Structural and Effective Pathways to the Amygdala involved in Spatial Frequency and Emotion Processing Jessica McFadyen1,6, Martial Mermillod2,3, Veronika Halász1,4, Jason B. Mattingley4,5,6, & Marta Garrido1,4,6 1 Centre for Advanced Imaging, University of Queensland, St Lucia, QLD, Australia | 2 University Grenoble Alpes, Grenoble, France | 3 Institut Universitaire de France, Paris, France 4 Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia | 5 School of Psychology, University of Queensland, St Lucia, QLD, Australia 6 Australian Research Centre of Excellence for Integrative Brain Function, Australia Method Participants N = 26, 50% female, 18-32 years (M = 22.69) Design Duration = 200ms, ISI = 750-1500ms, Viewing angle = 22.8° Technique = Magnetoencephalography (MEG) Task = Report the gender of the face Spatiotemporal Results References 1 Garvert, M. M., Friston, K. J., Dolan, R. J., & Garrido, M. I. (2014). Subcortical amygdala pathways enable rapid face processing. NeuroImage, 102, 309-316. 2 Tamietto, M., & De Gelder, B. (2010). Neural bases of the non-conscious perception of emotional signals. Nature Reviews Neuroscience, 11(10), 697-709. 3 Pessoa, L., & Adolphs, R. (2010). Emotion processing and the amygdala: from a ‘low road’ to ‘many roads’ of evaluating biological significance. Nature Reviews Neuroscience, 11(11), 773-783. Lateral Geniculate Nucleus (LGN) Pulvinar (PUL) Primary Visual Cortex (V1) Amygdala (AMY) Subcortical Medial Cortical [ 3780 ] 0 15 5 Latency Advantage for Low SF (ms) 10 fT/mm -4 -3 -2 -1 0 1 2 3 0 100 200 300 400 500 600 Lag = 13ms Time (ms) BSF LSF HSF Fearful Neutral Research Question Is there a functional subcortical route to the amygdala that bypasses the visual cortex and, if so, what spatial frequency and emotional content does it carry? Cortical Hypothesis3: Transmission of visual information to the amygdala is via the cortex: • Just as fast • Used for all information • Any pulvinar influence is due to cortical input Background Dual Hypothesis2: There is a colliculo-pulvinar pathway to the amygdala: • Fast • Direct • Used for low spatial frequencies and emotional information Conclusions Using statistical parametric mapping (SPM) and dynamic causal modelling (DCM) we found: 1. A dual model explained the data better than other plausible anatomical models1. 2. Simulated amygdala activity was influenced by the subcortical route as early as 70ms. 3. Low spatial frequency modulated neural activity earlier than high spatial frequency. 4. The subcortical route was not modulated by spatial frequency, while the cortical route conveyed primarily high spatial frequencies. p < .05 FWE -0.8 -0.4 0 0.4 0.8 0 100 200 300 400 500 600 Lag = 12ms Time (ms) Latency Cross-Correlation Analysis 10 20 30Left Right 0 10 20Posterior Anterior 30 600 450 300 150 0 Time (ms) Difference in Field Intensity (fT/mm) -1.6 0.8 0 1.6 -0.8 Low High 10 20 30Left Right 0 10 20Posterior Anterior 30 0 300 200 100 0 400 Neutral vs. Fearful Emotional Expressions Field Intensity (fT/mm) -0.4 0.2 0 0.4 -0.2 Fearful Neutral 470ms 310ms 175ms 150ms 370ms Statistical Parametric Mapping Low vs. High Spatial Frequency Dynamic Causal Modelling Anatomical Models V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT Cortical Dual Medial All = included in some models = included in all models 0 5 10 15 20 Exceedance Probability (%) Models 1 36 18 9 27 V1 AMY LGN PUL INPUT Model 21 V1 AMY LGN PUL INPUT Model 29 Cortical Dual All Medial 0 10 20 30 40 50 60 70 80 90 100 Exceedance Probability (%) 1 14 28 Models V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT V1 AMY LGN PUL INPUT = modulation by either: 1. Spatial Frequency (Low vs. High) 2. Emotional Expression (Neutral vs. Fearful) 3. Spatial Frequency & Emotional Expression V1 AMY LGN PUL INPUT