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TY - JOUR AU - Fitzgerald, Maria PY - 1987 DA - 1987/04/01 TI - Spontaneous and evoked activity of fetal primary afferents in vivo JO - Nature SP - 603 EP - 605 VL - 326 IS - 6113 AB - The first movements of the fetus are apparently random and spontaneous1,2. Their onset coincides with the growth of dorsal root afferents into the spinal cord3,4 and it is possible that they are not simply a result of spontaneous motoneuron activity but are reflex responses to sensory stimulation5. It is not clear what stimuli could normally evoke such reflexes because nothing is known of the properties of primary afferent neurons in the fetus. I have investigated this by making recordings from single dorsal root ganglion cells in fetal rats in vivo. The afferents have small, defined receptive fields and respond to mechanical stimulation of skin or muscle at intensities that might occur in utero. Many of them are also chemosensitive. Unlike postnatal afferents they display background activity which peaks at the same age as fetal movements. Repeated stimulation causes long-lasting increases of both background and evoked activity. Such sensory input is likely to have a considerable influence on fetal movements and on the development of spinal cord connections. SN - 1476-4687 UR - https://doi.org/10.1038/326603a0 DO - 10.1038/326603a0 ID - Fitzgerald1987 ER -