Objective 2 4 Discuss two effects of the

Objective 2. 4: *Discuss two effects of the environment on physiological processes. *section B essay question 1

Things to consider…. Early 20 th century: believed that brain was only influenced by genes and thus unchangeable Now we know that environmental enrichment /deprivation(an environmental factor) can modify the brain (a physiological process). 2

Two effects: The effect of Enriched Environments on Brain Plasticity The effect of the environment on mirror neurons. 3

Environment and Brain Plasticity Neuroplasticity is a term referring to the ability of physiological processes in all species to change structurally and functionally as a result of input from the environment • Plasticity occurs on a variety of levels, ranging from cellular changes involved in learning, to large-scale changes involved in cortical remapping in response to injury and disease. • 4

Environment and Brain Plasticity The idea of Brain Plasticity suggest that the brain has the ability to rearrange connections between its neurons-that is, the ability for the brain to physically change due to learning or experience. The changes represent our brain’s adaptation to the environment. • 5

1. Environmental Enrichment • Neurons can compensate for injury or disease or to adjust their activities in response to new situations or changes in the environment. The brain is most plastic early in life (This is known as the critical period). • The brain can rearrange the connections between neurons (dendritic branching) 6

Environment and Brain Plasticity • The brain can generate new neurons throughout life (neurogenesis) • Learning can increase/decrease neurotransmission between specific neurons (long term potentiation) • It is assumed that as your behavior changes (in most cases because of environmental change), so does the underlying neural circuitry. 7

Effects of environmental enrichment on brain plasticity. Environmental enrichment concerns how the brain is affected by the stimulation of its information processing provided by its surroundings (including the opportunity to interact socially). Brains in richer, more stimulating environments, have increased numbers of synapses, and the dendrite arbors upon which they reside are more complex. This effect happens particularly during neurodevelopment, but also to a lesser degree in adulthood. What does this suggest? 8

Rosenzweig & Bennett (1972) • Aim: To investigate the effect of enrichment or deprivation on the development of neurons in the cerebral cortex in rats • Research method: Experiment • Procedure: Rats were placed in either a stimulating environment (toys) or a deprived environment (no toys). • The rats spent 30 or 60 days in their environment and then they were dissected.

Rosenzweig & Bennett (1972) • Findings: Post mortem studies of the rats´ brains showed that those that had been in a stimulating environment had an increased thickness in the cortex.

Kolb (1999) • Aim: To investigate if stimulating environments affect the growth of neurons in rats • Research method: Experiment • Procedure: Rats were placed in enriched environments beginning at weaning or as young adults. Control group were placed in standard cages

Kolb (1999) • Findings: Both age groups raised in enriched environments showed a large increase of the length of dendrites in cortical neurons.

Research on environmental enrichment cont. • Two important and consistent findings have emerged from this type literature. o First, and not surprisingly, rodents learn and remember better in an enriched environment. o Second, neurogenesis (the creation of new nerve cells) is increased in an enriched environment, specifically in the hippocampus. o Thus, animal studies showing the benefits of environmental enrichment provide important corroborating evidence. 13

• • Research on environmental enrichment cont. Such studies suggest that brains are physically sculpted by our environments. Aspects of the brain can be changed as we go through experiences. As a person develops a greater number of skills and abilities, the brain actually becomes more complex and heavier. Research has also suggested that Children who are unable to have certain experiences, will have specific parts of their brain significantly less developed, less intricate, and thinner in comparison to those who have had those experiences. 14

Research on deprivation and brain damage. • According to the principle that states animal research can be used in place of human because of their biological similarities, we can infer that a lack of stimulation (deprivation—such as in old-style orphanages) delays and impairs physiological parts of the brain responsible for cognitive development. 15

Extra Credit Summary: The Case of Genie 16

Responding to the environment Have you ever have a sensation where you’re watching someone do something and you can just feel exactly what they must be feeling, as if you were in their shoes? Think of an example. 17

Mirror neurons and the environment. • Another way in which the brain and environment interact is through the activity of the recently discovered mirror neurons. Mirror neurons are neurons that fire when an animal performs an action or when the animal observes somebody else perform the same action. • This means we subconsciously mimic the actions of others and thus share, to some extent, their experience. How can this be effected by your environment? 18

Mirror neurons and the environment. • Scientists have long wondered why we get that feeling, and more than two decades ago, a team of Italian researchers thought they stumbled on an answer. • While observing monkeys’ brains, Gallese et. Al (1996) noticed that certain cells activated both when a monkey performed an action and when that monkey watched another monkey perform the same action. “Mirror neurons” were discovered. 19

Mirror neurons and the environment. • Scientists have long wondered why we get that feeling. A team of Italian researchers thought they stumbled on an answer. • While observing monkeys’ brains, Gallese et. al (1996) noticed that certain cells activated both when a monkey performed an action and when that monkey watched another monkey perform the same action. “Mirror neurons” were discovered. 20

Mirror neurons and the environment. http: //www. ted. com/talks/vs_ramachandran_the_neurons_that_s haped_civilization. html 21

2. Mirror neurons and the environment. • The proposed mechanism is rather simple. Each time an individual sees an action done by another individual, neurons that represent that action are activated in the observer’s premotor cortex. • This automatically induced, motor representation of the observed action corresponds to that which is spontaneously generated during active action and whose outcome is known to the acting individual. • Thus, the mirror-neuron system transforms visual information into knowledge. 22

Mirror neurons and the environment. • These mirror neurons, as they are known, also allow us to know what another person is feeling, without having to think about it. • The discovery of mirror neurons is among the most significant neuroscientific discoveries in recent years. • This mean that when you see someone doing something, in your brain you do it too - for instance, when you watch a person running, the bit of your brain concerned with planning to move the legs is activated. 23

Mirror neurons and the environment. • When you see another person expressing an emotion, the areas of your brain associated with feeling that emotion are also activated, making emotions transmittable. • Emotion mirroring is thought to be the basis of empathy. Autistic people often lack empathy and have been found to show less mirror-neuron activity. • Mirror neurons explain why emotion is whipped up in horror film audiences - seeing someone else looking frightened makes you feel scared yourself. 24

• More Info: http: //www. robotcub. org/misc/papers/06_Rizzolatti_Craighero. pdf 25