Introduction and Visual Processing Flashcards
Definition
a form of remembering characterized by a feeling of familiarity when something previously experienced is again encountered
Recognition
Definition
what takes place when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
Transduction
Definition
any physical object or event in the external world that reflects light
Distal stimulus
Definition
The surround of a receptive field that when stimulated causes an excitation response
Excitatory-surround
Definition
a layered, multi-sensory structure. Its upper layer receives visual signals from the retina of the eye, while the lower layers process multiple signals from various other parts of the brain
Superior colliculus
Definition
a graph of the relationship between orientation an neuron firing which is determined by measuring the responses of a simple cortical cell to bars with different orientations
Orientation tuning curve
Definition
each of the paired lobes of the brain lying beneath the temples, including areas concerned with the understanding of speech
Temporal lobe
True or False:
Receptive fields overlap
True
Receptive fields overlap and provide accurate location information
Define
Cones
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides color vision and sharp central vision
Definition
the tendency to give a diminished response when faced with sustained stimuli
Selective adaptation
On average, how many cones converge to each ganglion cell?
6 cones to 1 ganglion cell
1:1 in the fovea
Define
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
Define
Sensation
the process that allows our brains to take in information via our five senses, which can then be experienced and interpreted by the brain
Define
Axon
the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.
Definition
refers to antagonistic interactions between center and surround regions of the receptive fields of photoreceptor cells in the retina. It enables edge detection and contrast enhancement within the visual cortex
Centre-surround antagonism
Define
Phenomenological method
aims to describe, understand and interpret the meanings of experiences of human life. It focuses on research questions such as what it is like to experience a particular situation
Define
Method of adjustment
a method of testing perception where the observer or the researcher continuously adjusts the stimulus until they can or cannot perceive it
Definition
individual neurons—or groups of neurons—in the brain which code for perceptually significant stimuli
Feature detectors
Definition
an optical illusion characterized by “ghostlike” grey blobs perceived at the intersections of a white (or light-colored) grid on a black background
Hermann grid
Definition
the first stage of cortical processing of visual information. It contains a complete map of the visual field covered by the eyes
Area V1
Definition
a type of neuron which has two extensions (one axon and one dendrite)and are specialized sensory neurons for the transmission of sense
Bipolar cells
Definition
either of the paired lobes of the brain at the top of the head, including areas concerned with the reception and correlation of sensory information.
Parietal lobe
Define
Method of limits
a psychophysical procedure for determining the sensory threshold by gradually increasing or decreasing the magnitude of the stimulus presented in discrete steps
Definition
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
Retina
Definition
a type of information processing that occurs in nervous systems and can be thought of as four separate yet related phenomena
Sensory coding
Define
Response expansion
As intensity increases, the perceived magnitude increases more quickly than the intensity
Define
Staircase illusion
a two-dimensional depiction of a staircase in which the stairs make four 90-degree turns as they ascend or descend yet form a continuous loop, so that a person could climb them forever and never get any higher
Define
Feature detectors
individual neurons—or groups of neurons—in the brain which code for perceptually significant stimuli
Definition
a period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation
Refractory period
Define
Primary receiving area
the primary cortical regions of the five sensory systems in the brain (taste, olfaction, touch, hearing and vision)
Define
Stimulus-perception relationship
the first stimulus relationship which relates stimuli to behavioural responses. This was the main relationship measured during the first 100 years of the scientific study of perception.
Definition
a self-initiated sequence of movements, usually with respect to some goal
Action
Definition
a mental and intellectual process in which objects and ideas are recognized, understood, compared to and differentiated from one another
Categorise
What are the three stages that perceptual processes can be observed?
