The same as Fig. 17, but for a monochromatic wave excitation of frequency f2=0.2Hz and amplitude A2=0.50m.
... Oscillating water column... The same as Fig. 18, but for a monochromatic wave excitation of frequency f2=0.2Hz and amplitude A2=0.50m.
... The same as Fig. 22, but for a monochromatic wave excitation of frequency f2=0.2Hz and amplitude A2=0.50m.
... The same as Fig. 3, but for different constant frequency, i.e., f2=0.05Hz.
... Frequency-amplitude domain... Maximum dynamic pressure, max(pD(t;Aexc,Texc)), against (mean wave elevation) oscillation's amplitude Aexc.
Contributors:Geraint G. Vernon, David M. Woolley
(A) Frame-by-frame analysis of the movements illustrated in Fig. 5 A. The curvature of the proximal 10μm of the flagellum is plotted using a mixture of open circles and crosses; the open circles represent video frames illustrated in Fig. 5 A. The curvature is seen to oscillate rapidly until the trailing edge of the antecedent full-sized R-bend (solid circles) has propagated off the tip. Downward deflection of curvature represents cryptic P-bends. (B) Another example of a hesitation cycle from the same headless sperm. (C) Frame-by-frame analysis, as in Fig. 6 A, of the intact specimen illustrated in Fig. 5 B. (D) Another example from a different intact sperm. In all four graphs, the velocity of propagation of the full-size R-bend shows irregularities that may possibly be related to the oscillatory movements on the proximal flagellum.... (A) Sequential images, from left to right, of a headless sperm in motion, during a beat cycle that showed “hesitation” in developing the reverse (R) bend. Bends P1 and R1 are identified in image 1. P1 reaches its greatest curvature proximally in image 3. Then in image 4, a slight proximal straightening indicates that the cryptic bend R2 has developed. Image 5 shows the cryptic bend P2. The rapid oscillation continues with cryptic R-bends in images 6, 8, and 10, and cryptic P-bends in images 7, 9, and 11. Only when bend R1 finally leaves the tip, in image 12, does the next full-size R-bend develop (images 13 and 14), followed without hesitation by (the first stages of) the next full-size P-bend (images 15 and 16). Duration of sequence 3.84s. Time intervals (left to right) were 0.23, 0.12, 0.07, 0.41, 0.12, 0.12, 0.07, 0.17, 0.36, 0.67, 0.36, 0.41, 0.43, 0.24, and 0.05s. (B) Sequential images, as in A but showing an intact sperm. P1 reaches its maximal angle in image 5. Cryptic R-bends are maximally developed in images 6, 8, 10, 12, and 14. Cryptic P-bends are seen in images 7, 9, 11, and 13. Bend R1 leaves the tip in image 15. Only then does the next full-size R-bend develop (images 16–19), followed immediately by the next full-size P-bend (beginning in image 20). Duration of sequence 3.54s. Time intervals (left to right) were 0.12, 0.24, 0.05, 0.72, 0.07, 0.17, 0.07, 0.14, 0.05, 0.12, 0.12, 0.19, 0.29, 0.12, 0.24, 0.19, 0.17, 0.24, and 0.24s. In both A and B, the individual frames have been selected to show the peaks of the oscillation, which is more obvious in B because of the tilting of the head. At this scale, the basal protrusions in A are difficult to see but are represented in Fig. 1. The sequence of frames has been spread from left to right to minimize confusing superimposition. Frame-by-frame quantitative analyses of these specimens is given in Fig. 6, A and C. Scale bar, 4μm. (Also see supplementary videos.)
... Measurements of the maximum angle reached by bend P1, taken from 21 beat cycles, from six spermatozoa. They are arranged in two columns according to whether or not bend P1 was followed by hesitations (i.e., rapid oscillations before the next full-size R-bend). The angle was measured just before the hesitations or normal propagations began.
