Sensation and Perception Flashcards
Terminal Boutons
the specialized presynaptic terminal at the end of an axon which contain necessary organelles proteins and molecules needed to transmit chemical/electrical information to the postsynaptic cell.
Synesthesia
a neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic involuntary experiences in a second sensory or cognitive pathway.
Apoptosis
cell suicide
Pruning
Getting rid of the connection between cells
Vestigial Structure
an anatomical feature that no longer seems to have a purpose in the current form of an organism of the given species.
Palpebra Tertia
a nictitating membrane (from Latin nictare to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility.
Ampulla of Lorenzini
special sensing organs called electroreceptors found in cartilaginous fish (sharks rays and chimaeras);
Absolute Threshold
the minimum amount of stimulation an animal can detect 50% of the time.
Just Noticable Difference
a personÍs concept of the magnitude of a stimulus increases proportional to the stimulus intensity
Signal Detection Theory
there will be variation in your ability to detect stimuli based on your expectations
JohanneÍs MullerÍs Doctrine of Specific Nerve Energies
the nature of perception is defined by the pathway over which the sensory information is carried. Hence the origin of the sensation is not important.
In vision wavelenght translates to
color
In vision saturation (purness of the wavelength) translates to
pureness of color
In vision amplitude (wavelength height) translates to
intensity/brightness
Lateral Inhibition
the capacity of an excited neuron to reduce the activity of its neighboring neurons
Transduction
process by which receptor cells transform external stimuli into a neutral stimulus to be sent to the brain
Mach Bands
exaggeration of the contrast between light dark and grey that makes edges and borders much more distinct to the eye.
Phosphenes
a ring or spot of light produced by pressure on the eyeball or direct stimulation of the visual system other than by light.
Chromatin
the material which composes chromosomes
Cyclic Guanosine Monophosphate (cGMP)
mechanism of action in cellular protein responses
Phosphodiestrase
breaks down the bond of cGMP
Isomerization
changing the shape of a molecule as a result of a magnetic field
Cup Eyes
a cup shaped eye is beneficial to simple organisms because it helps them detect light and move closer or farther away from it
Convergent Evolution
the process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments
Iris
a flat colored ring-shaped membrane behind the cornea of the eye with an adjustable circular opening (pupil) in the center
Sclera
Aka the white of the eye it is a fibrous protective tissue that contains collagen and elastic fiber and forms the thin white film that is the outer layer of the eye
Cornea
built like a brick wall it does not have blood supply but gets nutrients form the fluid around it
Aqueous Humor
clear fluid between the lens and the cornea that provides glucose to cells in the cornea
Conjunctiva
the mucous membrane that covers the front of the eye and lines the inside of the eyelids. It provides a shelf for the sclera as well
Lens
transparent biconvex structure in the eye that along with the cornea helps to refract light to be focused on the retina
Canals of Schlemm
is a circular channel in the eye that collects aqueous humor from the anterior chamber and delivers it into the bloodstream via the anterior ciliary veins
Glaucoma
a painful condition caused by the blocking of the Canals of Schlemm and the buildup of aqueous humor
Ciliary Muscles
responsible for altering the curvature of the lens
Ciliary Body
ring of smooth muscle inside the vascular (middle) layer of the eye that allows for viewing objects from a variety of distances. It changes the shape of the lens of the eye (not the pupil!) and regulates flow and production of the aqueous humor
Vitreous Humor
jelly-like tissue filling the eyeball behind the lens
Fovea
small depression in the retina where visual acuity is highest. The center vision is focused in this region because it is where retinal cones are particularly concentrated
Macula
the part of the eye that is responsible for sight in the center of the field of vision. It sits in the center of the retina
Retina
a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain where a visual image is formed
5 Types of cells
bipolar cells photoreceptors horizontal cells retinal ganglion cells amacrine
Bipolar Cells
located between photoreceptors they act to transmit signals from the photoreceptors to the ganglion cells
Trichromatic Theory
based on the premise that there are three classes of cone receptors subserving color vision
Phi Phenomena
the optical illusion of perceiving continuous motion between separate objects viewed rapidly in succession
