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Firing patterns of hippocampal complex-spike neurons were examined for the capacity to encode information important to the memory demands of a task even when the overt behavior and location of the animal are held constant. Neuronal activity was recorded as rats continuously alternated left and right turns from the central stem of a modified T maze.(More)
and more recently in animals as well (Eichenbaum, 1997). Furthermore, several recent electrophysiological McGill University Montreal PQH3A 1B1 studies have revealed properties of hippocampal neu-ronal firing patterns that are inconsistent with the notion Canada ‡ Department of Neuroscience and Neurology of a cognitive map and indicate a broader scope of(More)
Recent work has shown that lesions of the hippocampus in monkeys cause deficits in the capacity to remember increasing numbers of objects, colors, and spatial locations (). However, others have observed that hippocampectomized monkeys can show intact memory for a list of objects or locations (). We wished to explore the effects of hippocampal damage on the(More)
In humans the hippocampal region of the brain is crucial for declarative or episodic memory for a broad range of materials. In contrast, there has been controversy over whether the hippocampus mediates a similarly general memory function in other species, or whether it is dedicated to spatial memory processing. Evidence for the spatial view is derived(More)
The hippocampus encodes both spatial and nonspatial aspects of a rat's ongoing behavior at the single-cell level. In this study, we examined the encoding of intended destination by hippocampal (CA1) place cells during performance of a serial reversal task on a double Y-maze. On the maze, rats had to make two choices to access one of four possible goal(More)
The occurrence of cells that encode spatial location (place cells) or head direction (HD cells) in the rat limbic system suggests that these cell types are important for spatial navigation. We sought to determine whether place fields of hippocampal CA1 place cells would be altered in animals receiving lesions of brain areas containing HD cells. Rats(More)
The hypothesis that the cognitive decline in senile dementia is related to the loss of cortical cholinergic afferent projections predicts that pharmacological manipulations of the remaining cholinergic neurons will have therapeutic effects. However, treatment with cholinesterase inhibitors or muscarinic agonists has been, for the most part, largely(More)
Fischer-344 rats aged 4, 12, or 18 months were trained in a simple or choice reaction time task (SRTT; CRTT). Animals were required to detect a brief (50 ms), rarely, and unpredictably occurring signal that was presented either at the central panel light (SRTT) or above one of the two levers (CRTT). Animals reported detection by pressing either lever (SRTT)(More)
This study examined the effects of disorientation on the acquisition of different spatial reference memory tasks. In an appetitively motivated radial arm maze task in which 1 arm was consistently baited, rats that were disoriented before each trial were impaired in their ability to acquire the task relative to rats placed in a clear container and not(More)
Rats were trained in an operant spatial delayed alternation task utilizing retention intervals from 2 to 32 s. In addition to response accuracy, operations of the levers during the retention intervals were recorded and analyzed. Animals were tested following the administration of the muscarinic antagonists scopolamine hydrobromide and methylbromide, and the(More)