Canine Models

Cognitive Test Screens

Memory Tests

Short-term memory loss is one of the earliest signs of cognitive dysfunction associated with age and Alzheimer's disease in people. Old dogs also develop short-term memory loss, which may be related to the development Alzheimer's-like pathology.

We use the delayed-non-matching-to-position task (DNMP) to assess short-term working memory in dogs. We also use a spatial list task, which is a more complex tool for studying memory processes.

Visuospatial Function

Landmark and egocentric tests are used to determine a subject's ability to make a choice based on spatial position. The Landmark task tests allocentric spatial discrimination and spatial perception, and is age sensitive. The Egocentric task studies egocentric spatial discrimination ability and can be used to help identify demented animals.

The delayed-non-matching-to-position task is used to assess visuospatial memory.

Executive Function

Discrimination and reversal tests are used to determine a subject's ability to make a choice based on the properties of objects. On initial learning, age differences tend to be small, depending on the degree of similarity of the objects. With experience however, aged dogs demonstrate deficits. Reversal learning, which is a measure of executive functioning, is highly sensitive to age and brain pathology.

Complex Learning Ability and Attention

Assessment of attention and the ability to efficiently solve complex problems is particularly useful for characterizing age dependent cognitive changes in dogs as well as humans. CanCog provides the following screens for assessment of complex learning and attention.

Oddity Discrimination Learning

Subjects are given one or more three-choice discrimination problems of graded difficulty. Performance depends on task difficulty and age-dependency. Performance is linked to deficiencies in attention and learning ability.

Four-Choice Oddity

This is a visual search in which a subject's ability to respond to a target is impaired by the presence of distractors. Provides a measure of selective attention.

Acquisition of the delayed-non-matching-to-position task is also a very useful tool for assessment of complex learning ability.

Motor Learning

To assess motor learning and performance, we have developed a reaching task in which animals are trained to extend their forepaw to retrieve an object. This provides a measure of motor learning. The task becomes more difficult as the distance to the object is increased. Aged animals are known to learn more slowly and respond less effectively than younger cohorts.

Visual Processing

Contrast discrimination learning. Subjects are trained to distinguish line drawings at various contrasts. This provides a measure of visual processing ability, which deteriorates with age in dogs and in people.

Behavioral Screens

The following screens are used to assess general behavioral effects, appropriate dose levels, and to examine day-night activity cycles, as well as exploratory and social behaviors.

Behavioral Activity

We use two different screens for assessing general behavioral activity: the open field activity test and the Actiwatch test. The open field test looks at overall activity within a limited and specific time frame. The Actiwatch test provides a continuous record of locomotor activity.

Exploratory Behavior

Exploratory Behavior refers to the extent and quality of an organism's interaction with its environment. We have developed a curiosity test, in which we monitor interactions of the subject with objects in its environment in a controlled setting.

Social Behavior

The human interaction test involves monitoring the activity and behavior of the dog with and without a human in the test environment. This provides one index of social behavior.

The Mirror Test is used as another measure for assessing social behavior. In this test, we observe the response of the subject to its mirror image.

Day-Night Activity Rhythms

Day-Night Activity (Sleep/Wakefulness) is monitored using the Actiwatch test.