Ongoing Studies
Women’s health matters !
Our current studies use non-invasive approaches to assess cognitive function (using voluntary participation on touchscreen tasks), sleep quality (using non-invasive actiwatches) and thermoregulation (using a non-invasive thermal imaging camera) to examine the therapeutic benefits of a novel estrogen. We also measure hormone levels by collecting urine (non-invasive, we only collect pee !) and blood samples (when possible, collected when animals are already anesthetized for their physical). Post-mortem, we will analyze brain tissues to determine the effects of the novel estrogen in the brain. These studies cannot be conducted in humans. They are important because they will tell us how this novel estrogen works and whether it can safely eliminate severe side-effects in women treated for estrogen-responsive breast cancers. Below are examples of our behavioral assessments (odor detection and motor function are from past studies)
Cognitive function
Here, a marmoset uses a touchscreen computer with a cognitive test in which the marmoset must discriminate between two shapes and remember which one is “correct.” Once they learn this rule (90% correct responses), we switch the rule and now the opposite shape is correct! This is called a standard reversal and tests their cognitive flexibility.
The marmoset to the left is in a temporary “transport box,” which is a small box which attaches to their large home cage. They can freely move around in this transport box and, once they are finished, they are placed back into their home cage with their cage mate. (Usually about 5 - 10 minutes of testing).
Odor detection
Anosmia, or loss of smell, is a common symptom of Alzheimer’s disease. In order to test if marmosets also lose smell with age, the marmoset to the right is doing an odor test. The marmoset is once again temporarily removed from their cage with the transport box. The researcher presents two containers with different scents (orange and vanilla.) The marmosets then have to smell the containers and push the correct one in order to get a marshmallow treat. They can see their cage mates, so they often get distracted and will call to them (as shown here) in between doing their testing. This is a normal part of their behavior and the testing does not last longer than 10 - 20 minutes. Afterwards, the animal goes back to their home cage.
Hill and Valley, a test of fine motor ability.
Here, a marmoset is doing the classic “Hill and Valley” test, which assesses their fine motor function. Marmosets are temporarily removed from their home cage and placed in a transport box where they can move freely (described above.). They are tested within their colony room. Marshmallows are placed in the center or the steps of the apparatus.. The monkey can VOLUNTARILY grasp the marshmallows.. Their accuracy and length of time to complete the task are measured. Once they are finished, they are returned back to their home cage and cage mate.
For the most recent paper on handedness in marmosets, click here.
Sleep quality
Impaired sleep is associated with cognitive impairment with age and is now regarded as a potential cause for AD, however the mechanisms linking sleep with AD are unknown. In order to assess sleep quality and its effect on cognition, we noninvasively monitor sleep with a small fitbit -like device that attaches temporarily to the marmoset on a collar. These small, lightweight devices are only on the marmosets for a few days at a time. They can freely move around their home cage (a 2-story cage with plenty of room to jump and play), with no change in behavior. We monitor the animals’ behavior daily; to do this, we have behavior logs. All researchers are trained to look for a long list of marmoset behaviors that indicate wellbeing, stress, etc. If any stress or abnormal behavior is detected, multiple veterinarians are on call as well as trained animal care staff to provide immediate support. Some of the marmosets have been implanted with a small device (telemeter) that records EEGs for more accurate measures of sleep. This is a subcutaneous, wireless system that is completely invisible and does not bother the animal. In this way, we can record the marmosets’ sleep without disturbing the animal. Although such telemeters are the most accurate way to record sleep, we have used the non-invasive fitbit-like devices for years and have no plans to re-implant animals with telemeters.
Here, a marmoset wears a temporary fitbit-like device (black circle) which measures their activity at night as a proxy for sleep.
Here is an image that the thermal camera produces. The nose reason is highlighted to show the large differences in temperature change. Understanding their ability to thermoregulate, or appropriately regulate their own body temperature, may help us better understand symptoms associated with menopause (e.g. hot flashes).
Measuring temperature with thermal imaging
We use a non-contact, infrared camera to record changes in facial temperature. This camera measures temperatures in the marmosets’ faces in a completely noninvasive manner, producing images like the one to the left. Marmosets are temporarily removed from their home cage by a skilled researcher. The marmoset is held in a researcher’s lap while the camera images from approximately 5 - 10 feet distance from the researcher and marmoset. After 20 minutes of imaging, the animal is returned to their home cage and cage mate.