AWAKE FMRI OF LANGUAGE PROCESSING IN DOGS SHOWS BIAS FOR NOVEL WORDS. Ashley Prichard Emory University

Transcription

1 AWAKE FMRI OF LANGUAGE PROCESSING IN DOGS SHOWS BIAS FOR NOVEL WORDS Ashley Prichard Emory University

2 OUTLINE Why MRI dogs? What is fmri? Dog Brain Anatomy Language in Dogs? How to test language processing in dogs?

3 WHY MRI DOGS?

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6 FMRI functional Magnetic Resonance Imaging BOLD Response Blood oxygen level dependent Noninvasive

7 BRAIN ANATOMY HUMAN DOG

8 Eyes HUMAN DOG

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12 DO DOGS SHOW LEXICAL PROCESSING? Differentiate between a word and a non-word Example: Bear vs J Ropp DO DOGS SHOW SEMANTIC PROCESSING? Different words have different meanings Example: Bear vs Bucket

13 BEHAVIORAL EXPERIMENTAL DESIGN BEHAVIORAL TRAINING Behavioral training to retrieve two selected objects Objects differed on features Two choice tests to determine discriminability Required 1 ~ 6 months training by owners at home

14 FMRI EXPERIMENTAL DESIGN Monkey Bobbu Compare neural responses to trained words vs pseudowords Subjects were already trained to complete fmri scans Compare neural responses to trained objects vs novel objects Mismatch condition: a trained word precedes a novel object Monkey Block Monkey

15 HYPOTHESES Similar to humans, should show differential activity in parietotemporal cortex in response to trained words relative to pseudowords Monkey > Bobbu Dogs should show increased activity in the caudate in response to trained words/ objects relative to pseudowords/ novel objects, as trained items have been associated with food or social praise Monkey > Bobbu > There should be a difference between the two trained words/ objects

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17 TWO CHOICE RESULTS 100% 90% 80% Percent Correct 70% 60% 50% 40% 30% Object 1 Object 2 20% 10% 0% Blue Monkey Piggy Monkey Taffy Yellow Duck HedgeHog Block Monkey Blue Star Duck Elephant Tux Stick Pig Blue Rhino Beach Ball Teddy Duck Caylin Eddie Kady Libby Ninja Ohana Pearl Stella Truffles Velcro Zen Dog and Objects Object 1 [M=85.73%, SE =3.87%], Object 2 [M=64.27%, SE=5.91%] [F (1, 20) = 9.21, P < 0.01].

18 FMRI SCAN VI

19 PARIETOTEMPORAL ROI (REGION OF INTEREST)

20 FMRI RESULTS: PARIETOTEMPORAL ROI WORDS Pseudowords > Trained Words [F (1, 20) = 7.42, P =.017] No significant difference between hemispheres Bobbu > Monkey No significant difference between trained words [F (1, 20) = 0.915, P = 0.35] No significant difference between hemispheres Parietotemporal ROI [Words - Nonwords] (% Signal Change) Words Pseudowords Monkey = Block -0.5 Left Hemisphere Right

21 CAUDATE ROI (REGION OF INTEREST)

22 FMRI RESULTS: CAUDATE ROI WORDS Pseudowords > Trained Words [F (1, 20) = 4.16, P = 0.055] No significant difference between hemispheres Bobbu > Monkey No significant difference between trained words [F (1, 20) = 0.38, P = 0.54] Monkey = Block Caudate ROI [Words - Pseudowords] (% Signal Change) Left Hemisphere Right Words Pseudowords

23 FMRI RESULTS: CAUDATE ROI OBJECTS Novel Objects > Trained Objects [F(1, 20) = 5.01, P = 0.037] No significant difference between hemispheres > No significant difference between trained objects [F (1, 20) = 1.135, P = 0.3], = No significant difference between novel objects when following pseudowords or when following trained words (mismatch) Monkey [F (1, 20) = 0, P = 0.99] Bobbu Caudate ROI [Trained Objects - Novel] (% Signal Change) Left Hemisphere Right Trained Novel Objects

24 LANGUAGE PROCESSING IN DOGS? LEXICAL PROCESSING Pseudowords and words are different from each other But pseudowords > words Behaviorally, trained words mean different objects x SEMANTIC PROCESSING In the brain, trained words are indistinguishable x In the brain, no difference in mismatch conditions

25 Dogs may be treating go get monkey! as one command and go get block! as another command, rather than separate verbs + nouns DISCUSSION The study sought to examine verbal processing in dogs with fmri Based on the fmri results, we found no evidence for dogs using words to symbolize objects, We did find evidence of lexical processing, though this is different than human language processing The most parsimonious explanation for our findings points to the saliency of novel sounds and objects to the dogs.

26 QUESTIONS?