The brain as the engine of sex differences in the organization of movement in rats.

Sex differences in the kinematic organization of non-reproductive behavior are often relegated to byproducts of sex differences in body morphology. We review evidence showing not only that male and female rats organize their posture and stepping differently during a variety of actions, but that these differences arise from sex differences in the organization of movement in the central nervous system (CNS). Indeed, the expression and choice of sex-typical patterns of movement can be altered by CNS injury.

Sexually dimorphic postural adjustments during vertical behaviour are altered in a unilateral 6-OHDA rat model of Parkinson's disease.

The study of sex differences in the onset, progression and symptoms of Parkinson's disease, in humans, has led to mixed results. In this study, we used a unilateral 6-hydroxydopamine (6-OHDA) lesion animal model of Parkinson's disease, to address whether there are sex differences in the composition of the movements used during vertical exploration within a confined cylinder. Tyrosine hydroxylase staining and apomorphine induced rotation were used to confirm lesion magnitude.

Play fighting in androgen-insensitive tfm rats: evidence that androgen receptors are necessary for the development of adult playful attack and defense.

The frequency of playful attack and the style of playful defense, are modifiable by gonadal steroids and change after puberty in male and female rats. The present study examined the play behavior exhibited by testicular feminized mutation (tfm)-affected males, who are insensitive to androgens but can bind estrogens aromatized from androgens, to determine the relative contributions of androgens and estrogens to the age-related changes in play behavior. tfm males did not exhibit a decrease in playful attack with age and were more likely to maintain the use of complete rotations, a juvenile form of playful defense, into adulthood.

Sexually dimorphic postural adjustments are used in a skilled reaching task in the rat.

Sex differences occur not only in the sexual repertoire of animals but also are evident in other aspects of movement. The present study asked whether sexually dimorphic motor behavior extends to the skilled movements used in reaching for food in the rat. Because we have previously shown that males and females are sexually dimorphic in their organization of lateral and rotatory movements and because postural adjustments are incorporated into skilled movements, both body posture and limb movements were examined during a skilled reaching task.

Sex differences in righting from supine to prone in rats (Rattus norvegicus): a masculinized skeletomusculature is not required.

Previous research has shown that sex differences exist in the composition of lateral movements (E. F. Field, I.

Neonatal and pubertal, but not adult, ovarian steroids are necessary for the development of female-typical patterns of dodging to protect a food item.

Rats protect food by dodging horizontally away from a conspecific. Females and males use different movement and stepping patterns to execute a dodge. An unresolved question is whether exposure to ovarian steroids in females is necessary for the development of the female-typical pattern.

A masculinized skeletomusculature is not necessary for male-typical patterns of food-protective movement.

Although sexual dimorphism in movement has been documented in rodents, the extent to which it relates to dimorphic neural control versus dimorphic body size/structure is unclear. We have shown previously that male and female rats are sexually dimorphic with regards to the lateral movements and hindpaw stepping they use to protect a food item. We addressed the question of whether this sexual dimorphism is due to sex differences in peripheral skeletomusculature or in the CNS by examining the movement composition used during dodging to protect a food item by tfm-affected males and their wild-type male (WTM) and female (WTF) controls.