Selective amplification of stimulus differences during categorical processing of speech.
The brain's perceptual stimuli are constantly changing: some of these changes are treated as invariances and are suppressed, whereas others are selectively amplified, giving emphasis to the distinctions that matter most. The starkest form of such amplification is categorical perception. In speech, for example, a continuum of phonetic stimuli gets carved into perceptually distinct categories. We used fMRI to measure the degree to which this process of selective amplification takes place. The most categorically processing area was the left supramarginal gyrus: stimuli from different phonetic categories, when presented together in a contrasting pair, were neurally amplified more than two-fold. Low-level auditory cortical areas, however, showed comparatively little amplification of changes that crossed category boundaries. Selective amplification serves to emphasizeMacalester College students have voted to end their relationship with Minnesota Public Interest Research Group, the student advocacy organization active on six other Minnesota college campuses.

Student activities fees pay for the organizing staff MPIRG installs at each supporting campus. Students at Macalester can opt out of paying that fee, but many at the private St. Paul college said the emails about that process are easy to miss.

That revenue structure drove much of the opposition in the run-up to student voting Monday and Tuesday, when 59.2 percent of voters said the school should not renegotiate its MPIRG contract. Turnout was 63 percent.

MPIRG is nonpartisan but historically has taken politically liberal positions. It has worked to protect same-sex marriage, increase the minimum wage and make it easy to vote, and