Thalamocortical Angular Tuning Domains within Individual Barrels of Rat Somatosensory Cortex

Bruno, Randy M.; Khatri, Vivek; Land, Peter W.; Simons, Daniel J.

doi:10.1523/jneurosci.23-29-09565.2003

Cited by 120 publications

(116 citation statements)

References 43 publications

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“…This enhances the signal-to-noise ratio of the system by limiting the ability of poorly temporally correlated inputs, which depolarize the cell more slowly, to evoke spikes. Finally, input location may also be a critical factor, particularly in layer 4, where it has been demonstrated recently that minicolumns exist in which thalamocortical axonal arbors that share a common direction preference are colocalized (Bruno et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…In the barrel cortex of rodents, neurons are selective for the angular direction in which their corresponding mystacial whisker [the principal whisker (PW)] is deflected (Simons, 1983;Simons and Carvell, 1989;Bruno and Simons, 2002). Direction selectivity is already present in the principal trigeminal nucleus Shoykhet et al, 2003) and in the ventrobasal nucleus of the thalamus (Simons and Carvell, 1989;Bruno et al, 2003;Timofeeva et al, 2003). Therefore, the spike output tuning of individual barrel cortex cells may simply be a faithful reproduction of the tuning properties of their synaptic inputs, or, alternatively, postsynaptic mechanisms may transform a broadly tuned synaptic input into a sharply tuned spike output.…”

Section: Introductionmentioning

confidence: 99%

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Stimulus-Dependent Changes in Spike Threshold Enhance Feature Selectivity in Rat Barrel Cortex Neurons

Wilent¹,

Contreras²

2005

J. Neurosci.

108

136

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Feature selectivity is a fundamental property of sensory cortex neurons, yet the mechanisms underlying its genesis are not fully understood. Using intracellular recordings in vivo from layers 2-6 of rat barrel cortex, we studied the selectivity of neurons to the angular direction of whisker deflection. The spike output and the underlying synaptic response decreased exponentially in magnitude as the direction of deflection diverged from the preferred. However, the spike output was more sharply tuned for direction than the underlying synaptic response amplitude. This difference in selectivity was attributable to the rectification imposed by the spike threshold on the input-output function of cells. As in the visual system, spike threshold was not constant and showed trial-to-trial variability. However, here we show that the mean spike threshold was direction dependent and increased as the direction diverged from the preferred. Spike threshold was also related to the rate of rise of the synaptic response, which was direction dependent and steepest for the preferred direction. To assess the impact of the direction-dependent changes in spike threshold on direction selectivity, we applied a fixed threshold to the synaptic responses and calculated a predicted spike output. The predicted output was more broadly tuned than the obtained spike response, demonstrating for the first time that the regulation of the spike threshold by the properties of the synaptic response effectively enhances the selectivity of the spike output.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stimulus-Dependent Changes in Spike Threshold Enhance Feature Selectivity in Rat Barrel Cortex Neurons

Wilent¹,

Contreras²

2005

J. Neurosci.

108

136

View full text Add to dashboard Cite

show abstract

“…Rats were subsequently maintained in a narcotized and sedated state by injections of fentanyl (3 g/kg, i.p. ; Janssen-Cilag, Issy-LesMoulineaux, France) repeated every 20 -30 min (Simons and Carvell, 1989;Pinault et al, 1998;Charpier et al, 1999;Slaght et al, 2002a;Bruno et al, 2003). To obtain long-lasting stable intracellular recordings, rats were immobilized with gallamine triethiodide (40 mg, i.m., every 2 hr; Specia, Paris, France) and artificially ventilated.…”

Section: Methodsmentioning

confidence: 99%

On the Activity of the Corticostriatal Networks during Spike-and-Wave Discharges in a Genetic Model of Absence Epilepsy