... (A) Frame-by-frame analysis of the movements illustrated in Fig. 5 A. The curvature of the proximal 10μm of the flagellum is plotted using a mixture of open circles and crosses; the open circles represent video frames illustrated in Fig. 5 A. The curvature is seen to oscillate rapidly until the trailing edge of the antecedent full-sized R-bend (solid circles) has propagated off the tip. Downward deflection of curvature represents cryptic P-bends. (B) Another example of a hesitation cycle from the same headless sperm. (C) Frame-by-frame analysis, as in Fig. 6 A, of the intact specimen illustrated in Fig. 5 B. (D) Another example from a different intact sperm. In all four graphs, the velocity of propagation of the full-size R-bend shows irregularities that may possibly be related to the oscillatory movements on the proximal flagellum.
Contributors:Myeong-Lok Seol, Jin-Woo Han, Sang-Jae Park, Seung-Bae Jeon, Yang-Kyu Choi
Operating principle of the FO-TEEM generator. (a) Operating principle of the TENG component. The TENG component responds to the displacement of the floating oscillator. (b) Simulated charge density profile of the two Al electrodes and the floating oscillator with various positions (COMSOL Multiphysics). (c) Operating principle of the EMG component. The EMG component responds to the velocity of the floating oscillator. (d) Simulated current density profile of the two coils with the floating oscillator moving in various directions.
... Structure of the FO-TEEM generator. (a) Schematics of the floating oscillator-embedded triboelectric nanogenerator (TENG), electromagnetic generator (EMG), and hybrid FO-TEEM generator. (b) A photograph of the prototype FO-TEEM generator. Inset shows a magnified view of the magnetic rod surrounded by the PTFE coated PDMS sponge, which is used as the floating oscillator. (c) A photograph showing the inside of the tube. (d) SEM image of the Al electrode with the nano-grass structures. (e) SEM image of the PDMS sponge before coating with the PTFE layer. (f) SEM image of the PDMS sponge after the PTFE layer coating.
Contributors:Anne Kösem, Alexandre Gramfort, Virginie van Wassenhove
Phase shifts reflect subjective timing. Individuals' PSS were plotted as a function of the difference in mean instantaneous phase (end minus beginning in a given lag-adaptation period) in auditory (A) and visual cortices (B). Each data point corresponds to an individual duplet, namely: the mean phase difference obtained in a given lag-adaptation period (S: black; A200V: red; V200A: green) and the associated individual's PSS measured during the following TOJ block. A linear regression was computed on a per individual basis between the mean PSS and the circular mean of the instantaneous phases of the 1Hz neural oscillation obtained across lag-adaptation blocks. A significant correlation was found between the phase shifts of the entrained 1Hz neural oscillation in auditory cortices and individuals' PSS (r=0.65, p<0.01) whereas no such correlation was found in visual cortices (r=−0.26, n.s.).
... Phase-shifts are specific to the frequency of the entrained neural oscillation. In order to test whether the reported phase shifts were specific to the entrained 1Hz neural oscillation, identical analyses were carried out on the same neural responses filtered at 2Hz (A) and 3Hz (B). In particular, if the observed phase shifts at 1Hz were confounded by the evoked responses, identical PLVs and instantaneous phase shifts should be observed at higher frequencies by virtue of the wide spectral impact of evoked responses. Phase distributions and preferential instantaneous phase at 2Hz and 3Hz were computed at the beginning (light gray) and at the end (colored) of a given lag-adaptation block (S: black; A200V: red; V200A: green). Phase distributions were computed at visual onset in visual cortices and at sound onset in auditory cortices. Phase distributions were individually normalized to the preferred instantaneous phase observed at the beginning of a given lag-adaptation block. Hence, all phase distributions at the beginning of a given block are centered on zero. No significant changes in 2Hz oscillation phase were seen between the beginning and the end of the lag-adaptation for A200V or for S in visual and auditory cortices. Only one significant difference in the mean instantaneous phase distribution was observed for the V200A condition in auditory cortices. Note however that 2Hz is a harmonic of 1Hz and may actually be a relevant spectral region to consider (albeit outside the scope of this report). No significant changes in 3Hz oscillatory behavior were seen except in visual cortex in condition A200V.
