Effect of environmental complexity on the latency of cortical vibrissa potentials

Abstract

The effect of differential rearing on evoked potentials was studied in the vibrissal representation of the rat neocortex. Young rats were reared in either enriched, standard, or impoverished conditions from the age of 24-25 days. At 55-60 days of age, the epicortical responses to electric stimulation of a whisker follicle were analyzed under urethane anesthesia. Slight but significant shortening of the latency of initial positivity in the evoked potential was observed after rearing in the enriched condition as compared to the data obtained from the littermates that were reared in the standard or impoverished conditions.

Large-scale reorganization of the tonotopic map in mouse auditory midbrain revealed by MRI

“…Previous studies have shown that the rearing environment profoundly influences neuronal coding properties recorded in the visual, auditory, somatosensory, and olfactory cortices (1)(2)(3)(4)(5)(6)(7)(8)(9). In the central auditory pathway, most ascending projections from the lower brainstem nuclei terminate in the inferior colliculus (IC), and this structure is the principal conduit of ascending projections to the thalamus.…”

The surface evoked potential and parvalbumin‐immunoreactivity in the somatosensory cortex of the developing rat

“…Animals younger than Day 21 were analyzed by their precise age, but those older than Day 22 were divided into three age groups, Days 22-28, Days 29-35, and Days 36-55. Electrical stimulation of the whisker C3 follicle, the recording of the resultant SEP in the primary somatosensory cortex, and its subsequent analysis were carried out as described previously (Seo, 1992) with some modifications. Under urethane anesthesia (1.4 g/kg i.p.1, the skin was stripped from the head, the point on the lateral ridge of the parietal bone at the level of half the distance between the bregma and the lamda SEP AND PV-IR I N SMl OF DEVELOPlNG RAT 339 was marked, and a hole of approximate size made at this point in the skull.…”

“…Figure l a shows the whisker region in a tangential section in which barrels in Layer 1V were visualized by histochemical reaction for succinic dehydrogenase, as previously described (Seo, 1992). To locate the somatosensory cortical point that responded best to electrical stimulation of the whisker C3 follicle on the contralateral face, a silverball electrode was carefully moved approximately 0.5 mm at a time over the dura, without touching the blood vessels.…”

“…We have previously shown that rearing rats in "enriched" conditions shortens the latency of positivity in the surface evoked potential (SEP) induced in the primary somatosensory cortex by electric stimulation of a whisker follicle (Seo, 1992). In that study, rats were reared under different conditions, starting on postnatal Days 24-25 and their effects were analyzed on Days 55-60.…”

Lasting facilitatory effects of neonatal vibrissae removal on the propagation of cortical spreading depression: an electrophysiological study in well-nourished and early-malnourished adult rats

“…13 The manipulation of the sensory conditions in developing organisms, either enhancing or depriving them, is an approach often employed in studies on neural plasticity. 4,[14][15][16] The rodent facial vibrissae system in particular has been used in several studies dedicated to this issue, 6,[17][18][19] providing valuable information in understanding plasticity in the adult cortex. 7,8 The vibrissae (whiskers) are important sensory receptors of environmental stimulus, 20,21 that remains highly segregated in the barrel fields of the primary somatosensory cortex and provides tactile skills that are, in some ways, similar to modules of finger representation in primates.…”