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| John Skoyles. |
| Human childhood and adolescence is the period in which adult cognitive competences (including those that create the unique cooperativeness of humans) are acquired. It is also a period when neural development puts a juvenile’s survival at risk due to the high vulnerability of their brain to energy shortage. The brain of a 4 year-old human uses ≈50% of its total energy expenditure (TEE) (cf. adult ≈12%). This brain expensiveness is due to (1) the brain making up ≈6% of a 4 year-old body compared to 2% in an adult, and (2) increased energy metabolism that is ≈100% greater in the gray matter of a child than in an adult (a result of the extra costs of synaptic neuromaturation). The high absolute number of... |
| Tipo: Manuscript |
Palavras-chave: Developmental Biology; Neuroscience; Evolutionary Biology. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/7096/version/1 |
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| John Skoyles; Bernt C. Skottun. |
| Dyslexia and attentional problems are often comorbid. This raises the question whether reading deficits might etiologically follow from attentional difficulties, a hypothesis that has been proposed in regard to visuo-spatial attention deficits. This visuo-spatial attention deficit hypothesis would predict that attention deficits should be specific to dyslexia. However, it is here estimated that at the population level there are more non-dyslexic individuals than dyslexic individuals with visuo-spatial attention deficits. The reason for this is that in the overall population level there are far more individuals without dyslexia than with dyslexia. Thus, a relatively modest percentage presence of attention problems in the non-dyslexic population can result... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5525/version/1 |
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| John Skoyles; Bernt C. Skottun. |
| Visual stream segregation has been proposed as a method to measure visual attention in dyslexia. Another task proposed to do this is the line-motion illusion. Both tasks, it is observed, can be carried out with spatially distributed stimuli. This, however, appears inconsistent with these tasks being linked speci?cally to attentional processes since this would require them to spatially focus cognitive resources. Also, both line-motion and visual stream segregation involve the perception of movement raising the possibility that what is actually measured by these tasks is not attention but some aspect of motion perception. |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5529/version/1 |
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| John Skoyles. |
| A four year old child devotes half their total energy expenditure (TEE) to their brains. Even by 10 years-of-age it is still 30% (compared to an adult’s ≈12%). This extreme energy use results from a high brain/body size ratio – combined with a doubling of cerebral gray matter energy utilization (due to synaptic exuberance during cognitive neuromaturation). 

With extreme energy expenditure goes extreme vulnerability to hypoglycemia: (1) children become hypoglycemic after 24-36 hours of fast (compared to 60-72 hours in adults), and (2) their brains suffer neurological impairment (shown in disrupted P300 potentials) at a lower decrease in plasma glucose: 3.6 - 4.2 mmol L-1 in children rather... |
| Tipo: Presentation |
Palavras-chave: Developmental Biology; Neuroscience; Evolutionary Biology. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/7097/version/1 |
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