Lecture 4 - Perception/Cognition

Sensation

Translating external info like light or sound into neural codes

Perception

Awareness of sensory input and links to stored knowledge

Transduction

Physical stimulus energy (electromagnetic, mechanical, or chemical) is converted into electrical signals interpreted by the nervous system

Ascending Sensory Pathways

Retina —> LGN / Thalamus —> V1 (Striate Cortex)

Contralateral Mapping

Right visual space/field into the left hemisphere

Retinotopic Mapping

Right visual field but each small part is mapped to specific brain areas in the left hemisphere

Akinetopsia

Impaired motion perception due to cortical damage, problems in MT & MST (Dorsal Stream)

Achromatopsia

Impaired color perception, absence of certain photoreceptors, problems in V4 (Ventral Stream)

Optic ataxia

Impairment in trying to reach for something (Dorsal lesions)

Visual agnosia

Ventral lesions - impairment in object recognition