Self-motion induced environmental kinetopsia and pop-out illusion - Insight from a single case phenomenology.

Stable visual perception, while we are moving, depends on complex interactions between multiple brain regions. We report a patient with damage to the right occipital and temporal lobes who presented with a visual disturbance of inward movement of roadside buildings towards the centre of his visual field, that occurred only when he moved forward on his motorbike. We describe this phenomenon as "self-motion induced environmental kinetopsia". Additionally, he was identified to have another illusion, in which objects displayed on the screen, appeared to pop out of the background. Here, we describe the clinical phenomena and the behavioural tasks specifically designed to document and measure this altered visual experience. Using the methods of lesion mapping and lesion network mapping we were able to demonstrate disrupted functional connectivity in the areas that process flow-parsing such as V3A and V6 that may underpin self-motion induced environmental kinetopsia. Moreover, we suggest that altered connectivity to the regions that process environmental frames of reference such as retrosplenial cortex (RSC) might explain the pop-out illusion. Our case adds novel and convergent lesion-based evidence to the role of these brain regions in visual processing.

Akinetopsia on Driving.

Akinetopsia is a quite rare symptom. Two types of akinetopsia have been reported: one is cinematographic vision, and the other is invisibility of moving objects. These symptoms are thought to occur due to dysfunction of the MT/V5 area at the occipitoparietal region. I herein describe a 54-year-old man who collided with a car parked on the left side of the road while driving. He complained that the parked car looked to be moving forwards and he could not stop his car when he noticed that it was parked. Magnetic resonance imaging disclosed the fresh infarction on the right temporoparietal region involving the MT/V5 area. His symptom during driving was considered cinematographic vision and it was the cause of the traffic accident. Akinetopsia resulted in illusory kinetopsia on driving and the traffic accident.

Precuneus and psychiatric manifestations: Novel neurobiological formulations through lesion based connectivity mapping of psychopathology.

Lesion-based investigations of psychopathology have preceded contemporary network-neuroscience initiatives. However, brain-lesions detected in routine psychiatric practice are often considered incidental and therefore ignored. Here, we illustrate a strategy to combine individual subject-level lesion information with open-source normative functional-connectomics data to make putative, neuroscience-informed symptom interpretation. Specifically, we report a patient with left precuneus granulomatous lesion and seizures followed by two distinct symptoms - kinetopsia and delusions of nihilism and guilt - which had a differential treatment response. The lesion-based brain-mapping approach could identify correlated (default-mode) and anti-correlated (temporo-parieto-occipital) networks, which enabled a neurobiological formulation of these diverse clinical manifestations.