas the MZ integrates uni- and multisensory thalamocortical afferent streams, it may ultimately influence brainstem multisensory structures such as the superior colliculus.

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Section: Extracellular Recordingsupporting

confidence: 89%

Section: Mz and Secondary Sensory Areasmentioning

confidence: 88%

Section: Sequential and Parallel Activation Of Mzmentioning

confidence: 95%

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A multisensory zone in rat parietotemporal cortex: Intra‐ and extracellular physiology and thalamocortical connections

Brett-Green

Fifková

Larue

et al. 2003

J of Comparative Neurology

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“…Recent studies in the rodent, combining somatosensory with either auditory (Brett-Green et al 2003;Simons 1986, 1987;Di et al 1994;Ramachandran et al 1993;Wallace et al 2004) or visual stimulation (Barth et al 1995;Ramachandran et al 1993;Wallace et al 2004), have suggested that one of the functions of SII, and indeed of secondary sensory cortex in general, may be in multisensory integration. However, while cells within SII responding to multisensory stimuli have been reported, the relative topographies of multisensory zones and SII have not been investigated in detail.…”

Section: Introductionmentioning

confidence: 97%

Two Distinct Regions of Secondary Somatosensory Cortex in the Rat: Topographical Organization and Multisensory Responses

Brett-Green

Paulsen

Staba

et al. 2004

Journal of Neurophysiology

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In rodents, as in other species, regions of secondary somatosensory cortex (SII) may be distinguished from primary cortex (SI) both anatomically and electrophysiologically. However, the number of rodent SII subregions, their somatotopic organization, and their function are poorly understood. The presence of multisensory responsive neurons in some areas of SII suggests that one of its roles may be in the integration of somatosensory information with information from other sensory modalities. In this study, we used auditory, somatosensory, or combined auditory/somatosensory stimuli, and high-resolution epipial-evoked potential maps of rat SII to identify the number of spatially discrete subregions, estimate their somatotopic organization, and delineate regions with multisensory response properties. Maps revealed two distinct subregions within SII, one rostral and the other caudal, which were situated lateral to the posteromedial barrel subfield. Distinct somatotopies were evident at both SII loci, and analysis of evoked responses within both areas indicated multisensory interactions. These data are consistent with the presence of classically defined rostral SII regions and provide functional evidence for a lesser known, but distinct, caudal SII area. Furthermore, evidence for multisensory interactions within SII suggests that both secondary areas may process features specifically associated with multisensory integration in parallel with unimodal processing in primary areas.

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“…7-13. Camera lucida drawings of tufted (7)(8)(9)(10)(11) or stellate (12-13) cells labeled in the ventral or dorsal divisions of MGB. These are the same MGB cells seen in Fig.…”

Section: Apamin Sensitive Conductancementioning

confidence: 99%

Unique combination of anatomy and physiology in cells of the rat paralaminar thalamic nuclei adjacent to the medial geniculate body

Smith

Bartlett

Kowalkowski

2006

J of Comparative Neurology

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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 when 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 when compared to those reported for "standard" thalamic neurons seen in the MGV/MGD and elsewhere in the thalamus. Compared to 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 to MGV/MGD neurons physiologically 1) their spikes are larger in amplitude and can be shorter in duration and 2) 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 some of our paralaminar cells. Like the labeled paralaminar cells, parafascicular cells had physiological features distinguishing them from typical thalamic neurons.

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A horseradish peroxidase study of parallel thalamocortical projections responsible for the generation of mid-latency auditory-evoked potentials

Cited by 19 publications

References 34 publications

A multisensory zone in rat parietotemporal cortex: Intra‐ and extracellular physiology and thalamocortical connections

A multisensory zone in rat parietotemporal cortex: Intra‐ and extracellular physiology and thalamocortical connections

Two Distinct Regions of Secondary Somatosensory Cortex in the Rat: Topographical Organization and Multisensory Responses

Unique combination of anatomy and physiology in cells of the rat paralaminar thalamic nuclei adjacent to the medial geniculate body

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