Impaired generation of high-frequency oscillations in a rat model of schizophrenia
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1
University of Newcastle, Australia
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2
University of Jyväskylä, Finland
Background: Schizophrenia patients have an impaired capacity to generate high-frequency gamma (>30Hz) oscillations. Gamma oscillations play an integral role in cognition and their reduction in schizophrenia is a candidate neurophysiological mechanism underlying cognitive impairments. The neurobiological and behavioural implications of disrupted gamma oscillations can be best understood using an animal model. Methods: MIA was induced in Wistar rats by administering pregnant rats with Poly (I:C), a viral mimic, at gestational day 19. The offspring grew to adulthood, when they underwent surgery to implant EEG electrodes. A wireless telemetric headstage was fixed to the rat's head and the EEG recorded while rats were exposed to auditory steady-state white noise clicks, presented at a range of frequencies (10-50Hz). Recordings were made from three separate drug-free sessions, then rats were administered MK-801, an NMDAR antagonist, over three separate sessions at escalating doses (0.1, 0.3, 0.5mg/kg). Oscillatory power and inter-trial coherence were extracted for each stimulus frequency. Results: MIA-exposed rats demonstrated a reduction in frontal 50Hz aSSRs. MK-801 dose-dependently reduced these 50Hz aSSRs. Conclusions: MIA in rats altered the trajectory of brain development, affecting systems responsible for the generation of high-frequency gamma oscillations. MK-801, a NMDAR antagonist that also indirectly impairs inhibitory neurotransmission also was found to reduce 50Hz oscillatory activity, perhaps indicating that both MK-801 and MIA are affecting similar neurobiological pathways. Further experiments will focus on the cognitive and neurobiological correlates of MIA-associated reductions in gamma oscillations, with the ultimate goal of furthering our understanding of the neurobiology underlying cognitive impairments in schizophrenia.
Keywords:
Schizophrenia,
EEG,
gamma oscillations,
animal model,
maternal immune activation
Conference:
XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014.
Presentation Type:
Poster
Topic:
Sensation and Perception
Citation:
Harms
L,
Hodgson
D,
Fulham
W,
Penttonen
M,
Schall
U,
Todd
J and
Michie
P
(2015). Impaired generation of high-frequency oscillations in a rat model of schizophrenia.
Conference Abstract:
XII International Conference on Cognitive Neuroscience (ICON-XII).
doi: 10.3389/conf.fnhum.2015.217.00207
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Received:
19 Feb 2015;
Published Online:
24 Apr 2015.
*
Correspondence:
Dr. Lauren Harms, University of Newcastle, Callaghan, Australia, lauren.harms@newcastle.edu.au