Lecture 21 - Fit body, fit brain?

Question 1

What is the rate of brain shrinkage?

Answer 1

The brain shrinks 5% per decade after the age of 40. the front parts of the brain are the most affected; the planning and execution of movements will be hindered. Due to ageing, the HIPPOCAMPUS (in temporal lobe) which consolidates short term memory to long term memory and this is impaired due to ageing

Question 2

What are the effects of age on cognition

Answer 2

• the most common effect is impaired memory
  there are four parts to memory
  1) Episodic (events) - recall events of life e.g. for 80 year old this would be hard
  2) Semantic (facts)
  3) Procedural (skills and habits) - ability to remember how to do physical things
  4) Working (short-term) - bench space -> capacity to process things at the same time

Question 3

What is the Nurses’ health study

Answer 3

obtained 121,700 nurses aged 30-55 were given a questionnaire every 2 years. The cognitive function was assessed 1995-2001, 18,766 women aged 70 - 81 yrs participated. Higher levels of activity associated with better cognitive function. Divided into 5 groups based on energy expenditure. The two highest energy groups had 20% lower risk of cognitive decline than the lowest energy group. There is a rate of cognitive decline and the level of energy expenditure. –> long term PA including walking is associated with significantly better cognitive function and less cognitive decline in older women. Those who walked at least 1.5 hours per week were significantly better off than those who walked for less than 40 min/week

Question 4

What is the Honolulu study

Answer 4

2,257 men 71 - 93 years, cognitive function at baseline and 6-8 years later. Higher levels of PA associated with fewer cases dementia (people who walked 2 miles a day show the least susceptibility to dementia

Question 5

Is exercise neuroprotective

Answer 5

PA slows down the cognitive decline. Importantly, the PA does not have to be particularly vigorous, with walking for 90 mins a week or at least a mile per day, sufficient to produce a beneficial effect

Question 6

what are the 4 categories of cognition

Answer 6

1) Executive - inhibition of a planner response; get ready to execute movement but last second you abort and change the movement
2) Controlled - choice reaction time task
3) Spatial - reproducing a complex line drawing from memory, and mental rotation tasks
4) Speed - simple reaction time task

Question 7

what are the fitness effects on cognitive function

Answer 7

11% improvement on task after walking but only 2% improvement after stretching - aerobic fitness levels associated with greater activity in brain areas required for executive function, but less in areas that resolve conflicting cues

Question 8

How does exercise help the brain

Answer 8

• it increases capillary supply - area of the brain responsible for memory is particularly vulnerable to decreases in blood flow (takes away waste material from the brain)
• increases brain growth factors - new connections between cells and new cells (connections to be made)

Question 9

What is the hippocampus

Answer 9

• it is important for long-term memory, shrinks in late adulthood - this impairs memory and increases the risk of dementia

Question 10

Can exercise prevent brain shrinkage

Answer 10

Yes, and participants with higher fitness at baseline had less decline. Fitness is protective, the exercise group had greater serum levels of BDNF a mediator of neurogenesis.

Question 11

What is BDNF

Answer 11

Brain derived Neurotrophic factor - enables hippocampus size to be increased and new connections and cells in brain

Question 12

Can exercise improve cognitive function/prevent cognitive decline

Answer 12

Yes, in healthy older adults

For people with dementia or Alzheimer’s disease –> in extreme cases, results could be minimal BUT if not extreme, exercise can help to improve overall behaviour and cognitive levels