 There is a consensus among developmental neurobiologists that the establishment of thalamocortical connections (at weeks 22-34, reliably at 29) is a critical event with regard to fetal perception of pain, as they allow peripheral sensory information to arrive at the cortex.Electroencephalography indicates that the capacity for functional pain perception in premature infants does not exist before 29 or 30 weeks; a 2005 meta-analysis states that withdrawal reflexes and changes in heart rates and hormone levels in response to invasive procedures are reflexes that do not indicate fetal pain.Several lines of evidence suggest that a fetus does not awaken during its time in the womb.