Sensation and Perception (CH2) Flashcards
What is behind the iris and helps control the refraction of the incoming light?
Lens of the eye
Contraction of the ciliary muscle (part of the ciliary body) is under what type of control?
Parasympathetic
Behind the lens of the eye, there is a transparent gel that supports the retina. This is called?
Vitreous Humor
When the ciliary muscle of the eye contracts, it pulls on suspensory ligaments and changes the shape of the lens. What is this phenomenon known as?
Accommodation
The back of the eye that behaves like a screen that consists of neural elements and blood vessels. It’s function is to convert incoming photons of light to electrical signals.
Retina
Used for color vision and to sense fine details in the retina.
Cones
More functional in reduced illumination (night vision), and only allow sensation of light and dark because they contain a single pigment called rhodpsin (not involved with color).
Rods
Rods and cones connect with these cells, which highlight gradients between adjacent rods or cones. These cells then synapse on ganglion cells, which group together to form the optic nerve.
Bipolar Cells
As the number of receptors that converge through the bipolar neurons onto one ganglion cell increases, the resolution _________?
Decreases
T/F: Color vision has a greater sensistivity to fine detail than black and white vision does.
True, because there more rods than cones
These cells receive input from multiple retinal cells in the same area before the information is passed on to ganglion cells. They accentuate slight differences b/w the visual information in each bipolar cell.
Amacrine and Horizontal Cells
The ability to simultaneously analyze and combine information regarding color, shape and motion (cohesive image of the world).
Parallel Processing
Our visual pathways contain cells specialized in detection of color, shape or motion.
Feature Detection
These cells permits us to see very fine details when thoroughly examining an object (high color spacial resolution makes this possible).
Parvocellular Cells
Parvocellular cells can only work with stationary or slow moving objects because they have a very low _____ _________.
Temporal Resolution
These cells are used to detect motion (they have a high temporal resolution). These cells also have have low color spatial resolution, so the image may appear blurry.
Magnocellular Cells
What is the only sense that does not pass through the thalamus (travels unfiltered-into higher order brain centers).
Smell
What are the four modalities of somatosensation?
- Pressure - Vibration - Pain - Temperature
Deep pressure and vibration
Pacinian Corpuscles
Light touch
Meissner Corpuscles
Deep pressure and texture
Merkel Cells (Discs)
Stretch
Ruffini Endings
Pain and Temperature
Free Nerve Endings
With Brown-Sequard Syndrome, half of the spinal cord is severed. On the severed side, the patient loses sense of pressure and vibration. What happens on the opposite side?
The patient will lose sense of pain and temperature.
This refers to the minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli. It’s size also depends on the density of nerves in the particular area of skin being tested.
Two Point Threshold
Temperature is judged relative to the normal temperature of the skin.
Physiological Zero
A theory that proposes that there is a special “gating” mechanism that can turn pain signals on or off, affecting whether or not we perceive pain. (For example, rubbing an injury seems to reduce the pain of the injury - aka it is more painful)
Gate Theory of Pain
Refers to the ability to tell where one’s body is in space.
Proprioception
Refers to object recognition by parallel processing and feature detection (the brain takes the individual sensory stimuli and combines them together to create a cohesive image before determining what the object is).
Bottom-Up Processing (AKA Data-Driven)
This processing is driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations (recognizing objects without needing to analyze their specific parts).
Top-Down Processing (AKA Conceptually Driven)
Refers to the ability to use two processes, in tandem with all of the other sensory clues about an object, to create a complete picture or idea.
Perceptual Organization
Can rely on both monocular and binocular cues (processes that involve one or both eyes, respectively).
Depth Perception
Refers to the idea that we perceive certain characteristics of objects to remain the same, despite differences in the enviornment.
Constancy
Ways for the brain to infer missing parts of a picture when a picture is incomplete.
Gestalt Principles
Elements close to one another tend to be perceived as a unit.
Law of Proximity
Objects that are similar tend to be grouped together.
Law of Similarity
Elements that appear to follow in the same pathway tend to be grouped together.
Law of Good Continuation
Perceiving contours and, therefore, shapes that are not actually present in the stimulus.
Subjective Contours
When a space is enclosed by a contour it tends to be perceived as a complete figure (certain figures tend to be perceived as more complete or closed than they really are).
Law of Closure
Perceptual organization will always be regular, simple and symmetric as possible.
Law of Prägnanz
Cells that have a very high temporal resolution are used to _______ ________?
Detect Motion
Focuses on the changes in our perception of the same stimuli depending on both the internal and external context (psychological vs. environmental).
Signal Detection Theory
Vibrates in phase with the incoming sound waves and the frequency of the sound waves determine the rate at which this membrane vibrates (also divides the outer from the middle ear)?
Tympanic Membrane
What are the three smallest bones of the body - they are titled “ossicles”?
- Malleus 2. Incus 3. Stapes
The bone affixed to the tympanic membrane.
Malleus
The malleus acts on this bone.
Incus
This bone’s baseplate rests on the oval window of the cochlea.
Stapes
What does the boney labyrinth of the ear contain?
The cochlea, vestibule and semicircular canals (aka the inner ear).
A pottasium rich fluid that is prominantely inside the semicircular ducts, utricle, and saccule?
Endolymph
Another fluid of the ear that transmits vibrations from the outside world and cushions the inner ear structures?
Perilymph
What part of the cochlea is responsible for the actual hearing apparatus?
The middle scalae houses this organ, called the organ of Corti, on a thin basilar membrane. The organ of corti houses thousands of hair cells in endolymph.
True/False: The sound entering the oval window causes vibrations in the perilymph (which is within the other two scalae), which are transmitted to the basilar membrane.
True
What nerves transmits the hearing’s electrical signals and to where?
The Auditory (Vestibulocochlear) Nerve transmits signals to the Central Nervous System (Brainstem), where it ascends to the Medial Geniculate Nucleus (MGN) of the thalamus and then finishes at auditory cortex of the temporal lobe.
Refers to the portion of the bony labyrinth that contains the utricle and saccule. These structures are sensitive to linear acceleration and are used as part of the balancing apparatus.
Vestibule
Refers to the portion of the bony labyrinth that is sensitive to rotational acceleration.
Semicircular Canals
What are the three main types of thresholds?
- Absolute Threshold 2. Threshold of Conscious Perception 3. Difference Threshold
The minimum of stimulus energy that is needed to activate a sensory system. For example, in the sound equation, the Io = 10-12 is a type of threshold for normal human hearing.
Absolute Threshold
Is the minimum of stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness.
Threshold of Conscious Perception
The minimum difference in magnitude between two stimuli before one can perceive the difference. Weber’s Law can be applicable to this.
Difference Threshold (aka Just-Noticeable Difference/JND)
States that the jnd for a stimulus is proportional to the magnitude of the stimulus and that this proportion is constant over most of the range of possible stimuli (usually around 0.68%).
Weber’s Law