Slaght¹,

Paz²,

Chávez³

et al. 2004

J. Neurosci.

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Absence seizures are characterized by impairment of consciousness associated with widespread bilaterally synchronous spike-and-wave discharges (SWDs) in the electroencephalogram (EEG), which reflect highly synchronized oscillations in thalamocortical networks. Although recent pharmacological studies suggest that the basal ganglia could provide a remote control system for absence seizures, the mechanisms of propagation of epileptic discharges in these subcortical nuclei remain unknown. In the present study, we provide the first description of the electrical events in the corticostriatal pathway during spontaneous SWDs in the genetic absence epilepsy rats from Strasbourg (GAERS), a genetic model of absence epilepsy. In corticostriatal neurons, the SWDs were associated with suprathreshold rhythmic depolarizations in-phase with local EEG spikes. Consistent with this synchronized firing in their excitatory cortical afferents, striatal output neurons (SONs) exhibited, during SWDs, large-amplitude rhythmic synaptic depolarizations. However, SONs did not discharge during SWDs. Instead, the rhythmic synaptic excitation of SONs was shunted by a Cl Ϫ -dependent increase in membrane conductance that was temporally correlated with bursts of action potentials in striatal GABAergic interneurons. The reduced SON excitability accompanying absence seizures may participate in the control of SWDs by affecting the flow of cortical information within the basal ganglia circuits.

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“…In layer 2/3, inhibitory connections were assumed to have a shorter length scale than excitatory ones. L4 neurons were assumed to be directionally selective (Bruno et al, 2003;Lee and Simons, 2004;Andermann and Moore, 2006). After implementing uniform random connectivity between L4 and L2/3, the simulated integrate-and-fire L2/3 neurons thus received a collection of plastic and directionally selective feedforward inputs.…”

Section: Neuropil Direction Selectivity Map Forms a Pinwheel-like Strmentioning

confidence: 99%

“…Neurons in SIbf (primary somatosensory cortex, barrel field) are known to have their activity modulated by numerous parameters. In addition to their tuning to the principal vibrissa identity (the barrel map), some neurons preferentially respond to specific directions of vibrissa deflections (Bruno et al, 2003;Lee and Simons, 2004), to high-frequency vibrations (Andermann et al, 2004), or to the apparent global motion of objects through the vibrissa pad (Jacob et al, 2008). However, no superposition of functional maps has been reproducibly observed in SIbf.…”

Section: Introductionmentioning

confidence: 99%

Late Emergence of the Vibrissa Direction Selectivity Map in the Rat Barrel Cortex

Kremer

Léger²,

Goodman³

et al. 2011

Journal of Neuroscience

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In the neocortex, neuronal selectivities for multiple sensorimotor modalities are often distributed in topographical maps thought to emerge during a restricted period in early postnatal development. Rodent barrel cortex contains a somatotopic map for vibrissa identity, but the existence of maps representing other tactile features has not been clearly demonstrated. We addressed the issue of the existence in the rat cortex of an intrabarrel map for vibrissa movement direction using in vivo two-photon imaging. We discovered that the emergence of a direction map in rat barrel cortex occurs long after all known critical periods in the somatosensory system. This map is remarkably specific, taking a pinwheel-like form centered near the barrel center and aligned to the barrel cortex somatotopy. We suggest that this map may arise from intracortical mechanisms and demonstrate by simulation that the combination of spike-timing-dependent plasticity at synapses between layer 4 and layer 2/3 and realistic pad stimulation is sufficient to produce such a map. Its late emergence long after other classical maps suggests that experience-dependent map formation and refinement continue throughout adult life.

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Thalamocortical Angular Tuning Domains within Individual Barrels of Rat Somatosensory Cortex

Cited by 120 publications

References 43 publications

Stimulus-Dependent Changes in Spike Threshold Enhance Feature Selectivity in Rat Barrel Cortex Neurons

Stimulus-Dependent Changes in Spike Threshold Enhance Feature Selectivity in Rat Barrel Cortex Neurons

On the Activity of the Corticostriatal Networks during Spike-and-Wave Discharges in a Genetic Model of Absence Epilepsy

Late Emergence of the Vibrissa Direction Selectivity Map in the Rat Barrel Cortex

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