Pain-related evoked potentials are modulated across the cardiac cycle

Evidence suggests that the arterial baroreceptors modulate pain. To examine whether cortical processing of nociception is modulated by natural variations in arterial baroreceptor stimulation during the cardiac cycle, peak-to-peak amplitudes of the N2–P2 pain-related potential and pain ratings were recorded in response to noxious laser stimulation at different times during the cardiac cycle in 10 healthy males. Significant variations in the N2–P2 amplitudes occurred across the cardiac cycle, with smaller amplitudes midcycle, indicating that cortical processing of nociception was attenuated during systole compared to diastole. Pain ratings did not vary across the cardiac cycle. These data support the hypothesis that arterial baroreceptors modulate the processing of nociception during each cardiac cycle

Stimuli used in this study.

<p>Stimuli used in this study.</p

The averaged clustering coefficient over the entire network (functional segregation).

<p>The averaged clustering coefficient decreased during attentional control versus the baseline interval.</p

Betweenness centrality (global hub).

<p>Higher centrality was observed in the sensori-motor and prefrontal regions throughout the periods tested.</p

Time-frequency analysis.

<p>Zero on the horizontal axis indicates the onset of target stimuli. Data are expressed in color-coded images as a change relative to the baseline interval. Power increases and decreases are shown in red and blue, respectively.</p

Asymmetric lateral inhibitory neural activity in the auditory system: a magnetoencephalographic study-2

<p><b>Copyright information:</b></p><p>Taken from "Asymmetric lateral inhibitory neural activity in the auditory system: a magnetoencephalographic study"</p><p>http://www.biomedcentral.com/1471-2202/8/33</p><p>BMC Neuroscience 2007;8():33-33.</p><p>Published online 17 May 2007</p><p>PMCID:PMC1884167.</p><p></p> each NFN (NFN1 to NFN5). Error-bars denote the 95 % confidence interval limits for the group means. White and gray bars represent responses from the left and right hemispheres, respectively

Mean (±SD) error rate (%) for each band-eliminated noise (BEN) condition.

<p>Mean (±SD) error rate (%) for each band-eliminated noise (BEN) condition.</p

Normalized N1m source strength.

<p>The graphs display the group means (N = 13) of the normalized N1m source strengths for each band-eliminated noise (BEN) condition during distracted (left panel) and focused (right panel) listening. Open and filled circles represent the exposed and control groups with the error bars denoting the 95% confidence limits.</p

Models of population-level frequency tuning.

<p>Left and right columns represent schematic illustrations of normal and broadened population-level frequency tuning. The three differently colored areas represent, (i) neural activity elicited merely by band-eliminated noises (BEN: light gray areas), (ii) neural activity elicited merely by test pure tones (TS: dark gray areas), and (iii) neural activity elicited by both BEN and TS (black areas). The rows represent wide (top: 1 critical band (CB)), middle (medium: 1/2 CB), and narrow (bottom: 1/4 CB) BEN conditions. The dark gray areas represent the N1m response amplitude as elicited by the TS-onset; the neural activity represented by the black areas has been masked by the simultaneously presented (but earlier on-setting) BEN. Notably, the dark gray areas (i.e., N1m amplitudes evoked by the TS) are less influenced by the eliminated bandwidths in case of normal frequency tuning compared to broadened frequency tuning, especially in the narrow BEN condition.</p

VEFs induced by bright light.

<p>A, Top view of MEG waveforms of a representative subject in Experiment 1. B, Location of the estimated dipole in the eye superimposed on a subject’s own MR image. C, Grand-averaged source strength waveforms of retinal activity.</p