Levels of biological plausibility

Notions of mechanism, emergence, reduction and explanation are all tied to levels of analysis. I cover the relationship between lower and higher levels, suggest a level of mechanism approach for neuroscience in which the components of a mechanism can themselves be further decomposed and argue that scientists'' goals are best realized by focusing on pragmatic concerns rather than on metaphysical claims about what is ‘real''. Inexplicably, neuroscientists are enchanted by both reduction and emergence. A fascination with reduction is misplaced given that theory is neither sufficiently developed nor formal to allow it, whereas metaphysical claims of emergence bring physicalism into question. Moreover, neuroscience''s existence as a discipline is owed to higher-level concepts that prove useful in practice. Claims of biological plausibility are shown to be incoherent from a level of mechanism view and more generally are vacuous. Instead, the relevant findings to address should be specified so that model selection procedures can adjudicate between competing accounts. Model selection can help reduce theoretical confusions and direct empirical investigations. Although measures themselves, such as behaviour, blood-oxygen-level-dependent (BOLD) and single-unit recordings, are not levels of analysis, like levels, no measure is fundamental and understanding how measures relate can hasten scientific progress.This article is part of the theme issue ‘Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity''.     

Visfatin Levels in Subclinical Hypothyroidism

Alterations in thyroid function are associated with changes in body weight, metabolism, and low-grade inflammation abnormal thyroid function may be associated with disturbances in the production of adipokines also. Although there have been studies showing changes in visfatin levels in thyroid dysfunction, exact relationship between them was still unclear. Our aim was to evaluate serum concentrations of visfatin in patients with subclinical thyroid dysfunction before and after normalization of thyroid function tests. The study included 43 patients (mean age 50.1 ± 10.6 years) with subclinical hypothyroidism. Serum insulin, visfatin, TSH, free T4 (FT4) and free T3 (FT3) levels of subjects were analyzed. Visfatin levels were measured in all patients before starting therapy and after normalization of thyroid function. Serum visfatin levels of subclinical hypothyroid patients were 0.99 ± 0.45 and they were similar after normalization of thyroid function (p = 0.394). Serum visfatin levels were negatively correlated with FT4 levels before treatment (r = ?0.329 p < 0.05). There was no significant correlation between serum levels of visfatin and the serum levels of TSH and FT3. Serum visfatin levels did not correlate with insulin, fasting blood glucose, total cholesterol, HDL cholesterol, LDL cholesterol and triglyceride levels. In this study, it was shown visfatin levels did not change after replacement therapy in patients with subclinical hypothyroidism. Subclinical hypothyroid state may be an earlier stage regarding the changes of adipocytokines specifically the visfatin secretion as seen in overt hypothyroidism.     

Levels of labile phosphorus-containing metabolites

The work deals with the investigation of possible use of 31P-NMR for revealing metabolism changes in the mouse liver during the development of leukemia. This method was shown to permit observation of the extreme pattern of relative concentrations of sugar phosphate and bioorganic phosphate in the latent period. This observed increase in the metabolic activity of hepatocytes correlates with biophysical shifts found by other methods.     

Radiofrequency Exposure Levels in Greece

Medical Physics Department (Medical School, University of Thessaly) participated in a Greek National EMF research program (EDBM34) with the scope to measure and evaluate radiofrequency (RF) exposure (27–3000 MHz) in areas of sensitive land use. A thousand (1000) measurements were carried out at two “metropolitan locations” (Athens and Thessaloniki: 624 points) and several rest urban/rural locations (376 points). SRM 3006 spectrum analyzer manufactured by Narda Safety Test Solutions was used. The broadband mean electric field in metropolitan areas was 0.41 V/m, while in the rest of Greece was 0.36 V/m. In metropolitan areas, the predominant RF source was the TV and Radio FM signals (36.2% mean contribution to the total RF exposure level). In the rest areas, the predominant source was the systems of the meteorological and military/defensive service (31.1%). The mobile sector contributed 14.9% in metropolitan areas versus 12.2% in the rest of Greece. The predominant mobile source was 900 MHz in both cases (4.5% in metropolitan areas vs. 3.3% in the rest of Greece). The total exposure from all RF sources complied with the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 2020 safety guidelines [ICNIRP, 2020]. The maximum exposure level was 0.129% of the limit for the metropolitan areas vs. 0.110% for the rest of Greece. Nonremarkable differences between metropolitan areas' exposure and the rest of Greece. In most cases, new 5 G antennas will be added to the existing base stations. Thus, the total exposure may be increased, leading to higher safety distances. © 2023 Bioelectromagnetics Society.