Objective 2.4: *Discuss two effects of the environment on physiological processes. *section B essay question

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Objective 2.4Discuss two effects of the
environment on physiological processes.
section B essay question
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Things to consider.

• Early 20th 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).

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Two effects

• The effect of Enriched Environments on Brain
  Plasticity
• The effect of the environment on mirror neurons.

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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.

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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 brains adaptation to
  the environment.

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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)

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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.

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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?

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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.

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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.

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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

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Kolb (1999)

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

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Research on environmental enrichment cont.

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

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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.

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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 (deprivationsuch as in
  old-style orphanages) delays and impairs
  physiological parts of the brain responsible for
  cognitive development.

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Extra Credit Summary The Case of Genie
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Responding to the environmentHave you ever have
a sensation where youre 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.
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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?

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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.

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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.

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Mirror neurons and the environment.

• http//www.ted.com/talks/vs_ramachandran_the_neuro
  ns_that_shaped_civilization.html

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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 observers 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.

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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.

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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.

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More Info

• http//www.robotcub.org/misc/papers/06_Rizzolatti_
  Craighero.pdf