Improved learning and memory with theta‐burst stimulation of the fornix in rat model of traumatic brain injury. Issue 12 (21st August 2014)

• Record Type: Journal Article
• Authors: Sweet, Jennifer A.; Eakin, Katharine C.; Munyon, Charles N.; Miller, Jonathan P.
• Is Part Of: Hippocampus. Volume 24:Issue 12(2014:Dec.)
• Page Start: 1592
• Page End: 1600
• Publication Date: 2014-08-21
• Subjects: Hippocampus (Brain) -- Periodicals; 612.825
• DOI: 10.1002/hipo.22338
• Languages: English
• ISSNs: 1050-9631

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p> <bold>Objective:</bold> Learning and memory deficits are a source of considerable morbidity after traumatic brain injury (TBI). We investigated the effect of different patterns of hippocampal stimulation via a fornix electrode on cognitively demanding tasks after TBI. <bold>Methods:</bold> Male Sprague‐Dawley rats underwent fluid‐percussion injury and were compared with sham‐operated rats. Electrodes were implanted into the fornix and hippocampus, and stimulation of the fornix produced robust evoked potentials in the hippocampus. A 60‐s delayed non‐match‐to‐sample (DNMS) swim T‐maze was serially performed using four stimulation patterns: no stimulation (No Stim), low‐frequency stimulation (LFS, 5 Hz), high‐frequency stimulation (HFS, 130 Hz), and theta‐burst stimulation (TBS, 200 Hz in 50 ms trains, five trains per second; 60 µA biphasic pulses). In a separate cohort of sham and injured animals, Morris water maze (MWM) was performed with or without TBS. <bold>Results:</bold> In the DNMS swim T‐maze, LFS and HFS did not significantly improve performance after TBI. However, there was a significant difference in performance between TBI + No Stim and TBI + TBS groups (<italic>P</italic> < 0.05) with no significant difference between Sham + No Stim and TBI + TBS. In the MWM, latency in the TBI + TBS group was significantly different from TBI + No Stim starting on day 2 (<italic>P</italic> < 0.05) and was not different from Sham + No Stim. The TBI + TBS group performed significantly more platform crossings in the probe trial (<italic>P</italic> < 0.01) and exhibited improved search strategy starting on day 3 (<italic>P</italic> < 0.05) compared with TBI + No Stim. <bold>Conclusions:</bold> Deficits in learning and memory after TBI are improved with TBS of the hippocampus. HFS and LFS do not appear to produce as great an effect as TBS. © 2014 Wiley Periodicals, Inc.</p> </abstract>