... Additional analyses were performed supporting the independence of evoked activity and neural oscillatory phase shifts. If the evoked responses impacted the phase of neural oscillations at 1Hz, a similar pattern of phase shifts in neighboring frequency regions should be found by virtue of evoked response being fixed-latencies and strongly phase-locked signals. Weak-to-no phase locking and no significant phase shifts were observed for 2 or 3Hz neural oscillations (Supplementary Fig. S2).... Participants underwent a series of alternating lag-adaptation and TOJ blocks while being recorded with MEG. Three AV delays were tested (Figs. 1a–b): simultaneous AV presentations (S, control condition), a sound leading a visual event by 200ms (A200V) and a visual event leading a sound by 200ms (V200A). Each TOJ block allowed establishing an individual's psychometric curve following each lag-adaptation block as well as deriving the progression of the individual's point of subjective simultaneity (PSS). Our hypothesis was that changes in neural activity during lag-adaptation would predict changes in subjects' perceived simultaneity. First, we tested the latency code hypothesis by comparing the event-related responses at the beginning and at the end of the lag-adaptation. We then tested the phase code hypothesis by comparing the phase of the entrained neural oscillation at the beginning and the end of the adaptation (Supplementary Fig. S1).... Additionally, 1Hz oscillatory activity showed a significant phase-locking in both sensory cortices. Phase preferences of the 1Hz oscillation were tested using a Rayleigh test against uniformity (p<0.05). At the beginning of all lag-adaptation periods (S, A200V, and V200A), phase preferences were found to be significant in both sensory cortices for 15 participants; at the end of all lag-adaptation periods (S, A200V, and V200A), significant phase preferences were found for all participants. For all conditions and in both sensory cortices, the observed phase locking values (PLV, index of the variance of phase distributions) did not significantly differ between the beginning and the end of each lag-adaptation period (Supplementary Table S1). Altogether, these results show the existence of robust phase preferences in all conditions throughout the course of the experiment.... 1Hz neural response: oscillatory phase differences during lag-adaptation. (A) One participant's visual evoked response obtained at the beginning (blue) and at the end (red) of an A200V lag-adaptation block. The top graph shows the unfiltered visual evoked response; the bottom graph shows the same visual evoked response band-pass filtered from 0.5 to 1.5Hz. The 1Hz oscillatory component at the end of the lag-adaptation block (red) shows a backward shift in time with respect to the same oscillatory component at the beginning of the lag-adaptation (blue): this backward temporal shift is quantified as an increase in the mean instantaneous phase value across the 30 single trials used to compute the evoked response (right panel). (B) One participant's auditory evoked response at the beginning (blue) and at the end (red) of an A200V lag-adaptation block. The unfiltered and 0.5–1.5Hz band-pass filtered auditory evoked responses are depicted in the top and bottom graph, respectively. The 1Hz oscillatory component at the end of the lag-adaptation block (red) shows a forward shift in time with respect to the same oscillatory component at the beginning of the lag-adaptation (blue). The mean instantaneous phase across the 30 trials used to build the auditory evoked response shows a decrease between the beginning and the end of the block (right panel). (C) Instantaneous phase distribution and preferential instantaneous phase of the entrained 1Hz neural oscillatory response at the beginning (light gray) and at the end (colored) of a given lag-adaptation block (S: black; A200V: red; V200A: green). Phase distributions were computed at visual onset in visual cortices (top) and at sound onset in auditory cortices (bottom). Phase distributions were individually normalized to the preferred instantaneous phase observed at the beginning of a given lag-adaptation block. Hence, all phase distributions at the beginning of a given block are centered on zero. In S, the phase distributions remained stable over time in both auditory (+1°, 95% confidence interval (CI)=[−6°, +5°]) and visual (−1°, CI=[−6°, +8°]) cortices. In the desynchronized blocks, the mean instantaneous phase shifted in opposite directions in the auditory and visual cortices during lag-adaptation: specifically, in A200V the preferential phase in visual cortices increased (+19° or −53ms, CI=[12°, 26°]) suggesting a backward shift in time of the entrained 1Hz oscillatory response, whereas a forward shift in time was observed in auditory cortices (−19° or +53ms, CI=[−27°, −9°]). Conversely, in V200A the mean instantaneous phase in visual cortices increased (+16° or −44ms, CI=[7°, 25°]) but decreased in auditory cortices (−19° or +53ms, CI=[−26°, −13°]). Hence, and as predicted, lag-adaptation to simultaneous AV stimuli (S) did not affect the phase of the entrained 1Hz neural oscillation in sensory cortices whereas desynchronized AV stimuli (A200V and V200A) shifted the preferential phase distribution in opposite direction in the auditory and visual cortices.
