Review ArticlesIs Alexithymia the Emotional Equivalent of Blindsight?
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The Nature of Alexithymia
A fundamental tenet of psychosomatic medicine is that interference with the experience and expression of emotions can have an adverse affect on health (Taylor 1987). Early in this century it was observed that the onset and course of certain physical diseases were adversely affected by the repression of certain conflictual ideas and their accompanying affects (Alexander 1950). A later alternative view was that a deficit or developmental arrest in the capacity for symbolic mental representation
The Functional Commissurotomy Model of Alexithymia
The association between alexithymia and physical disease has led to a search for the physiological mechanisms responsible for this association. A fundamental assumption in alexithymia research is that the deficit in the capacity for symbolic representation of emotion is somehow associated with an alteration in the normal physiology of emotion. To the extent that alexithymia is associated with physiological dysregulation, this dysregulation may arise from an alteration in the functional
Alexithymia as a Deficit in the Conscious Awareness of Emotion
An alternative view is that the fundamental deficit in alexithymia is a limited, and in extreme cases nonexistent, ability to consciously experience emotion. This view is consistent with the previous focus on a symbolization deficit in alexithymia to the extent that the way language is used to describe something may influence the nature of conscious experience in that area.
Wine tasting can be used to illustrate this association between language and conscious awareness. Solomon (1990)compared
The Role of the Anterior Cingulate Cortex in the Conscious Experience of Emotion
Given that the biological basis of consciousness is unknown at present, any model addressing the neuroanatomical basis of the conscious awareness of emotion must be speculative; however, clues to the underlying functional neuroanatomy of emotional awareness come from a positron emission tomography (PET) study of emotion by Lane et al 1996, Lane et al 1997).
Subjects included 12 right-handed female volunteers who were free of medical, neurological, or psychiatric abnormalities. The LEAS and other
Blindsight
The finding that emotional awareness is correlated with BF in the ACC during emotion raises the possibility that alexithymia may be associated with a deficit in ACC activity during emotional arousal. As such, alexithymia may be conceptualized as the emotional equivalent of blindsight.
Blindsight is a fascinating phenomenon associated with lesions in the primary visual cortical receiving area, V1 (Weiskrantz 1986; Cowey and Stoerig 1991). Patients with such lesions claim that they are blind. Yet,
Comparison with Other Neurological Lesions Affecting Emotion
This conceptualization of alexithymia as a phenomenon analogous to blindsight may be further elucidated by comparing and contrasting it with other neurological lesions associated with abnormal emotional behavior (Cummings 1985). These conditions include pseudobulbar palsy, orbitofrontal lesions, aprosodia, anosagnosia, and commissurotomy.
Pseudobulbar palsy is a condition manifested by uncontrolled expression of emotion, typically pathological crying or laughter, due to bilateral lesions of the
Testing the Blindfeel Hypothesis
The current hypothesis is presented in the context of an emerging view within the scientific community that consciousness is a valid subject for scientific investigation (Horgan 1994). Indeed, blindsight is one of several neurological phenomena (Crick 1994) that has contributed to this emerging consensus.
To demonstrate that the ACC is critically involved in mediating alexithymic phenomena, it will be necessary to adopt a two-pronged approach. First, lesions of the ACC must be shown to be
Discussion
The phenomenon of blindsight introduces the possibility that a deficit in conscious awareness could be due to a circumscribed, strategically located lesion. This observation has been extrapolated to alexithymia through the assumption that alexithymia arises from disruption of transmission of interoceptive emotional information to the ACC. As such, the proposed model is one of a disconnection syndrome rather than circumscribed pathology of the ACC, although the latter could theoretically produce
Acknowledgements
This work was supported by Research Scientist Development Award MH00972-02 from the National Institute of Mental Health to RDL. The authors thank Eric M. Reiman, MD for his valuable comments, Paul Bloom, PhD for his assistance with issues involving thought, language, and consciousness, and an anonymous reviewer who encouraged us to integrate recent findings in the latter areas into the manuscript.
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