It’s not unusual to hear people describe themselves as emotionally 'colder'

It’s not unusual to hear people who have undergone sympathectomies describe themselves as feeling emotionally “colder” than before. Among psychologists and neurologists alike there is concern, but no evidence, that the procedure limits alertness and arousal as well as fear, and might affect memory, empathy and mental performance. Professor Ronald Rapee, the director of the Centre of Emotional Health at Sydney’s Macquarie University, says he’s counselled several people who complain of feeling “robot-like” in the long-term wake of the operation. “They’re happy they no longer blush, but they miss the highs and lows they used to feel.”
(John van Tiggelen, Good Weekend Magazine, The Age and the Sydney Morning Herald, 10th March 2012)
https://archive.today/uURge

Thursday, 28 May 2015

Middle cerebral artery blood velocity during exercise with beta-1 adrenergic and unilateral stellate ganglion blockade in humans

 2000 Sep;170(1):33-8.

Middle cerebral artery blood velocity during exercise with beta-1 adrenergic and unilateral stellate ganglion blockade in humans.

Abstract

A reduced ability to increase cardiac output (CO) during exercise limits blood flow by vasoconstriction even in active skeletal muscle. Such a flow limitation may also take place in the brain as an increase in the transcranial Doppler determined middle cerebral artery blood velocity (MCA V(mean)) is attenuated during cycling with beta-1 adrenergic blockade and in patients with heart insufficiency. We studied whether sympathetic blockade at the level of the neck (0.1% lidocaine; 8 mL; n=8) affects the attenuated exercise - MCA V(mean following cardio-selective beta-1 adrenergic blockade (0.15 mg kg(-1) metoprolol i.v.) during cycling. Cardiac output determined by indocyanine green dye dilution, heart rate (HR), mean arterial pressure (MAP) and MCA V(mean) were obtained during moderate intensity cycling before and after pharmacological intervention. During control cycling the right and left MCA V(mean) increased to the same extent (11.4 +/- 1.9 vs. 11.1 +/- 1.9 cm s(-1)). With the pharmacological intervention the exercise CO (10 +/- 1 vs. 12 +/- 1 L min(-1); n=5), HR (115 +/- 4 vs. 134 +/- 4 beats min(-1)) and delta MCA V(mean) (8.7 +/- 2.2 vs. 11.4 +/- 1.9 cm s(-1) were reduced, and MAP was increased (100 +/- 5 vs. 86 +/- 2 mmHg; P < 0.05). However, sympathetic blockade at the level of the neck eliminated the beta-1 blockade induced attenuation in delta MCA V(mean) (10.2 +/- 2.5 cm s(-1)). These results indicate that a reduced ability to increase CO during exercise limits blood flow to a vital organ like the brain and that this flow limitation is likely to be by way of the sympathetic nervous system.

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