2/5/2013 Spontaneous Synchronization of Arm Motion Between Japanese - PDF document

2/5/2013 Spontaneous Synchronization of Arm Motion Between Japanese Macaques Edward Kim and Daniel Acker Japanese Macaque • • Division of Nature Publishing Group • Open-access, online • No impact factor (started in 2011) Laboratory for Adaptive Intelligence, Laboratory for Adaptive Intelligence, RIKEN RIKEN Brain Science Institute Brain Science Institute • Zenas Chao • • Naotaka Fujii Ph.D. in Biomedical Engineering, • M.D. in Ophthalmology, Tohoku University Georgia Institute of Technology • • Ph.D. in Physiology, Tohoku University Research Scientist, RIKEN BSI • • Lab Head, Lab for Adaptive Intelligence, Analyzed data • RIKEN Brain Science Institute Tomonori Notoya • Professor, Tokyo University • Technical Staff, RIKEN BSI • Primary interests: Social brain function, • Took care of monkeys, conducted Brain machine interface experiments • supervised project, provided ideas • Naomi Hasegawa • • Yasuo Nagasaka Doctor of Veterinary Medicine • Research Scientist, RIKEN BSI • Research Specialist, RIKEN • designed experiment, constructed BSI • Took care of monkeys, c onducted apparatus, developed computer programs, experiments analyzed data 1

2/5/2013 RIKEN Coordination • Independent practical and • Behavioral changes that occur continuously basic research institution during social interaction • Mostly funded by the Japanese government • Has employed multiple Nobel laureates Discussion Question: What are some examples of • Hideki Yukawa (Physics coordination in non-human species? 1949) • Shinichiro Tomonaga (Physics 1965) • Ryoji Noyori (Chemistry 2001) Intentional vs. Spontaneous Some Examples Coordination Schooling in fish. • Intentional: Flocking in birds. • action oriented Flash coordination in fireflies. • requires recognition Facial imitation in infant primates ______________________________________ • Spontaneous: Humans lifting heavy furniture. • not goal-oriented Humans playing music. • unconscious Lots of other human activities: Dance. Assembly line work. • does not engage higher cognitive processes Military formations. Etc. First Animal Model of Spontaneous Value of Spontaneous Synchronization Synchronization • Smoothes conversation • Intentional, learned synchronization has been • Ex. Unconscious mimicry increases in the socially excluded, analyzed in macaques and other animals perhaps as a subconscious attempt to recover from exclusion • Neural circuitry studies included • Facilitates building of social rapport • No previous controlled model of spontaneous • Ex. In student teacher pairings, self-reported relationship synchronization strength was correlated with independently assessed increased movement synchronization • May be important for the development of facial imitation • Mother's pay more attention to imitative infants 2

2/5/2013 Intentional synchronization is Training Training Cont. unlikely during later paired trials because it takes a long • Initially, both buttons were time to train for intentional synchronization (up to a year) • 3 male macaques (B, C, illuminated, and the • Training was complete when and T) monkey could press either the monkey pressed the one buttons 30 - 36 times with • Trained to press two • The LED on the pressed no pauses longer than 5s buttons repeatedly and button turned off, the • After a successful trial, a alternately with one hand monkey then pressed the chime was played, and the other • Individually trained monkey was rewarded with food • Button presses were accompanied by short sounds Test 1 Time Locked Synchronization • Monkeys were paired • Delay between button presses between monkeys (Δt XY ) and button presses per second were measured • Rewards were provided to both monkeys at the same time regardless of degree of synchronization • 90 trials over 3 days X axis is delay (ms) Harmonic Rate Synchronization and Harmonic Series Partner Dependence • A harmonic is an integer multiple of a fundamental number • Ex. 4, 8, 12, 16, 20, 24, 28, 32, 36, etc. 3

2/5/2013 Harmonic Adjustment toward Test 2 Synchronization • vMonkey simulated a partner • Assembled from video of monkey T • vMonkey speed was adjusted twice per trial as dictated by one of two paradigms • Fast-slow-fast (FSF) • Slow-fast-slow (SFS) Targets: • 10 trials per condition per • SFS: 1.9 Hz – 3.7 Hz – 1.9 Hz day • FSF: 3.7 Hz – 1.9 Hz – 3.7 Hz Graphic Representations of Data Test 3 • vMonkey, constant speed (2.8 Hz) • Differences in BP speed and synchrony in: Auditory-only (A) Visual-only (V) Auditory + Visual (AV) Harmonics of S-Post Target Auditory/Visual Effects: BP Speed Auditory/Visual Effects: Synchrony 4

2/5/2013 Major Conclusions Auditory/Visual Effects: Synchrony Test 1: When paired, monkeys synchronized their BP and adjusted their BP speed to the closest harmonic of their partner's Test 2: When vMonkey changes speed, the subject adjusts to match the nearest harmonic of vMonkey's speed Test 3: Different stimulus modalities did not affect BP speed, but A+V was required for synchronization (or at least V) Further Study 1: Clinical Further Study 2: Brain Regions Applications • Social synchronization must be automatic and general for • Mirror System is activated both when performing and observing the same action use in constantly changing environments in the wild o Ventral premotor cortex o BP task illustrates generality with synchronization during  Projects directly to the brain stem unnatural behavior (may be involved in involuntary motor function • Autistic children have difficulty responding to social cues o Rostral region of the inferior parietal lobule • BP task could quickly assess autism symptoms  Damage to this region can cause echopraxia and echolalia • Possibly caused by lack of inhibition to the cortex Further Study 2: Cont. Questions or Comments? • Future experiments would monitor multiple brain regions during the same behavioral tests • The most important finding: A behavioral paradigm that can be used as a basis for experiments exploring the neural mechanisms behind spontaneous social synchronization 5