Psychophysical approach (PP)
Physiological approach (PH1)
Physiological approach (PH2)
Define
Perception
the ability to see, hear, or become aware of something through the senses
Definition
An area of a receptive field that when stimulated causes an excitation response
Excitatory area
Define
Hyperpolarisation
movement of a cell’s membrane potential to a more negative value
Define
Physiological approach
suggests that our physiological make-up influences our behaviour, as the functioning of different areas of the brain relate to behaviour and experience
Define
Bipolar cells
a type of neuron which has two extensions (one axon and one dendrite)and are specialized sensory neurons for the transmission of sense
Define
Sparse coding
the study of algorithms which aim to learn a useful sparse representation of any given data
Definition
the light-absorbing molecules that mediate vision. They consist of an apoprotein, opsin, covalently linked to the chromophore cis-retinal
Visual pigment
Definition
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides side vision and the ability to see objects in dim light (night vision)
Rods
Define
Inhibitory response
a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential
Definition
a psychophysical method in which participants judge and assign numerical estimates to the perceived strength of a stimulus
Magnitude estimation
Define
Complex cells
neurons in V1 that respond optimally to a stimulus with a particular orientation. But, unlike simple cells, they respond to a variety of stimuli across different locations
What type of neural circuit does this graph depict?
A circuit with convergence and lateral inhibition
Define
Area V1
the first stage of cortical processing of visual information. It contains a complete map of the visual field covered by the eyes
Definition
stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception
Principle of transformation
What are the three ways to test absolute threshold?
Method of limits
Method of adjustment
Method of constant stimuli
Definition
describes the ability of a neuron to receive input from many neurons in a network
Neural convergence
Definition
a well-known 19th century brightness illusion, comprising adjacent homogeneous grey bands of different luminance, which are perceived as inhomogeneous
Chevreul illusion
Definition
one of the elements corresponding to a small simple eye that make up the compound eye of an arthropod
Ommatidia
Definition
the outer layer of the cerebrum (the cerebral cortex ), composed of folded gray matter and playing an important role in consciousness.
Cerebral cortex
Definition
the continuing process of the creation and organization of neuron connections that occurs as a result of a person’s life experiences
Experience-dependent plasticity
Define
Ommatidia
one of the elements corresponding to a small simple eye that make up the compound eye of an arthropod
What is the type of perceptual processing based on the perceiver’s previous knowledge?
Top-down processing
Define
Neural plasticity
the capacity of the nervous system to modify itself, functionally and structurally, in response to experience and injury
Definition
the capacity of an excited neuron to reduce the activity of its neighbors
Lateral inhibition
Definition
the pattern of energy impinging on the observer’s sensory receptors
Proximal stimulus
Definition
As intensity increases, the perceived magnitude increases more quickly than the intensity
Response expansion
Definition
The centre of a receptive field that when stimulated causes an inhibitory response
Inhibitory-centre
Define
Method of constant stimuli
a method of testing perception where you always present all stimuli. This technique prevents the observer from being able to predict or anticipate what the next stimulus will be
Definition
the minimum amount of stimulation required to trigger a reaction or produce a sensation
Absolute threshold
Define
Physiological-perception relationship
relates physiological responses and behavioural responses
What law describes the difference threshold for sensation?
Weber’s Law
Define
Contrast threshold
the minimum contrast that can be resolved by the patient
Definition
aims to describe, understand and interpret the meanings of experiences of human life. It focuses on research questions such as what it is like to experience a particular situation
Phenomenological method
Definition
the minimum contrast that can be resolved by the patient
Contrast threshold
Define
Hermann grid
an optical illusion characterized by “ghostlike” grey blobs perceived at the intersections of a white (or light-colored) grid on a black background
Define
Action
a self-initiated sequence of movements, usually with respect to some goal
Definition
The centre of a receptive field that when stimulated causes an excitation response
Excitatory-centre
Definition
a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential
Inhibitory response
Define
Depolarisation
loss of polarization
Definition
the tools for measuring perception and performance. These tools are used to reveal basic perceptual processes, to assess observer performance, and to specify the required characteristics of a display
Classical psychophysical methods
Definition
the imbalance of electrical charge that exists between the interior of electrically excitable neurons (nerve cells) and their surroundings
Resting potential
Definition
an electrically excitable cell that communicates with other cells via specialized connections called synapses
Neurons
Define
Inhibitory-centre
The centre of a receptive field that when stimulated causes an inhibitory response
What is the method of constant stimuli?
