The long-term objective of the proposed research is to determine the relative roles of juvenile and adult behavior patterns in the development of cortical representational areas in primary (S1) and secondary (S2) somatosensory cortex. The animal model for this research is the star nosed mole, which has perhaps the most sensitive and highly developed sense of touch among mammals. Each of the eleven tactile nasal appendages or """"""""rays"""""""" that ring the mole's nostrils is represented in both the S1 and S2 somatosensory areas by a stripe of tissue visible in sections processed for histochemical markers. The pattern of cortical magnification across the nasal rays does not match anatomical parameters of the ray, such as size or innervation density, but instead prescisely matches the pattern of behavioral use of the rays during search for prey and feeding. This suggests behaviors play a role in shaping the cortical representation. The goals of the proposed research are 1) determine the developmental mechanisms by which the patterns of cortical specialization in S1 and S2 are matched to the behavior patterns, 2) identify the functional circuitry of the cortical representations, including intrinsic, intercortical and callosal connections between areas, and 3) determine the effects of changes in the behavior patterns or surgical alteration of the nose on subsequent cortical development. Initial studies will relate the time course of prenatal and postnatal nose development to the emergence of nose related patterns in the cortex, and concurrently determine when the nose is first used for tactile explorations. Previous research on a range of species suggests that cortical specializations, such as barrels in rodent cortex, develop and become fixed during early critical periods. However, the nose of the star nosed mole does not fully develop until weeks after birth, after expected critical periods. Do relatively late emerging behavior patterns influence subsequenct cortical organization, or is the pattern of magnification independently matched to the adult behaviors during early development? By establishing the time course of pattern formation in the nose and cortex and then subsequently disrupting the normal development by altering the nose, the relative role of use dependent influences and possible critical periods can be determined. Few animal models have sensory systems in which discrete brain characters are correlated with specific patterns of behavior. The influence of early behaviors on brain development and learning remains an important public health issue. Results will be interpreted in a comparative framework to identify principles that may be generalized to other species and other sensory systems.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH058909-02
Application #
2891130
Study Section
Cognitive Functional Neuroscience Review Committee (CFN)
Project Start
1998-07-01
Project End
2003-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
2
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Catania, Kenneth C; Remple, Fiona E (2004) Tactile foveation in the star-nosed mole. Brain Behav Evol 63:1-12
Remple, Michael S; Henry, Erin C; Catania, Kenneth C (2003) Organization of somatosensory cortex in the laboratory rat (Rattus norvegicus): Evidence for two lateral areas joined at the representation of the teeth. J Comp Neurol 467:105-18
Crish, Samuel D; Comer, Christopher M; Marasco, Paul D et al. (2003) Somatosensation in the superior colliculus of the star-nosed mole. J Comp Neurol 464:415-25
Sachdev, R N S; Catania, K C (2002) Effects of stimulus duration on neuronal response properties in the somatosensory cortex of the star-nosed mole. Somatosens Mot Res 19:272-8
Sachdev, Robert N S; Catania, Kenneth C (2002) Receptive fields and response properties of neurons in the star-nosed mole's somatosensory fovea. J Neurophysiol 87:2602-11
Catania, Kenneth C; Remple, Michael S (2002) Somatosensory cortex dominated by the representation of teeth in the naked mole-rat brain. Proc Natl Acad Sci U S A 99:5692-7
Catania, K C (2001) Early development of a somatosensory fovea: a head start in the cortical space race? Nat Neurosci 4:353-4
Catania, K C (2000) Epidermal sensory organs of moles, shrew moles, and desmans: a study of the family talpidae with comments on the function and evolution of Eimer's organ. Brain Behav Evol 56:146-74
Catania, K C; Collins, C E; Kaas, J H (2000) Organization of sensory cortex in the East African hedgehog (Atelerix albiventris). J Comp Neurol 421:256-74
Catania, K C (2000) Cortical-organization in moles: evidence of new areas and a specialized S2. Somatosens Mot Res 17:335-47

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