Role of whiskers in sensorimotor development of C57BL/6 mice

Abstract

The mystacial vibrissae (whiskers) of nocturnal rodents play a major role in their sensorimotor behaviors. Relatively little information exists on the role of whiskers during early development. We characterized the contribution of whiskers to sensorimotor development in postnatal C57BL/6 mice. A comparison between intact and whisker-clipped mice in a battery of behavioral tests from postnatal day (P) 4 to 17 revealed that both male and female pups develop reflexive motor behavior even when the whiskers are clipped. Daily whisker trimming from P3 onwards results in diminished weight gain by P17, and impairment in whisker sensorimotor coordination behaviors, such as cliff avoidance and littermate huddling from P4 through P17, while facilitation of righting reflex at P4 and grasp response at P12. Since active whisker palpation does not start until 2 weeks of age, passive whisker touch during early neonatal stage must play a role in regulating these behaviors. Around the onset of exploratory behaviors (P12) neonatal whisker-clipped pups also display persistent searching movements when they encounter cage walls as a compensatory mechanism of sensorimotor development. Spontaneous whisker motion (whisking) is distinct from respiratory fluttering of whiskers. It is a symmetrical vibration of whiskers at a rate of approximately ∼8 Hz, and begins around P10. Oriented, bundled movements of whiskers at higher frequencies of ∼12 Hz during scanning object surfaces, i.e., palpation whisking, emerges at P14. The establishment of locomotive body coordination before eyes open accompanies palpation whisking, indicating an important role in the guidance of exploratory motor behaviors.

Sensory input drives rapid homeostatic scaling of the axon initial segment in mouse barrel cortex

“…The AIS scaffolding protein βIV-spectrin, a wellestablished target for morphometrical analysis of the AIS (Gutzmann et al, 2014;Kim et al, 2019;Schlüter et al, 2017) was utilized, while immunoblot analysis was directed against the known isoforms of ankG, the main regulator of AIS assembly and maintenance (Jenkins et al, 2015b;Rasband, 2011). In line with previous reports (Galiano et al, 2012;Gutzmann et al, 2014), we found that the AIS elongated during the early postnatal period until the end of the second postnatal week, a time at which mice begin active whisking to explore their environment (Arakawa and Erzurumlu, 2015), indicated by grey boxes in Fig.1B). With the onset of active whisking behavior, however, a significant shortening of AIS length was observed both in pyramidal neurons of layers II/III and V ( Fig 1B).…”

“…The significant reduction in AIS length seen from P15 (in layer II/III) and P10 (in layer V) onwards coincides with the onset of explorative, active whisking behavior in mice (Arakawa and Erzurumlu, 2015). A similar AIS maturation pattern (early postnatal elongation, followed by length reduction and subsequent stable adult length) was previously described for the primary visual cortex and shown to be regulated by the onset of vision at P13-14 (Gutzmann et al, 2014).…”

Therapeutic Hypothermia Provides Variable Protection against Behavioral Deficits after Neonatal Hypoxia-Ischemia: A Potential Role for Brain-Derived Neurotrophic Factor

“…While TH after HI preserved sensorimotor processing in female mice, TH preserved motor balance and coordination in male mice. Since intact sensorimotor processing is necessary for development of exploratory behaviors, including food seeking [76], we hypothesize that these very refined differences in protection of various motor domains with TH may account for sexual dimorphism in growth seen in our experiments.…”

Temporal refinement of sensory‐evoked activity across layers in developing mouse barrel cortex

“…In mice, active whisking fully matures during the first three postnatal weeks. Vibrissae movements transition from spontaneous unilateral muscle twitches of the whisker pad in the first week after birth to regular bilateral rhythmic sweeps at the end of the third postnatal week (Arakawa & Erzurumlu, 2015;Grant, Mitchinson, & Prescott, 2012;Tiriac, Uitermarkt, Fanning, Sokoloff, & Blumberg, 2012). During the same period, cortical connectivity undergoes major reorganization, including the maturation of connectivity between layer (L) 4 and L2/3 (Feldmeyer, Lübke, Silver, & Sakmann, 2002;Stern, Maravall, & Svoboda, 2001) and strengthening of local connectivity within L2/3 (Clem & Barth, 2006;Clem, Celikel, & Barth, 2008;Feldmeyer, Lübke, & Sakmann, 2006;Itami & Kimura, 2012;Wen & Barth, 2011).…”