Early Cortical Changes in Gamma Oscillations in Alzheimer's Disease.
The entorhinal cortices in the temporal lobe of the brain are key structures relaying memory related information between the neocortex and the hippocampus. The medial entorhinal cortex (MEC) routes spatial information, whereas the lateral entorhinal cortex (LEC) routes predominantly olfactory information to the hippocampus. Gamma oscillations are known to coordinate information transfer between brain regions by precisely timing population activity of neuronal ensembles. Here, we studied the organization ofin vitrogamma oscillations in the MEC and LEC of the transgenic (tg) amyloid precursor protein (APP)-presenilin 1 (PS1) mouse model of Alzheimer's Disease (AD) at 4-5 months of age.In vitrogamma oscillations using the kainate model peaked between 30-50 Hz and therefore we analyzed the oscillatory properties in the 20-60 Hz range. Our results indicate that the LEC shows clear alterations in frequency and power of gamma oscillations at an early stage of AD as compared to the MEC. The gamma-frequency oscillation slows down in the LEC and also the gamma power in dorsal LEC is decreased as early as 4-5 months in the tg APP-PS1 mice. The results of this study suggest that the timing of olfactory inputs from LEC to the hippocampus might be affected at an early stage of AD, resulting in a possible erroneous integration of the information carried by the two input pathways to the hippocampal subfields.
Neuroscience Research Center, Charité University Berlin, Germany.
Alexandra S
AS
Klein
Department of Biology, Institute for Theoretical Biology, Humboldt UniversityBerlin, Germany; Bernstein Center for Computational NeuroscienceBerlin, Germany.
José R
JR
Donoso
Department of Biology, Institute for Theoretical Biology, Humboldt UniversityBerlin, Germany; Bernstein Center for Computational NeuroscienceBerlin, Germany.
Richard
R
Kempter
Neuroscience Research Center, Charité UniversityBerlin, Germany; Bernstein Center for Computational NeuroscienceBerlin, Germany; Cluster of Excellence "NeuroCure", Charité UniversityBerlin, Germany; DZNE - German Center for Neurodegenerative DiseasesBerlin, Germany; Einstein Foundation BerlinBerlin, Germany.
Dietmar
D
Schmitz
Neuroscience Research Center, Charité UniversityBerlin, Germany; DZNE - German Center for Neurodegenerative DiseasesBerlin, Germany; Berlin Institute of HealthBerlin, Germany.
Prateep
P
Beed
Alzheimers disease; entorhinal cortex; gamma oscillation; interneurons; presymptomatic