A new intrathalamic pathway linking modality-related nuclei in the dorsal thalamus

Crabtree, John W.; Collingridge, Graham L.; Isaac, John T.R.

doi:10.1038/1603

Cited by 103 publications

(92 citation statements)

References 51 publications

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“…All of these structures are responsive to visual stimulation. In addition, recent studies revealed that supposedly unisensory thalamic nuclei can modulate each other via the thalamic reticular nucleus (Crabtree et al, 1998;Crabtree and Isaac, 2002). It is likely that such subcortical exchange of multisensory information occurs between visual and auditory modalities, yet this hypothesis has not been tested.…”

Section: Pathways Of Multisensory Enhancement Of Auditory Cortexmentioning

confidence: 99%

Functional Imaging Reveals Visual Modulation of Specific Fields in Auditory Cortex

Kayser¹,

Petkov²,

Augath³

et al. 2007

J. Neurosci.

226

161

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Merging the information from different senses is essential for successful interaction with real-life situations. Indeed, sensory integration can reduce perceptual ambiguity, speed reactions, or change the qualitative sensory experience. It is widely held that integration occurs at later processing stages and mostly in higher association cortices; however, recent studies suggest that sensory convergence can occur in primary sensory cortex. A good model for early convergence proved to be the auditory cortex, which can be modulated by visual and tactile stimulation; however, given the large number and small size of auditory fields, neither human imaging nor microelectrode recordings have systematically identified which fields are susceptible to multisensory influences. To reconcile findings from human imaging with anatomical knowledge from nonhuman primates, we exploited high-resolution imaging (functional magnetic resonance imaging) of the macaque monkey to study the modulation of auditory processing by visual stimulation. Using a functional parcellation of auditory cortex, we localized modulations to individual fields. Our results demonstrate that both primary (core) and nonprimary (belt) auditory fields can be activated by the mere presentation of visual scenes. Audiovisual convergence was restricted to caudal fields [prominently the core field (primary auditory cortex) and belt fields (caudomedial field, caudolateral field, and mediomedial field)] and continued in the auditory parabelt and the superior temporal sulcus. The same fields exhibited enhancement of auditory activation by visual stimulation and showed stronger enhancement for less effective stimuli, two characteristics of sensory integration. Together, these findings reveal multisensory modulation of auditory processing prominently in caudal fields but also at the lowest stages of auditory cortical processing.

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Section: Pathways Of Multisensory Enhancement Of Auditory Cortexmentioning

confidence: 99%

Functional Imaging Reveals Visual Modulation of Specific Fields in Auditory Cortex

Kayser¹,

Petkov²,

Augath³

et al. 2007

J. Neurosci.

226

161

View full text Add to dashboard Cite

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“…First, in agreement with our experience in rats , the reticulothalamic input to the ventral posterior nucleus is already highly topographic even at this age, suggesting an early development of the somatosensory system in rats and mice. Second, injection of retrograde tracers into the posterior nucleus has indicated that differences between the reticular inputs to the first-and higher-order relays are found in adults (Crabtree 1996;Crabtree et al 1998).…”

Section: Technical Considerationsmentioning

confidence: 99%

“…One difference is suggested by prior retrograde tracing studies in cats and rats: the higher-order posterior nucleus was reported to have a more diffusely organized reticulothalamic input compared with the first-order ventral posterior nucleus (Crabtree 1996;Crabtree et al 1998). Labeling of a large number (Ͼ100) of cells juxtacellularly in the somatosensory and other sections of the thalamic reticular nucleus of rats, however, has led to a somewhat different conclusion, namely, that the axonal arbors of reticular neurons are mostly circumscribed, quite topographically organized and usually contained within a single thalamic nucleus (Pinault and Deschênes 1998;Pinault et al 1995).…”

Section: Introductionmentioning

confidence: 97%

Different Topography of the Reticulothalmic Inputs to First- and Higher-Order Somatosensory Thalamic Relays Revealed Using Photostimulation

