How Enriched Environments Benefit The Brain
Animal studies have found that enriched environments can induce important changes in the brain, including enhanced functioning and development in areas related to cognitive capacity, learning, memory, and resilience. Depending on the design of the study, the results might include more neurons, longer dendrites, more connections, heavier brains, greater brain mass, more intra- and intercortex connectivity, and enlarged capillaries. Changed brains can be contrasted with a control group and measured in many ways.
To understand, measure, and validate these changes, researchers use a variety of both "old school" methods and very smart new ones. These include
- Behavioral tasks such as running a radial arm maze or swimming in a Morris water maze
- Brain scans such as an MRI to measure changes in tissue volume
- Use of marker dyes such as a green fluorescent protein that glows when a cell divides to show increased new cell generation
- Autopsies, which can reveal precise measurements of brain weight, cell-to-cell connectivity, or even the density of synapses
Enhanced environmental stimulation can affect the brain in many ways. To simplify the discussion here, I'll focus on six fundamentally different effects. They are consistent—and for every study I describe, there are many others with similar findings.
- Metabolic allostasis: Changes in blood flow, baseline chemical levels, and metabolic functioning
- Enhanced anatomical structures: Larger neurons and more developed cell structures
- Increased connectivity: Increased circuitry and branching from one neuron to another
- Responsiveness and learning efficiency: Enhanced electrical signaling, cell efficiency, and neural processing
- Increased neurogenesis and growth factors: Production of new brain cells as well as special proteins important for the brain's survival
- Recovery from trauma and system disorders: Protection from stress and greater capacity to heal when damaged
It is true that any of these changes can (and sometimes do) happen without efforts to enhance the environment. But it is the degree, the rate, and the complexity of change that differentiate efforts at environmental enrichment from other, more basic, learning or maturational processes. The studies reliably show that changes do occur from enhanced environmental efforts.13 In many cases, they can facilitate what seem like miracles. For the moment, suffice it to say that there are many verifiable and enticing benefits to the enrichment process. When taken as a whole, they really do seem remarkable.
The word allostasis refers to a resetting or readjustment of baseline brain levels. Environmental stimulation can enhance blood flow in the brain as well as boost levels of chemicals important to learning, mood, and cognition. The first group of relevant studies were by neuroscientist Matti Saari, whose group in Canada has shown changes in regional cerebral metabolism.14 In addition, his group found that these changes in blood flow are regionally specific to the thalamic, cortical, and hippocampal areas.15 Those areas play critical roles in learning, consciousness, and memory, and we must pay close attention to the results.
Another area of high interest is the neurotransmitters, a group of chemicals that includes erotonin and dopamine. These are essential for learning, mood, memory, and communication within the brain. Animal studies have found that levels of these chemicals can be altered as a result of enrichment efforts. Acetylcholine, a common neurotransmitter known to help with memory formation, also increases in enrichment studies.16 Remarkably, enrichment exercise can even enhance activity of opioid (pleasure and analgesic) sites.17 Enrichment efforts can help regulate serotonin to enhance mood and improve cognitive flexibility.18 This research is highly relevant because of the relationship to stress and stress disorders.
Studies show that rats getting an enrichment protocol gain some protection from stress disorders. In fact, it can lead to pronounced changes in neuroendocrine regulation compared with those in a more basic control environment.19 The enrichment protocols decrease the release of stress-responsive hormones.20 In addition, enrichment studies support the reversal of social isolation, too.21
Researchers find, as a result of changes in specific chemicals, a reduction in nonhuman primate aggression from an enrichment effect in the environment.22 These are all positive effects from essential brain chemicals that can improve mood, memory cognition, or both. Most teachers would be ecstatic to have students with enhancements in these areas.