# HIPPOCAMPAL SPATIAL REPRESENTATIONS

> **NIH NIH R01** · UTAH STATE HIGHER EDUCATION SYSTEM--UNIVERSITY OF UTAH · 1992 · $70,593

## Abstract

Spatial abilities are often observed to decline as a result of normal aging
in both humans and rats.  In the interest of the future development of
appropriate therapeutic treatments, it is necessary to understand the
contribution of age-related changes in brain organization.  The hippocampus
is a particularly interesting structure for study in this regard because it
is considered critical for the acquisition of new spatial information, and
it appears particularly susceptible to age-associated pathological
abnormalities.  Thus, the prim,dry focus of this research is to understand
the relationship between physiological properties of a senescent
hippocampal formation and spatial performance in rats.  Since synaptic
activation within hippocampus is extensively modulated by different
subcortical afferents (some of which are known to undergo significant
changes with age), this research will also examine the possibility that
age-related changes in subcortical inputs influence the accuracy with which
the hippocampus represents spatial aspects if an environment.

The specific goals of this proposal is to provide a comprehensive
evaluation of the contributions of neural representations of space and
movement in the hippocampus to impaired spatial performance by aged rats.
This goal will be accomplished in two parts: First discharge of different
populations of single hippocampal neurons will be correlated with specific
behaviors and spatial cognitive skills of young and old animals.  Also,
possible age differences in factors such as attention to spatial cues will
be considered in terms of age-related changes in choice accuracy and
neurophysiological function.  Part 2 of this proposal will assess the
effects of age on subcortical modulation of hippocampal function by
monitoring behavioral and physiological consequences of selective and
reversible deafferentation in young and old rats performing a spatial
memory task.  Seven afferent structures will be examined.  Temporary
deafferentation will be achieved by microinjection of a local anesthetic
(tetracaine) or a GABA agonist (muscimol) into afferent nuclei.  Using an
injection-recording procedure that was recently developed for this
research, the immediate behavioral and physiological consequences of
selective deafferentation, as well as recovery back to baseline conditions.
will be observed.  Afferent activation effects will be tested by local
injection of glutamate or carbachol.  In summary, these results should
provide important insight into possible age-changes in the neural
representation of information critical for accurate spatial behaviors.

## Key facts

- **NIH application ID:** 3121131
- **Project number:** 1R01AG009299-01A1
- **Recipient organization:** UTAH STATE HIGHER EDUCATION SYSTEM--UNIVERSITY OF UTAH
- **SAM.gov UEI:** LL8GLEVH6MG3
- **Principal Investigator:** SHERI J. Y. MIZUMORI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $70,593
- **Award type:** 1
- **Project period:** 1992-05-01 → 1994-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3121131

## Citation

> US National Institutes of Health, RePORTER application 3121131, HIPPOCAMPAL SPATIAL REPRESENTATIONS (1R01AG009299-01A1). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3121131. Licensed CC0.

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