SENSES
Ability to perceive
Nervous system is highly organized
Each type of sensation = modality
Modality: form of energy
Converted by receptor organ
Neuronal impulse
Understood and interpreted by specific areas, brain
Various modalities
- Touch
- Pressure
- Movement
- Light
- Sound
Inform nervous system
- internal environment
- External environment
Specific neuro pathways for specific modalities
Several forms of energy can excite, receptor
Receptors , classified by location, body
Exteroreceptors
- Body surface
- External environment
- Body Surface
- External environment and it’s effects
- Special Somati Afferents (SSA)
- Light and sound (wave energy)
Proprioceptors: movement
GENERAL: Muscles, Tendons, Joints
Special: Labyrinth, inner ear (SP)
Interoceptors
- Located in the body viscera
- General visceral afferent (GVA)
o Temp, BP, gas conc, pressure, movement
- Special visceral afferents (SVA)
o Chemical energy
o Taste
o Smell
Sensory system; classified, location, dentritic zone
Somatic afferents
- General somatic afferents (GSA)
o Craial nerve V
o Spinal nerves, body
Somatic Afferents
- Special somatic afferents (SSA)
o Visual System (CNii)
o Auditory System (CNVIII)
Visceral afferents
- Special visceral afferents
Taste (CN VI, IX and X)
Smell (CNI)
Proprioception
General proprioception
Unconscious proprioception
Information to cerebellum
Special proprioception
Vestibular system (CNVIII, vestibular division)
Information on head and neck in 3D
Sense Associated with Migration
Celestial cues
Magnetic detection
Barometric pressure
Cranial nerve V
Cranial nerve I ?????
Free nerve endings
Nociception
Mechanoreceptors
Herbst corpuscles, merkel cells
Grandry corpuscles, Ruffini endings
Somotosensory Mechanoreceptors
Beak, rehensile – hand
Feet, herbst corpursles, detect vibrations, possible earthquakes
Detect disorders of plumage
Detect turbulence, plumage, during flight
Nociception = Pain
Stimuli that threaten, skin or body surface
Responses:
- Reflex/escape i.e. flight or fight
- Immobility i.e. conservation / withdrawal
- HIGH BP and HR
- Chronic pain, beak experiments
Nociception = Pain
- Perceived in the brain
- No direct projection, thalamus
Somotosensory Pathways
- Trigeminal system, somatotopic projection
o Medulla
o Thalamus
o Frontal neostriatum
 Circuit for Feeding
- Spinal System
o Dorsal columns
o Spinocerebellar pathways
o Pain pathways
Visual System
Highly visual
Large eyes
Visual field; mono vs binocular vision
Bulbar Axis
Visual field
Binocular vision
Birds have a pectin –
Glope shape
Influences, visual acuity
Flat Eye
Globular Eye (chickadee, raptors)
Tubular Eye (Owls)
Visual System / Enhanced Acuity
Ganglion cell hook-up
One cone, one bipolar, one ganglion cell
Diurnal Birds
Several rods, single bipolar, several bipolars
Synapse, several ganglion cells
Convergence
Excellent Visual Sensitivity
Binocular – sueriotemporal area
Fixate distance objects
 Lateral monocular field (area centralis)
Orient sideways / Visual acuity
Pigeons, monocular vision descreased acuity with age
Reduction at dusk
Binocular viewing, doubles acuity
Otic medium transparent
Oil droplets, absorb light
Act as lenses increases pigment reception
Differential distribution across retina
UV sensitivity, 320-680 nm
Color perception varies
View objects differently
Ripeness of fruit
Korble (Dr. University of Munich)
Visual System/Accomodation
Skeletal muscle-sclerocorneal m.
- Lens changes altering curvature
o Compression, whole lens, posterior sclerocorneal m.
o Compression, anterior lens, pupillary bulge
- Distortion of the corneal center
Pupillary light response
Pupilary dilation
Skeletal muscle control CN III
D-tubocurarine 3%
Darkening the room
Sight: SSA, CN ii
Sensory to the globe: CNV
Anesthetics to globe: oxybuprocaine
Eye blink from menace test: CN VII vs V3
Dr. Korbel – looked at frequency – Euroeans have a higher frequency
Centrifugal system
Pecking and visual food selection
Tectofugal pathway
Movement oriented
Maximum Spatial (flicker) frequency
Birds: 250 frames/second
Man: 10-15/sec
Minimum detection, movement
15 degrees / hour
Visual memory – 6600 food caches
Same vs. different visual images
Neocortex, humans ?
Auditory System
Sensitive hearing and vocal communication
Hearing performance, similar to humans
Upper range, limit of 20 kHz
Some birds hear infrasound
Sensitive hearing and vocal communication
Hearing performance, similar to humans
Upper range, limit
External ear
Coverts lacking barbules, turbulence
Facial disc, ruff and operculum
Sound amplification
Asymmetry, external ears
Assymmetry, skull
Divers
Protection feathers and lower diameter
Actual closure, ear canal
Middle Ear
Extracolumella & columella
Footplate, oval window, cochlea
M. columellae, CN VII
Communicate via infraorbital status
Inner Ear cochlea
Length, fairly short
Slightly curved, not coiled
Hair cells, CN VIII
Processing, intensity
- inferior colliculus and CN VII
- Processing, time
o NM, NL and Field L or forebrain somatosensory area (L)
All, tonotopic
Tones – ranging
Audiograms, best at 1-4 khz
Frequency differences, similar, humans
Intensity discrimination, similar
Time Resolution, 2-10 msec
Capable of complex learned motor behavior
Taste
Location is species dependent
Confined to regions
Non cornified epithelium, glandular
Fewer taste receptrs. 300-400 parrot
CN VII, IX
Assume that the sensory world of taste is similar to us
Not true
Sweet, sour, salt and bitter
Taste affets food choice, avoid toxins
Hyperosm naCI
More sensitive inorganic acids
Citric acid ph 5.5-5.0, cockatiels
Olfaction
Cauidal conchae
Receptor cells, nurve dentrites
Locating Food
Vultures
Albatross
Ravens, crows
Hummingbirds
Kiwis
Navigational cues, pigeons
Reproductive behavior
Mallards, breeding
Ring doves, parental care
Pigeons, nests
Selection, fumigation materials