Biological Bases of Behavior
1. Biological psychologists are gaining a better understanding of our experiences of sights and
sounds, meanings and memories, pain and passion. Franz Gall invented phrenology, a popular
theory that claimed that bumps on the skull reveal our mental abilities and our character traits.
Although wrong, this information revealed that various brain regions have specific functions.
2. A neuron consists of a cell body and branching fibers:The dendrite fibers receive information
from sensory receptors or other neurons, and the axon fibers pass that information along to other
neurons. Sensory neurons send information from the body’s tissues and sensory organs inward
to the brain and spinal cord, which process the information. Motor neurons carry outgoing
information from the central nervous system to the body’s tissues.Interneurons in the central
nervous system communicate internally and intervene between the sensory inputs and the motor
outputs. The axons of some neurons are encased by a myelin sheath, which helps speed their
impulses. A neural impulse, or action potential, fires when the neuron is stimulated by signals
from the senses or when triggered by chemical signals from neighboring neurons. Received
signals trigger an impulse only if the excitatory signals minus the inhibitory signals exceeds a
minimum intensity called the threshold. The neuron’s reaction is an all-or-none response. During
the resting potential, the fluid interior of the axon carries mostly negatively charged atoms(ions),
while the fluid outside has mostly positively charged atoms.Then, the first bit of the axon is
depolarized (its selectively permeable surface allows positive ions in), and the electrical impulse
travels down the axon as channels open, admitting ions with a positive charge. When these
channels close, others open and positive ions are pumped back out, restoring the neuron to its
polarized state.
3. When
sounds, meanings and memories, pain and passion. Franz Gall invented phrenology, a popular
theory that claimed that bumps on the skull reveal our mental abilities and our character traits.
Although wrong, this information revealed that various brain regions have specific functions.
2. A neuron consists of a cell body and branching fibers:The dendrite fibers receive information
from sensory receptors or other neurons, and the axon fibers pass that information along to other
neurons. Sensory neurons send information from the body’s tissues and sensory organs inward
to the brain and spinal cord, which process the information. Motor neurons carry outgoing
information from the central nervous system to the body’s tissues.Interneurons in the central
nervous system communicate internally and intervene between the sensory inputs and the motor
outputs. The axons of some neurons are encased by a myelin sheath, which helps speed their
impulses. A neural impulse, or action potential, fires when the neuron is stimulated by signals
from the senses or when triggered by chemical signals from neighboring neurons. Received
signals trigger an impulse only if the excitatory signals minus the inhibitory signals exceeds a
minimum intensity called the threshold. The neuron’s reaction is an all-or-none response. During
the resting potential, the fluid interior of the axon carries mostly negatively charged atoms(ions),
while the fluid outside has mostly positively charged atoms.Then, the first bit of the axon is
depolarized (its selectively permeable surface allows positive ions in), and the electrical impulse
travels down the axon as channels open, admitting ions with a positive charge. When these
channels close, others open and positive ions are pumped back out, restoring the neuron to its
polarized state.
3. When