The oasis maze is a spatial memory task used in psychology and neuroscience research and is the dry version of the Morris water navigation task. It is a land-based spatial memory task in which a thirsty rat uses distal spatial cues to search an open field for a specific location (Oasis) containing water. The maze consists of an enclosed space (usually the same shape and dimensions of the space used in the Morris water maze) in which a small amount of water is hidden. A thirsty rat is then placed in the maze and learns where the water is by trial and error. The maze tests memory by allowing the researcher to record the rat's performance on this task after it is learned and various time intervals or other events supposedly disruptive to memory have occurred.
The Oasis maze is a circular, acrylic board (1.8 m in diameter) that is painted flat white and raised 76 cm from the floor by a table with a lazy Susan attached, allowing the board to be freely rotated about its central axis. The surface of the board contains 426 evenly spaced wells (2.5 cm in diameter, 1.3 cm in depth) in which small amounts of water (0.3 ml) can be hidden. Water is used as a reward because, unlike food rewards, rats cannot locate the water using olfactory cues.
In the first phase, rats are water deprived by removing their water for 23 h/day for 3 days. Next, water is randomly placed in half of the 426 wells on the Oasis maze platform (0.3 ml per well), and the rats are given 5 min to find and drink as much water as they can on 2 occasions, separated by 30 min. The next day this procedure is repeated with only 25% of the wells containing water. On the final day, only 5 of the wells contain water. Pretraining on this day ends when the rats locate and consume water from all 5 baited wells.
Following pretraining, rats are given 8 trials a day for 10 days. On each trial, water is placed in a single well. For each rat, the water is always located in the same position relative to the testing room and distal spatial cues. Four different target well locations are used; 1 in the center of each quadrant, to control for any position biases the rats might have. The target well location to which each rat is assigned is counterbalanced within each experimental group. Local cues are made irrelevant (including odor trails) by rotating the entire apparatus a predetermined distance and direction after each trial. However, the water is always placed in the same location relative to the testing room and distal spatial cues.
In addition to the groups trained to find water by using spatial cues, another group (RANDOM) is given an equivalent amount of training, except that the location of the water varies randomly from trial to trial and could appear in any of the 426 wells. Thus, this group could develop optimal strategies for finding the water efficiently, but memory of specific locations is irrelevant. The RANDOM group provides a measure of where rats with no spatial memory of a trained location will spend their search time during probe trials. The probe trials for this group are administered 14 days after the end of training.
At the beginning of each acquisition trial, the rats are placed at 1 of 4 start points (North, South, East, and West) around the edge of the board. Across the 8 trials of each day (intertrial interval was approximately 15 min), 2 trials are given from each of the 4 start points, and the sequence is counterbalanced within each group. A trial is terminated when the rat locates the water or after 5 min, whichever comes first. If the rat fails to find the water within 5 min, it is guided to the correct well and allowed to drink. Once the water is located, the rat is allowed to drink the water before being returned to his home cage. Following each training session, the rats are allowed to drink freely for 1 h.
A 5-min probe trial is given a couple of weeks after training. The trial begins by placing the rat at 1 of 2 start points around the edge of the Oasis platform. Start points are always in 1 of the 2 quadrants adjacent to the quadrant that contains the training well location. For example, for rats with training wells in the North, start points for the probe trial are either West or East (counterbalanced within each group). No water is available during the probe trial.
Probe trials on the Oasis maze differ in 2 important ways from probe trials in the Morris water maze. First, 5-min probe trials are used, rather than 1-min probe trials, to ensure that rats explore a substantial portion of the Oasis maze. Second, in the Oasis maze rats have a strong tendency to explore the edges of the board and also to return to the start point. For these reasons, chance performance cannot be calculated in a straightforward way.