Define
Receptor sites
A molecular site or the docking port on the surface of, or within, a cell, usually involving proteins that are capable of recognizing and binding with specific molecules
Define
Magnitude estimation
a psychophysical method in which participants judge and assign numerical estimates to the perceived strength of a stimulus
Definition
the aspect of visual acuity involving the ability to distinguish the elements of a fine grating composed of alternating dark and light stripes or squares
Grating acuity
Definition
the process that allows our brains to take in information via our five senses, which can then be experienced and interpreted by the brain
Sensation
Definition
the rearmost lobe in each cerebral hemisphere of the brain
Occipital lobe
Define
Oblique effect
the name given to the relative deficiency in perceptual performance for oblique contours as compared to the performance for horizontal or vertical contours
What is the method of adjustment?
- Stimulus intensity is adjusted continuously until observer detects it
- Repeated trials averaged for threshold
Define
Rat-man demonstration
The demonstration in which presentation of a “ratlike” or “manlike” picture influences an observer’s perception of a second picture, which can be interpreted either as a rat or a man
Definition
loss of polarization
Depolarisation
Definition
relates physiological responses and behavioural responses
Physiological-perception relationship
Definition
a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina
Lateral geniculate nucleus (LGN)
Definition
the part of the visual cortex that is involved in processing visual information. It is the first cortical visual area that receives input from the lateral geniculate nucleus in the thalamus
Striate cortex
Define
Contextual modulation
the influence of a surround pattern on either the perception of, or the neural responses to, a target pattern
Definition
a cell that responds primarily to oriented edges and gratings (bars of particular orientations). These cells were discovered by Torsten Wiesel and David Hubel in the late 1950s
Simple cortical cell
Define
Sensory coding
a type of information processing that occurs in nervous systems and can be thought of as four separate yet related phenomena
True or False
Perception can be both conscious and unconscious
True
Perception is largely unconscious but, at times conscious effort is needed to interpret sensory data
Define
Cerebral cortex
the outer layer of the cerebrum (the cerebral cortex ), composed of folded gray matter and playing an important role in consciousness.
Definition
An area of a receptive field that when stimulated causes an inhibitory response
Inhibitory area
Definition
the capacity of the nervous system to modify itself, functionally and structurally, in response to experience and injury
Neural plasticity
Define
Psychophysics
the branch of psychology that deals with the relationships between physical stimuli and mental phenomena
Define
Neurotransmitters
a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure
Describe the magnitude estimation for brightness and electric shock
Define
Centre-surround organisation
a type of neural organisation that allows ganglion cells to transmit information not merely about whether photoreceptor cells are exposed to light, but also about the differences in firing rates of cells in the center and surround
Definition
the second stimulus relationship which depicts the relationship between stimuli and physiological responses
Stimulus-physiology relationship
Define
Recognition
a form of remembering characterized by a feeling of familiarity when something previously experienced is again encountered
Why is the difference threshold for electric shock smaller than for light intensity?
A small change in electric shock (pain) can cause a drastic change in injury whereas something like light intensity is less important
Define
Principle of representation
everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system
Definition
everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system
Principle of representation
Define
End-stopped cell
a type of visual processing neuron in the mammalian cerebral cortex. They are defined by the property of end-stopping, which is a decrease in firing strength with increasingly larger stimuli
Define
Centre-surround antagonism
refers to antagonistic interactions between center and surround regions of the receptive fields of photoreceptor cells in the retina. It enables edge detection and contrast enhancement within the visual cortex
Definition
The demonstration in which presentation of a “ratlike” or “manlike” picture influences an observer’s perception of a second picture, which can be interpreted either as a rat or a man
Rat-man demonstration
Definition
Experiential paradigm wherein an organism is brought up from arrival or from the time that the eyes open under circumstances that limit its optical experience
Selective rearing
What is the output of a centre-surround receptive field for each of these situations?
