Distal Stimulus
the object/event that can actually exist in the world (Ex: the tree or beeping of your phone)
Proximal Stimulus
the physical phenomenon evoked by a distal stimulus that impinges on the specialized cells of the relevant sense.(What activates neurotransmitters, light photons, sound waves, etc. Ex: the reflected light or sound wave. )
Sensation
Direct measure of some aspect of the environment. Allows you to respond to the world. Measures some property of the external world (Physical Stim)
Perception
Something from the world & our brain reacts to it. (Reflex; How your brain interprets the stimulus)
Absolute Threshold
Minimal intensity to detect a stimulus. Defined as the stimulus intensity leading to a 50/50 balance between "yes" & "no" responses.
Resting Potential
Neuron potential when not firing (-70 mV, 70 less than outside)
Eye Anatomy
Know Retina, Lens, Fovea, Optic Nerve, and Visual Pathway
Retina
Holds photoreceptors
Lens
Bends to refract light to retina
Fovea
Lots of cones, high acuity.
Optic Nerve
Blindspot where it goes in.
Visual Pathway
Left hits right retina, crossing over, etc.
Functional Specialization
Areas specialize in what they process. Specific to senses.
Cortical Magnification in V1
More space dedicated to foveal RF. The foveal region of the retina is magnified in the cortex relative to the peripheral regions of the retina.
Perceptual Interpolation
Edges and surfaces assumed to perceive objects as whole.
Border Ownership
Assume the border belongs to only one object in our visual field.
Grandmother Cell
Cell dedicated to grandmother recognition.
Photopigment Bleaching
When a photopigment absorbs a photon, it takes a bit of time before it’s ready to absorb a new one.
Cell runs out of chemicals to send. Can't send signals, stop seeing color. Stare at bright red light, stare at white screen, green. Causes Afterimage.
Color Constancy
"We take cues from our surroundings to perceive color." Observed light is the product of the SPD (spectral power distribution) of the illumination & reflectance of the object.
Binocular Disparity
Difference in the relative positions of objects in the retinal images of the two eyes.
Oculomotor Cues
Feedback from muscles around and within the eye. Cues from eye movement. Include Accommodation and Convergence.
Accommodation
Relaxing (thinner lens, weaker focus, distant objects) and contracting (thicker lens, stronger focus, closer objects) the ciliary muscles changes the shape of the lens. Relays information for objects within about 2 meters.
Convergence
Eyes turn inward to keep objects in focus.
Deletion and Accretion
Objects are occluded (deleted) or revealed from behind occlusion (accreted). Specific distance where eyes do not cross.
Bimodal Neurons
Respond to TWO modalities (kinds of senses such as visual and tactile).
Motion Aftereffect
Cells get tired, perceive things spinning in one direction as spinning in the opposite.
Broadbent's Filter Theory of Attention
"People do not process unattended stimuli beyond basic physical properties." States that Information is unavailable for later recall.
Cocktail Party Problem
Attend to and understand a single convo in a sea of noise. Other conversations are unattended.
Attention Cueing
Response time faster to the area that attention is allocated to.
Divided Attention
Ability to pay attention to more than one thing at once.
Top-Down vs Bottom-Up Attention
Top-Down Control: Voluntary attention, reflects deliberate conscious goals. “Goal-relevant stimuli.”
Bottom-Up Control: When low-level stimuli “capture” attention independent from the observer’s goals or intentions.
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Top down is effortful conscious focus (trying to take notes at mach 5). Bottom up is whatever grabs your attention against your will (a gunshot). Voluntary vs. Involuntary.
Loudness
Perception of how loud something is, amplitude. Physical pressure of sound.
Ear Anatomy
Know Pinna and Cochlea
Pinna
Weird ear wiggle shape. Useful in perceiving elevation.
Cochlea
In the inner ear. Contains the organ of Corti, produces nerve impulses in response to sound vibrations.
Aphasias
Broca's and Wernicke's
Broca's Aphasia
Frontal lobe damage, impaired production but intact comprehension. (If it’s Broca [broke-a], you can’t talk-a)
Wernicke's Aphasia
Near the temporal junction, impaired comprehension but intact production. Can't read either.
Merkel's Disks
Small RF, high tactile acuity. On fingertips, useful for feeling small textures.
Pacinian Corpuscles
Deep pressure and vibration. Large RFs.
Two-Point Threshold
Smallest distance to be able to tell if 2 stimuli can be detected. Sensitive parts have higher acuity.
C-Tactile Mechanoreceptors
The Good Feels transmitters. Free nerve endings present only in hair skin, respond to slow gentle touch
Neuropathic Pain
DMG to peripheral or central nervous system, causes pain in the areas that the nerve is normally linked to. (Arising from damage to the nervous system)
Thermoreceptors
Fire to sudden change in temp, fast
Dorsal Root Ganglion
Sensory info to the dorsal part of the spinal cord. Senses pain, temperature, and touch.
Otolith Organs
The wiggly shit in your ear that helps you understand which way your head is tilted.
Somatosensory Cortex
Processing tactile info, in anterior parietal lobe. Weird naked homunculus dude. Right next to the motor cortex. There's apparently a motor homunculus. RFs correlated to sensitivity of part they're wired to.
Contextual Info (Smell)
Bad at distinguishing smell alone. Context info used to help perceive it.
Adaptation
Reduced sensitivity to odorants which we are continuously exposed to. (Why you don’t smell your perfume after some time)
Cross Adaptation
Adapt to odorants that are similar. Lemon and Lime smells weaken each other.
Olfactory System Path
Doesn't go through thalamus, direct paths to olfactory cortex.
Smell to Hippocampus
Smells super tied to memories. Tied to amygdala too.
Taste Receptor Cell
Transduces taste info.
Primary Taste Cortex (Gustatory Cortex)
Where taste quality (elements of flavor and identification) is processed. Parietal lobe.
Orbitofrontal Cortex
Where we process the reward value of food.
Lateral Inhibition
Excited neurons reduce activity in their neighbors. Increases contrast. Nearby neurons don't send signals. Not just visual.