Synchrony

Statistics in general is a discipline dealing with ideas on description of data, implications of data (relation to general pharmacological models), and questions such as what effects are real and what effects are different Biological systems are variable. Moreover, often they are living. What this means is that they are collections of biochemical reactions going on in synchrony. Such systems will have an intrinsic variation in their output due to the variances in the... 

Bacillus thuringiensis produces a variety of organic compounds which are toxic to the larvae of certain susceptible insect hosts. Among the toxic entities are proteinaceous crystals, probably three soluble toxins, and certain enzymes. The protein material is the major toxin active in killing lepidopterous larvae. The protein is formed by the cells apparently in close synchrony with sporulation, and its nature is a constant function of bacterial strain. The mode of action of the protein is under study. The sequence of events in the pathology observed is probably solubilization of the crystal (enzymatic or physical)—>liberation of toxic unit—>alteration of permeability of larval gut wall— change in hemolymph pH—>invasion of hemolymph by spores or vegetative cells of the bacterium. 

Oscillations in the EEG of between 0.5 and 4 Hz, sometimes also called delta activity. SWA is a hallmark of the sleeping brain, and is most prevalent in the deepest sleep stages (stages 3 4). The slow oscillations arise from widespread synchrony of neuronal firing, particularly in the thalamocortical circuits. 

The synchronised oscillatory activity between the intrinsically linked thalamus and cortex. Under normal circumstances there is a level of activity which changes during the sleep-wake cycle increasing during periods of slow wave sleep. Excess synchrony occurs in conditions such as epilepsy. Thiazolidinedione... 

These chemical constituents all vary in synchrony and two climatic states as defined by temperature coincide with the "climatic states"... 

Fellin T, Pascual O, Gobbo S, Pozzan T, Haydon PC, Carmignoto G (2004) Neuronal synchrony mediated by astrocytic glutamate through activation of extrasynaptic NMDA receptors. Neuron 43 729-743... 

Ascending inputs from the brainstem ascending reticular activating system (ARAS). As described below, these seem to be particularly important and probably disrupt the thalamo-cortical synchrony. 

Figure 22.5 Pathways involved in cortico-thalamic synchrony and EEG arousal. The ascending reticular activating system (ARAS) extends from the cephalic medulla through the pons and midbrain to the thalamus (see Moruzzi and Mayoun 1949). It is activated by impulses in collaterals of the spinothalamic sensory pathway running to specific thalamic nuclei (SpThNc) and in turn activates much of the cortex, partly through the non-specific thalamic nuclei (NspThNc), which also receive inputs from SpThNc and also via the nucleus basalis (NcB). Its stimulation is followed by EEG arousal. It is probable that reciprocal links between cortical areas and the thalamus, particularly NspThN, lead to slow-wave (8 Hz) cortical EEG synchrony and, in the absence of appropriate sensory input and ARAS activity, a sleep state...

Augment, or more probably, break up thalamic-cortico synchrony and its tendency to promote slow-wave EEG activity and non-REM sleep. Whether this results in full arousal, or merely a temporary disruption of sleep to give REM periods without full awaking, will depend on the balance of inputs and the overall state of cortical activity. 

Setting aside the general anaesthetics, which do not directly modify the function of any particular neurotransmitter, all the drugs that are used to induce sleep, i.e. the hypnotics , augment the function of GABA and so directly depress neuronal function and probably facilitate cortico-thalamic synchrony. Most of them are benzodiazepines... 

Bronson F. and Marsden H.M. (1964). Male-induced synchrony of estrus in Deermice. Gen Comp Endocr 4, 634-637. 

McClintock M. (1983). Pheromomal regulation of the ovarian cycle enhancement, suppression and synchrony. In Pheromones and Reproduction in Mammals (Vandenberg J.G., ed.). Academic Press, New York, pp. 113-150. 

Morofushi M., Shinohara K.F.T. and Kimura F. (2000). Positive relationship between menstrual synchrony and ability to smell 5alpha-androst-16-en-3alpha-ol. Chem Senses 25, 407-411. 

Thompson K.V. (1995a). Flehmen and birth synchrony among female Sable Antelope, Hippotragus niger. Anim Behav 50, 475-484. 

Weller L. and Weller A. (1993). Human menstrual synchrony a critical assessment. Neurosci BioBehav Rev 17, 427-439. 

Abstract Sexual orientation influences human olfactory function. Following a brief review of the biological basis of homosexuality, this chapter explores exactly how olfactory function varies as a result of sexual orientation. Three separate areas of research are considered recent studies on the neural processing of social odorants by heterosexuals and homosexuals the influence of sexual orientation on the production and perception of body odours and the influence of female sexual orientation on menstrual synchrony. 

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