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	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

In a recent study, Yoon et al¹ investigated heart rate (HR) control before and after intracarotid amobarbital injection by means of spectral analysis. There are several methodological problems we would like to comment on.

As the authors stated, HR oscillations in the high-frequency (HF) band (0.15-0.4 Hz) are purely mediated by parasympathetic efferents at least for the supine position.^2-4 Low-frequency (LF) oscillations in HR (0.04-0.15 Hz) were thought to reflect "predominantly sympathetic" activity. Several studies using pharmacological autonomic blockades have shown, however, that there is little^2-3 if any⁴ sympathetic contribution to the LF band of HR for the supine position. The assumption that the LF/HF ratio provides a measure of "sympathovagal balance" seems even more problematic, particularly for the supine position.⁴ This approach would have been more appropriate if LF and HF oscillations were indicators of a stable sympathetic and parasympathetic tone, respectively, only modulated by cerebral hemispheric control. This . . . [Full Text of this Article]