Perception and Vision Lecture Notes

Vocabulary flashcards generated from the perception and vision lecture notes.

Perception

Awareness and experience of the world.

Naive Realism

The idea that we sense the world directly and experience reality exactly as it really is.

Representative Realism

The idea that we construct a representation or approximation of reality using information from our senses, experiences, and assumptions.

Solipsism

The skeptical idea that you could be the only mind that exists and that you cannot confirm or disconfirm whether an outside world exists.

Perceptual Process

The process of taking information from the environment, processing it through the nervous system, experiencing/perceiving it, recognizing it, and then using it to take action.

Distal Stimulus

The actual physical object or event in the environment that you are focusing on.

Proximal Stimulus

The stimulus pattern that reaches your sensory receptors, such as the image of an object on your retina.

Receptor

A neuron exposed to the external world that responds to a specific type of energy.

Transduction

The process of converting external energy into a neural impulse.

Thalamus

A structure deep in the brain that routes sensory information to the appropriate areas of the brain.

Occipital Lobe

The area at the back of the brain associated with processing vision.

Temporal Lobe

An area of the brain involved in processing sound/auditory information.

Parietal Lobe

An area involved in processing touch, pain, and temperature information.

Frontal Lobe

An area involved in processing taste and smell according to your class notes.

Sensation

Detecting stimuli through sensory systems such as the eyes, ears, and nose.

Recognition

Identifying what something is based partly on previous experience.

Bottom-Up Processing

Taking information from the world and sending it up into the brain; also called data-based processing.

Top-Down Processing

Using knowledge and previous experience to help detect and interpret stimuli; also called knowledge-based processing.

Psychophysics

The study of the relationship between physical stimuli and perception/experience.

Intuitive Psychophysics

Describing or categorizing stimuli based on a person's perceptual experience.

Phenomenological Report

A person's description of their perceptual experience.

Classical Psychophysics

Studying the relationship between physical stimuli and perception using systematic, quantitative measurements.

Gustav Fechner

Researcher who established methods for measuring perceptual boundaries.

Absolute Threshold

The smallest amount of energy needed to detect a stimulus.

Difference Threshold

The smallest change in energy that can be detected as different.

Weber

Researcher associated with measuring perceptual sensitivity to changes in stimuli.

Electrophysiology

Measuring electrical activity in neurons, such as through single-cell recordings.

Single-Cell Recording

Measuring the electrical activity of an individual neuron.

Neuroimaging

Measuring brain activity/processes using techniques such as PET and fMRI.

fMRI

A brain-imaging method that measures changes such as blood flow associated with brain activity.

PET

A neuroimaging method used to examine brain activity.

Lesion Study

Studying what happens when a particular area of the brain is damaged to determine what function that area may be involved in.

Fusiform Gyrus

A brain area associated with face perception; damage can impair the ability to recognize faces.

Neuron

A cell involved in transmitting neural information.

Cell Body/Soma

The part of the neuron that keeps the cell alive and functioning.

Dendrites

Structures that receive signals or information from other neurons or the outside world.

Axon/Nerve Fiber

The part of the neuron that sends signals away from the neuron.

Sodium ($\text{Na}^+$)

A positively charged ion; there is more sodium outside the neuron when it is at rest.

Potassium ($\text{K}^+$)

A positively charged ion that flows out of the neuron during the process of resetting after an action potential.

Resting Potential

The negative electrical charge of a neuron when it is at rest and has the potential to change.

Polarized

The state of a resting neuron when the inside is negatively charged relative to the outside, around $-70\,\text{mV}$.

Action Potential

The electrical signal produced when a neuron fires.

Depolarization

When the inside of the neuron becomes more positive.

Selective Permeability

The neuron's membrane controls/modulates which ions can flow into and out of the cell.

Propagated Response

The action potential traveling down the axon.

Refractory Period

The brief period after firing when the neuron resets before it can fire again.

Spontaneous Activity/Baseline Firing

Action potentials that occur without external stimulation.

Neural Circuit

A group of neurons that signal one another.

Synapse

The tiny space between neurons.

Neurotransmitter

A chemical released by a presynaptic neuron that can affect a postsynaptic neuron.

