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Good News About Gettin Old

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  • medit8ionsociety
    Older but Mellower: Aging brain shifts gears to emotional advantage Bruce Bower Given all the bad news that science has delivered about brain cells withering
    Message 1 of 1 , Jun 28, 2006
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      Older but Mellower: Aging brain shifts gears to
      emotional advantage
      Bruce Bower
      Given all the bad news that science has delivered about
      brain cells withering and memory waning as the years mount,
      older people have a right to be cranky. But, instead, the
      over-50 crowd handles life's rotten realities and finds
      life's bright side more effectively than whippersnappers
      do. In no small part, that's because the aging brain makes
      critical emotional adjustments, a new study indicates.

      Advancing age heralds a growth in emotional stability
      accompanied by a neural transition to increased control
      over negative emotions and greater accessibility of
      positive emotions, according to a team led by neuroscientist
      Leanne M. Williams of Westmead (Australia) Hospital. A brain
      area needed for conscious thought, the medial prefrontal
      cortex, primarily influences these emotional reactions in
      older adults, Williams and her colleagues say.

      In contrast, people under age 50 experience negative
      emotions more easily than they do positive ones. These
      younger adults' emotion-related activity centers on the
      amygdala, a brain structure previously implicated in
      automatic fear responses.

      This gradual reorganization of the brain's emotion system
      may result from older folk responding to accumulating
      personal experiences by increasingly looking for meaning
      in life, the researchers propose in the June 14 Journal of
      Neuroscience.

      Evidence that emotional functions improve in older brains
      "indicates that our ability to register the significance of
      information is preserved, and even enhanced, as we age,"
      Williams says. Older people may benefit from associating
      information they need to remember with personally
      significant matters, such as a favorite tune, he adds.

      Ironically, older individuals' reliance on the medial
      prefrontal cortex to regulate emotions comes as aging kills
      cells in this area. The surviving neurons somehow pick up
      the slack, the investigators note.

      The researchers studied 122 males and 120 females, ages 12
      to 79, who had no current or past mental illnesses and good
      physical health.

      Scores on a questionnaire that assesses emotional stability
      rose steadily from adolescence into the senior years.

      Brain testing occurred as volunteers viewed images of various
      facial expressions. They had been told to identify the
      emotion in each expression and to rank its intensity.
      Researchers measured neural response using functional
      magnetic resonance imaging, which tracked blood-flow changes,
      and an electrode-studded cap that monitored brain cells'
      electrical responses.

      In older adults, mushrooming medial prefrontal cortex
      activity triggered by negative facial expressions occurred
      in conjunction with neural responses that have been linked
      to conscious thought. This pattern appeared even in older
      adults who displayed especially low numbers of prefrontal
      neurons.

      In contrast, young people showed far more medial prefrontal
      activity, and thus conscious thought, in response to positive
      facial expressions than older people did.

      The new results provide a neural framework for growing
      evidence that, unlike young people, older adults focus on
      positive information and downplay negative events, remarks
      psychologist Mara Mather of the University of California,
      Santa Cruz. The amygdala showed little volume decline with
      age in the new study, so it's unlikely that age-related
      shrinkage of that structure causes the psychological shift,
      she adds.

      "Older adults apparently use cognitive-control processes
      supported by prefrontal brain regions to help them avoid
      experiencing negative information and focus instead on
      positive information," Mather says.
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