... Oscillatory entrainment and jitter procedure. In all lag-adaptation blocks, AV stimuli were presented at a rate of 1Hz±100ms. The temporal jitter was introduced to prevent full neural response time-locking and enable the dissociation of the oscillatory component from the evoked response (Lakatos et al., 2008). In both (A) and (C): one participant's superimposed single trial data (black) with the visual evoked response (red) at the end of A200V in visual cortex (A) and in auditory cortex (C). As can readily be seen in these two examples, the time-locked averaging of one stimulus (at zero) prevented to see the evoked responses of the preceding and following stimuli (which would be expected at about −1 and +1s, respectively). As predicted, the temporal jittering procedure massively reduced the temporally adjacent evoked responses. Despite the absence of evoked response at −1 and +1s, a clear single-trial oscillatory component at 1Hz could be seen in both sensory cortices. In both (B) and (D): Frequency power spectra of neural responses in visual (B) and auditory (D) cortices for all lag-adaptation blocks. After 1/f correction (see Section 2.5.4.), a significant 1Hz peak was readily observable (on sample t-test against Ho=zero power, p<0.01) in both sensory cortices. No significant differences in 1Hz power were observed between the beginning and the end of the lag-adaptation periods irrespective of the experimental conditions. In visual cortices (panel B): S: t(15)=−0.9, n.s.; A200V: t(15)=0.6, n.s.; and V200A: t(15)=−0.7, n.s.. In auditory cortices (panel D): S: t(15)=−1.8, n.s.; A200V: t(15)=0.05, n.s.; V200A: t(15)=1.7, n.s..
Contributors:Shengzhuo Zhang, Songjing Li
Pressure oscillation with inlet pressure 2MPa. (a) Calculated pressure oscillation. (b) Power density of oscillation.
... Pressure oscillation at inlet pressure 3MPa. (a) Calculated pressure oscillation. (b) Power density of oscillation.
... Pressure oscillation
Contributors:N. Mykytenko, D. Fink, A. Kiv
Current spikes in conditions of real experiment . Region I corresponds to regular oscillations, region II corresponds to current spikes (a). Illustration of model spikes in the model experiment. At the horizontal axis is the average amplitude of MP oscillations (b).
... The model for explanation of current oscillation effect in the track structure: oscillations of the model particles in the upper plane simulate current oscillations in tracks (see text).
... Illustration to the model: in the plane that intersects tracks we have a system of currents that oscillate depending on the appropriate conditions.
... Dependence of the maximum value, Amax of spike height on the frequency of FR.
... (a) Dependence of the average amplitude, A¯ of MP oscillations on the frequency of FR. (b) Dependence of the average spike height on the frequency of applied voltage; Points: measurements, the curve is drown by the method of least squares .
Contributors:Jacques Pecreaux, Jens-Christian Röper, Karsten Kruse, Frank Jülicher, Anthony A. Hyman, Stephan W. Grill, Jonathon Howard
Model of the Time Course of Motor Activation
Prior to metaphase, the pool of motors that can be activated is established at the cortex via GPR-1/2. The size of the pool is indicated by the thickness of the green shaded areas: The pool is larger in the posterior half than in the anterior half but remains constant throughout metaphase and anaphase. Over time, the activity of the motors increases, indicated by the increasing opacity of the green shaded regions. The increasing motor activity accounts for the dynamics of both the oscillations and the posterior displacement.
