Previous studies have demonstrated that the anterior cingulate cortex modulates the activity of the autonomic nervous system, and that the posterior cingulate (retrosplenial) cortex in concert with the hippocampus plays an important role in learning and memory. When an expected result does not follow a learned responses, these regions of the limbic cortex will reduce the probability of future responses, and the mismatch will also elicit autonomic responses that will tend to alert the organism to the new conditions. Conversely, if the expected conditions are consistently present then visceromotor responses will tend to diminish. A major route by which the autonomic responses are modulated appears to be the direct projections from the posterior to anterior cingulate cortex. In the proposed studies we will directly assess this pathway electrophysiologically and determine the capacity of anterior and posterior cingulate cortex to modulate autonomic nervous system activity individually and in concert. Both cardiovascular and sympathetic nervous system responses to electrical and chemical stimulation of the midline cortex will be characterized in anesthetized and conscious rats. To elucidate the functional data generated from these studies, anatomical and physiological studies will be conducted. Our past anatomical studies have demonstrated a high degree of organization in the projections to and from the cingulate cortex and are clarifying the morphology of the neurons that contribute to the function of this cortex. The proposed studies will use a newly developed slice preparation to define the morphology of cingulate cortex neurons that have specific neuronal projections. A major focus will be on the superficial neurons which display a unique form of dendritic bundling in the retrosplenial cortex. Intracellular in vitro experiments will characterize the cortical and thalamic inputs that contribute importantly to the activity and function of the cingulate neurons. Anatomical studies will test the hypothesis that inputs terminate selectively on groups of thalamic neurons that have a common cortical projection. Both anatomical and electrophysiological experiments will delineate the influence of neuromodulators on the activity of the neurons in the cingulate cortex. These studies will elucidate the structure and function of the cingulate cortex, and the results will provide significant new information on which to base future studies on learning disorders and stress induced hypertension.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL034315-06
Application #
3347088
Study Section
Neurosciences Research Review Committee (BPN)
Project Start
1985-01-01
Project End
1991-12-31
Budget Start
1990-01-01
Budget End
1991-12-31
Support Year
6
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Alabama Birmingham
Department
Type
Schools of Dentistry
DUNS #
004514360
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Fisk, G D; Wyss, J M (2000) Descending projections of infralimbic cortex that mediate stimulation-evoked changes in arterial pressure. Brain Res 859:83-95
Fisk, G D; Wyss, J M (1999) Associational projections of the anterior midline cortex in the rat: intracingulate and retrosplenial connections. Brain Res 825:1-13
Fisk, G D; Wyss, J M (1997) Pressor and depressor sites are intermingled in the cingulate cortex of the rat. Brain Res 754:204-12
van Groen, T; Wyss, J M (1992) Connections of the retrosplenial dysgranular cortex in the rat. J Comp Neurol 315:200-16
Wyss, J M; Van Groen, T (1992) Connections between the retrosplenial cortex and the hippocampal formation in the rat: a review. Hippocampus 2:1-11
van Groen, T; Wyss, J M (1992) Projections from the laterodorsal nucleus of the thalamus to the limbic and visual cortices in the rat. J Comp Neurol 324:427-48
Wyss, J M; Van Groen, T; Sripanidkulchai, K (1990) Dendritic bundling in layer I of granular retrosplenial cortex: intracellular labeling and selectivity of innervation. J Comp Neurol 295:33-42
van Groen, T; Wyss, J M (1990) The connections of presubiculum and parasubiculum in the rat. Brain Res 518:227-43
van Groen, T; Wyss, J M (1990) Extrinsic projections from area CA1 of the rat hippocampus: olfactory, cortical, subcortical, and bilateral hippocampal formation projections. J Comp Neurol 302:515-28
van Groen, T; Wyss, J M (1990) The postsubicular cortex in the rat: characterization of the fourth region of the subicular cortex and its connections. Brain Res 529:165-77

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