Chance performance can be estimated by assessing the performance of the RANDOM group (because rats in this group could not acquire a memory for a specific spatial location). To do this, the percentage of time that a trained rat spend within a 58-cm- diameter circle around the trained well is compared with the percentage of time that rats in the RANDOM group spend in this same region (target locations for the RANDOM group are counterbalanced across rats). A 58-cm circle is the diameter of the largest circle that could be completely contained within 1 quadrant of the maze.
Animal cognition encompasses the mental capacities of non-human animals including insect cognition. The study of animal conditioning and learning used in this field was developed from comparative psychology. It has also been strongly influenced by research in ethology, behavioral ecology, and evolutionary psychology; the alternative name cognitive ethology is sometimes used. Many behaviors associated with the term animal intelligence are also subsumed within animal cognition.
In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Spatial memory is necessary for orientation in space. Spatial memory can also be divided into egocentric and allocentric spatial memory. A person's spatial memory is required to navigate around a familiar city. A rat's spatial memory is needed to learn the location of food at the end of a maze. In both humans and animals, spatial memories are summarized as a cognitive map.
The Morris water navigation task, also known as the Morris water maze, is a behavioral procedure mostly used with rodents. It is widely used in behavioral neuroscience to study spatial learning and memory. It enables learning, memory, and spatial working to be studied with great accuracy, and can also be used to assess damage to particular cortical regions of the brain. It is used by neuroscientists to measure the effect of neurocognitive disorders on spatial learning and possible neural treatments, to test the effect of lesions to the brain in areas concerned with memory, and to study how age influences cognitive function and spatial learning. The task is also used as a tool to study drug-abuse, neural systems, neurotransmitters, and brain development.
The radial arm maze was designed by Olton and Samuelson in 1976 to measure spatial learning and memory in rats. The original apparatus consists of eight equidistantly spaced arms, each about 4 feet long, and all radiating from a small circular central platform. At the end of each arm there is a food site, the contents of which are not visible from the central platform.
A place cell is a kind of pyramidal neuron in the hippocampus that becomes active when an animal enters a particular place in its environment, which is known as the place field. Place cells are thought to act collectively as a cognitive representation of a specific location in space, known as a cognitive map. Place cells work with other types of neurons in the hippocampus and surrounding regions to perform this kind of spatial processing. They have been found in a variety of animals, including rodents, bats, monkeys and humans.
A cognitive map is a type of mental representation which serves an individual to acquire, code, store, recall, and decode information about the relative locations and attributes of phenomena in their everyday or metaphorical spatial environment. The concept was introduced by Edward Tolman in 1948. He tried to explain the behavior of rats that appeared to learn the spatial layout of a maze, and subsequently the concept was applied to other animals, including humans. The term was later generalized by some researchers, especially in the field of operations research, to refer to a kind of semantic network representing an individual's personal knowledge or schemas.
Explicit memory is one of the two main types of long-term human memory, the other of which is implicit memory. Explicit memory is the conscious, intentional recollection of factual information, previous experiences, and concepts. This type of memory is dependent upon three processes: acquisition, consolidation, and retrieval. Explicit memory can be divided into two categories: episodic memory, which stores specific personal experiences, and semantic memory, which stores factual information. Explicit memory requires gradual learning, with multiple presentations of a stimulus and response.
The Barnes maze is a tool used in psychological laboratory experiments to measure spatial learning and memory. The test was first developed by Dr. Carol Barnes in 1979. The test subjects are usually rodents such as mice or lab rats, which either serve as a control or may have some genetic variable or deficiency present in them which will cause them to react to the maze differently. The basic function of Barnes maze is to measure the ability of a mouse to learn and remember the location of a target zone using a configuration of distal visual cues located around the testing area. This noninvasive task is useful for evaluating novel chemical entities for their effects on cognition as well as identifying cognitive deficits in transgenic strains of rodents that model for disease such as Alzheimer's disease. It is also used by neuroscientists to determine whether there is a causative effect after mild traumatic brain injury on learning deficits and spatial memory retention (probe) at acute and chronic time points. This task is dependent on the intrinsic inclination of the subjects to escape from an aversive environment and on hippocampal-dependent spatial reference memory.
