Department of Neurobiology
Simons, Daniel J.
Professor Emeritus, Neurobiology
Ph.D., Washington University (1977)
Address: E1452 BST
  203 Lothrop Street
  Pittsburgh, PA 15213-2548
Telephone: 412-648-9442
Fax: 412-648-1441

Sensory physiology of the cerebral cortex

Dr. Simons' laboratory investigated neuronal integration within identified, small networks of cerebral cortical neurons. Experimental approaches included single- and multi-electrode recordings, animal behavioral training, computer-based data analyses, and mathematical simulation. Studies focused on the component of the rodent somatosensory system that processes tactile information arising from the large facial vibrissae, or whiskers. Each whisker correlates one-to-one with an anatomically defined group of cortical neurons, called a barrel, that represents a morphological correlate of a functional cortical column. Barrels are local circuits that perform an initial transformation of incoming signals from the somatosensory thalamus.

Computer-controlled whisker stimuli and single cell recording techniques were used to examine how information is integrated by cortical neurons, with a strong emphasis on processing in thalamocortical circuits and the effects of corticothalamic feedback. Other studies examined the physiological and behavioral effects of abnormal tactile experiences early in life that are produced by trimming the whiskers during critical developmental stages. Computer modeling and simulations, with Dr. Bard Ermentrout, were used to understand the dynamical properties of the local circuits and their development. In collaboration with Dr. George Carvell, recordings were obtained from animals trained to perform sensorimotor tasks using their whiskers.

Sample Publications:

Thalamocortical dysfunction and thalamic injury after asphyxial cardiac arrest in developing rats.
Shoykhet M, Simons DJ, Alexander H, Hosler C, Kochanek PM, Clark RS.
J Neurosci. 2012 Apr 4;32(14):4972-81.

Neural correlation is stimulus modulated by feedforward inhibitory circuitry.
Middleton JW, Omar C, Doiron B, Simons DJ.
J Neurosci. 2012 Jan 11;32(2):506-18.

Consistency of angular tuning in the rat vibrissa system.
Hemelt ME, Kwegyir-Afful EE, Bruno RM, Simons DJ, Keller A.
J Neurophysiol. 2010 Dec;104(6):3105-12.

Subbarrel patterns in somatosensory cortical barrels can emerge from local dynamic instabilities.
Ermentrout B, Simons DJ, Land PW.
PLoS Comput Biol. 2009 Oct;5(10):e1000537.

Effects of thalamic high-frequency electrical stimulation on whisker-evoked cortical adaptation.
Middleton JW, Kinnischtzke A, Simons DJ.
Exp Brain Res. 2010 Jan;200(3-4):239-50.

Stimulus-specific and stimulus-nonspecific firing synchrony and its modulation by sensory adaptation in the whisker-to-barrel pathway.
Khatri V, Bruno RM, Simons DJ.
J Neurophysiol. 2009 May;101(5):2328-38.

Subthreshold receptive field properties distinguish different classes of corticothalamic neurons in the somatosensory system.
Kwegyir-Afful EE, Simons DJ.
J Neurosci. 2009 Jan 28;29(4):964-72.

Motor modulation of afferent somatosensory circuits.
Lee S, Carvell GE, Simons DJ.
Nat Neurosci. 2008 Dec;11(12):1430-8.

Rapid changes in thalamic firing synchrony during repetitive whisker stimulation.
Temereanca S, Brown EN, Simons DJ.
J Neurosci. 2008 Oct 29;28(44):11153-64.

Development of thalamocortical response transformation in the rat whisker-barrel system.
Shoyket M, Simons DJ.
J Neurophysiol. 2008 Jan;99(1):356-66.

Thalamocortical conduction times and stimulus-evoked responses in the rat whisker-to-barrel- system.
Simons DJ, Carvell GE, Kyriazi HT, Bruno RM.
J Neurophysiol. 2007 Nov;98(5):2842-7.

Layer- and cell-type-specific effects of neonatal whisker-trimming in adult rat barrel cortex.
Lee SH, Land PW, Simons DJ.
J Neurophysiol. 2007 Jun;97(6):4380-5.


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