Sensory system tuning (filtering) and organization

All sensory systems are designed to extract information from the environmentSensory systems are usually selective

•Systems tend to focus on a range of what is available•Range tends to be restricted to what is “biologically meaningful”•Range is thus “tuned” based on the specificity of the ecological demands

•Tuning tends to have an “optimum” or “best” stimulus •Deviation from this “best” yields less than optimal sensitivity

Keep track of the origin of the tuning curve: it is behavioral or neural data.

Katydid killer auditory tuningParasitoid fly auditory tuning

Optimum sensitivity does not necessarily mean “most meaningful”

VisionOlfaction

Moth olfactory tuning:Concentration response function (receptor neurons) for different odors

Moth olfactory tuning concentration response function (output)

Detection threshold

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Moth olfactory tuning:Concentration response function (behavioral)

Increased sensitivity usually means increased neural representation in sensory array

Vision

Olfaction

Increased sensitivity usually means increased neural representation in sensory array

Moth olfactory tuningIncreased sensitivity usually means increased neural representation centrally

Male antennal lobe Female antennal lobe

Increased sensitivity usually means increased neural representation centrallyRelative volume of somatosensory cortex devoted to area of skin

Somatotopic integrity: maintains an organized representation

Central organization

Retinotopic integrity of sensory input at the level of primary visual cortex

Chemotopic integrity: maintains an organized representation of receptor type

Chemotopic integrity: maintains an organized representation of receptor type

Types of sensory systems found in nature

1. Chemical senses• Olfaction• Taste

2. Vision 3. Auditory4. Vestibular 5. Somatosensory

• Proprioception• Nociception• Mechanosensation• Thermosensation

6. Magnosensation • Electromagnosensation• Geomagnosensation

7. Geosensation