Physiological Explanations for Changes in the Brain with Age

Types of Changes Large scale anatomical changes Changes at the level of the neuron Plasticity in the aging nervous system

Functional MRI Detects changes in blood flow to active areas of brain Different ages = differences in task-related activity in a given brain region? Inconclusive results

Changes in Cerebral Cortex Frontal lobe: planning/decision making Hippocampus: involved in memory Some 60 to 90 year olds, no appreciable neuronal loss Multiple influences: mental activity and aerobic activity

Other Structural Changes Subcortical basal forebrain: lower brain centers that support more advanced brain structures involved in higher-order cognitive functions Growth factor gene therapy

Sex Differences in Age-Related Changes in the Brain Male: more pronounced brain atrophy with age Males: left hemisphere Female: less brain atrophy Female: symmetrical changes Role of estrogen in brain health

Influences on Neurological Changes Psychological, social and environmental Circulatory system Blood-brain barrier

Changes in and Between Neurons Parts of a Neuron –Dendrites - branch-like structures that receive messages from other neurons. –Axon - long tube-like structure that carries the neural message to other cells. –Synapse- site of communication between neurons

Neuron communication

Changes In and Between Neurons Some cell death does occur Larger neurons most susceptible Redundancy Compensatory mechanisms Sprouting Environmental enrichment/deprivation Aerobic fitness/diet

Plasticity Prenatal development-mitosis Neurogenesis Dynamic nervous system