Biopsychlogy

• Plasticity describes the nervous system's ability to change
• Most behaviors and characteristics are not "hard-wired", they can change over time
• Plasticity is greatest when we are babies
• Different brain areas remain plastic for longer or shorter
• Different brain regions develop at different rates
• Neurons change in four ways during development:
• Growth of dendrites and axons
• Synaptogenesis: formation of new synapses
• Pruning: consisting of the death of certain neurons and the retraction of axons to remove connections that aren't useful
• Myelination: the insulation of axons with a myelin sheath
• Pruning:
• As many as 70 percent of neurons die off
• This streamlines neural communication (less is more)
• Our brains change as we learn:
• Formation of new synapses, generating increased connections and communication among neurons
• Potentiation: strengthening of existing synaptic connections
• Neurotransmitters released into synapses produce a stronger and more prolonged response from neighboring neurons
• Learning may also change the shape of neurons (structural plasticity)
• Rats raised in enriched environments:
• Large cages with multiple animals, toys, and running wheels
• Once we reach adulthood, our plasticity decreases sharply and we can recover only partially from brain injury and illness
• Stem cells have the capacity to make any cell, even neurons
• Researchers can implant stem cells directly into the host's nervous system and induce them to grow and replace damaged cells
• Some people believe these cells are an early form of human life
• Neurogenesis (generation of new neurons) may occur in the adult brain to a limited extent
• Enhancing neurogenesis could improve function
• Sensory information comes into - and decisions come out of - the central nervous system (CNS)
• Central Nervous System includes the brain and spinal cord, controls mind and behavior
• The nerves outside the CNS are called the peripheral nervous system (PNS)
• Many areas of the brain are associated with a particular function (localization of function)
• Complex tasks often require numerous parts working together
• Each region participates in many functions, so coordination across multiple brain regions contributes to each function
• Cortex:
• Outermost part of the forebrain
• Analyses sensory information and higher brain functions
• Can be divided into four sections: Frontal lobe, Parietal lobe, Occipital lobe, Temporal lobe
• Cortex consists of two cerebral hemispheres, which serve distinct but highly integrated functions
• Cerebral hemispheres are connected by the corpus callosum
• Lateralization:
• Cognitive function that relies more on one side of the brain than the other