Slowly Changing Potential Modified by Controlled Respiratory Cycle

Abstract

The present study was designed to investigate the effect of respiration upon slowly changing potential (SCP) using controlled respiratory cycles. EEG and respiration were monitored under 3 different respiration conditions, 7.5, 15, and 30 cycles per min. The results indicated that SCP amplitude decreased as a function of respiration rate. Cross-correlation analysis also showed that SCP variation is correlated with respiration phase. Considering these results, it was suggested that respiratory phase is a variable to be controlled in studies of contingent negative variation (CNV) and other slowly changing potentials.Walter, Cooper, Aldridge, McCallum, and Winter (1964) first reported the existence of the contingent negative variation (CNV) utilizing the simple reaction time paradigm, in which a warning stimulus is followed by an imperative stimulus to which the S has been instructed to respond. Since then, a number of studies concerning CNV have been reported and they were reviewed by Tecce (1972) who showed that CNV is related to the psychological factors of expectancy, conation, motivation and attention. As CNV is a slowly changing potential (SCP), a d.c. or a.c. amplifier with long time constant must be used for recording this potential. In analyzing the recordings, an increased attention should be called to the fact that recordings by this method are vulnerable to slow potential artifacts arising in the organism as evidenced by the current studies (Tecce, 1972). The most serious artifacts for CNV result from eyeball and eyelid movements, artifacts of which can be eliminated by several techniques (Hilyard, 1974). The other movements, however, might generate slow potential shift at scalp. There is a possibility that respiration modifies the activity of nervous system, since Pitts (1946) has postulated an influence of the inspiratory center over ascending brain-stem activating mechanisms. No systematic study, however, has been done on the relationship between SCP and respiration. In order to investigate this relationship in a systematic way, a controlled respiration technique was employed in this experiment. The present study was, therefore, designed to investigate the effect of respiration upon SCP in the controlled respiratory cycles. METHODSubjects. The Ss were 12 college students; all had participated in previous experiments of CNV. Three of them were discarded from analysis, because of failure to control respiration.Apparatus. The EEG for measuring SCP was recorded between vertex and right earlobe sites using Beckman bio-potential electrodes.Respiration was recorded by a San'ei thermofor Scientific Researches (#131038), Ministry of Education.2 Appreciation is expressed to Takashi Matsuda and Naomasa Nomura for their assistance in conducting this experiment.

The effects of respiration rate on contingent negative variation during a relaxation method (Self-Regulation Method)

“…Thus, respiration may play an important role in such methods. A few studies have shown the association between respiration and CNV (Gullickson & Darrow, 1973;Kakigi. Hagino, Mori, & Tominaga, 1976: Roithak, Dedahrishvili, Gotsiridze, 1977.…”