what is the advantage to locomotor behavior in having a reduced greater tubercle? course hero

What is locomotor activity?

Locomotor activity can be a sensitive indicator of developmental toxicity and hence, measurement of this behavior is typically included in screening batteries (see later this chapter). Locomotion can be divided into two elements: ambulation (horizontally directed movement) and rearing (vertically directed movement).

What do we know about locomotor behavior in postnatal development?

While there is a wealth of knowledge on the development of locomotor behavior in human infants, children, and adolescents, pre-clinical animal models have fallen behind on the study of the emergence of behavioral motifs in locomotor function across postnatal development.

How to evaluate locomotor activity in rodents?

Methods for evaluating locomotor behavior in rodents fall into two general categories: automated monitoring of behavior and direct observational techniques. This unit presents protocols for measurement of locomotor activity using photocell-based automated monitoring systems, and direct observation using interval and ordinal scales.

What is the difference between total and ambulatory locomotor activity?

Total locomotor activity refers to any movement made by the rat that is picked up by the sensors. This can include repeated activation of a single sensor. Ambulatory locomotor activity refers to the movement made by the rat as it moves between distinct sensors, excluding repeated activation of a single sensor.

How to measure locomotor activity?

Locomotor activity can be measured in specially designed cages that project infrared beams from one side of the cage to the other. Each time an animal moves around the cage, it breaks the beam and a computer records the time and position (Figure 2.1 ). Alternatively, if cages with infrared beams are not available, a scientist can place a camera above the cage and record activity. Computer tracking programs can then be used to statistically analyze the total locomotor activity over time. Depending on the specific setup, a scientist can examine horizontal activity, vertical activity, time spent in various regions of the cage, and total distance traveled.

Why is locomotor activity considered an apical measure?

Despite its apparent simplicity; however, locomotor activity is considered an apical measure because it is influenced not only by the state of the animal’s motor system but also by sensory and motivational factors.

How do mice ambulate?

Up to PD 7–8 in mice 84 and PD 10 in rats, 85 pups ambulate primarily by pivoting and crawling. Thereafter, however, a rapid transition to walking occurs such that by PD 15 in rats, the animals have begun to display adult-like gait. 85 Interestingly, there is also a large surge in the amount of locomotor activity between PD 10 and 15, followed by further changes that depend on how the behavior is measured (Bâ et al.). 69,72,86 Given the rapid development of ambulation during the second postnatal week, testing of subjects around this time period may reveal whether prenatal or early postnatal toxicant exposure has caused a maturational delay.

What are the two elements of locomotion?

Locomotion can be divided into two elements: ambulation (horizontally directed movement) and rearing (vertically directed movement).

Which lobes are crucial to the circadian system?

The experimental results have clearly shown that the optic lobes are crucial elements in the circadian system and suggested that they might, in fact, be the site of the circadian pacemakers: removal of both lobes produces locomotor arrhythmia, whereas animals remained rhythmic following removal of either lobe alone.

What is the result of repeated exposure to a psychostimulant drug?

Subsequent increases in accumbal dopamine release that result from repeated exposure to a psychostimulant drug.

What is a neuronal retrograde tracer?

A neuronal retrograde tracer used experimentally to visualize afferent fibers and cell bodies connecting to the targeted injection site.

How does the olfactory tubercle affect behavior?

The olfactory tubercle has been shown to play a large role in behavior. Unilateral lesions in the olfactory tubercle have been shown to alter attention, social and sensory responsiveness, and even locomotor behavior. Bilateral lesions have been shown to reduce copulatory behavior in male rats. The olfactory tubercle has also been shown to be especially involved in reward and addictive behaviors. Rats have been shown to administer cocaine into the olfactory tubercle more than the nucleus accumbens and ventral pallidum, other reward centers in the brain. In fact, they will administer cocaine into the olfactory tubercle at about 200 times per hour and even till death.

Why is the olfactory tubercle not easy to identify?

In humans and other primates, visual identification of the olfactory tubercle is not easy because the basal forebrain bulge is small in these animals. With regard to functional anatomy, the olfactory tubercle can be considered to be a part of three larger networks.