Excitatory area is stimulated:
Inhibitory area is stimulated:
Both areas are stimulated:
Define
Excitatory area
An area of a receptive field that when stimulated causes an excitation response
Define
Reaction time
the amount of time it takes to respond to a stimulus
Definition
inhibitory neurons, and they project their dendritic arbors onto the inner plexiform layer (IPL), they interact with retinal ganglion cells and/or bipolar cells
Amacrine cells
What is the type of perceptual processing based on incoming stimuli?
Bottom-up processing
Definition
neurons in V1 that respond optimally to a stimulus with a particular orientation. But, unlike simple cells, they respond to a variety of stimuli across different locations
Complex cells
Define
Grating acuity
the aspect of visual acuity involving the ability to distinguish the elements of a fine grating composed of alternating dark and light stripes or squares
Definition
a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body
Dendrites
Definition
an impairment in recognition of visually presented objects
Visual form agnosia
Definition
suggests that our physiological make-up influences our behaviour, as the functioning of different areas of the brain relate to behaviour and experience
Physiological approach
Definition
a synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a postsynaptic cell.
Excitatory synapse
Definition
the primary cortical regions of the five sensory systems in the brain (taste, olfaction, touch, hearing and vision)
Primary receiving area
Definition
As intensity increases, the perceived magnitude increases more slowly than the intensity
Response compression
Definition
the ability to see, hear, or become aware of something through the senses
Perception
Define
Absolute threshold
the minimum amount of stimulation required to trigger a reaction or produce a sensation
Define
Orientation tuning curve
a graph of the relationship between orientation an neuron firing which is determined by measuring the responses of a simple cortical cell to bars with different orientations
Definition
the influence of a surround pattern on either the perception of, or the neural responses to, a target pattern
Contextual modulation
Definition
a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure
Neurotransmitters
Definition
The surround of a receptive field that when stimulated causes an inhibitory response
Inhibitory-surround receptive field
Define
Mach bands
an optical illusion that exaggerates the contrast between edges of the slightly differing shades of gray, as soon as they contact one another, by triggering edge-detection in the human visual system
Define
Transduction
what takes place when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
Define
Dendrites
a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body
Definition
the collection of facts, information and experience that a person has collected throughout their life and education that they are able to use and apply to new life experiences
Knowledge
Define
Ganglion cells
the projection neurons of the vertebrate retina, conveying information from other retinal neurons to the rest of the brain
Definition
a portion of sensory space that can elicit neuronal responses when stimulated
Receptive field
What does Weber’s law say about difference threshold?
Define
Knowledge
the collection of facts, information and experience that a person has collected throughout their life and education that they are able to use and apply to new life experiences
Definition
the projection neurons of the vertebrate retina, conveying information from other retinal neurons to the rest of the brain
Ganglion cells
Define
Horizontal cells
the laterally interconnecting neurons having cell bodies in the inner nuclear layer of the retina of vertebrate eyes. They help integrate and regulate the input from multiple photoreceptor cells
Definition
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides color vision and sharp central vision
Cones
Define
Parietal lobe
either of the paired lobes of the brain at the top of the head, including areas concerned with the reception and correlation of sensory information.
Define
Perceptual process
the sequence of psychological steps that a person uses to organize and interpret information from the outside world
Define
Inhibitory area
An area of a receptive field that when stimulated causes an inhibitory response
Definition
the range of wavelengths or frequencies over which electromagnetic radiation extends
Electromagnetic spectrum
Define
Excitatory synapse
a synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a postsynaptic cell.
On average , how many rods converge to each ganglion cell?
120 rods per ganglion cell
Definition
a two-dimensional depiction of a staircase in which the stairs make four 90-degree turns as they ascend or descend yet form a continuous loop, so that a person could climb them forever and never get any higher
Staircase illusion
Definition
the laterally interconnecting neurons having cell bodies in the inner nuclear layer of the retina of vertebrate eyes. They help integrate and regulate the input from multiple photoreceptor cells
Horizontal cells
Define
Classical psychophysical methods
the tools for measuring perception and performance. These tools are used to reveal basic perceptual processes, to assess observer performance, and to specify the required characteristics of a display
What are the two interacting aspects of perception?