Opponent Process Theory
first developed by Ewald Hering and suggests that color perception is controlled by the activity of three opponent systems (red-green or yellow-blue)
Horizontal Cells
laterally interconnecting neurons in the outer layer of the retina that help integrate and regulate the input from multiple photoreceptor cells
Retinal Ganglion Cells
vary in terms of size connections and responses to visual stimulation but share the defining property of having a long axon that extends into the brain. These axons form the optic nerve optic chiasm and optic tract
Amacrine
inhibitory interneurons in the retina which link bipolar and ganglion cells (giving an alternate route between them)
Optic disk
the raised disk on the retina at the point of entry of the optic nerve lacking visual receptors and so creating a blind spot
Optic Nerve
each of the second pair of cranial nerves transmitting impulses to the brain from the retina at the back of the eye. There are 125 million axons in the optic nerve alone
Open Angle Glaucoma
the angular opening of the canal gets clogged-happens quickly
Closed Angle Glaucoma
the iris sheds pigments and they block the canals of Schlemm causing a backup. They need eye drops to dilate the canals in order to drain the blockage. Usually happens over time-like a clogged sink
Myopia
aka nearsightedness the focal point no longer resides on the fovea-its too far forward as a result everything far away is blurry
Refractive Myopia
the cornea bends the light too much so it doesnÍt hit the fovea
Axial Myopia
the eyeball is extra long and so the light doesnÍt hit the back of the eyeball like it should
Hyperopia
aka far sightedness the focal point no longer hits the fovea its too far backward and everything close up is blurry
Refractive Hyperopia
the cornea doesnÍt bend the light enough
Axial Hyperopia
the eyeball is too short so the light doesnÍt converge at the back of the eye like it should
Presbyopia
literally means ñold eyeî the near point accommodation starts to change due to loss of lens elasticity
Monochromat
no cones (completely colorblind) leads to loss of foveal detection terrible daytime vision fuzzy vision (no visual acuity because of lots of rod convergence)
Dichromat
ñnormal colorblindnessî they have 2/3 cones but are missing one kind
Commissure
a band of tissue connecting two pats of the brain spinal cord or bone (such as the corpus collosum)
Decussation
the crossing of a nerve from one side of the brain to the other.
Bitemporal Hemianopsia
losing peripheral vision due to damage in both hemispheres
Contralateral Hemianopsia
losing vision on one side due to damage to the other side
Schetoma
a partial loss of vision or a blind spot in an otherwise normal visual field.
Frontal Field
controls pursuit movements (following objects with our eyes)
Superior Colliculus
controls gaze orientation
Vergence movements
crosses the eyes
Nystagmus
wobbling or darting movements designed to keep us from fatiguing the retina by staring at one place for too long
Congenital Nystagmus
exaggerated wobbling (crazy eyes)
Sacchasdes
rapid eye movement between two points
Pulvinar Nuclei
the nuclei that allows us to ignore the time it takes for out gaze to orient (Sacchadic Suppression)
Sacchadic Suppression
ignoring the time it takes for out gaze to orient
Chronostasis
an illusion in which a first impression followed quickly by the introduction of a new event or task makes the brain trick us into thinking time is extended slightly (clock hands)
Receptive Fields
a particular part of the eye which when stimulated will trigger the firing of a particular neuron
Lateral Geniculate Nucleus
responds really well to dots (cat experiments)
On-Center Off Surround Receptive Fields
A form of lateral inhibition designed to help detect borders. Retinal ganglion cells go crazy if you stimulate their centers but if you stimulate the sides they shut down completely.
Simple Cortical Cells
cells located in the cortex which respond to angled lines
Orientation Tuning Curve
a cell responds to a specific line and a small curve surrounding the ideal line (5 degrees or so). So a line that fires at 180 might fire from 178-183 but stop dead at 184
Complex Cortical Cells
respond to an angle but only if the angle is moving in a specific direction
Hypercomplex Cells
sensitive to angles specifically the length of a particular line/angle.
Cytochrome Oxidase
found in the mitochondria the more present in a cell the more energy utilization happening
Endolymph
fluid inside the semicircular canals of your ear
Otoliths
small calcium deposits in the semicircular canals. They float in the endolymph
Ultrasonic
high pitches humans cant hear
Infrasonic
low pitches humans cant hear
Vomeronasl system
detects pheromones