How many times can rats inject cocaine into the olfactory tubercle?

In fact, they will administer cocaine into the olfactory tubercle at about 200 times per hour and even till death.

What is the olfactory tubercle?

Olfactory tubercle. The olfactory tubercle ( OT ), also known as the tuberculum olfactorium, is a multi-sensory processing center that is contained within the olfactory cortex and ventral striatum and plays a role in reward cognition. The OT has also been shown to play a role in locomotor and attentional behaviors, ...

Where is the olfactory tubercle located?

In general, the olfactory tubercle is located at the basal forebrain of the animal within the medial temporal lobe. Specifically, parts of the tubercle are included in the olfactory cortex and nested between the optic chiasm and olfactory tract and ventral to the nucleus accumbens.

Which part of the brain is the olfactory tubercle?

The olfactory tubercle is a multi-sensory processing center due to the number of innervations going to and from other brain regions such as the amygdala, thalamus, hypothalamus, hippocampus , brain stem, auditory and visual sensory fibers, and a number of structures in the reward–arousal system, as well as the olfactory cortex.

Which neurons are in the mesolimbic pathway?

The dopaminergic neurons of the mesolimbic pathway project onto the GABAergic medium spiny neurons of the nucleus accumbens and olfactory tubercle (receptor D3 is abundant in these two areas ). In addition, the OT contains tightly packed cell clusters known as the islands of Calleja, which consist of granule cells.

What are the different types of locomotion in primates?

Five categories of primate locomotion are typically recognized : -arboreal quadrapedalism - terrestrial quadrupedalism - vertical clinging and leaping - suspensory - bipedalism

Why is bipedalism better than other activities?

Humans foragers have long day ranges. Through bipedalism, their hands are free for other activities. Experiments have shown that bipedalism is more efficient. Costs less energy to cover the same distance. Bipedal animals could conserve energy while foraging.

Why focus on features of the skeleton?

For locomotion, we focus on features of the skeleton because they...- can provide info about both phylogeny and adaptation - are best documented aspects of primate locomotor anatomy - are the most useful in reconstructing locomotor habits of fossils

What are terrestrial quadrupeds?

Terrestrial quadrupeds are relatively rare among primates, and none show the striking adaptions of terrestrial runner such as cheetahs or antelopes . Most of their adaptations relate to the use of more extended limb postures on a flat broad surface. They have a deep trunk and long limbs for striding and speed. Restricted shoulder joint provides more limited anterior posterior movement, then complex rotational movement. Forelimbs and hindlimbs long and of similar length which are effective adaptations for speed and for aft movement. Reduced tail not needed for support or balance in terrestrial habitats. Short toes suitable for weight bearing, rather than grasping branches.

Is bipedal locomotion dangerous?

There are potential risks associated with the combo of bipedal locomotion and encephalization. Demands of bipedalism have restricted the size of the pelvis and birth canal. Humans are unique among large bodied primates in producing infants with large heads relative to mother's weight and birth canal dimensions.

What is the function of the greater tubercle?

The greater tubercle therefore acts as a location for the transfer of forces from the rotator cuff muscles to the humerus.

What is the lateral surface of the tubercle?

The lateral surface of the greater tubercle is convex, rough, and continuous with the lateral surface of the body of the humerus. It can be described as having a cranial and a caudal part.

Where is the greater tubercle of the humerus located?

23390. Anatomical terms of bone. The greater tubercle of the humerus is situated lateral to the head of the humerus and posterolateral to the lesser tubercle .

Which muscle is inserted in the upper surface of the greater tubercle?

The upper surface of the greater tubercle is rounded, and marked by three flat impressions: the highest ("superior facet") gives insertion to the supraspinatus muscle. the middle ("middle facet") gives insertion to the infraspinatus muscle.

Is the greater tubercle fractured?

The greater tubercle may be fractured, but is quite rare. The greater tubercle is usually the easiest part of the humerus to palpate. It can be a useful surface landmark during surgery.

Overview

Structure

Function

Clinical significance

History

See also

Further reading

External links