Chapter 1 Flashcards
Perception
The later steps in the perceptual process whereby the initial sensory signals are used to represent objects and events so they can be identified, stored, and used in thought and action
Sensation
The initial steps in the perceptual process, physical features in the environment are converted into electrochemical signals
Distal stimulus
The perceived object or event in the world
Proximal stimulus
A physical phenomenon evoked by a distal stimulus that impinges on the specialized cells of a sense
Top down information
An observers knowledge, expectations, and goals, which can affect perception.
Bottom up information
The information contained in neural signals from receptors
Transduction
The transformation of a physical stimulus into neural signals
Neural code
A patters of neural signals that carries information about a stimulus and can serve as a representation of that stimulus
Psychophysics
A field of study concerned with relating psychological experience to physical stimuli
Neuron doctrine
The principle that perception depends on the combined activity of many specialized neurons, each of which respond to specific aspects of a stimulus
Depolarization
Part of the sequence of events of an action potential, during which an inflow of positively charged ions causes the membrane potential to become markedly more positive.
Refractory period
Following an action potential, a brief period during which a new action potential cannot be initiated
Firing rate
The rate at which a neuron produces action potentials; usually expressed in terms of spikes per second
Baseline firing rate
A neurons low rate of spontaneous firing at fairly random intervals in the absence of any stimulus
Synapse
A tiny gap between the axon terminal of one neuron and the dendrite or cell body of another neuron
Presynaptic membrane
The membrane at the axon terminal of a neuron producing an action potential
Post synaptic membrane
The membrane of the dendrite or cell body receiving a neural signal
Synaptic vesicles
Within axon terminals, tiny sacs that contain neurotransmitter molecules
Excitatory neurotransmitters
Neurotransmitters that have an excitatory effect on the postsynaptic neuron, increasing the probability that an action potential will be initiated
Inhibitory neurotransmitters
Neurotransmitters that have an inhibitory effect on the postsynaptic neuron, decreasing the probability that an action potential will be initiated
Excitatory postsynaptic potential
The effect of an excitatory neurotransmitter, making the postsynaptic neuron’s membrane potential more positive
Inhibitory postsynaptic potential
The effect of an inhibitory neurotransmitter, making the postsynaptic neuron’s membrane potential more negative
Corpus callosum
The large bundle of axons that constitutes the two cerebral hemispheres
Gyrus
An elongated bump on the surface of the cerebral hemispheres
Suculus
An indentation between the gyri on the surface of the two cerebral hemispheres
Cerebral cortex
Outermost layer of the cerebral hemispheres; 2-4 mm thick consisting mostly of gray matter (neural cell bodies)
Gray matter
The cell bodies of neuron’s make up the cerebral cortex
White matter
The myelin-covered axons of cortical neurons, making up the interior parts of the cerebral hemispheres
Thalamus
The most important subcortical structure involved in perception; most neural signals pass through the thalamus on their paths from the sensory organs to the cortex ( not olfaction)
Dissociation
A pattern of brain damage and impaired function in which damage to some specific brain region is associated with some specific function but not with impairment with another function
Double dissociation
Book page 18
Functional neuroimaging
An array of techniques for measuring brain activity of healthy volunteers carrying out carefully designed tasks
Positron emission tomography (PET)
A functional neuroimaging technique based on measurement of the change in blood flow associated with brain activity. Using a radioactive substance introduced into the blood
Functional magnetic resonance imaging (fMRI)
A functional neuroimaging technique based on measurement of the changes in blood oxygenation associated with brain activity
Absolute threshold
The minimum intensity of a physical stimulus that can just be detected by an observer
Method of adjustment
A behavioral method used in psychophysical experiments; the participant observes a stimulus and adjusts a knob that directly controls the intensity of the stimulus
Method of constant stimuli
A behavioral method used in psychophysical experiments; the participant is presented with a fixed set of stimuli covering a range of intensities that are presented repeatedly in random order, and the participant must indicate whether or not each stimulus was detected
Psychometric function
A curve that relates a measure of perceptual experience to the intensity of a physical stimulus.
Staircase method
A behavioral method used in psychophysical experiments the participant is presented with a stimulus and indicates whether it was detecte, based on that response, the next stimulus is either one step up or one step down in intensity.
Difference threshold
The minimum difference between two stimuli that allows an observer to perceive that the two stimuli are different
Weber’s law
A statement of relationship between the intensity of a standard stimulus and the size of the just noticeable difference
Psychophysical scaling
The process of measuring how changes in stimulus intensity relate to changes in the perceived intensity
Fechner’s law
A statement of how the perceived intensity of a stimulus changes as its physical intensity changes
Magnitude estimation
A behavioral method used in psychophysical experiments to estimate perceived intensity directly; the experimenter assigns an arbitrary number to represent the intensity of a standard stimulus, then the participant assigns numbers to other stimuli to indicate their perceived intensity relative to the standard.
Noise
In the study of neural activity, slight random variation in the number of action potentials produced by neurons in response to a fixed sensory stimulus
Signal detection theory
A framework for measuring how people make decisions based on noisy perceptive evidence
