The neocortex receives inputs from two classes of thalamic nuclei. First-order (""""""""specific"""""""") nuclei relay to the neocortex sensory inputs from the periphery. Higher-order (""""""""non-specific"""""""") thalamic nuclei receive and provide inputs to various cortical areas. Based on exciting new data we hypothesize that this dichotomy is overly simplistic, in that higher-order nuclei function also as important relays of sensory inputs from the periphery to cortical and subcortical structures. We will show that sensory processing by higher-order nuclei-specifically the posterior medial nucleus (POm), the higher-order nucleus of the somatosensory system-is regulated by a critical subthalamic nucleus - the zona incerta (ZI). We will further show that ZI's inhibitory regulation of POm is dynamically modulated by brainstem cholinergic inputs related to sleep-wake states, and by phasic motor cortex inputs related to voluntary movements. This State Dependent Gating (SDG) hypothesis is relevant to understanding the functions of all """"""""higher-order"""""""" thalamic nuclei, as they are all subject to potent inhibition from ZI. Because both ZI and POm are implicated in various movement disorders, the anticipated findings may be relevant for understanding the pathogenesis of disorders such as Parkinson's disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS051799-03
Application #
7177458
Study Section
Sensorimotor Integration Study Section (SMI)
Program Officer
Babcock, Debra J
Project Start
2005-05-01
Project End
2009-02-28
Budget Start
2007-03-01
Budget End
2008-02-29
Support Year
3
Fiscal Year
2007
Total Cost
$325,611
Indirect Cost
Name
University of Maryland Baltimore
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
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Bezdudnaya, Tatiana; Keller, Asaf (2008) Laterodorsal nucleus of the thalamus: A processor of somatosensory inputs. J Comp Neurol 507:1979-89

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