... Phenotypes of Progressive Depletion of DLI-1 and GPR-1/2
Examples of the trajectories of the anterior (red) and posterior (blue) spindle poles are superimposed on the contour of the embryo. The circles represent the starting positions. Each panel shows a different embryo.
(A–C) Depletion of dynein light intermediate chain in worms fed bacteria expressing inactivating RNA directed against dli-1. (A) An embryo 12 hr 40 min after transfer onto the feeding plates in which the oscillation is normal. (B) A different embryo 13 hr 30 min after transfer in which the oscillation was not present. (C) At 17 hr after transfer, the spindle was not aligned properly on the AP axis.
(D–F) Depletion of GPR-1/2 after injection of dsRNA directed against gpr-1/2. (D) At short times after injection, the phenotype is almost normal. (E). At 11 hr 30 min, the oscillations are completely absent, although posterior displacement still occurs. (F) At 35 hr 12 min, there are no oscillations or posterior displacement, although spindles still elongate to 85% of their normal length. Interestingly, all the reduction of spindle elongation occurred over the first 13 hr, suggesting that spindle oscillations may be required to elongate the spindle to its full extent.
... Transverse Oscillations and Posterior Displacement of the Mitotic Spindle in an Unperturbed Embryo
(A) Fluorescence image of the one-cell C. elegans embryo showing GFP-tagged γ-tubulin localizing preferentially to the centrosomes (spindle poles). The anterior spindle pole (left) is circled in red, the posterior (right) in blue.
(B) The trajectories of the two poles during metaphase and anaphase measured every 0.5 s. The circles denote the initial positions.
(C) The distances of the spindle poles from the anterior-posterior axis shows the buildup and die-down of the oscillations. The approximate onset of oscillations is indicated by the dashed line.
(D) The position of the spindle (defined as the midpoint of the poles) along the AP axis (black). Zero is the center of the embryo. The slight oscillations are due to the arcing motion of the spindle apparent in the posterior trace in (B). The spindle length is shown in gray. All panels are from the same cell.
... The Antagonistic-Motors Model Accounts for the Buildup and Die-down of the Oscillations
(A) The processivity of the motors is postulated to increase steadily during metaphase and anaphase (i.e., the off rate, k¯off, decreases).
(B) As a consequence of the varying off rate, the mean attached probability, p¯, a measure of the activity of the motors, steadily increases. The probability is 0.5 when the off rate equals the on rate (kon) indicated by the vertical dashed line in (A).
(C) As the probability increases, the coefficient of negative damping (Ξ) first increases and then decreases. When the coefficient of negative damping exceeds that of the positive damping (Γ), indicated by the horizontal dashed line, the system becomes unstable (shown as the hatched region), and spontaneous oscillations occur. When the coefficient of negative damping drops below the positive damping, the oscillations die out.
(D) The instability occurs while the inertial coefficient (I) is increasing (solid curve). This leads to the observed decrease in the oscillationfrequency over the course of the oscillations (Figure 4). The dashed curve shows the case if the on rate were decreasing.
(E) Simulation of the oscillation. The gray region denotes the time when oscillations are resolved above the noise.
(F) Because the probability increases monotonically, so too does the net posterior-directed force and the posterior displacement: Γ = 85.8 μN·s/m, K = 10 μN/m, N = 28, f¯ = 6 pN, fc = 1.5 pN, f′= 3 μN·s/m, kon = 0.6 s−1.
... Decrease in Frequency during the Oscillations
The oscillationfrequency decreased by about one-third over the duration of the oscillations. Four frequency measurements were made during each period of an oscillation by measuring the times in the cycle at which the position and velocity were at an extremum. The frequency was normalized to that at the peak amplitude and is plotted against time, measured in periods of oscillation, for 22 embryos. The slope is 0.0769 ± 0.0071 (mean ± SEM, p oscillationfrequency and time for the average oscillation.
