Several speculative and yet untested hypotheses suggest that endogenous DMT is produced in the human brain and is involved in certain psychological and neurological states.

Several clinical and experimental data have implicated the failure of blood – brain barrier ( BBB ) function in triggering chronic or acute seizures, some studies implicate the interactions between a common blood protein — albumin and astrocytes.

Several types of brain lesions can occur in individuals with TSC and 60 %-90 % of people with TSC develop epilepsy.

Several brain structures other than the amygdala have also been observed to be activated when individuals are presented with fearful vs. neutral faces, namely the occipitocerebellar regions including the fusiform gyrus and the inferior parietal / superior temporal gyri.

Several conditions can cause facial paralysis, e. g., brain tumor, stroke, and Lyme disease.

Several neuropathological studies on postmortem brain samples argued for an SNpc alteration evidenced by neuromelanin hypopigmentation, reduction in the structure area, and even controversial, signs of apoptosis.

Several adaptations combine to protect the woodpecker's brain from the substantial pounding that the pecking behaviour causes: it has a relatively thick skull with relatively spongy bone to cushion the brain ; there is very little cerebrospinal fluid in its small subarachnoid space ; the bird contracts mandibular muscles just before impact, thus transmitting the impact past the brain and allowing its whole body to help absorb the shock ; its relatively small brain is less prone to concussion than other animals '.

Several areas of the human brain are not on the brain side of the BBB.

Several clinical and experimental data have implicated the failure of blood – brain barrier function in triggering chronic or acute seizures.

Several contradictory predictions have been made about when a whole human brain can be emulated ; some of the predicted dates have already passed.

Several neurological conditions such as Alzheimer's disease, various types of brain injury, Klüver-Bucy syndrome, Kleine-Levin syndrome, and many more neuro-degenerative diseases can cause hypersexual behavior.

Several areas in the brain, and especially the nucleus paragigantocellularis, have been identified to be involved in ejaculatory control.

Several published studies in the medical literature on psychoneuroendocrinology have examined the hypothesis that prenatal exposure to estrogens ( including DES ) may cause significant developmental impact on sexual differentiation of the brain, and on subsequent behavioral and gender identity development in exposed males and females.

Several studies have demonstrated correlations between race and brain size, with varying results.

Several mutations of genes involving the melanocortins ( used in brain signaling associated with appetite ) and their receptors have also been identified as causing obesity in a larger portion of the population than leptin mutations.

Several decades earlier, refugees from Earth fled to join a pre-existing human colony on Mars to escape the domination of One True, a massively parallel / cellular automata program that runs on the interconnected brains of most of the human beings on Earth ; the program in the individual human brain is called Resuna, probably a contraction from the Latin for One Thing.

Several functional subunits ( like vocal muscles and brain areals ) are needed to produce the echolocating system.

Several different regions of the brain govern the act of writing.

: Several studies have used the fMRI paradigm to observe brain states brought about by adjustments of paralinguistic information.

Several important applications of astrography, including astronomical spectroscopy and astrometry require greater dimensional stability than film could provide, and continued using plates until digital imaging improved to the point of supplanting photochemical photography for these purposes.

Several functional imaging studies have also shown that the insula is activated when drug users are exposed to drug cues, and that this activity is correlated with subjective urges.

Several brain imaging studies using positron emission tomography and functional magnetic resonance imaging techniques have shown that higher levels of processing correlate with more brain activity and activity in different parts of the brain than lower levels.

Combinations of the above techniques produce a " hybrid " or " hyphenated " technique .< ref name =" pmid9008869 "> Several examples are in popular use today and new hybrid techniques are under development.

Several different techniques exist to study cells are

Several laboratory scale techniques for distillation exist ( see also distillation types ).

Several modern theories have ventured to explain this decline, including the breakdown of trade routes to supply the needed metals, the lack of trace impurities in the metals, the possible loss of knowledge on the crafting techniques through secrecy and lack of transmission, or a combination of all the above.

Several techniques are used by DJs as a means to better mix and blend recorded music.

Several decades after Pearson's work with early versions of meta-analysis, Glass published the first application of modern meta-analytic techniques and triggered their broad application across the social and biomedical sciences.

Several different telephone line modulation techniques are used by fax machines.

Several of the most common techniques for producing glass art include: blowing, kiln-casting, fusing, slumping, pate-de-verre, flame-working, hot-sculpting and cold-working.

Several common genotyping techniques include restriction fragment length polymorphism ( RFLP ), terminal restriction fragment length polymorphism ( t-RFLP ), amplified fragment length polymorphism ( AFLP ), and multiplex ligation-dependent probe amplification ( MLPA ).

Several of these siege techniques were used by the Romans but experienced a rebirth during the Crusades.

Several Baseball Prospectus authors have invented or improved upon widely relied upon sabermetric measures and techniques.

Several techniques have been performed for over a century, from the more invasive saphenous stripping, to less invasive procedures like ambulatory phlebectomy and CHIVA.

Several designer-makers established workshops in rural areas and revived old techniques.

Several mechanical techniques are used to dislodge sputum and encourage its expectoration.

Several techniques soon developed, such as the " stop trick ", wholly original to motion pictures.

Several important therapeutic techniques were pioneered at St. Elizabeths, and it served as a model for later institutions.

Several just-in-time compilation ( JIT ) techniques were pioneered and improved in Self research as they were required to allow a very high level object oriented language to perform at up to half the speed of optimized C. Much of the development of Self took place at Sun Microsystems, and the techniques they developed were later deployed for Java's HotSpot virtual machine.

Several other techniques are available depending on suitability and time constraints.

Several modern needlework designers have incorporated elements of Hardanger cut work into their embroidery designs and samplers, often combining them with other needlework techniques, stitches, speciality threads and other embellishments to great effect.

Several broad disciplines including Psychology, Human Factors and Cognitive Science subsume usability engineering, but the theoretical foundations of the field come from more specific domains: human perception and action ; human cognition ; behavioral research methodologies ; and, to a lesser extent, quantitative and statistical analysis techniques.

Several snapshotting techniques exists:

Several different recognition techniques are currently available.