Presynaptic Neuron

The neuron sending the signal.

Postsynaptic Neuron

The neuron receiving the signal.

Receptor Site

A site on the postsynaptic neuron where a neurotransmitter binds.

Excitatory Neurotransmitter

A neurotransmitter that causes depolarization and increases the likelihood of an action potential.

Glutamate and Epinepheran

An example of an excitatory neurotransmitter.

Inhibitory Neurotransmitter

A neurotransmitter that causes hyperpolarization and decreases the likelihood of an action potential.

GABA and Serotonin

An example of an inhibitory neurotransmitter.

Hyperpolarization

When the neuron becomes more negative, decreasing the likelihood of an action potential.

Sensory Code

The way neural firing represents perceived stimuli.

Specificity Coding

The idea that specific neurons are tuned to specific stimuli or concepts.

Grandmother Cell Hypothesis

The idea that one specific neuron could represent one specific concept, such as your grandmother.

Sparse Coding

A stimulus or experience is represented by a pattern of firing in a small group of neurons, while many neurons remain silent.

Population Coding

A stimulus or experience is represented by a pattern of firing across a larger group/population of neurons.

Modularity Hypothesis

The idea that specific brain areas are specialized for specific types of stimuli or functions.

Distributed Representation Hypothesis

The idea that information is represented through patterns of activity distributed across multiple areas of the cortex.

Structural Connectivity

The physical “road map” of fibers connecting different areas of the brain.

Functional Connectivity

The “traffic flow” of neural activity associated with a particular function moving through the brain's structural network.

Mind-Body Problem

The question of how physical brain/neural processes produce subjective experiences and consciousness.

Qualia

Subjective experiences or conscious experiences.

Neural Correlate of Consciousness (NCC)

Physiological/neural responses that correlate with conscious experience.

Easy Problem of Consciousness

Determining the neural/physiological processes associated with consciousness.

Hard Problem of Consciousness

Explaining how physiological processes actually produce subjective internal experiences.

David Chalmers

Philosopher who argues that the hard problem of consciousness cannot currently be fully explained.

Daniel Dennett

Philosopher who argues that consciousness can be viewed as an illusion or “user interface.”

Connectionism

Computing modeled after neurons and neural circuits, such as artificial neural networks.

Situated Intelligence/Consciousness/Cognition

The idea that human-like intelligence requires perceiving the world through senses.

Light

Electromagnetic radiation.

Photon

An elementary particle/quantum of light.

Electromagnetic Spectrum

The full range of electromagnetic energy; humans can only see a small portion.

Visible Light

The wavelengths humans can see, approximately $400\text{--}700\,\text{nm}$ according to your notes.

Wavelength

The distance from one peak of a wave to the next peak (or valley to valley).

Frequency

The number of oscillations occurring in a given amount of time.

Amplitude

The height of a wave; related to the energy/intensity of radiation.

Cornea

The primary lens of the eye; bends light and focuses about $80\%$ of it.

Lens

Changes thickness/curvature to help focus light on the retina.

Accommodation

The lens changing shape to refocus light onto the retina.

Retina

The light-sensitive surface at the back of the eye where the image is focused.

Pupil

The opening that allows light to enter the eye.

Iris

The muscle that controls the size of the pupil.

Aqueous Humor

Fluid located between the cornea and lens.

Glaucoma

A condition involving increased pressure in the eye that can damage the optic nerve and lead to blindness.

Astigmatism

A condition in which the cornea or another lens is not perfectly smooth/rounded.

Presbyopia

Difficulty focusing on nearby objects due to reduced ability of the lens to accommodate, associated with aging.

Near Point

The closest point at which the lens can adjust to bring an object into focus.

Myopia

Nearsightedness; difficulty seeing distant objects.

Far Point

The farthest point at which light can be focused on the retina.

Refractive Myopia

Nearsightedness caused by the cornea and/or lens bending light too much.

Axial Myopia

Nearsightedness caused by the eyeball being too long.

Hyperopia

Farsightedness; difficulty seeing nearby objects.

Refractive Hyperopia

Farsightedness caused by the cornea and/or lens bending light too little.