Indiana University-Purdue University Indianapolis (IUPUI) / Social processing is the reception, interpretation, and reciprocation of social
information and is critical for mental health. The neural structures, circuits, and substrates
regulating these complex mechanisms are not well understood. Social processing in the
form of social safety learning, as measured by a rat model of social familiarity-induced
anxiolysis (SoFiA), was impaired following mild blast traumatic brain injury (mbTBI).
Initial findings indicated that mbTBI altered resting state network activity in the
orbitofrontal cortex (OFC) and was associated with accumulation of neurotoxin marker,
acrolein, in lateral prefrontal cortex (PFC) (including OFC), indicating OFC as a brain
region of interest that may contribute to social processing. Measuring GABA and
Glutamate-related gene expression in OFC of mbTBI or sham-exposed rat brain revealed
specific elevations of metabotropic glutamate receptor type 1 and 5 (mGluR1/5) expression
in mbTBI but not sham OFC. Exposure-naïve rats intracranially injected with mGluR1/5
agonist demonstrated attenuated SoFiA, and this coincided with an impairment of social
recognition (SR) behavior. Additionally, inactivation of OFC by local intracranial
injection of GABAA agonist, muscimol, impaired two different measures of SR in which
two conspecifics, or members of the same species, one novel and one familiar, were
presented and required discrimination. Novelty seeking, decision-making, memory, and
gregariousness were tested in isolation to determine OFC contributions to these specific
behavioral contributions to SR test performance. OFC inactivation did not impair novelty
seeking, non-social decision-making, or non-social memory as measured by novel object
recognition (NOR) test, or gregariousness or social decision-making as measure by social preference (SP) test. When measuring SR behavior via consecutive presentation of two
different conspecifics, OFC inactivation did not impact SR. Therefore, OFC is not directly
responsible for social recognition, but rather the discrimination or ability to act upon
discrimination of two simultaneously present conspecifics. These data suggest a novel role
for OFC in high order processing or execution of action based on social information. / 2 years (2021-05-24)
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/19636 |
| Date | 05 1900 |
| Creators | Andrews, Katharine DiAnn |
| Contributors | Xu, Xiao-Ming, Lamb, Bruce, McAllister, Thomas, McDonald, Brenna, Truitt, William, Wu, Yu-Chien |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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