Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Cortex Is Driven by Weak but Synchronously Active Thalamocortical Synapses
Randy M. Bruno* and
Bert Sakmann
Sensory stimuli reach the brain via the thalamocortical projection,a group of axons thought to be among the most powerful in theneocortex. Surprisingly, these axons account for only 15% ofsynapses onto cortical neurons. The thalamocortical pathwaymight thus achieve its effectiveness via high-efficacy thalamocorticalsynapses or via amplification within cortical layer 4. In ratsomatosensory cortex, we measured in vivo the excitatory postsynapticpotential evoked by a single synaptic connection and found thatthalamocortical synapses have low efficacy. Convergent inputs,however, are both numerous and synchronous, and intracorticalamplification is not required. Our results suggest a mechanismof cortical activation by which thalamic input alone can drivecortex.
Department of Cell Physiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
* To whom correspondence should be addressed. E-mail: bruno{at}mpimf-heidelberg.mpg.de
The Relation between Dendritic Geometry, Electrical Excitability, and Axonal Projections of L2/3 Interneurons in Rat Barrel Cortex.
M. Helmstaedter, B. Sakmann, and D. Feldmeyer (2009)
Cereb Cortex
19, 938-950
|Abstract »|Full Text »|PDF »
Postsynaptic Receptive Field Size and Spike Threshold Determine Encoding of High-Frequency Information Via Sensitivity to Synchronous Presynaptic Activity.
J. W. Middleton, A. Longtin, J. Benda, and L. Maler (2009)
J Neurophysiol
101, 1160-1170
|Abstract »|Full Text »|PDF »
Early Bilateral Sensory Deprivation Blocks the Development of Coincident Discharge in Rat Barrel Cortex.
A. Ghoshal, P. Pouget, M. Popescu, and F. Ebner (2009)
J. Neurosci.
29, 2384-2392
|Abstract »|Full Text »|PDF »
Input Specificity and Dependence of Spike Timing-Dependent Plasticity on Preceding Postsynaptic Activity at Unitary Connections between Neocortical Layer 2/3 Pyramidal Cells.
M. Zilberter, C. Holmgren, I. Shemer, G. Silberberg, S. Grillner, T. Harkany, and Y. Zilberter (2009)
Cereb Cortex
|Abstract »|Full Text »|PDF »
Shift in the Balance between Excitation and Inhibition during Sensory Adaptation of S1 Neurons.
J. E. Heiss, Y. Katz, E. Ganmor, and I. Lampl (2008)
J. Neurosci.
28, 13320-13330
|Abstract »|Full Text »|PDF »
Behavioral Detectability of Single-Cell Stimulation in the Ventral Posterior Medial Nucleus of the Thalamus.
B. C. Voigt, M. Brecht, and A. R. Houweling (2008)
J. Neurosci.
28, 12362-12367
|Abstract »|Full Text »|PDF »
Rapid Changes in Thalamic Firing Synchrony during Repetitive Whisker Stimulation.
S. Temereanca, E. N. Brown, and D. J. Simons (2008)
J. Neurosci.
28, 11153-11164
|Abstract »|Full Text »|PDF »
Roles of Ephrin-As and Structured Activity in the Development of Functional Maps in the Superior Colliculus.
J. Cang, L. Wang, M. P. Stryker, and D. A. Feldheim (2008)
J. Neurosci.
28, 11015-11023
|Abstract »|Full Text »|PDF »
Driver or Coincidence Detector: Modal Switch of a Corticothalamic Giant Synapse Controlled by Spontaneous Activity and Short-Term Depression.
A. Groh, C. P. J. de Kock, V. C. Wimmer, B. Sakmann, and T. Kuner (2008)
J. Neurosci.
28, 9652-9663
|Abstract »|Full Text »|PDF »
Efficient Recruitment of Layer 2/3 Interneurons by Layer 4 Input in Single Columns of Rat Somatosensory Cortex.
M. Helmstaedter, J. F. Staiger, B. Sakmann, and D. Feldmeyer (2008)
J. Neurosci.
28, 8273-8284
|Abstract »|Full Text »|PDF »
Widespread spatial integration in primary somatosensory cortex.
J. L. Reed, P. Pouget, H.-X. Qi, Z. Zhou, M. R. Bernard, M. J. Burish, J. Haitas, A. B. Bonds, and J. H. Kaas (2008)
PNAS
105, 10233-10237
|Abstract »|Full Text »|PDF »
Cortical Transformation of Wide-Field (Multiwhisker) Sensory Responses.
Spatial Organization of Neuronal Population Responses in Layer 2/3 of Rat Barrel Cortex.
J. N. D. Kerr, C. P. J. de Kock, D. S. Greenberg, R. M. Bruno, B. Sakmann, and F. Helmchen (2007)
J. Neurosci.
27, 13316-13328
|Abstract »|Full Text »|PDF »
Thalamocortical Conduction Times and Stimulus-Evoked Responses in the Rat Whisker-to-Barrel System.
D. J. Simons, G. E. Carvell, H. T. Kyriazi, and R. M. Bruno (2007)
J Neurophysiol
98, 2842-2847
|Abstract »|Full Text »|PDF »
Modeling a layer 4-to-layer 2/3 module of a single column in rat neocortex: Interweaving in vitro and in vivo experimental observations.
L. Sarid, R. Bruno, B. Sakmann, I. Segev, and D. Feldmeyer (2007)
PNAS
104, 16353-16358
|Abstract »|Full Text »|PDF »
A Biologically Realistic Model of Contrast Invariant Orientation Tuning by Thalamocortical Synaptic Depression.
Y. Banitt, K. A. C. Martin, and I. Segev (2007)
J. Neurosci.
27, 10230-10239
|Abstract »|Full Text »|PDF »
Interspike Interval Analysis of Retinal Ganglion Cell Receptive Fields.
D. L. Rathbun, H. J. Alitto, T. G. Weyand, and W. M. Usrey (2007)
J Neurophysiol
98, 911-919
|Abstract »|Full Text »|PDF »
Enhancement of Visual Responsiveness by Spontaneous Local Network Activity In Vivo.
B. Haider, A. Duque, A. R. Hasenstaub, Y. Yu, and D. A. McCormick (2007)
J Neurophysiol
97, 4186-4202
|Abstract »|Full Text »|PDF »
Layer- and cell-type-specific suprathreshold stimulus representation in rat primary somatosensory cortex.
C. P. J. de Kock, R. M. Bruno, H. Spors, and B. Sakmann (2007)
J. Physiol.
581, 139-154
|Abstract »|Full Text »|PDF »
Feedback control in active sensing: rat exploratory whisking is modulated by environmental contact.
B. Mitchinson, C. J Martin, R. A Grant, and T. J Prescott (2007)
Proc R Soc B
274, 1035-1041
|Abstract »|Full Text »|PDF »
Thalamocortical Up States: Differential Effects of Intrinsic and Extrinsic Cortical Inputs on Persistent Activity.
Cranial Visceral Afferent Pathways through the Nucleus of the Solitary Tract to Caudal Ventrolateral Medulla or Paraventricular Hypothalamus: Target-Specific Synaptic Reliability and Convergence Patterns..
T. W. Bailey, S. M. Hermes, M. C. Andresen, and S. A. Aicher (2006)
J. Neurosci.
26, 11893-11902
|Abstract »|Full Text »|PDF »
Efficacy and connectivity of intracolumnar pairs of layer 2/3 pyramidal cells in the barrel cortex of juvenile rats.