Biology Reference
In-Depth Information
11
Defence and Defeat Reaction:
Central Control and Peripheral
Effects
Ingibjörg H. Jonsdottir
1,2
, Björn Folkow
2
1
Institute of Stress Medicine, Flölunda, Sweden,
2
Institute of
Neuroscience and Physiology, Department of Physiology, The
Sahlgrenska Academy, Göteborg University, Göteborg, Sweden
11.1 Introduction
When the sophisticated psychosocial challenges of today's modern life evoke
human emotion, they engage the same age-old behavioural-neuroendocrine response
patterns, which in primitive life serve to protect self and species (
Figure 11.1
).
These response patterns are since eons-of-time imprinted in the limbic-amygdala-
hippocampus section of the mammalian brain (paleocortex), as well as in the subor-
dinate hypothalamic and brainstem centres. Among these patterns are the so-called
defence and defeat reactions which are our age-old emotional response patterns,
intended to reinforce behavioural expression such as running away or fight.
Largely all parts of the brain are engaged in the control of emotion and their
expressions, and the somatomotor-behavioral, autonomic and neuroendocrine effer-
ent links are in various ways combined into “triads-of-expression”; designed to cope
with whatever challenge and threats life can offer. The difference between humans
and other species depends particularly on our sophisticated neocortex, allowing us
to intellectually cope with different situations. Further, once emotions are induced,
we can learn, at least to certain extent, to voluntarily suppress or modify the somato-
motor-behavioural responses, while the autonomic and hormonal expressions cannot
be suppressed voluntarily in the same manner. Therefore, if often repeated, the acti-
vation of these emotional response patterns may in the long run have sinister con-
sequences, as largely all tissues and organ systems, including the immune system,
become exposed to neuroendocrine mobilisations that no longer serve to support
fight or flight and physical exertion, and hence could disturb the balance in physi-
ological systems or “homostasis”, to use Walter Bradford Cannon's term
[1]
.
There is now increasingly strong evidence that chronic activation of physiologi-
cal stress responses can contribute to several lifestyle related disorders, like primary
(essential) hypertension and the so-called metabolic syndrome (abdominal obesity,