Bottom-up processing
Top-down processing
What is the method of limits?
- Stimuli of different intensities presented in ascending and decending order
- Observer responds to whether she perceived the stimulus
- Cross-over point is the threshold
What process in the brain allows us to see edges?
Lateral inhibition
Define
Sensory receptors
a structure that reacts to a physical stimulus in the environment, whether internal or external
Definition
a method of testing perception where the observer or the researcher continuously adjusts the stimulus until they can or cannot perceive it
Method of adjustment
Define
Neurons
an electrically excitable cell that communicates with other cells via specialized connections called synapses
Define
Synapse
a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter
Define
Neural circuits
a population of neurons interconnected by synapses to carry out a specific function when activated
Define
Occipital lobe
the rearmost lobe in each cerebral hemisphere of the brain
Definition
the sequence of psychological steps that a person uses to organize and interpret information from the outside world
Perceptual process
Definition
arise from a pool of photoreceptors On-center and off-center fields in retinal bipolar and ganglion cells form by pooling the response of groups of photoreceptors
Centre-surround receptive fields
Definition
a psychophysical procedure for determining the sensory threshold by gradually increasing or decreasing the magnitude of the stimulus presented in discrete steps
Method of limits
Definition
a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter
Synapse
Define
Cell body
the spherical part of the neuron that contains the nucleus
Define
Resting potential
the imbalance of electrical charge that exists between the interior of electrically excitable neurons (nerve cells) and their surroundings
Define
Excitatory-centre
The centre of a receptive field that when stimulated causes an excitation response
Define
Visual form agnosia
an impairment in recognition of visually presented objects
What three lightness perception phenomena can be explained by lateral inhibition?
The Hermann Grid
Mach Bands
Simultaneous Contrast
Define
Inferotemporal (IT) cortex
cortex covering the inferior side of the temporal lobe, it is thought to be especially important to visual processing and visual object recognition.
Define
Stimulus-physiology relationship
the second stimulus relationship which depicts the relationship between stimuli and physiological responses
Definition
the phase of the action potential caused by an increase permeability to K+
Falling phase of the action potential
Define
Psychophysical approach
the tools for measuring perception and performance. These tools are used to reveal basic perceptual processes, to assess observer performance, and to specify the required characteristics of a display
Definition
an explanation for perception that involves starting with an incoming stimulus and working upwards until a representation of the object is formed in our minds
Bottom-up processing
Definition
the study of algorithms which aim to learn a useful sparse representation of any given data
Sparse coding
Define
Receptive field
a portion of sensory space that can elicit neuronal responses when stimulated
Define
Temporal lobe
each of the paired lobes of the brain lying beneath the temples, including areas concerned with the understanding of speech
Define
Excitatory-surround
The surround of a receptive field that when stimulated causes an excitation response
Define
Population coding
a method to represent stimuli by using the joint activities of a number of neurons. Each neuron has a distribution of responses over some set of inputs, and the responses of many neurons may be combined to determine some value about the inputs
Define
Bottom-up processing
an explanation for perception that involves starting with an incoming stimulus and working upwards until a representation of the object is formed in our minds
Define
Chevreul illusion
a well-known 19th century brightness illusion, comprising adjacent homogeneous grey bands of different luminance, which are perceived as inhomogeneous
Define
Inhibitory-surround receptive field
The surround of a receptive field that when stimulated causes an inhibitory response
Definition
a type of neural organisation that allows ganglion cells to transmit information not merely about whether photoreceptor cells are exposed to light, but also about the differences in firing rates of cells in the center and surround
Centre-surround organisation
Definition
the idea that an object could be represented by the firing of a specialised neuron that responds only to that object
Specificity coding
Definition
how our brains make use of information that has already been brought into the brain by one or more of the sensory systems
Top-down processing
Define
Response compression
As intensity increases, the perceived magnitude increases more slowly than the intensity
Definition
a method to represent stimuli by using the joint activities of a number of neurons. Each neuron has a distribution of responses over some set of inputs, and the responses of many neurons may be combined to determine some value about the inputs
Population coding
Definition
describes the occipital lobe - the place where signals from the retina and LGN first reach the cortex
Visual receiving area
Define
Superior colliculus
a layered, multi-sensory structure. Its upper layer receives visual signals from the retina of the eye, while the lower layers process multiple signals from various other parts of the brain
Define
Top-down processing
how our brains make use of information that has already been brought into the brain by one or more of the sensory systems
Are rods or cones more sensitive to light? Why?
