PMID- 8389835
OWN - NLM
STAT- MEDLINE
DCOM- 19930715
LR  - 20171213
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 69
IP  - 5
DP  - 1993 May
TI  - Effects of transient depolarizing potentials on the firing rate of cat 
      neocortical neurons.
PG  - 1673-83
AB  - 1. The effects of excitatory postsynaptic potentials (EPSPs) on interspike 
      intervals (ISIs) of neocortical neurons can be mimicked by pulse potentials (PPs) 
      produced by current injection. The present report documents the dependence of the 
      ISI shortening on the amplitudes of PPs and EPSPs and on the firing rate of the 
      affected neuron. 2. In rhythmically firing necortical neurons, the ISI 
      shortenings caused by PPs arriving at specific times in the ISI can be described 
      by a shortening-delay (S-D) curve. The S-D curve yields three measures of the 
      PPs' ability to shorten the ISI: 1) the mean ISI shortening, S; 2) the maximum 
      shortening, Smax; and 3) the effective interval, defined as the portion of the 
      ISI in which the PP consistently shortens the ISI. For PPs ranging between 80 
      microV and 3.6 mV (and cells firing at 25 imp/s), the mean shortening increased 
      with amplitude h as S (ms) = 1.2*h (mV)1.24 (r = 0.94; P < 0.01). Smax increased 
      linearly with amplitude as 4.9 ms/mV (r = 0.86, P < 0.01). The effective interval 
      (as a percentage of the ISI) increased slightly with PP amplitude and had a mean 
      value of 65 +/- 21% (mean +/- SD). 3. S-D curves obtained with stimulus-evoked 
      EPSPs varied with EPSP amplitude in a manner similar to those of PPs. The 
      relations obtained for stimulus-evoked EPSPs were not statistically different 
      from those obtained for PPs in the same cells. 4. To determine the effect of 
      firing rate. PPs were applied while neurons fired at frequencies ranging from 8 
      to 71 imp/s. Both S and Smax were approximately inversely proportional to the 
      baseline firing rate (fo) and could be described as: S or Smax = kfo-m. The mean 
      value of the exponent m (+/- SD) was 0.96 +/- 0.25 for S and 1.2 +/- 0.4 for 
      Smax. These values were not statistically different from a value of 1 (1 group, 
      2-tailed t test). The effective interval did not vary significantly with firing 
      rate. 5. The dependence of S on PP amplitude and baseline firing rate was 
      incorporated into an expression for the average change in firing rate (delta f) 
      produced by PPs occurring at rate fs: delta f = 0.03 h1.24 fs. The delta f 
      increased with PP amplitude but did not vary significantly with the baseline 
      firing rate. The values of delta f calculated from the S-D curves matched the 
      values that were computed directly from the spike trains.(ABSTRACT TRUNCATED AT 
      400 WORDS)
FAU - Reyes, A D
AU  - Reyes AD
AD  - Department of Physiology and Biophysics, University of Washington, Seattle 98195.
FAU - Fetz, E E
AU  - Fetz EE
LA  - eng
GR  - NS-12542/NS/NINDS NIH HHS/United States
GR  - RR-00166/RR/NCRR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
SB  - IM
MH  - Animals
MH  - Cats
MH  - Culture Techniques
MH  - Electric Stimulation
MH  - Evoked Potentials, Somatosensory/*physiology
MH  - Female
MH  - Male
MH  - Neurons/physiology
MH  - Reaction Time/*physiology
MH  - Somatosensory Cortex/*physiology
MH  - Synapses/*physiology
MH  - Synaptic Transmission/*physiology
EDAT- 1993/05/01 00:00
MHDA- 1993/05/01 00:01
CRDT- 1993/05/01 00:00
PHST- 1993/05/01 00:00 [pubmed]
PHST- 1993/05/01 00:01 [medline]
PHST- 1993/05/01 00:00 [entrez]
AID - 10.1152/jn.1993.69.5.1673 [doi]
PST - ppublish
SO  - J Neurophysiol. 1993 May;69(5):1673-83. doi: 10.1152/jn.1993.69.5.1673.