Magnetic Resonance Imaging (MRI)

Although neuropsychological studies of the amnesic patient H. M. provide compelling evidence that normal memory function depends on the medial temporal lobe, the full extent of his surgical resection has not been elucidated. We conducted magnetic resonance imaging studies to specify precisely the extent of his bilateral resection and to document any other brain abnormalities.

To test the hypothesis that cortical remapping supports phantom sensations, we examined referred phantom sensations and cortical activation in humans after spinal-cord injury (SCI) at the thoracic level (T3-T12). Of 12 SCI subjects, 9 reported phantom sensations, and 2 reported referred phantom sensations.

Anatomic and functional neuroimaging have a potential for clarifying the differential diagnosis of dementia and for evaluating new treatments for memory impairment. Our neuroimaging research examines the neural abnormalities underlying memory impairment in aging and Alzheimer's disease. We use data from high-resolution magnetic resonance imaging (MRI) to measure hippocampal volumes, and data from high-speed echo-planar imaging to evaluate cortical physiology.

Memory for recently encountered information can be reflected in conscious recall and recognition of that material, or in facilitated reprocessing of that material, an effect known as repetition priming. Repetition priming may be perceptual (form-based) or conceptual (meaning-based). A patient with bilateral occipital-lobe lesions (L.H.) and a patient with bilateral medial-temporal lobe lesions (H.M.) showed a double dissociation between visuoperceptual priming (impaired in L.H. and intact in H.M.) and visual recognition memory (intact in L.H. and impaired in H.M.). L.H.

We studied a woman (Case 1) who acquired achromatopsia, prosopagnosia, and memory loss after sustaining bilateral temporal-lobe lesions. Given her symptoms and locus of lesion, the affected area may be related to the monkey visual area IT. In order to examine her deficits, we assessed her basic discrimination capacities in several domains. She performed normally when stimuli differed in contrast, size, or motion. her performance was abnormal for patterned targets, and was markedly impaired when the patterned targets were less prominent than distractors.

Modern scientific knowledge of how memory functions are organized in the human brain originated from the case of Henry G. Molaison (H.M.), an epileptic patient whose amnesia ensued unexpectedly following a bilateral surgical ablation of medial temporal lobe structures, including the hippocampus. The neuroanatomical extent of the 1953 operation could not be assessed definitively during H.M.'s life. Here we describe the results of a procedure designed to reconstruct a microscopic anatomical model of the whole brain and conduct detailed 3D measurements in the medial temporal lobe region.

BACKGROUND: Neurodevelopmental evidence of the cerebellum's protracted course of postnatal development suggests that it is particularly sensitive to early toxic insult from cancer therapy. If this is the case, one would expect that there is a relationship between the pattern of neuropsychological and magnetic resonance imaging deficits and that both may indicate cerebellar abnormalities.

BACKGROUND: Long-term survivors of acute lymphoblastic leukemia (ALL) are reported to have post-treatment neurological changes as well as neuropsychological changes. Few studies have investigated the relationship between magnetic resonance imaging (MRI) volumetric measurements of brain regions of interest and cognitive functioning. This study examined the relationship between hippocampal volumes and long-term memory abilities in survivors of ALL.

BACKGROUND: Following brain insult in early childhood, the later maturing neocerebellum and frontal lobes frequently show abnormalities.

Neurotoxic intrathecal chemotherapy for childhood acute lymphoblastic leukemia (ALL) affects developing structures and functions of memory and learning subsystems selectively.