Psychedelic Research

Roland Zahn and colleagues have published an interesting case report of a person who reportedly lost the implicit knowledge that his perceptions are not his own. Sadly, they do not report any neurocognitive tasks that might provides an objective correlate of the experience.

Psychopathological and neurological examinations revealed that D.P. did not see doubled objects in the literal sense – instead he described his sensations as follows: when looking at or concentrating on a new visual object, he is able to see the object as a single object, but that the way he perceived things had markedly changed in a way which he had never experienced before. It appeared to him that he was able to see everything normally, but that he did not immediately recognize that he was the one who perceives and that he needed a second step to become aware that he himself was the one who perceives the object. In contrast, his actions felt unchanged, and he was always immediately aware of his actions as the one who acts and perceives his body while acting.

Fig. 1. Significant areas of hypometabolism (voxel level: p = 0.01, uncorrected, 15 voxels for visual display; only areas surviving uncorrected p = 0.001 and familywise-error-corrected p = 0.05 over a 12-mm sphere around the peak voxel are reported in table 1 and text) for patient D.P. versus 12 normal controls are shown. Data were projected on a standard brain using MRIcron software (http://www.sph.sc.edu/comd/rorden/mricron/) [21] after statistical analysis using statistical parametric mapping software (SPM5, http://www.fil.ion.ucl.ac.uk/spm/) [22] , smoothing with a 12 ! 12 ! 12-mm Gaussian kernel and a global cerebral metabolic rate for glucose normalization to a mean of 50 mol/100 ml/min. A voxel-by-voxel t statistic for the detection of hypometabolic areas was computed [methods further described in 19 ].

To the authors’ knowledge, this is the first report of an isolated loss of the sense of self-ownership. As mentioned in the introduction the disappearance of such a phenom enon may serve as indirect proof of its previous existence, and indirectly points to an identifiable neurobiological basis. That means that this aspect of the ‘minimal self’ as a philosophical construct probably has a neurobiological basis that exists independently from philosophical theories. This finding thereby challenges the widely accepted philosophical conviction of the immunity to error through misidentification relative to the first-person pronoun [23, 24] , i.e. the access to my self in first-person experience is not necessarily immediate and non-observational, and it is not just a logical consequence of the structure of language and grammar. Instead, as shown in the case report, the access may involve a perceptual or reflective act of consciousness different from the notion of the immunity principle. Critics may argue that we did not describe a loss of self-ownership, since self-consciousness was only delayed but not abolished. However, the minimal self is defined by being unextended in time, and even if the sense of self-ownership was not lost entirely, at least its defining characteristics and quality were affected. Furthermore, our case shows an unexpected dissociation of an impaired sense of self-ownership only for perceptions of objects but not for perceptions of the own body and actions.

Zahn R, Talazko J, Ebert D.
Loss of the Sense of Self-Ownership for Perceptions of Objects in a Case of Right
Inferior Temporal, Parieto-Occipital and Precentral Hypometabolism
Psychopathology. 2008 Sep 25;41(6):397-402. Online preprint

Abstract: Philosophers define the ‘minimal self’ as the immediate awareness of being the agent and owner of one’s actions and perceptions. Here, we describe a patient with a selective loss of one part of this ‘minimal self’, namely the immediate sense of self-ownership for perceptions of objects. In contrast, his sense of self-ownership for body perceptions and for self-agency during actions remained intact. 18-Fluorodeoxyglucose positron emission tomography revealed predominantly right inferior temporal hypometabolism in comparison with healthy controls (parahippocampal and fusiform gyri). In addition, dysfunction of the right parieto-occipital junction and precentral cortex were detected. Taken together, we demonstrate selective changes in the quality of the sense of self-ownership for perceptions of objects but not actions and an intact sense of self-agency, which points to anatomically separable systems underpinning different aspects of the ‘minimal self’. The associated hypometabolism in inferior temporal, parieto-occipital and motor regions, but not in medial prefrontal areas most consistently associated with self-referential processing, are most parsimoniously explained when self-consciousness is not assumed to be an anatomically localized cognitive function, but instead is conceived as emerging from integration across anatomically distributed networks of regions with different functional specializations, not all of which need to be special for the ‘self’.