Perception and other cognitive functions such as planning, thought and learning reflect processing of complex information by the cerebral neocortex. The great expanse of brain tissue that comprises the cerebral cortex is composed of iterated, local neuronal circuits that transform afferent information and distribute it to other brain regions, forming large distributed neural systems. An emerging view is that these spatially distributed networks use a minimal number of spikes to perform their functions rapidly and accurately. Neuronal assemblies are readily identified in the rodent somatosensory cortex, which contains groups of synaptically interconnected neurons, called 'barrels', that a related one-to-one to individual whiskers on the contralateral face. Each barrel receives its afferent input from similarly organized groups of thalamic neurons, called 'barreloids'. We have discovered that thalamocortical circuits in the rodent somatosensory system are highly sensitive to thalamic response timing. Employing the rat whisker/barrel cortex as a model sytem, we will evaluate spike timing and response synchrony in thalamocortical circuits and their modulation by corticothalamic feedback. Hypotheses will be evaluated using microelectrodes to record simultaneously the activities of thalamic and cortical neurons that are functionally connected. The research plan is based on the premise that abnormalities in the time-critical operations of thalamocortical circuits produce a cascade of events leading to dysfunctions in cortical processing. Understanding the role of local thalamocortical circuitry in promoting adaptive properties of cerebral cortical function is essential for bridging the gap between cellular physiology and the eventual accurate diagnosis and treatment of perceptual/motor and other cognitive dysfunctions due to abnormal cortical development, aging, disease, or trauma.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS019950-21
Application #
6604674
Study Section
Special Emphasis Panel (ZRG1-IFCN-5 (01))
Program Officer
Chen, Daofen
Project Start
1983-07-01
Project End
2004-06-30
Budget Start
2003-07-01
Budget End
2004-06-30
Support Year
21
Fiscal Year
2003
Total Cost
$362,311
Indirect Cost
Name
University of Pittsburgh
Department
Biology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Simons, D J; Carvell, G E; Kyriazi, H T (2015) Alterations in functional thalamocortical connectivity following neonatal whisker trimming with adult regrowth. J Neurophysiol 114:1912-22
Kinnischtzke, Amanda K; Simons, Daniel J; Fanselow, Erika E (2014) Motor cortex broadly engages excitatory and inhibitory neurons in somatosensory barrel cortex. Cereb Cortex 24:2237-48
Kwegyir-Afful, E E; Kyriazi, H T; Simons, D J (2013) Weaker feedforward inhibition accounts for less pronounced thalamocortical response transformation in mouse vs. rat barrels. J Neurophysiol 110:2378-92
Middleton, Jason W; Omar, Cyrus; Doiron, Brent et al. (2012) Neural correlation is stimulus modulated by feedforward inhibitory circuitry. J Neurosci 32:506-18
Shoykhet, Michael; Simons, Daniel J; Alexander, Henry et al. (2012) Thalamocortical dysfunction and thalamic injury after asphyxial cardiac arrest in developing rats. J Neurosci 32:4972-81
Hemelt, Marie E; Kwegyir-Afful, Ernest E; Bruno, Randy M et al. (2010) Consistency of angular tuning in the rat vibrissa system. J Neurophysiol 104:3105-12
Middleton, Jason W; Kinnischtzke, Amanda; Simons, Daniel J (2010) Effects of thalamic high-frequency electrical stimulation on whisker-evoked cortical adaptation. Exp Brain Res 200:239-50
Khatri, Vivek; Bruno, Randy M; Simons, Daniel J (2009) Stimulus-specific and stimulus-nonspecific firing synchrony and its modulation by sensory adaptation in the whisker-to-barrel pathway. J Neurophysiol 101:2328-38
Washington, Kia M; Solari, Mario G; Sacks, Justin M et al. (2009) A model for functional recovery and cortical reintegration after hemifacial composite tissue allotransplantation. Plast Reconstr Surg 123:26S-33S
Lee, SooHyun; Carvell, George E; Simons, Daniel J (2008) Motor modulation of afferent somatosensory circuits. Nat Neurosci 11:1430-8

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