Invitation to Psychology

COn

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ept Map

Chapter 4

Neurons,

h

ormones, and the Brain

Chapter 4 Neurons, Hormones, and the Brain 151

A Tour Through the Brain

The Realms of Sleep

All modern brain theories assume localization of function.

• In the brain stem, the medulla controls automatic
  functions such as heartbeat and breathing and the pons is
  involved in sleeping, waking, and dreaming. The reticu-
  lar activating system (RAS), a dense network of neurons,
  screens incoming information, and is responsible for
  alertness.


• The cerebellum contributes to balance and muscle
  coordination.


• The thalamus directs sensory messages.


• The hypothalamus is involved in emotion and drives vital
  to survival, and controls operations of the autonomic
  nervous system. It controls the pituitary gland, or master
  gland.


• The amygdala evaluates sensory information and
  determines its
  emotional
  importance and
  helps to make the
  initial decision to
  approach or
  withdraw from a
  situation.


• The hippocampus
  plays a critical role
  in forming and
  retrieving long-term
  memories.


• The cerebrum contains much of the brain’s circuitry; it is
  divided into two cerebral hemispheres, connected by a
  band of fibers called the corpus callosum. The cerebrum
  is covered by thin layers of cells called the cerebral
  cortex.


• The occipital lobes contain the visual cortex.


• The parietal lobes contain the somatosensory cortex, which
  receives information about pressure, pain, touch, and
  temperature.


• The temporal lobes are involved in memory, perception,
  and emotion.


• The frontal lobes are involved in social judgment, the
  making and carrying out of plans, and decision making.
  They also contain the motor cortex, which controls volun-
  tary movement.


• The association cortex
  appears to be
  responsible for
  higher mental
  processes.
  
  
  • Lateralization is the specialization of each hemisphere
    for certain functions.
  
  
  • The left hemisphere is more active in processing
    language, logic, and symbolic–sequential tasks.
  
  
  • The right hemisphere is associated with spatial-visual
    tasks, facial recognition, and the creation and apprecia-
    tion of art and music.
  
  
  • In most mental activities, the two sides cooperate.
  
  
  
  

The brain is not a fixed and unchanging organ.

The Two Hemispheres of the Brain

Split Brains

• Learning and stimulating
  environments increase

The Riddle of Hypnosis

synaptic connections,

whereas unused connec-

tions are pruned away.

• The flexibility and ability
  of the brain to adapt to
  new circumstances is
  known as plasticity.

The Flexible Brain

Experience and

the Brain

Brain scans reveal some

anatomical and functional

differences in male and female

brains. However, the real-life

significance of these and other

findings remains unclear:

• Many supposed gender
  differences are stereotypes;
  the overlap between the
  sexes is greater than their
  differences.


• A brain difference does not
  necessarily produce a
  behavioral difference.


• Sex differences in the brain
  do not account for behaviors
  that vary with the situation.


• Some accepted findings on
  male-female brain differ-
  ences have failed to
  replicate.


• Some brain differences
  could be a result rather than
  a cause of sex differences in
  behavior and experience.

Are There “His” and “Her”

Brains?

Motor corteexx

Frontal lobe

Temporal lobe

Auditory cortex Visualcortex

Occipital lobe

Parietal lobe

Somatosensory cortex