Defining Space
Defining Space Encoding sound location with respect to the eyes
Coordinating across senses • Jay MF, Sparks DL (1984) Auditory receptive fields in primate superior colliculus shift with changes in eye position. Nature 309:345-347. • Lee J, Groh JM (2012) Auditory signals evolve from hybrid- to eye-centered coordinates in the primate superior colliculus. J Neurophysiol 108:227-242.
Superior Colliculus: Vision, Hearing, and Touch
Sounds"
Neural Activity
Eye fixations"
Location – defined with respect to head
Sounds"
Neural Activity
Eye fixations"
Neurons signal location of sound with respect to the eyes
Location – defined with respect to eyes
How is sound location calculated with respect to the eyes? • Groh JM, Sparks DL (1992) Two models for transforming auditory signals from headcentered to eye- centered coordinates. Biological Cybernetics 67:291-302. • Porter KK, Metzger RR, Groh JM (2006) Representation of eye position in primate inferior colliculus. J Neurophysiol 95:1826-1842.
The underlying math is easy! • Vector subtraction Sound Eyes Head
Possible neural implementation: Vector subtraction model Meter for sound location with respect to eyes Meter for sound with respect to head
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Meter for eye position with respect to head
Summary • Senses communicate! • Reference frames are a challenge • The brain translates between reference frames • “Early” brain areas involved, suggesting widespread interactions between the senses
Next up: Going Places
Coordinating across senses • Jay MF, Sparks DL (1984) Auditory receptive fields in primate superior colliculus shift with changes in eye position. Nature 309:345-347. • Lee J, Groh JM (2012) Auditory signals evolve from hybrid- to eye-centered coordinates in the primate superior colliculus. J Neurophysiol 108:227-242.
Superior Colliculus: Vision, Hearing, and Touch
Sounds"
Neural Activity
Eye fixations"
Location – defined with respect to head
Sounds"
Neural Activity
Eye fixations"
Neurons signal location of sound with respect to the eyes
Location – defined with respect to eyes
How is sound location calculated with respect to the eyes? • Groh JM, Sparks DL (1992) Two models for transforming auditory signals from headcentered to eye- centered coordinates. Biological Cybernetics 67:291-302. • Porter KK, Metzger RR, Groh JM (2006) Representation of eye position in primate inferior colliculus. J Neurophysiol 95:1826-1842.
The underlying math is easy! • Vector subtraction Sound Eyes Head
Possible neural implementation: Vector subtraction model Meter for sound location with respect to eyes Meter for sound with respect to head
+
-
Meter for eye position with respect to head
Summary • Senses communicate! • Reference frames are a challenge • The brain translates between reference frames • “Early” brain areas involved, suggesting widespread interactions between the senses
Next up: Going Places
