A report by Buhr et al. (2010) proposed that the suprachiasmatic nucleus (SCN) is resistant to phase shifts induced by heat pulses and to entrainment by temperature cycles. These findings are inconsistent with those from studies by other laboratories in which the SCN readily phase shifts in response to heat pulses. I propose that their negative findings are not due to the SCN being temperature insensitive but are based on an explant culture preparation that does not fully express the properties of the SCN that are present in other in vitro preparations.

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