News event memory in amnestic and non-amnestic MCI, heritable risk for dementia, and subjective memory complaints.

Robust and sensitive clinical measures are needed for more accurate and earlier detection of Alzheimer's disease (AD), for staging preclinical AD, and for gauging the efficacy of treatments. Mild impairment on episodic memory tests is thought to indicate a cognitive risk of developing AD and mild cognitive impairment (MCI), considered to be a transitional stage between normal aging and AD. Novel tests of semantic memory, such as memory for news events, are also impaired early on but have received little clinical attention even though they may provide a novel way to assess cognitive risk for AD.

The Retrograde Memory for News Events Test (RM-NET) and the relationship between news event memory and performance on standard neuropsychological tests.

Novel tests of semantic memory (SM)-for example, memory for news events (NE; news facts) or famous personalities-are useful for estimating the severity of retrograde amnesia. Individuals with mild cognitive impairment exhibit relatively intact SM/language on traditional neuropsychological tests but exhibit consistent impairment on novel tests of SM, suggesting novel SM tests are dissimilar from traditional SM tests. To identify the relationship between NE memory and traditional cognitive measures, older adults ( = 51) completed a traditional neuropsychological battery and the Retrograde Memory News Events Test (RM-NET; a new test that robustly measures NE memory across the adult life span with high temporal resolution), and the relationship between performance on these tests was examined.

One-trial perceptual learning in the absence of conscious remembering and independent of the medial temporal lobe.

A degraded, black-and-white image of an object, which appears meaningless on first presentation, is easily identified after a single exposure to the original, intact image. This striking example of perceptual learning reflects a rapid (one-trial) change in performance, but the kind of learning that is involved is not known. We asked whether this learning depends on conscious (hippocampus-dependent) memory for the images that have been presented or on an unconscious (hippocampus-independent) change in the perception of images, independently of the ability to remember them.

Neuropsychological and neuropathological observations of a long-studied case of memory impairment.

We report neuropsychological and neuropathological findings for a patient (A.B.), who developed memory impairment after a cardiac arrest at age 39.

Learning and remembering real-world events after medial temporal lobe damage.

The hippocampus is important for autobiographical memory, but its role is unclear. In the study, patients with hippocampal damage and controls were taken on a 25-min walk on the University of California, San Diego, campus during which 11 planned events occurred. Memory was tested directly after the walk.

When recognition memory is independent of hippocampal function.

Hippocampal damage has been thought to result in broad memory impairment. Recent studies in humans, however, have raised the possibility that recognition memory for faces might be spared. In five experiments we investigated face recognition in patients with hippocampal lesions (H) or large medial temporal lobe (MTL) lesions, including patients where neurohistological information was available.

The nature of anterograde and retrograde memory impairment after damage to the medial temporal lobe.

The study of anterograde and retrograde amnesia (AA and RA) in the laboratory and the clinic has provided important information about the structure and organization of memory. The severity of AA is usually correlated with the severity of RA. Nevertheless, variations in the expression of AA and RA have been reported, which presumably reflect variation in the locus and extent of brain damage.

Memory, visual discrimination performance, and the human hippocampus.

We evaluated recent proposals that the hippocampus supports certain kinds of visual discrimination performance, for example, when spatial processing is required and the stimuli have a high degree of feature overlap. Patients with circumscribed hippocampal lesions tried to discriminate between images of similar faces or images of similar scenes. In one condition, elements of the stimulus display repeated from trial to trial, and in another condition every trial was unique.

Role of the hippocampus in remembering the past and imagining the future.

It has been proposed that a core network of brain regions, including the hippocampus, supports both past remembering and future imagining. We investigated the importance of the hippocampus for these functions. Five patients with bilateral hippocampal damage and one patient with large medial temporal lobe lesions were tested for their ability to recount autobiographical episodes from the remote past, the recent past, and to imagine plausible episodes in the near future.

Losing memories overnight: a unique form of human amnesia.

Since an automobile accident in 2005, patient FL has reported difficulty retaining information from one day to the next. During the course of any given day, she describes her memory as normal. However, memory for each day disappears during a night of sleep.

Robust habit learning in the absence of awareness and independent of the medial temporal lobe.

Habit memory is thought to involve slowly acquired associations between stimuli and responses and to depend on the basal ganglia. Habit memory has been well studied in experimental animals but is poorly understood in humans because of their strong tendency to acquire information as conscious (declarative) knowledge. Here we show that humans have a robust capacity for gradual trial-and-error learning that operates outside awareness for what is learned and independently of the medial temporal lobe.

Failure of serum ferritin levels to predict bone-marrow iron content after intravenous iron-dextran therapy.

The relation between serum ferritin levels and stainable-iron deposits in the liver, spleen, and bone marrow was investigated in 36 patients with chronic renal failure who died after being on haemodialysis for 1-103 months. Elemental iron (mean, 5450 mg) had been given intravenously as iron dextran to patients in a long-term subgroup, who had been on dialysis for more than 3 months. The results of semiquantitative histochemical assessment of tissue iron in slides obtained at necropsy (scale 0 to 4+) were confirmed by chemical analyses of tissue iron.

Hemosiderosis in hemodialysis patients. An autopsy study of 50 cases.

The distribution of stainable iron stores was investigated in various organs of 50 hemodialysis patients with chronic renal disease. Massive iron deposits were found in the liver and spleen. Among 18 patients with severe hepatosplenic siderosis, iron deposits were abundant in the adrenal glands, lymph nodes, and lungs and were sparse in the heart, kidneys, and pancreas.

Acute renal failure in sickle cell trait.

Acute renal failure and a syndrome characteristic of acute renal vein thrombosis developed in a patient with sickle trait and gram-negative bacteremia. It is suggested that intrarenal vaso-occlusion by sickled erythrocytes produced signs and symptoms typical of renal vein thrombosis and contributed to the severity of the acute renal failure.