Subject(s)
Brain Injuries/diagnosis , Brain Mapping/methods , Brain/pathology , Diffuse Axonal Injury/diagnosis , Diffusion Magnetic Resonance Imaging/methods , Adult , Anisotropy , Brain/physiology , Brain Injuries/complications , Brain Injuries/pathology , Brain Mapping/instrumentation , Diffuse Axonal Injury/complications , Humans , Reference ValuesABSTRACT
Recent studies have indicated a role for the thalamus in attention, arousal and the capacity to perform tasks of speeded information processing. The present study evaluated the role of the thalamus in age-related cognitive decline by investigating the correlations between thalamic volume, cognition and age. This was done in 57 healthy subjects ranging from 21 to 82 years of age. All subjects underwent neurocognitive testing with information processing tests and structural magnetic resonance imaging. A significant decrease in volume of the thalamus with increasing age was found, relatively stronger than and independent of the decrease of total brain volume. The decrease of thalamic volume was apparent before the onset of loss of volume of the total brain. Over the age-span studied, the thalamic decrease in volume correlated with the diminished performance on tests of cognitive speed. Additionally, in young and middle-aged, but not in old subjects, the size of the thalamus predicted performance on tasks that require cognitive speed.
Subject(s)
Aging/physiology , Aging/psychology , Cognition/physiology , Magnetic Resonance Imaging , Thalamus/anatomy & histology , Thalamus/physiology , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Reaction Time/physiology , Reference ValuesABSTRACT
In a cross-sectional analysis of 818 healthy older individuals (aged 50 to 81 years), head size was found to be related to performance on tests measuring intelligence, global cognitive functioning, and speed of information processing, but not memory. These relations were not confounded by educational level, socioeconomic background, or height. Large head/brain size may protect elderly people against cognitive deterioration, supporting a reserve hypothesis of brain aging.
Subject(s)
Aging/physiology , Cognition/physiology , Dementia/physiopathology , Head/anatomy & histology , Aged , Aged, 80 and over , Dementia/psychology , Female , Humans , Male , Middle Aged , Neuropsychological TestsABSTRACT
The present study investigated the range of age-related changes in brain morphology and the relation with performance on memory and other cognitive tests in a healthy population. A group of 61 subjects (21 to 81 years old, mean = 55.7), free from cognitive and medical deficits, underwent MRI scanning and neuropsychological assessment encompassing memory and other cognitive tests. Volumetry of the hippocampus, parahippocampal gyrus, mamillary bodies, third ventricle, and total brain matter was performed. The results indicate that in healthy individuals increases in ventricular volume and volume decreases in total brain matter, hippocampus and parahippocampal gyrus, but not mamillary bodies, are clearly apparent with increasing age. However, no relation could be established between the brain volumes and test performance when controlling for the effects of age. To conclude, variations in total and limbic brain volumes do not seem predictive for cognitive performance independent of age.
