Space, time, and causality in the human brain

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2014-05, Vol.92, p.285-297
• Main Authors: Woods, Adam J., Hamilton, Roy H., Kranjec, Alexander, Minhaus, Preet, Bikson, Marom, Yu, Jonathan, Chatterjee, Anjan
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Autism; Biological and medical sciences; Brain; Brain - physiology; Brain Mapping - methods; Decision making; Decision Making - physiology; Experiments; Female; fMRI; Fundamental and applied biological sciences. Psychology; Humans; Hypotheses; Magnetic Resonance Imaging - methods; Male; Nerve Net - physiology; Perceptual causality; Space; Space Perception - physiology; tDCS; Time; Time Perception - physiology; Transcranial Magnetic Stimulation - methods; Vertebrates: nervous system and sense organs; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2014.02.015

The ability to perceive causality is a central human ability constructed from elemental spatial and temporal information present in the environment. Although the nature of causality has captivated philosophers and scientists since antiquity, the neural correlates of causality remain poorly understood. In the present study, we used functional magnetic resonance imaging (fMRI) to generate hypotheses for candidate brain regions related to component processes important for perceptual causality in the human brain: elemental space perception, elemental time perception, and decision-making (Experiment 1; n=16). We then used transcranial direct current stimulation (tDCS) to test neural hypotheses generated from the fMRI experiment (Experiment 2; n=16). In both experiments, participants judged causality in billiard-ball style launching events; a blue ball approaches and contacts a red ball. Spatial and temporal contributions to causal perception were assessed by parametrically varying the spatial linearity and the temporal delays of the movement of the balls. Experiment 1 demonstrated unique patterns of activation correlated with spatial, temporal, and decision-making components of causality perception. Using tDCS, we then tested hypotheses for the specific roles of the parietal and frontal cortices found in the fMRI experiment. Parietal stimulation only decreased participants' perception of causality based on spatial violations, while frontal stimulation made participants less likely to perceive causality based on violations of space and time. Converging results from fMRI and tDCS indicate that parietal cortices contribute to causal perception because of their specific role in processing spatial relations, while the frontal cortices contribute more generally, consistent with their role in decision-making. [Display omitted] •Transcranial direct current stimulation reduces the perception of causality.•Frontal stimulation reduces causal perceptions of time and space.•Parietal stimulation reduces causal perceptions of space.•Parallel fMRI and tDCS provide direct probe of neural hypotheses.