Transient BP spikes coupled to learning in brain

Date:
February 14, 2022
Source:
University of Gothenburg
Summary:
Minor everyday rises in blood pressure due to short-term stressors
can be linked to a brain area that controls conscious and learned
motor skills.

This discovery paves the way for a chance to influence the rises
in blood pressure and, in the long run, prevent hypertension.



FULL STORY ========================================================================== Minor everyday rises in blood pressure due to short-term stressors
can be linked to a brain area that controls conscious and learned motor
skills. This discovery, presented by University of Gothenburg researchers, paves the way for a chance to influence the rises in blood pressure and,
in the long run, prevent hypertension.


==========================================================================
In roughly half of all people with hypertension -- persistently high
blood pressure (BP) -- there is no known cause. One plausible theory
is, however, that hypertension might be the result of a long period of
many recurrent BP peaks. Hundreds or thousands of micro-stress events
may occur daily -- the telephone ringing, a car horn sounding in the
street -- with BP spiking every time as a result.

For nearly 20 years now, a University of Gothenburg research group has
been investigating how this kind of micro-stress affects nerve signals
to our muscles and the throughput (perfusion) of blood in their vessels
(muscle vasculature). In half of the over 150 men included in the group's studies to date, the pattern of their reaction system leads to BP peaks,
while for the other half the reactions taking place in their bodies do
not bring about any change in BP.

Ultramodern brain-imaging techniques The latest results are published in Scientific Reports. For the study, 20 men aged 19-45 were examined. The experiment involved triggering a response in the nervous system with
unexpected electric shocks that emulate the sudden and/or stressful
stimuli to which we are exposed daily. The researchers combined two
measurement methods. In one, a traditional research technique called microneurography, very thin needle electrodes are used to probe the
signaling in nerve fibers (specifically, muscle sympathetic nerve
activity, MSNA) directed to the vascular bed (blood vessels) of the
muscles. The other was a modern brain-imaging technique known as magnetoencephalography (MEG).

For the first time, the researchers can now link the increased
susceptibility to micro-stress to a reflex-like signal in the brain. The
brain area (the "rolandic area") that activates the signal controls
several conscious brain functions. This finding opens the question
of whether the BP peaks may be learned and could therefore also, with
training, be eliminated.



==========================================================================
"We see a surprisingly strong connection between the peripheral autonomic vascular reaction, which takes place subconsciously, and a reaction
pattern - - one that was already previously well known -- in a part of
the brain where emotional impressions and motor skills undergo conscious interpretation. This raises questions about how independently the
'autonomic nervous system', as it's called, really works," says Mikael
Elam, Professor of Clinical Neurophysiology at Sahlgrenska Academy,
University of Gothenburg.

Long road ahead to clinical use The idea that the discovery might come
to be used to prevent hypertension is not unrealistic, but much research remains to be done.

"If we can develop ways of boosting the signal-to-noise ratio, in the
future it may be possible to extract the relevant brain signals from a
regular electroencephalogram [EEG], which is available in every Swedish hospital today.

That would enable us, at an early stage, to identify people who react
with BP spikes before they develop hypertension. Many other opportunities
for preventive measures and research would then follow," says Justin Schneiderman, Senior Lecturer in experimental multimodal neuroimaging
at Sahlgrenska Academy, University of Gothenburg.

Environmental factors decisive Interestingly, our environment seems to
matter more than our genetic code when it comes to which reaction pattern
we develop, and thus whether we experience many daily BP spikes or not. An earlier study by the research group on identical twins showed that basic activity in the twins' blood-vessel- regulating autonomic nervous systems
was very similar, while their stress- triggered reactions diverged.



==========================================================================
"One may speculate that, today, many people have learned to suppress
the primitive fight-or-flight response, since it's not that relevant in
modern society. It's an impulse that prepares us for action, by reducing
the vasoconstrictor nerve activity and thereby increase blood flow in
the muscles.

In terms of long-term health consequences, it might be beneficial to
preserve the old flight-or-fight impulse in response to sudden stressors,"
Elam ponders.

A wide-ranging collaboration The research group hopes to be able to
facilitate studies at the population level, monitoring large groups of
people over a long period. This would enable investigation of, first,
whether individuals with reaction patterns that cause many peaks in
blood pressure during the day are indeed at increased risk of developing hypertension later in life and, second, whether influencing this reaction pattern is feasible.

The research that maps the biological processes and signals controlling autonomic regulation of our blood vessels is taking place in a
wide-ranging collaboration involving the University of Gothenburg,
Sahlgrenska University Hospital, and Chalmers University of Technology.

FACTS ABOUT HYPERTENSION
* Hypertension (chronically high BP) is the main treatable cause
of illness
and death worldwide.

* The risk of developing hypertension is affected by many different
factors, including obesity, smoking, type 2 diabetes, and kidney
disease.

In about half of cases, however, an underlying explanation is
lacking.

* It may take up to some 15 years to develop hypertension, a condition
defined as sustained systolic BP of 140 mmHg (millimeters of
mercury, a unit for measuring blood pressure) or higher, or
diastolic pressure of 90 mmHg or higher.

* Hypertension elevates the risk of several dangerous illnesses,
such as
heart attack and stroke, and of premature death.

special promotion Get a free digital "Metabolism Myths"
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always get wrong about diet and exercise. Claim_yours_now_>>> ========================================================================== Story Source: Materials provided by University_of_Gothenburg. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Bushra Riaz, John J. Eskelin, Linda C. Lundblad, B. Gunnar Wallin,
Tomas
Karlsson, Go"ran Starck, Daniel Lundqvist, Robert Oostenveld,
Justin F.

Schneiderman, Mikael Elam. Brain structural and functional
correlates to defense-related inhibition of muscle sympathetic
nerve activity in man.

Scientific Reports, 2022; 12 (1) DOI: 10.1038/s41598-022-05910-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214111815.htm

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