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