Philip H. Smith

 

 

Auditory processing in the thalamus and cortex

E-mail: smith@physiology.wisc.edu

Research Strength: Neural Circuits

I study auditory brainstem, midbrain and thalamic and cortical neurons used to execute normal and abnormal (audiogenic seizure) behavior. I use physiological and anatomical methods, including intracellular recording from both in vivo and in vitro preparations, using sharp and patch electrodes, as well as light and electron microscopy. One question addressed is the destination of auditory information encoded by cochlear nucleus (CN) cells. I intraaxonally label single axons carrying auditory information out of the CN in vivo. I then study innervation patterns of different, physiologically characterized cell types at light and electron microscopic levels to begin to understand how this first stop in the auditory CNS is acting to encode, process, and transmit information. I also combine information from both in vitro slice methods and in vivo methods to explore questions in auditory thalamus and cortex. As an example, using both preparations we are characterizing a subset of pyramidal cells in auditory cortex that provide feedback to the auditory thalamus and are thought to modulate the "throughput" of auditory information through the auditory thalamus or to serve as a communication link between two cortical areas by way of the thalamus.

Selected Publications:

• Smith, P.H., E.L. Bartlett, and A. Kowalkowski. 2007. Cortical, superior and inferior collicular inputs to cells in the rat paralaminar thalamic nuclei adjacent to the medial geniculate body. J. Neurophysiol. In Press
• Smith, P.H., E.L. Bartlett, and A. Kowalkowski. 2006. Unique combination of anatomy and physiology in cells of the rat paralaminar thalamic nuclei adjacent to the medial geniculate body. J. Comp. Neurol. 496: 314-334 [PDF]
• Smith, P.H., A. Massie, and P.X. Joris. 2005. The acoustic stria: Anatomy of physiologically characterized cells and their axonal projection patterns. J. Comp. Neurol. 482: 349-71 [PDF]
• Hefti, B. and P.H. Smith. 2003. Distribution and kinetic properties of GABAergic inputs to layer V pyramidal cells in rat auditory cortex. JARO 4: 106-121.
• Bartlett, E.L. and P.H. Smith. 2002. Effects of paired-pulse and repetitive stimulation on neurons in the rat medial geniculate body. Neuroscience 113: 957-974. [PDF]
• D. Oertel, R. Bal, S.M. Gardner, P.H. Smith, and P.X. Joris. 2000. Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus. Proc. Nat. Acad. Sci. 97: 11773-11779. [PDF]
• Bartlett, E.L. and P.H. Smith. 2000. An ultrastructural comparison of axon terminals in the rat MGB. Neuroscience 100: 811-828. [PDF]
• Bartlett, E.L. and P.H. Smith. 1999. Anatomical, intrinsic, and synaptic properties of dorsal and ventral division neurons in the rat medial geniculate body. J. Neurophysiol. 81: 1999-2006. [PDF]
• Joris, P.X., P.H. Smith, and T.C.T. Yin. 1998. Coincidence detection in the auditory system: 50 years after Jeffress. Neuron 21: 1235-1238. [PDF]
• Peruzzi, D., E.L. Bartlett, P.H. Smith, and D.L. Oliver. 1997. A monosynaptic GABAergic input from the inferior colliculus to the medial geniculate body in rat. J. Neurosci. 17: 3766-3777. [PDF]