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Explanations of memory-guided navigation in rodents typically suggest that cue- and place-based navigation are independent aspects of behaviour and neurobiology. The results of many experiments show that hippocampal damage causes both anterograde and retrograde amnesia (AA; RA) for place memory, but only RA for cue memory. In the present experiments, we used a concurrent cue-place water task (CWT) to study the effects of hippocampal damage before or after training on cue- and place-guided navigation, and how cue and place memory interact in damaged and control rats. We found that damaging the hippocampus before training caused a delay in the expression of cue-place navigation strategies relative to intact control animals; surprisingly, place navigation strategies emerged following pre-training hippocampal damage. With additional training, both control and damaged rats used local cues to navigate in the CWT. Damaged animals also show minor impairments in latency to navigate to the correct cue following a cue contingency reversal. By contrast to these anterograde effects, damage made after training causes RA for cue choice accuracy and latency to navigate to the correct cue. In addition, the extent of hippocampal damage predicted impairments in choice accuracy when lesions were made after training. These data extend previous work on the role of the hippocampus in cue and place memory-guided navigation, and show that the hippocampus plays an important role in both aspects of memory and navigation when present during the learning experience.
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Contextual fear conditioning relies upon a network of cortical and subcortical structures, including the hippocampus and the retrosplenial cortex (RSC). However, the contribution of the hippocampus is...
To investigate long-term recovery of allocentric and egocentric spatial orientation as a sensitive marker for hippocampal and extrahippocampal network function in transient global amnesia (TGA).
Neurons in hippocampal output area CA1 are thought to exhibit redundancy across cortical and hippocampal inputs. Here we show instead that acute silencing of CA3 terminals drastically reduces place fi...
Transient global amnesia (TGA) is a rare, benign condition characterised by a sudden deficit of anterograde and retrograde memory that usually lasts for a few hours and is not accompanied by other foc...
The activity of hippocampal cell assemblies is considered to function as the neural substrate for a cognitive map in various animal species. The firing rate of hippocampal place cells increases when a...
Hippocampal Sclerosis (HS) leads to anterograde amnesia mimicking early Alzheimer's disease (AD) (so called HSA-nonAD). Recent studies showed that (a) the deficit of episodic memory as wel...
This study will compare the clinical efficacy and side effects of Magnetic Seizure Therapy (MST) and Electroconvulsive Therapy (ECT) in patients currently experiencing a major depressive e...
The purpose of this study is to investigate if a systematic intervention with early identifying of patients with posttraumatic amnesia using a reality orientation therapy can reduce the pe...
The transient global amnesia (IA) is defined clinically as a temporary suspension and isolated from the ante and retrograde memory, totally regressing within 24 hours. The causes of AI rem...
OBJECTIVES: I. Evaluate whether chronic hypercortisolemia is specifically toxic to hippocampal cells and causes structural reduction of hippocampal volume in patients with Cushing's syndr...
Pathologic partial or complete loss of the ability to recall past experiences (AMNESIA, RETROGRADE) or to form new memories (AMNESIA, ANTEROGRADE). This condition may be of organic or psychologic origin. Organic forms of amnesia are usually associated with dysfunction of the DIENCEPHALON or HIPPOCAMPUS. (From Adams et al., Principles of Neurology, 6th ed, pp426-7)
Loss of the ability to recall information that had been previously encoded in memory prior to a specified or approximate point in time. This process may be organic or psychogenic in origin. Organic forms may be associated with CRANIOCEREBRAL TRAUMA; CEREBROVASCULAR ACCIDENTS; SEIZURES; DEMENTIA; and a wide variety of other conditions that impair cerebral function. (From Adams et al., Principles of Neurology, 6th ed, pp426-9)
A curved elevation of gray matter extending the entire length of the floor of the temporal horn of the lateral ventricle. The hippocampus, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.
Loss of the ability to form new memories beyond a certain point in time. This condition may be organic or psychogenic in origin. Organically induced anterograde amnesia may follow CRANIOCEREBRAL TRAUMA; SEIZURES; ANOXIA; and other conditions which adversely affect neural structures associated with memory formation (e.g., the HIPPOCAMPUS; FORNIX (BRAIN); MAMMILLARY BODIES; and ANTERIOR THALAMIC NUCLEI). (From Memory 1997 Jan-Mar;5(1-2):49-71)
Fiberoptic endoscopy designed for duodenal observation and cannulation of VATER'S AMPULLA, in order to visualize the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (Vater) papillotomy (SPHINCTEROTOMY, ENDOSCOPIC) may be performed during this procedure.
Mergers & Acquisitions
Commercial and market reports on mergers and acquisitions in the biotechnology, pharmaceutical, medical device and life-science industries. Mergers and acquisitions (abbreviated M&A;) is an aspect of corporate strategy, corporate finance and manageme...