The novel object recognition (NOR) test is a widely used behavioral paradigm in animal models to assess memory and learning. This test evaluates the preference for novel objects over familiar ones, which can be influenced by various factors such as time, environment, and brain regions involved. The NOR test consists of three phases: habituation, familiarization, and testing. Animals are initially exposed to an open-field arena without objects, then to two identical objects during the familiarization phase, and finally to one novel and one familiar object during the test phase. The test measures the time spent exploring each object, with the difference in exploration time between the novel and familiar objects serving as an index of recognition memory. The NOR test has been modified to study various aspects of memory and learning, including working memory, attention, anxiety, and preference for novelty. These modifications include changes in the number of objects, object positions, and the use of different apparatuses and cleaning solutions. The test has also been adapted for use with different species, such as monkeys and transgenic mice, to study specific conditions like Alzheimer's disease. The NOR test is sensitive to both hippocampal and cortical lesions, with the perirhinal cortex playing a crucial role in object recognition memory. The test can be further enhanced by using automatic recording devices, such as EthoVision tracking software, to measure various locomotor parameters and exclude confounding variables. Overall, the NOR test provides a valuable tool for studying memory and learning in animals, with its flexibility allowing for the investigation of a wide range of cognitive functions and the effects of pharmacological treatments and brain damage.The novel object recognition (NOR) test is a widely used behavioral paradigm in animal models to assess memory and learning. This test evaluates the preference for novel objects over familiar ones, which can be influenced by various factors such as time, environment, and brain regions involved. The NOR test consists of three phases: habituation, familiarization, and testing. Animals are initially exposed to an open-field arena without objects, then to two identical objects during the familiarization phase, and finally to one novel and one familiar object during the test phase. The test measures the time spent exploring each object, with the difference in exploration time between the novel and familiar objects serving as an index of recognition memory. The NOR test has been modified to study various aspects of memory and learning, including working memory, attention, anxiety, and preference for novelty. These modifications include changes in the number of objects, object positions, and the use of different apparatuses and cleaning solutions. The test has also been adapted for use with different species, such as monkeys and transgenic mice, to study specific conditions like Alzheimer's disease. The NOR test is sensitive to both hippocampal and cortical lesions, with the perirhinal cortex playing a crucial role in object recognition memory. The test can be further enhanced by using automatic recording devices, such as EthoVision tracking software, to measure various locomotor parameters and exclude confounding variables. Overall, the NOR test provides a valuable tool for studying memory and learning in animals, with its flexibility allowing for the investigation of a wide range of cognitive functions and the effects of pharmacological treatments and brain damage.