ageing brain

The Ageing Brain: Memory, Adaptation & Resilience Notes

Introduction to Neurological Ageing

What is neurological ageing?

• Progressive biochemical, structural and functional changes in the nervous system over time.

• Leads to gradual decline in:

  • Motor function

  • Sensory function

  • Cognitive function

Why study neurological ageing?

• By 2050, nearly 1 in 6 people worldwide will be over 65.

• Higher age = higher risk of neurological disorders.

• Important for:

  • Brain health maintenance

  • Medical and scientific research

  • Everyday functioning and quality of life

Normal Ageing vs Disease

Normal ageing ≠ neurodegenerative disease

Progression

Healthy ageing → Mild cognitive changes → Neurodegenerative disease

Structural Brain Changes in Ageing

Cerebral atrophy

Main features:

1. Ventricular enlargement

2. Cortical thinning

3. White and grey matter volume loss

4. Sulcal widening

Biochemical Mechanisms of Brain Ageing

Key mechanisms:

• Neuroinflammation

• Oxidative stress

• Mitochondrial impairment

• Impaired proteostasis

• Decline in neurotransmitters and neurotrophic factors

Cognitive Changes in Ageing

Common cognitive declines

Memory impairment

• Hippocampal atrophy reduces synaptic plasticity.

• Decline in BDNF (Brain-Derived Neurotrophic Factor).

Slower processing speed

• Reduced white matter integrity slows neural transmission.

Reduced attention & multitasking

• Prefrontal cortex shrinkage affects working memory.

• Dopamine and acetylcholine decline.

Executive function decline

• Problems with:

  • Decision making

  • Planning

  • Problem solving

  • Judgement

  • Cognitive flexibility

Ageing and Memory Systems

Important point

Ageing affects different memory systems differently.

Some decline, while others remain stable or improve.

Types of Memory in Ageing

Working Memory

Associated brain area:

• Prefrontal cortex

Function:

• Temporary holding/manipulation of information

Effect of ageing:

• Reduced capacity

• Slower processing

Episodic Memory

Associated brain area:

• Hippocampus

• Medial temporal lobe

Function:

• Personal experiences/events

Effect of ageing:

• Often declines with age

Semantic Memory

Associated brain area:

• Temporal & parietal cortex

Function:

• Facts, vocabulary, concepts

Effect of ageing:

• Often stable or improves

Procedural Memory

Associated brain area:

• Basal ganglia & cerebellum

Function:

• Skills/habits (e.g., cycling, typing)

Effect of ageing:

• Largely preserved

Cognitive Reserve & Compensation

Cognitive reserve

Definition:

• Brain’s ability to cope with age-related damage/change.

Built through:

• Education

• Learning

• Life experiences

• Cognitive stimulation

Compensation

Definition:

• Recruitment of additional/alternative brain networks.

Features:

• Increased bilateral brain activation.

• Brain adapts instead of simply declining.

Risk Factors for Brain Ageing

Modifiable lifestyle factors

(can be changed)

• Smoking

• Physical inactivity

• Poor diet

• Excess alcohol

• Depression

• Social isolation

• Air pollution

Health & physiological factors

(can be managed)

• Cardiovascular disease

• Metabolic disease

• Hearing/vision loss

• Traumatic brain injury

Cognitive & educational factors

• Educational experience

• Cognitive reserve

Non-modifiable factors

• Age

• Genetics

• Sex

• Ethnicity

Supporting Brain Resilience

Healthy brain ageing strategies

Lifestyle factors

• Regular exercise

• Healthy diet

• Social engagement

• Mental stimulation

• Good sleep

Therapeutic interventions

• Early treatment

• Risk-factor management

Physiological adaptive mechanisms

• Neuroplasticity

• Brain network compensation

Key Points Summary

1. Normal ageing changes the brain but is not a disease.

2. Different memory systems are affected differently.

3. Lifestyle and environment strongly influence brain ageing.

4. Early intervention and risk management are important for healthy ageing.