Effects of superior colliculus ablation on the air-righting reflex in the rat

Abstract

To examine how the superior colliculus, the motor center of orientation and avoidance, could interact with postural reflexes, we investigated effects of unilateral and bilateral ablations on air-righting reflex movements in otherwise intact rats. Superior colliculus ablations variously modified righting movements: After falling from the supine position, the rats sometimes showed dorsiflexion instead of normal ventriflexion; the motor sequence of rotation from the fore- to the hindquarter was often modified to simultaneous rotation; lateral turn from supine to prone position was occasionally insufficient; body direction that was normally kept constant during falling was often changed; final posture sometimes deviated from the horizontal position. The first three abnormalities occurred almost twice in frequency as lesions increased from unilateral to bilateral ablation, and in unilaterally ablated rats, did so in righting contraversive to the lesions. Multiple influences of tectoreticular input to the air-righting reflex center are discussed.

Chronic amphetamine treatment affects collicular-dependent behaviour

“…In line with previous studies, we found that animals dropped from a lower height righted with a shorter latency [21,39,40,50]. This relationship was similar for all drug doses.…”

“…In addition, there was no alteration to the plane in which righting occurred. Previous work with SC-lesioned animals suggested plane changes do occur in these circumstances [50]. The fact that they were not apparent in the present study is perhaps unsurprising given that the colliculus was not removed, rather its activity was just likely suppressed by amphetamine [31,32,57].…”

“…The footage was then analysed frame by frame to obtain: i) the number of trials for which each animal could successfully right at each drop height ii) the average latency from the animals' release to successful air-righting across the four trials at each height, and iii) the plane in which the rotation took place (whether the animals turned longitudinally or laterally). Plane was included as a dependent variable because previous studies in animals with different types of SC lesion revealed variation in the plane of righting [50].…”

Repeated intermittent alcohol exposure during the third trimester-equivalent increases expression of the GABAA receptor δ subunit in cerebellar granule neurons and delays motor development in rats

“…This suggests that EtOH exposure during the 3 rd trimester-equivalent has a greater impact on the acquisition of the air-righting reflex than EtOH exposure during earlier stages of development. Although the neuronal circuits that mediate this reflex have not been fully characterized, they may involve vestibular and visual neuronal networks (Pellis et al, 1989; Pellis et al, 1991), the superior colliculus (Yan et al, 2010), the striatum (Masuda and Yamaguchi, 2000), and the cerebellum (Bouet et al, 2004). Particularly, the cerebellar vermis contributes to this reflex, where PCs inhibit neurons in the fastigial nucleus, one of the deep cerebellar nuclei involved in vestibular integration (Brooks and Cullen, 2009).…”

Altered visual processing in a rodent model of Attention-Deficit Hyperactivity Disorder

“…Secondly, collicular dysfunction has been reported in rodent models of ADHD. For example, in the spontaneously hypertensive rat (SHR), the most commonly used rodent model of ADHD, altered height dependency of air righting reflexes has been found (Dommett and Rostron, 2011) dysfunction (Pellis et al, 1989;Pellis et al, 1991;Yan et al, 2010). More recently, orienting behavior to a repeated visual stimulus has been shown to be increased in the SHR (Robinson and Bucci, 2014).…”