Abstract
D.Litt. et Phil.
The condition known as hypertensive encephalopathy has thrust high
blood pressure as a factor in cognitive dysfunction into the limelight. The
present study seeks to explore this phenomenon, the allied
considerations of adrenergic activation and blockade (as induced by the
class of anti-hypertensives termed beta-adrenergic antagonists) and their
relationship with attention and memory. The main impetus for the thesis
derives from the disparate results of studies into the functioning of
attention and memory processes in both medicated and unmedicated
hypertensives, despite consistent outcomes having emerged from animal
studies. An integrative, explanatory psychophysiological model 1s
consequently developed to help illuminate this scientific terrain.
The study constitutes an analysis of the course and pathogenesis of
hypertension, with a specific emphasis on factors that maintain the
disease as well as those that serve to lessen its adverse health effects.
The association between hypertension and sympathetic nervous system
activation receives much attention together with relevant personality and
behavioural variables. It is discussed how sympathetic nervous system
activation and the failure of certain negative feedback mechanisms relate
to hypertension as well as memory consolidation.
The disparate study outcomes and explanations regarding the connection
between adrenergic activation and memory are traced to certain
paradigmatic roots. These include the computer analogy of mental
functioning, Cartesian dualist notions and the case of 'HM'. In contrast
to, notably, the Cartesian dualist notions, it is shown that body and
brain are a necessary unity for memory formation. This unity is
explicated through an analysis of baroreceptor function as an example of
a 'simple' cybernetic system involved in maintaining regulated cerebral
blood flow.