Abstract
We investigated interaction between neural activities (I- or C-response) in rat somatosensory cortex evoked by ipsi-(I-stim) or contra-lateral electrical stimulation (C-stim) of the whisker face area, by recording electric field potentials (FP), fluorescence of voltage-sensitive dye or local changes in cerebral blood flow (reflection of 605 nm light). Stimulation are one single square pulses (0.2-3.0 mA, 0.5ms duration). Latencies [or latency of peak value] were 6.3-16 ms [9.5-26 ms] in C-response and 14-19 ms [15-35 ms] in I-response, decreased in parallel with intensity of C-stim, but were almost constant (16.4 ± 1.7ms) [23.5 ± 4.2] with I-stim. Peak value increased in parallel with intensity of both I- and C-stimulation, but their time course differed between I- and C-responses. Area of the FP increased proportionally with intensity of C-stim, but they dispersed much with I-stim. When used at intensity of a half of max value of stimulation (1/2 T), C-response (or I-response) were suppressed for 90-100 ms after I-stim (or C-stim), and recovered within 150-200 ms. Similar results were obtained with fluorescence-recording and 605nm light reflection. [Jpn J Physiol 55 Suppl:S181 (2005)]