Contributors:Cecilia Garmendia-Torres, Albert Goldbeter, Michel Jacquet
Model for Nucleocytoplasmic Shuttling of Msn2 Coupled to Oscillations in the cAMP-PKA System
Scheme of the model showing the different interactions between the components of the cAMP-PKA system and the coupling to Msn2 shuttling between cytosol and nucleus in yeast. The variables of the model are the following: the fractions GEFa and GAPa of active GEF (Cdc25) and GAP proteins (Ira1 and Ira2); the fraction Ras-GTP (RGTP) of Ras proteins (Ras1 and Ras2) bound to GTP; the fraction CYCLa of adenylate cyclase (Cyr1) in the active state; the concentration of cAMP; the fraction of active phosphodiesterase PDEa (Pde1 and Pde2); the fraction R2C2 of PKA in the form of a holoenzyme complex between the regulatory subunit Bcy1 (R) and the three catalytic subunits, free of cAMP (C). R2cAMP2 denotes the holoenzyme with a cAMP molecule bound to each of the two regulatory subunits. We assume that stress (of intensity Str) elicits the inactivation of GEF and the dephosphorylation of Msn2 both in the nucleus and in the cytosol.
... Dynamic Behavior Predicted by the Model
(A) Time evolution of RGTP, cAMP, active PKA, and nuclear Msn2 predicted by the model for three different values of Str, the dimensionless parameter measuring stress intensity. At low value, Str = 0 (dotted blue curves), and at high value, Str = 2.5 (dotted red curves), a steady-state level is observed for the different components, whereas at intermediate value, Str = 1 (green curves), sustained oscillations occur. The curves show the oscillatory behavior after the elimination of transients.
(B) Envelope of cAMP oscillations as a function of stress intensity showing the maximum (red curve) and the minimum (blue curve) values during sustained oscillations. The variation of periodicity (green dots) is also shown.
(C) Envelope of oscillations in Msn2 subcellular localization. The curves show the maximum values (Max) and minimum values (Min) for cytoplasmic Msn2 (in blue) and nuclear Msn2 (in red). Outside of the oscillatory range, the system reaches a stable steady state.
The curves have been obtained with the Berkeley Madonna program, by numerical integration of Equations S1–S4. Parameter values are given in Table S2. Initial conditions were as follows: GEFa 0.36, GAPa 0.5, RGTP 0.1, CYCLa 0.1, cAMP 1, R2C2 0.5, MC 0.25, MN 0.25, MCP 0.25, MNP 0.25, and PDEa 0.5.
... Lack of Oscillations in Mutants with Impaired Regulation of the cAMP-PKA Pathway
(A) Dynamics of Msn2-GFP in a mutant tpk2w(E235Q). The Y3399 strain has been transformed with plasmid pJL42 coding for MSN2-GFP. Similar results were obtained with the strain Y2857 [tpk2w(V218G)], whereas in the strain Y3398 [tpk2w(Q138E)], Msn2-GFP was always in the nucleus, presumably because the residual activity of PKA was lower. The sequence of pictures (above) and the kinetic curve (below) are given as in Figure 1, except that pictures were taken every 20 s.
(B) Dynamics of Msn2-GFP in a mutant ras1Δ, ras2Δ CRI4 (B). The F1D strain has been transformed with plasmid pGR213 coding for Msn2-GFP. The sequence of pictures (above) and the kinetic curve (below) are given as in Figure 1.
Contributors:Gianluca Gatti, Ivana Kovacic, Michael J. Brennan
Effects of the damping parameter ζs on the bifurcation curves given by Eq. (12a), depicted by a thick line and Eq. (12b), depicted by a thin line, defining the transition from one to three real solutions for the frequency-amplitude response of W, for ζ=0.03: ζs=0.005 (solid curve); ζs=0.03 (dash curve); and ζs=0.07 (dot curve).
