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Biomedical subjects

Jean Faber

Publications and source records attributed to Jean Faber.

4 recordsLinked to original sources
PubMed2005

Information processing in brain microtubules.

Models of the mind are based on the idea that neuron microtubules can perform computation. From this point of view, information processing is the fundamental issue for understanding the brain mechanisms that produce consciousness. The cytoskeleton polymers could store and process information through their dynamic coupling mediated by mechanical energy. We analyze the problem of information transfer and storage in brain microtubules, considering them as a communication channel. We discuss the implications of assuming that consciousness is generated by the subneuronal process.

Biophysical Phenomena↗
PubMed2004

Quantum models of the mind: are they compatible with environment decoherence?

Quantum models of the mind associate consciousness with coherent superposition of states in the brain. Some authors consider consciousness to be the result of a kind of internal quantum measurement process in the brain. In this paper we discuss the ideas of Hameroff-Penrose and Tegmark and their calculation for an estimate of decoherence time. We criticize the Hameroff-Penrose model in the context of a quantum brain model by gravitational collapse orchestrated objective reduction (OOR), assumed by Penrose, and we propose instead that the decoherence process is caused by interaction with the environment. We consider it useful to exploit this possibility because of the growing importance of the decoherence theory in quantum measurement, and also because quantum mechanics can be applied to brain study independently of the Hameroff-Penrose model for mind and consciousness. Our conclusion is that the Hameroff-Penrose model is not compatible with decoherence, but nevertheless the quantum brain can still be considered if we replace gravitational collapse OOR with decoherence. However, our result does not agree with Tegmark's conclusion of refuting not only the Hameroff-Penrose gravitational collapse but also the quantum brain, based on decoherence time calculations in specific cases in the brain. In spite of this fact we also disagree with some points of the response to Tegmark's article given by Hagan, Hameroff, and Tuszynski.

Adaptation, Physiological↗
PubMed2004

Synchronous lesions detected by autofluorescence bronchoscopy in patients with high-grade preinvasive lesions and occult invasive squamous cell carcinoma of the proximal airways.

The cancerization field concept implies that lung cancer multicentricity may be a frequent event and primary studies using white-light bronchoscopy (WLB) have reported a high prevalence of multicentricity in patients with roentgenographically occult lung cancer. We have used autofluorescence bronchoscopy (AFB) to reassess the prevalence of synchronous lesions in patients referred for the staging and/or treatment of occult lesions initially detected during WLB. All the patients referred with high-grade preinvasive lesions (severe dysplasia, DYS S and carcinoma in situ, CIS) and occult invasive squamous cell carcinoma (CIV) of the bronchus initially detected during WLB at other centers, underwent AFB. Data were prospectively collected and retrospectively analyzed to assess the prevalence of synchronous occult lesions. From January 1996 to December 2001, 28 patients (26 males, 2 females; mean age: 65 +/- 11) were assessed. After re-evaluation, in two cases, the referred lesions corresponded only to metaplasia and were discarded from analysis. The 26 other patients were referred for 28 lesions (3 DYS S, 19 CIS and 6 CIV; 2 patients were referred with two synchronous lesions). AFB revealed, in these 26 patients, six additional lesions (1 DYS S, 4 CIS and 1 CIV). Multicentricity in this group, initially estimated to amount to 7% with WLB alone, raised to 23% by using AFB. The high prevalence of synchronous lesions in this series of patients with occult DYS S, CIS and occult CIV suggests that AFB may be a useful adjunct in the pretreatment evaluation.

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