title: Effects of nicotine stimulation on spikes, theta frequency oscillations, and spike-theta oscillation relationship in rat medial septum diagonal band Broca slices.
abstract: OBJECTIVE
  Spiking activities and neuronal network oscillations in the theta frequency range have been found in many cortical areas during information processing. The aim of this study is to determine whether nicotinic acetylcholine receptors (nAChRs) mediate neuronal network activity in rat medial septum diagonal band Broca (MSDB) slices.
  
  
  METHODS
  Extracellular field potentials were recorded in the slices using an Axoprobe 1A amplifier. Data analysis was performed off-line. Spike sorting and local field potential (LFP) analyses were performed using Spike2 software. The role of spiking activity in the generation of LFP oscillations in the slices was determined by analyzing the phase-time relationship between the spikes and LFP oscillations. Circular statistic analysis based on the Rayleigh test was used to determine the significance of phase relationships between the spikes and LFP oscillations. The timing relationship was examined by quantifying the spike-field coherence (SFC).
  
  
  RESULTS
  Application of nicotine (250 nmol/L) induced prominent LFP oscillations in the theta frequency band and both small- and large-amplitude population spiking activity in the slices. These spikes were phase-locked to theta oscillations at specific phases. The Rayleigh test showed a statistically significant relationship in phase-locking between the spikes and theta oscillations. Larger changes in the SFC were observed for large-amplitude spikes, indicating an accurate timing relationship between this type of spike and LFP oscillations. The nicotine-induced spiking activity (large-amplitude population spikes) was suppressed by the nAChR antagonist dihydro-β-erythroidine (0.3 μmol/L).
  
  
  CONCLUSIONS
  The results demonstrate that large-amplitude spikes are phase-locked to theta oscillations and have a high spike-timing accuracy, which are likely a main contributor to the theta oscillations generated in MSDB during nicotine receptor activation.
authors.affiliation: The Key Laboratory for Computer Virtual Technology and System Integration of Hebei Province, Yanshan University, Qinhuangdao 066004, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wen
authors.forename: Ce
authors.initials: C
authors.lastname: Peng
authors.forename: Gao-xiang
authors.initials: GX
authors.lastname: Ou-Yang
authors.forename: Zainab
authors.initials: Z
authors.lastname: Henderson
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Li
authors.forename: Cheng-biao
authors.initials: CB
authors.lastname: Lu
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D005625:Frontal Lobe / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000378:metabolism; D012686:Septal Nuclei / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D013268:Stimulation, Chemical; D013826:Theta Rhythm / Q000187:drug effects* / Q000502:physiology
chemical_list: D011978:Receptors, Nicotinic; D009538:Nicotine