Latent learning is the subconscious retention of information without reinforcement or motivation. In latent learning, one changes behavior only when there is sufficient motivation later than when they subconsciously retained the information.
Selective amnesia is a type of amnesia in which the sufferer loses only certain parts of their memory. Common elements that may be forgotten are relationships, where they live, and certain special abilities and talents.
The elevated plus maze (EPM) is a test measuring anxiety in laboratory animals that usually uses rodents as a screening test for putative anxiolytic or anxiogenic compounds and as a general research tool in neurobiological anxiety research such as PTSD and TBI. The model is based on the test animal's aversion to open spaces and tendency to be thigmotaxic. In the EPM, this anxiety is expressed by the animal spending more time in the enclosed arms.
The study of memory incorporates research methodologies from neuropsychology, human development and animal testing using a wide range of species. The complex phenomenon of memory is explored by combining evidence from many areas of research. New technologies, experimental methods and animal experimentation have led to an increased understanding of the workings of memory.
The relationship between sleep and memory has been studied since at least the early 19th century. Memory, the cognitive process of storing and retrieving past experiences, learning and recognition, is a product of brain plasticity, the structural changes within synapses that create associations between stimuli. Stimuli are encoded within milliseconds; however, the long-term maintenance of memories can take additional minutes, days, or even years to fully consolidate and become a stable memory that is accessible. Therefore, the formation of a specific memory occurs rapidly, but the evolution of a memory is often an ongoing process.
Spontaneous Alternation Behavior (SAB) describes the tendency to alternate in their pursuit of different stimuli in consecutive trials despite a lack of training or reinforcement. The Behavior emerged from experiments using animals, mainly rodents, who naturally demonstrated the behavioral pattern when placed in previously unexplored maze shapes.
Episodic-like memory is the memory system in animals that is comparable to human episodic memory. The term was first described by Clayton & Dickinson referring to an animal's ability to encode and retrieve information about 'what' occurred during an episode, 'where' the episode took place, and 'when' the episode happened. This ability in animals is considered 'episodic-like' because there is currently no way of knowing whether or not this form of remembering is accompanied by conscious recollection—a key component of Endel Tulving's original definition of episodic memory.
Serial memory processing is the act of attending to and processing one item at a time. This is usually contrasted against parallel memory processing, which is the act of attending to and processing all items simultaneously.
In behavioral science, a T-maze is a simple forked passage used in animal cognition experiments. It is shaped like the letter T, providing the subject, typically a rodent, with a straightforward choice. T-mazes are used to study how the rodents function with memory and spatial learning through applying various stimuli. Starting in the early 20th century, rodents were used in experiments such as the T-maze. These concepts of T-mazes are used to assess rodent behavior. The different tasks, such as left-right discrimination and forced alternation, are mainly used with rodents to test reference and working memory.
The Cincinnati Water Maze (CWM) is a type of water maze. Water mazes are experimental equipment used in laboratories; they are mazes that are partially filled with water, and rodents are put in them to be observed and timed as they make their way through the maze. Generally two sets of rodents are put through the maze, one that has been treated, and another that has not, and the results are compared. The experimenter uses this type of maze to learn about the subject's cognitive or emotional processes.
Michela Gallagher is an American cognitive psychologist and neuroscientist. She is the Krieger-Eisenhower Professor of Psychology and Neuroscience at Johns Hopkins University. Her scientific work has changed the model of neurocognitive aging, and developed new indices for its study. Previously, work had focused on neurodegeneration as a primary cause of memory loss.
Gina R. Poe is an American neuroscientist specializing in the study of sleep and its effect on memory and learning. Her findings have shown that the absence of noradrenaline and low levels of serotonin during sleep spindles allow the brain to form new memories during REM, as well as restructure old memory circuits to allow for more learning during later waking periods. She currently works as a professor at the University of California, Los Angeles (UCLA).