Brain mechanisms of anxiety

Journal/Book: N Z J Psychol. 1995; 24: Business Manager, PO Box 4092, Wellington, New Zealand. New Zealand Psychol Soc. 11-18.

Abstract: This paper suggests a mapping of elements of anxiety to a hierarchically organized set of neural structures. Panic attacks are viewed as occupying the lowest level controlled by the periaqueductal greay. Phobia is viewed as occupying the next level controlled, principally, by the amygdala. Anxiety proper (i.e. the anxiety which can exist in the absence of panic but which can also accompany panic) is controlled by the septo-hippocampal system which not only has descending links to the amygdala but also ascending links to prefrontal and cingulate cortex. Obsessions and compulsions are held to depend on activity in the cingulate cortex and basal ganglia respectively - and particularly on the reciprocal interactions between these structures. It is also assumed that they can occur independently of anxiety. While, on this view, anxiety proper is fundamentally associated with the septohippocampal system (and the monoaminergic afferents to it), the prefrontal cortex is also a key structure for the more cognitive aspects of anxiety. A crucial point about this hierarchical system is that each level is reciprocally connected to the next, and the higher cortical levels have direct descending connections to the lowest levels. On this view anxiety disorders will often involve (but need not necessarily involve) a mixture of panic, obsession and anxiety proper. Further superficially similar anxiety syndromes could, in principle, be produced by quite different aetiologies because of the strong dialectical links between the different levels of the system.

Note: Article N Mcnaughton, Univ Otago, Dept Psychol, POB 56, Dunedin, New Zealand

Keyword(s): HIPPOCAMPAL THETA RHYTHM; SLOW ACTIVITY; ANXIOLYTIC DRUGS; PLACE NAVIGATION; RATS; CHLORDIAZEPOXIDE; DISCRIMINATION; PERFORMANCE; FREQUENCY

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