NE101 Lecture Notes

Aside critical transitions a tipping point at which

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ASIDE: Critical transitions A tipping point at which the system shifts abruptly from one state to another Example: potential well change parameters until number of fixed points changes Propose: seizures terminate by crossing a tipping point Warning signs (I) Critical transitions can be preceded by dynamical signatures: Critical slowing downstream: Near the transition, the system becomes increasingly slow in recovering from small pertubations. Far from tipping point – move back to position quickly Close to tipping point – move back to position more slowly Flickering: The system moves back and forth between two alternative attractors just before the tipping point. Small kicks – stays in same position Big kicks – go back to a different tipping point December 7, 2012: How the Brain Thinks – Putting the Pieces Together Basic Common Principles Receptive Fields Internal unit of external world, gradually reconstructed Representation of External World Streams of Processing Receptive Fields Retina: Photoreceptors (rods and cones) connect to bipolar/ganglion cells many photoreceptors connect to fewer bipolar/ganglion cells that connect to fewer V1 cells Primary Visual Cortex: simple/complex cells sees a straight line Secondary Visual cortex: shape Tertiary Visual Cortex: form and color Unimodal Association Cortex: whole objects (inferotemporal cortex) Visual processing of faces occurs in ventral stream – more objects dorsal stream has more of a “map” Unimodal Association Cortices Whole objects (vision) + voice (audition) Multimodal Association Cortex: Assign meaning behind information – put modalities together Example: Voice is associated with face Relation Memory (context)
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Declarative: episodic memory What you were doing Where you were When it was happening Streams of Processing Ventral Stream Object Recognition (faces, houses, animals, etc. ..) Perceptual Constancy Allocentric space = “body independent” space (cardinal directions) Relationships between objects Dorsal stream Maps of the external world Representation of External World Allocentric space: what defines a space? What is a room? Relationships between objects → hippocampus (memory) Vision Primary visual cortex: elementary sensory features line orientation color retinotopic maps (map of retina in visual cortex) REMINDER: inside of each eye (“nasal”) projects to opposite side of brain Secondary cortex: Elaboration of features shapes Unimodal Association Cortex: integration of features Audition Primary Auditory Cortex Elemental sensory features tonotopic maps tones Secondary cortex Elaboration of features simple tunes Unimodal Association Cortex Integration of features songs Somatosensation Primary Somatosensory Cortex (post-central gyrus) Elemental sensory features Somatotopic (homunculi): pressure touch
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temperature Secondary (Unimodal Association) Cortex: Integration & Elaboration of features egocentric space Dorsal stream Spatial Cognition egocentric space As your body moves, the world does not. Agnosia: localizing vs. identifying
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ASIDE Critical transitions A tipping point at which the...

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