... Effects of the damping parameter ζ on the bifurcation curves given by Eq. (12a), depicted by a thick line and Eq. (12b), depicted by a thin line, defining the transition from one to three real solutions for the frequency-amplitude response of W, for ζs=0.03: ζ=0 (solid curve); ζ=0.03 (dash curve); ζ=0.07 (dot curve); ζ=0.15 (dash-dot curve).
... FRCs of the normalized relative displacement W as a function of the normalized frequency Ω for ζs=0.046, ζ=0.015 and for different values of the nonlinear parameter γ: (a) γ=10‐5; (b) γ=10‐3; (c) γ=1.4×10‐3; (d) γ=10‐2; (e) γ=2.6×10‐2; and (f) γ=3×10‐2. Stable solution (blue solid line), unstable solution (red dashed line). Numerical solution by integrating Eqs. (5a,b) (black ‘○’). (For interpretation of the references to the colour in this figure legend, the reader is referred to the web version of this article.)
... FRCs of the normalized relative displacement W as a function of the normalized frequency Ω for ζs=0.046, ζ=0.026 and for different values of the nonlinear parameter γ: (a) γ=10‐5; (b) γ=10‐3; (c) γ=3.3×10‐3; (d) γ=10‐2; (e) γ=2.6×10‐2; and (f) γ=3×10‐2. Stable solution (blue solid line), unstable solution (red dashed line). Numerical solution by integrating Eqs. (5a, b) (black ‘○’). (For interpretation of the references to the colour in this figure legend, the reader is referred to the web version of this article.)
Contributors:Stanislav Koulchitsky, Charlotte Delairesse, Thom Beeken, Alexandre Monteforte, Julie Dethier, Etienne Quertemont, Rolf Findeisen, Eric Bullinger, Vincent Seutin
Maximal power (means of normalized values ± SEM), and corresponding frequencies (means ± SEM) of the LFP oscillation recorded in the different groups at the period from the 10th to the 30th min after the injection. For the low-dose quinpirole + cocaine group the period is taken after the second injection.
... Scheme of the general experimental protocol and data analysis. Electrophysiological recordings were performed for 45 min in the baseline and for 60 min after the drug injections. Note that in the case of co-administration of quinpirole and cocaine, there were two injections with a 15 min interval. Upper area: For spectral power analysis of the LFPs we took 20 min periods starting from 10th min after the injection (see Fig. 2 for results). Lower area: To exclude the possible effect of the variations in locomotor velocity on the theta frequency, we extracted locomotor bouts, 10 s each, with similar patterns across groups, and took the corresponding LFP segments for frequency analysis and comparison (see Fig. 3 for results). Squared inset on the left side represents the scheme of the locomotor bout.
... Local field potential characteristics during the locomotor bouts in the different groups. Scatter plots depicting the frequency of the peak power (X axis) and the peak power normalized to the average power (Y axis), calculated for the 10 s LFP segments. In each panel, individual values during various drug regimens are compared to the values of the saline group (crosses, represented in each panel for comparative purposes). In addition, the area occupied by the saline values is outlined by the dashed line and filled in gray. Insets show the corresponding 10 s locomotor bouts. The number of segments used and the statistical values are indicated in Table 2.
... Maximal power (means of normalized values ± SEM), and corresponding frequencies (means ± SEM) of the LFP oscillation in the different groups, calculated for the LFP segments corresponding to the 10 s locomotor bouts.
... Electrophysiological effects of various drug regimens. A to D. Averaged power spectral densities of the LFPs recorded from the 10th to the 30th min after the injection in the different groups. Vertical dashed lines mark the peaks of frequency power in the saline and low-dose quinpirole + cocaine groups, respectively. Squared insets at the right side of each graph are schemes of the open-field arena with a corresponding example of the locomotor trajectories. The degree of significance versus the saline group is represented as °°p frequency).