Unveiling the diversity of thalamocortical neuron subtypes

Clascá, Francisco; Rubio-Garrido, Pablo; Jabaudon, Denis

doi:10.1111/j.1460-9568.2012.08033.x

Cited by 184 publications

(189 citation statements)

References 122 publications

(289 reference statements)

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“…Previously, we were able to assign spindles to either of these two thalamocortical systems by observing their spatial characteristics and presence in either MEG or EEG, simultaneously recorded (Dehghani et al, 2011; Dehghani et al, 2010). In this light, the current finding that the spatial extent of spindles varies between brain areas is in agreement with the observations that the distribution of the matrix and core pathways might not be homogeneous throughout the cortex (Clascá et al, 2012; Jones, 2001; Piantoni et al, 2016). …”

Section: Discussionsupporting

confidence: 90%

Spatiotemporal characteristics of sleep spindles depend on cortical location

2017

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Since their discovery almost one century ago, sleep spindles, 0.5–2 s long bursts of oscillatory activity at 9–16 Hz during NREM sleep, have been thought to be global and relatively uniform throughout the cortex. Recent work, however, has brought this concept into question but it remains unclear to what degree spindles are global or local and if their properties are uniform or location-dependent. We addressed this question by recording sleep in eight patients undergoing evaluation for epilepsy with intracranial electrocorticography, which combines high spatial resolution with extensive cortical coverage. We find that spindle characteristics are not uniform but are strongly influenced by the underlying cortical regions, particularly for spindle density and fundamental frequency. We observe both highly isolated and spatially distributed spindles, but in highly skewed proportions: while most spindles are restricted to one or very few recording channels at any given time, there are spindles that occur over widespread areas, often involving lateral prefrontal cortices and superior temporal gyri. Their co-occurrence is affected by a subtle but significant propagation of spindles from the superior prefrontal regions and the temporal cortices towards the orbitofrontal cortex. This work provides a brain-wide characterization of sleep spindles as mostly local graphoelements with heterogeneous characteristics that depend on the underlying cortical area. We propose that the combination of local characteristics and global organization reflects the dual properties of the thalamo-cortical generators and provides a flexible framework to support the many functions ascribed to sleep in general and spindles specifically.

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Section: Discussionsupporting

confidence: 90%

Spatiotemporal characteristics of sleep spindles depend on cortical location

2017

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“…These neurons were selected due to their modulatory role in nociceptive transmission, associated with the perception of pain in humans ( Clasca et al , 2012; Cox et al , 1997; DeFelipe & Farinas, 1992; Gentet & Ulrich, 2003). Previous work ( Brown et al , 2015) on murine neurons of the cortex and thalamocortical neurons of the ventrobasal (VB) thalamus revealed that fluctuations in the endogenous neurosteroid tone during development (P7–P24) influenced the duration of miniature inhibitory postsynaptic currents (mIPSCs).…”

Section: Resultsmentioning

confidence: 99%

Neurosteroids are reduced in diabetic neuropathy and may be associated with the development of neuropathic pain

Humble

2016

F1000Res

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Introduction: Peripheral and central sensitisation are implicated in the development of neuropathic pain. Hypersensitivity of pain pathway neurons has been described in animal models of diabetic neuropathy, which is postulated to be related to an imbalance between inhibitory and excitatory signals within the spinal cord. GABAergic neurons within the pain pathway are vital for the transmission of painful stimuli to higher centres. A developmental change in the rate of exponential decay of GABAergic synaptic events has been observed in other types of neurons and this may be associated with fluctuations in endogenous neurosteroid tone. Methods: The whole-cell patch-clamp technique was used on slices of neural tissue. Electrophysiological recordings were obtained from wild type mice between the ages of 6 and 80 days in the spinal cord, the nucleus reticularis of the thalamus and the cerebral cortex. Recordings were also obtained from mice with diabetic neuropathy (ob/ob and db/db) between the ages of 60 and 80 days. Behavioural experiments were performed to examine mechanical and thermal nociception. Results: Electrophysiological recordings from cortical pain pathway neurons from mature type-2 diabetic mice revealed that the endogenous neurosteroid tone is reduced compared to control. However, selected neurosteroid compounds had a more pronounced effect on the GABA A receptors of these diabetic mice. ob/ob mice exhibit mechanical hyperalgesia and allodynia, which was reduced by neurosteroids applied exogenously. Conclusions: The reduced endogenous neurosteroid tone in ob/ob mice may be linked to their hypersensitivity. Neurosteroids may exert analgesic effects in pathological pain states by attempting to restore the physiological GABAergic inhibitory tone.

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“…Some nuclei, such as those conveying primary sensory information, project quite selectively to one or a small number of cortical areas, while others, which integrate signals from multiple sources, project in a more diffuse manner across larger areas of cortex. Within each nucleus there are also varying proportions of distinct cell types that either project to specific areas, driving receptive field properties in input layers of cortex, such as layer 4, or that project more widely across cortex and provide modulatory inputs, for example to layer 1 [6, 7]. …”

Section: Introductionmentioning

confidence: 99%

A dual-strategy expression screen for candidate connectivity labels in the developing thalamus

et al. 2017

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The thalamus or “inner chamber” of the brain is divided into ~30 discrete nuclei, with highly specific patterns of afferent and efferent connectivity. To identify genes that may direct these patterns of connectivity, we used two strategies. First, we used a bioinformatics pipeline to survey the predicted proteomes of nematode, fruitfly, mouse and human for extracellular proteins containing any of a list of motifs found in known guidance or connectivity molecules. Second, we performed clustering analyses on the Allen Developing Mouse Brain Atlas data to identify genes encoding surface proteins expressed with temporal profiles similar to known guidance or connectivity molecules. In both cases, we then screened the resultant genes for selective expression patterns in the developing thalamus. These approaches identified 82 candidate connectivity labels in the developing thalamus. These molecules include many members of the Ephrin, Eph-receptor, cadherin, protocadherin, semaphorin, plexin, Odz/teneurin, Neto, cerebellin, calsyntenin and Netrin-G families, as well as diverse members of the immunoglobulin (Ig) and leucine-rich receptor (LRR) superfamilies, receptor tyrosine kinases and phosphatases, a variety of growth factors and receptors, and a large number of miscellaneous membrane-associated or secreted proteins not previously implicated in axonal guidance or neuronal connectivity. The diversity of their expression patterns indicates that thalamic nuclei are highly differentiated from each other, with each one displaying a unique repertoire of these molecules, consistent with a combinatorial logic to the specification of thalamic connectivity.

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Unveiling the diversity of thalamocortical neuron subtypes

Cited by 184 publications

References 122 publications

Spatiotemporal characteristics of sleep spindles depend on cortical location

Spatiotemporal characteristics of sleep spindles depend on cortical location

Neurosteroids are reduced in diabetic neuropathy and may be associated with the development of neuropathic pain

A dual-strategy expression screen for candidate connectivity labels in the developing thalamus

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