Lam

Sherman²

2007

Journal of Neurophysiology

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Lam YW, Sherman SM. Different topography of the reticulothalmic inputs to first-and higher-order somatosensory thalamic relays revealed using photostimulation. J Neurophysiol 98: 2903-2909. First published September 19, 2007 doi:10.1152/jn.00782.2007. The thalamic reticular nucleus is a layer of GABAergic neurons that occupy a strategic position between the thalamus and cortex. Here we used laser scanning photostimulation to compare in young mice (9 -12 days old) the organization of the reticular inputs to first-and higher-order somatosensory relays, namely, the ventral posterior lateral nucleus and posterior nucleus, respectively. The reticulothalamic input footprints to the ventral posterior lateral nucleus neurons consisted of small, single, topographically organized elliptical regions in a tier away from the reticulothalamic border. In contrast, those to the posterior nucleus were complicated and varied considerably among neurons: although almost all contained a single elliptical region near the reticulothalamic border, in most cases, they consisted of additional discontinuous regions or relatively diffuse regions throughout the thickness of the thalamic reticular nucleus. Our results suggest two sources of reticular inputs to the posterior nucleus neurons: one that is relatively topographic from regions near the reticulothalamic border and one that is relatively diffuse and convergent from most or all of the thickness of the thalamic reticular nucleus. We propose that the more topographic reticular input is the basis of local inhibition seen in posterior nucleus neurons and that the more diffuse and convergent input may represent circuitry through which the ventral posterior lateral and posterior nuclei interact. I N T R O D U C T I O NThe thalamic reticular nucleus is a thin layer of GABAergic cells adjacent to the relay nuclei of the (dorsal) thalamus. Most axons connecting the thalamus and cortex in either direction pass through the thalamic reticular nucleus and innervate neurons there with collaterals; reticular neurons, in turn, provide strong inhibition to thalamic relay cells. Due to its strategic location between the thalamus and cortex, the thalamic reticular nucleus is often suggested as a key player in regulating the relay of information through the thalamus to cortex (Crick 1984;Guillery and Sherman 2002;Guillery et al. 1998;McAlonan et al. 2006;Pinault 2004;Sherman and Koch 1986;Yingling and Skinner 2007). Understanding the functional organization of inputs from the thalamic reticular nucleus to thalamic relay nuclei, and how it varies among these nuclei, is of obvious importance.Thalamic nuclei have been classified into first-and higher-order relays: the first-order relays receive their driver inputs, which represent the main information to be relayed, from subcortical sources, whereas the higher-order relays receive their driver inputs from layer 5 of the cortex as part of a cortico-thalamo-cortical route (Guillery and Sherman 2002). The somatosensory thalamic examples of these different rel...

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“…Our mapping results do not provide direct information regarding the anatomical basis (axodendritic vs dendrodendritic) of intranuclear inhibition. Topographic and sensory modality-specific organization exist in nRt both longitudinally (sectors), as well as within the mediolateral extent of the nucleus (tiers) (Jones, 1975;Shosaku et al, 1984;Crabtree, 1996;Crabtree et al, 1998;Lam and Sherman, 2005). For example, neurons located in the central tier of somatosensory nRt project to the ventral posterior nuclei, whereas medial tier neurons connect to the posterior complex (Crabtree, 1996).…”

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confidence: 99%

Distinct Electrical and Chemical Connectivity Maps in the Thalamic Reticular Nucleus: Potential Roles in Synchronization and Sensation

2006

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GABAergic neurons of the thalamic reticular nucleus (nRt) provide thalamocortical relay neurons with feedback inhibition that influences sensory processing and thalamocortical rhythm generation. Mutual interactions between reticular neurons coordinate oscillatory activities developed within the network during normal sleep and in absence epilepsy, but the chemical versus electrical nature of these connections and their functional influence remain controversial. Here, we investigated the incidence and spatial extent of intra-nRt connectivity in vitro in horizontal and coronal thalamic slices from rat. Laser scanning photostimulation activated presynaptic nRt cells during patch-clamp recordings of postsynaptic neurons. Photolysis of caged glutamate evoked GABAergic IPSCs and/or depolarizing events (spikelets, mediated via electrical coupling) in a large proportion of neurons, thus indicating connectivity with presynaptic cell(s). Synaptic inputs were organized along the major axis of the nucleus in the same orientation as, but commonly exceeding the extent of, dendritic arborization of the postsynaptic neuron. In the anteroposterior (horizontal) plane, chemical connectivity had higher incidence (60% of recorded neurons vs 40% in vertical plane) and longer spatial extent, whereas in the dorsoventral (vertical) plane, electrical coupling dominated (47% incidence vs 37% in horizontal plane) and was more widely distributed. These data demonstrate that both electrical and chemical synapses are prominent within nRt and suggest different roles for the two types of connections. We thus propose that, along the vertical plane, electrical connectivity will promote coordinated rhythmic activity of sleep and/or thalamocortical epilepsy, whereas along the horizontal plane, chemical connectivity will oppose widespread thalamocortical synchronization and modulate sensory throughput.

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A new intrathalamic pathway linking modality-related nuclei in the dorsal thalamus

Cited by 103 publications

References 51 publications

Functional Imaging Reveals Visual Modulation of Specific Fields in Auditory Cortex

Functional Imaging Reveals Visual Modulation of Specific Fields in Auditory Cortex

Different Topography of the Reticulothalmic Inputs to First- and Higher-Order Somatosensory Thalamic Relays Revealed Using Photostimulation

Distinct Electrical and Chemical Connectivity Maps in the Thalamic Reticular Nucleus: Potential Roles in Synchronization and Sensation

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