Developmental aspects and neurobiological correlates of working and associative memory.

Objective: It has been shown that verbal working and associative memory have different developmental trajectories with working memory, taking a linear course from early childhood to adolescence, whereas associative memory takes a curvilinear course asymptoting at about age 12. This study made a determination of whether these trajectories tracked with 2 magnetic resonance spectroscopy imaging (MRSI) variables: phosphocreatine level (PCr) and gray matter percentage (GM%).

Method: In a cross-sectional study, 94 children ranging in age from 6-14 years were administered tests of verbal working and associative memory and underwent an MRSI procedure evaluating 6 major brain regions.

Molecular neurodevelopment: an in vivo 31P-1H MRSI study.

Synaptic development and elimination are normal neurodevelopmental processes, which if altered could contribute to various neuropsychiatric disorders. 31P-1H magnetic resonance spectroscopic imaging (MRSI) and structural magnetic resonance imaging (MRI) exams were conducted on 105 healthy children ages 6-18 years old to identify neuromolecular indices of synaptic development and elimination. Over the age range studied, age-related changes in high-energy phosphate (phosphocreatine), membrane phospholipid metabolism (precursors and breakdown products), and percent gray matter volume were found.

31P-MRS study of acetyl-L-carnitine treatment in geriatric depression: preliminary results.

Objective: This 12-week study of two elderly, depressed subjects investigated the effect of acetyl-L-carnitine (ALCAR) treatment on the Hamilton Depression Rating Scale (HDRS) and on measures of high-energy phosphate and membrane phospholipid metabolism.

Methods: Two mildly depressed (HDRS 15-20), non-demented male subjects 70 and 80 years old were compared with six non-demented controls (all males, mean age of 73.6 +/- 3.

Psychosis in Alzheimer disease: postmortem magnetic resonance spectroscopy evidence of excess neuronal and membrane phospholipid pathology.

Background: The presence of psychotic symptoms in Alzheimer Disease subjects (AD+psychosis, AD+P) is a marker for a phenotype characterized by more severe cognitive impairment and a more rapidly deteriorating course. Although AD+P has been inconsistently associated with more severe neuropathology, no prior studies have examined measures of neuronal and synaptic integrity.

Objective: To determine whether AD+P is associated with evidence of disrupted neuronal and synaptic integrity, as indicated by magnetic resonance spectroscopy (MRS) measurement of N-acetyl-L-aspartate and the membrane breakdown products, glycerophosphocholine and glycerophosphoethanolamine.