Disrupted hippocampal synchrony following maternal immune activation in a rat model.
Robert Gordon Keith MunnAmy WolffLucinda J SpeersDavid K BilkeyPublished in: Hippocampus (2023)
Maternal immune activation (MIA) is a risk factor for schizophrenia and other neurodevelopmental disorders. MIA in rats models a number of the brain and behavioral changes that are observed in schizophrenia, including impaired memory. Recent studies in the MIA model have shown that the firing of the hippocampal place cells that are involved in memory processes appear relatively normal, but with abnormalities in the temporal ordering of firing. In this study, we re-analyzed data from prior hippocampal electrophysiological recordings of MIA and control animals to determine whether temporal dysfunction was evident. We find that there is a decreased ratio of slow to fast gamma power, resulting from an increase in fast gamma power and a tendency toward reduced slow gamma power in MIA rats. Moreover, we observe a robust reduction in spectral coherence between hippocampal theta and both fast and slow gamma rhythms, as well as changes in the phase of theta at which fast gamma occurs. We also find the phasic organization of place cell phase precession on the theta wave to be abnormal in MIA rats. Lastly, we observe that the local field potential of MIA rats contains more frequent sharp-wave ripple events, and that place cells were more likely to fire spikes during ripples in these animals than control. These findings provide further evidence of desynchrony in MIA animals and may point to circuit-level changes that underlie failures to integrate and encode information in schizophrenia.
Keyphrases
- working memory
- bipolar disorder
- induced apoptosis
- cerebral ischemia
- cell cycle arrest
- oxidative stress
- healthcare
- physical activity
- optical coherence tomography
- resting state
- stem cells
- cell death
- mesenchymal stem cells
- blood brain barrier
- cell therapy
- prefrontal cortex
- magnetic resonance
- endoplasmic reticulum stress
- white matter
- body mass index
- case control