Spike amplitude

Figure 3-27 The effects of interleaving on the electrical waveforms of an off-line flyback converter. (Note spike amplitude and overall degree of "ringing.")...

The inset in A is a representative evoked potential recorded from the CA1 pyramidal cell layer. Calibration hards vertical 2 mV, horizontal 10 msec. The population spike amplitude was defined as an average of the amplitude from the first positive peak 1 to the succeeding negative peak 2 and the amplitude from die negative peak 2 to the second positive peak 3. A Time-course of potentiation induced by strong tetanic stimulation in the control slices (O, n=23) and in the slices treated with 30% of ethanol (IS ml/kg) (, n=27 ) and in the slices treated with 30% of ethanol (IS ml/kg) and 20 mg/kg crocin ( A, n-7). (1) and (2) indicated 30% ethanol of IS ml/kg and 10 ml/kg, respectively. Ethanol or crocin was added in the perfusing ACSF from 15 or 20 min, respectively, before tetanic stimulation. The ordinate indicates the population spike amplitude expressed as a percentage of the baseline values immediately before tetanic stimulation. 

B Summary ofthe effects of ethanol and crocin on the induction of LTP. The magnitude ofLTP was evaluated with die population spike amplitude 30 min after tetanic stimulation. The numbers of observations in each group are shown in parentheses. All data are represented as the mean SEM. p<0.01 vs. control, p<0.05 vs. 30% of ethanol (IS ml/kg) alone. Duncan s multiple range test. 

Anesthetized male Wistar rats 7-9 weeks old were used. Extracellular recording of population spike amplitude in the dentate gyrus in hippocampus were performed according to the method employed in our laboratory [10]. CSE was administered orally, ethanol was administered via three different routes, i.e. orally, intravenously or... 

Hippocampal slices (400-500 frm) were quickly prepared from male Wistar rats (8- to 9-weeks-old) and maintained in a chamber at 35 °C, where they were continuously perfused with artificial cerebrospinal fluid as described in our previous paper [11]. A bipolar tungsten electrode was placed in the stratum radiatum to stimulate Schaffer collateral and commissural afferents. The evoked potential was extracellularly recorded from the pyramidal cell layer of the CA1 subfield with a glass capillary microelectrode. A single test stimulation (0.05 msec duration) was applied at intervals of 30 sec. Drugs were delivered by perfusion. To induce potentiation of the evoked potentials, tetanic stimulation was applied at the same intensity through the same stimulating electrode as used for the test stimulation. The magnitude of LTP was evaluated by the population spike amplitude 30 min after tetanic stimulation. 

A Time-course of potentiation of population spike amplitude induced by application of tetanic stimulation (30 pulses at 60 Hz). Saline (, n=9) or ethanol (10%, A, n=5 20%, ... 

A Time-course of potentiation of population spike amplitude. Saline (, 0) or CSE (250 mg/kg, A ) was orally administered 30 min before tetanus, and then saline ( ) or 30% ethanol (O.A ) was orally administered 10 min later (20 min prior to tetanus). B The dose-dependency of the influence of CSE on the LTP-blocking effect of ethanol. The numbers of observations are as follows saline alone (control), n=9 ethanol alone, n=8 ethanol and 125 mg/kg CSE, n=5 ethanol and 250 mg/kg CSE, n=ll. All data are represented mean SEM of n observations. p<0.0l vs. saline group (control). p<0.01 vs. ethanol alone (Duncan s multiple range test). 

Siminuscula trichodea, responded with the same spike amplitude to both the minor component Zll-16 Ald and to the behavioral antagonist Z9-14 Ac. The two behavioral antagonists of M. brassicae, Z9-14 Ac and Zll-16 OH, are pheromone components of sympatric species in the South of France Agrotis ipsilon (Z9-14 Ac, Zll-16 OH), A. segetum (Z9-14 Ac) mdMythimna unipuncta (Zll-16 OH). Both M. brassicae and M. unipuncta use Zll-16 Ac as the main pheromone component, but the M. unipuncta pheromone contains 2 percent of Zll-16 OH which may ensure the chemical isolation of these two species (Farine etal., 1981). Zll-16 OH inhibits the behavior of male M. brassicae when included at 0.1 percent of the blend (Descoins et al 1978 Struble et al 1980). 

