PMID- 2337779
OWN - NLM
STAT- MEDLINE
DCOM- 19900620
LR  - 20190613
IS  - 0006-8993 (Print)
IS  - 0006-8993 (Linking)
VI  - 508
IP  - 1
DP  - 1990 Jan 29
TI  - Laminar interactions in rat motor cortex during cyclical excitability changes of 
      the penicillin focus.
PG  - 105-17
AB  - Laminar interactions between neurons in rat motor cortex during cyclical seizure 
      episodes in the penicillin focus were studied using a combination of current 
      source-density (CSD) and principal component analysis (PCA), combined with 
      computer-based physical modeling. These data suggest that all phases of cyclical 
      seizure phenomena are produced by interactions between two distinct populations 
      of neurons, the same neuronal circuits previously reported to give rise to the 
      direct cortical response (DCR) and electrically evoked interictal penicillin 
      spikes (EIIS). The first population consists of small pyramidal cells in the 
      supragranular layer, and the second population consists of larger pyramidal cells 
      in the infragranular layers with apical dendrites extending to the cortical 
      surface. The supragranular cells serve as a trigger zone for initiating both 
      spontaneous interictal spikes (IIS) and polyspike bursts (PSB) during seizures. 
      Fast activity in the supragranular cells is typically followed by a 
      hyperpolarizing slow wave that may be the result of Ca2+-activated K+ currents. 
      This slow wave increases during seizures, possibly reflecting changes in 
      extracellular Ca2+ associated with seizure onset and termination. The monophasic 
      response of infragranular cells is similar for both IIS and PSB and consists of a 
      large depolarizing shift followed by a rapid but partial repolarization period 
      and a subsequent gradual repolarization period lasting several hundred 
      milliseconds. The infragranular response is similar in polarity and morphology to 
      the intracellularly recorded paroxysmal depolarization shift (PDS) and may 
      indicate that these deeper neurons are mainly responsible for this phenomena in 
      neocortex. Finally, there is a marked postictal slow oscillation between the 
      supra- and infragranular layers. This oscillation appears first and largest in 
      the supragranular cells and may reflect a disturbance in excitatory feedback in 
      these cells produced by the disinhibitory effect of penicillin, a disturbance 
      capable of pathologically synchronizing the epileptic neuronal aggregate 
      sufficiently for activation of the spike-generating mechanism and subsequent 
      seizures.
FAU - Barth, D S
AU  - Barth DS
AD  - Department of Neurology, University of California, Los Angeles 90024.
FAU - Baumgartner, C
AU  - Baumgartner C
FAU - Di, S
AU  - Di S
LA  - eng
GR  - 1-R01-NS22575/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Brain Res
JT  - Brain research
JID - 0045503
RN  - 0 (Penicillins)
SB  - IM
MH  - Animals
MH  - Electronic Data Processing
MH  - Evoked Potentials/drug effects
MH  - Models, Neurological
MH  - Motor Cortex/drug effects/*physiopathology
MH  - *Penicillins
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Seizures/chemically induced/*physiopathology
EDAT- 1990/01/29 00:00
MHDA- 1990/01/29 00:01
CRDT- 1990/01/29 00:00
PHST- 1990/01/29 00:00 [pubmed]
PHST- 1990/01/29 00:01 [medline]
PHST- 1990/01/29 00:00 [entrez]
AID - 0006-8993(90)91123-X [pii]
AID - 10.1016/0006-8993(90)91123-x [doi]
PST - ppublish
SO  - Brain Res. 1990 Jan 29;508(1):105-17. doi: 10.1016/0006-8993(90)91123-x.