History & Systems Chapter 1 Rosenzweig, Bennett, & Diamond (1972) Brain Changes in Response to Experience Study

How many rats were studied? ____ sets of ____ rats from the same/different litter

576 rats; 12 sets of 3 male rats (tested rats were siblings but cagemates did not have to be related)

What was the control group like?

The standard laboratory colony cage contained several rats in an adequate space with food and water always available.

What was the impoverished group like?

The impoverished environment was a slightly smaller cage isolated in a separate room in which the rat was placed alone with adequate food and water.

What was the enriched group like?

Six to eight rats lived in a large cage furnished with a variety of objects with which they could play. A new set of rat toys, from a selection 25 objects, was placed in the cage each day, so the enriched rats experienced a lot of variety or play activities.

All rats had sufficient food and water (true or false)?

true

How did the researchers avoid bias?

the examinations were done in random order by code number so that the person doing the autopsy would not know which condition the rat was raised

________ _________ of enriched mice were thicker and heavier

Cerebral cortexes

Increased activity of the enzyme ____________ in enriched mice (important for memory)

acetylcholinesterase

Enriched rats had larger _______

neurons

Enriched rats had a greater _____ to _____ ratio (important for cell growth)

RNA to DNA

Enriched rats had ________ that were 50% larger

synapses

In a follow-up study, Olson found the most important factor was:

exercise wheel in the enriched cage

What environment increases brain growth?

Enriched environment

What was the main research question?

Does experience change the brain

What animal was studied?

Rats

How long were the rats exposed to environmental conditions?

Four to ten weeks

What rat brain measures were taken?

Weight and thickness

What chemicals were analyzed in the rats?

Neurotransmitter activity

What did experience alter?

Brain anatomy and chemistry

What psychological idea was proven?

Brain plasticity

What can enriched environments help improve?

Memory

What condition can be studied further?

Malnutrition effects