The firing rate of hippocampal CA1 pyramidal cells is known to depend on spatial location, that is, contextual environment information related to exploration behavior is encoded by cell activity (Hollup et al., 2001 Thompson and Best, 1990). In the present study, the population spike amplitude (PSA), measured with simultaneous determination of locomotor activity, in the CA1 field evoked by Schaffer collaterals stimulation was slightly decreased during exposure to the open field (Fig. 1). However, no significant difference in changes of synaptic transmission in the CA1 field was observed between the FS groups and non-FS controls (Koseki et al., 2007). 

Fig. 1. Behavioral response and hippocampal synaptic transmission during exposure to open field stress in freely moving rats. Behavior analysis and electrophysiological experiments were performed simultaneously during the postadolescent period (10-12 weeks old). (A) Locomotor activity estimated by total crossings for 30 min and (B) time-course of crossings during exposure to open field stress. (C) Time-course of population spike amplitude (PSA) in the hippocampal CA1 field evoked by Schaffer collaterals stimulation. Values are expressed as a percentage of the baseline level before open field stress. Non-FS, pups exposed to the footshock (FS) box without FS 2W-FS and 3W-FS, pups exposed to FS during the second and third postnatal weeks, respectively. Each value represents the mean S.E.M. p < 0.05 versus non-FS controls (modified from Koseki etal., 2007).

In general, a decrease of the opposition spike amplitude with increasing albedo contradicts the coherent backscattering mechanism that predicts an increase of the spike amplitude with increasing albedo. One possible explanation of this contradiction is that with the albedo increase, the width of the spike becomes significantly smaller than 0.1° and the phase ratio 7(0.1°)//(3°) is not sensitive to this spike. 

The impulse activity of sensory neurons can be analyzed using computers. Different systems have been devised to simplify the task of discriminating between nerve impulses of different amplitudes and to produce spike frequency time histograms (van der Molen et al., 1978). A simpler device modified from the design of McCook et al. (1975) was used to generate the histograms in Fig. 1.1. The question remains as to whether spike amplitude is the only useful parameter to discriminate between the nerve impulses of different cells (Frazier and Hanson, unpublished in Stadler, 1982). 

The number of s. trichodea sensory cells varies from one to five, depending on the lepidopteran species (Priesner, 1979a). In some species the cell generating the largest spike amplitude in each sensillum consistently belong to the same cell type, i.e. maximally responds to the same key substance, which is the... 

Contrary to the majority of published reports, some labs reported that nicotine neither enhanced nor depressed HFS-induced LTP in normal animals [85,109], For example, Itoh et al. [109] found that in slices from Ap-infused (300 pmol/day Apl 40> 11-12 days) rats, 50 pM of nicotine, perfused for 10 min, decreased population spike amplitude in area CAl of control rats. Similarly, studies by Freir et al. [85] found that coinjection of 3 mg/kg nicotine with 1 or 10 nmol Api 40,1 h prior to HFS, significantly depressed LTP, measured 1 h post-tetanus, more than Apl-40 alone. 

By comparing quantal sizes from multiple cells, quinpirole has been found to reduce the average quantal size to about 51% of control values [56]. Quinpirole also decreases the maximum amperometric spike amplitude (i ), the spike width at half-height(tj/2) and the spike frequency. Each of these Dj-mediated effects on quantal size can be blocked by co-incubation in the D2 antagonist sulpiride however, exposure to sulpiride alone does not affect quantal size and the individual exocytotic event characteristics are very similar to those of controls. 

Quirk MC, Blum KI, Wilson MA (2001) Experience-dependent changes in extracellular spike amplitude may reflect regulation of dendritic action potential back-propagation in rat hippocampal pyramidal cells. J f Neurosci 21(1) 240-248, Jan. 2001. 

Kaneko H, Tamura H, Suzuki SS (2007) Tracking spike-amplitude changes to improve the quality of multineuronal data analysis. IEEE Trans Biomed Eng 54(2) 262-272, Feb. 2007. 

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