The Brain: Neuroplasticity and Tools of Discover 1.4a

1.4-1 Why are psychologists concerned with human biology?

• Phrenology: studying bumps on the skull and now a debunked practice

• Biological psychologists use advanced technology to study links between biological (genetic, neural, hormonal) and psychological processes

• Researchers discovered:

  • among the body’s cells are neurons that conduct electricity and “Talk to one another by sending chemical messages across a synapse

  • our experiences wire our adaptive brain

  • specific brain systems serve specific functions

  • we integrate info processed in these brain systems to construct our experiences of sights and sounds, meanings and memories, pain and passion

  • we are each a system composed of subsystems that are in turn composed of even smaller systems

• the biopsychosocial approach uses three levels on analysis: biological, psychological, and social-cultural

  • Biological: Genetics, brain mechanisms, and hormonal influences.

  • Psychological: Emotions, learned experiences, and cognitive processing.

  • Social-Cultural: Influence of culture, relationships, and social environments

The Power of Neuroplasticity

• your brain is constantly changing as it adjusts to new experiences (neuroplasticity)

• Ex: If a pianist practices 45 min a day on the piano their motor learning-related brain areas will grow

Main Idea: Neuroplasticity is how humans are able to adapt, this leads to growth in systems of the brain. Think of how much the world changed in 50 years and how it’ll continue to change

Tools of Discovery: Having our Head Examined

• we think with our brain, by releasing billions of neurotransmitter molecules across trillions of synapses

• damage to one side of the brain caused numbness or paralysis on the opposite side

  • suggesting that the body’s right side if wired to the brain’s left and vice versa

• damage to the back of the brain disputed vision

• damage to the left front part of the brain produced speech difficulties

• now, scientists can selectively lesion (destroy) tiny clusters of brain cells, observing brain function

• now, neuroscientists can stimulate brain parts (electrically, chemically, or magnetically) and note the effects

• optogenetics: a technique that allows neuroscientists to control the activity of individual neurons

• EEG (electroencephalogram): amplified readout of waves of electrical activity sweeping across the brain’s surface

  • recorded through a shower-cap-like hat filled with electrodes covered with conductive gel

  • researchers lack direct access to the brain but can present a stimulus repeatedly and have a computer filter out brain activity unrelated to the stimulus

  • Good for measuring brain activity but lacks detailed spatial resolution

• MEG (magnetoencephalography): measures magnetic fields from the brain’s natural electrical activity

  • to isolate the brain’s magnetic fields, researchers create special rooms that cancel out other magnetic signals

  • participants sit underneath a head coil that’s like a salon hair dryer

  • participants complete activities that send tens of thousands of neurons that generate electrical pulses, which creates a magnetic field

• CT (computed tomography) scan: examines the brain by taking X ray photographs that reveal brain damage

  • able to see inside the living brain

• PET (positron emission tomography): depicts brain activity by showing each brain area’s consumption of sugar glucose

  • active neurons eat glucose

  • after a person receives temporarily radioactive glucose, the PET scan tracks the gamma rays released by this “food for thought” as a task is performed

  • PET scan “hot spots” show the most active brain areas as the person does math calculation, daydreams, looks at images of people

• MRI (magnetic resonance imaging): uses magnetic fields and radio waves to produced computer-generated images of soft tissue

  • show brain anatomy

  • patient’s head is put into a magnetic field, which aligns spinning atoms in brain molecules

    • then radio wave pulse momentarily disorients the atoms

    • after atoms return to normal spin, they emit signals that provide detailed pictures of soft tissues

  • Ex: scans revealed larger than average neural area in left hemisphere of musicians who display perfect pitch

• fMRI (functional MRI): a technique for revealing blood and flow, and brain activity by comparing succecsive MRI scans

  • where the brain is especially active, blood goes

  • by comparing successive MRI scans, researchers can watch as specific brain areas activate, showing increased oxygen-laden blood flow

  • Provides detailed images of brain activity but requires the subject to remain still

Understanding the tools and techniques used in neuroscience helps us appreciate how our adaptive and complex brain works. Neuroplasticity, for example, highlights the brain's resilience and potential for growth, while imaging technologies like fMRI and PET scans help us visualize brain activity and its links to behavior