Rods are more sensitive to light than cones.
- Rods take less light to respond
- Rods have greater convergence which results in summation of the inputs of many rods into ganglion cells increasing the likelihood of response
- Trade-off is that rods cannot distinguish detail
Define
Simple cortical cell
a cell that responds primarily to oriented edges and gratings (bars of particular orientations). These cells were discovered by Torsten Wiesel and David Hubel in the late 1950s
Define
Action potential
the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell
Define
Electromagnetic spectrum
the range of wavelengths or frequencies over which electromagnetic radiation extends
Define
Specificity coding
the idea that an object could be represented by the firing of a specialised neuron that responds only to that object
Define
Categorise
a mental and intellectual process in which objects and ideas are recognized, understood, compared to and differentiated from one another
Definition
the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell
Action potential
Definition
the amount of time it takes to respond to a stimulus
Reaction time
Definition
the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.
Axon
Define
Frontal lobe
each of the paired lobes of the brain lying immediately behind the forehead, including areas concerned with behaviour, learning, personality, and voluntary movement
Define
Falling phase of the action potential
the phase of the action potential caused by an increase permeability to K+
Define
Rods
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides side vision and the ability to see objects in dim light (night vision)
Definition
each of the paired lobes of the brain lying immediately behind the forehead, including areas concerned with behaviour, learning, personality, and voluntary movement
Frontal lobe
Definition
an optical illusion that exaggerates the contrast between edges of the slightly differing shades of gray, as soon as they contact one another, by triggering edge-detection in the human visual system
Mach bands
Define
Selective rearing
Experiential paradigm wherein an organism is brought up from arrival or from the time that the eyes open under circumstances that limit its optical experience
Definition
A molecular site or the docking port on the surface of, or within, a cell, usually involving proteins that are capable of recognizing and binding with specific molecules
Receptor sites
Definition
the spherical part of the neuron that contains the nucleus
Cell body
Define
Striate cortex
the part of the visual cortex that is involved in processing visual information. It is the first cortical visual area that receives input from the lateral geniculate nucleus in the thalamus
Define
Selective adaptation
the tendency to give a diminished response when faced with sustained stimuli
Definition
a method of testing perception where you always present all stimuli. This technique prevents the observer from being able to predict or anticipate what the next stimulus will be
Method of constant stimuli
Define
Difference threshold
the smallest amount by which two sensory stimuli can differ in order for an individual to perceive them as different
Define
Distal stimulus
any physical object or event in the external world that reflects light
Define
Visual receiving area
describes the occipital lobe - the place where signals from the retina and LGN first reach the cortex
Definition
a structure that reacts to a physical stimulus in the environment, whether internal or external
Sensory receptors
Define
Visual pigment
the light-absorbing molecules that mediate vision. They consist of an apoprotein, opsin, covalently linked to the chromophore cis-retinal
Define
Neural convergence
describes the ability of a neuron to receive input from many neurons in a network
Define
Centre-surround receptive fields
arise from a pool of photoreceptors On-center and off-center fields in retinal bipolar and ganglion cells form by pooling the response of groups of photoreceptors
Define
Refractory period
a period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation
Define
Principle of transformation
stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception
Define
Lateral inhibition
the capacity of an excited neuron to reduce the activity of its neighbors
Definition
cortex covering the inferior side of the temporal lobe, it is thought to be especially important to visual processing and visual object recognition.
Inferotemporal (IT) cortex
Define
Lateral geniculate nucleus (LGN)
a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina
Define
Thresholds
the change in a stimulus that is detectably different 50% of the time
Definition
the smallest amount by which two sensory stimuli can differ in order for an individual to perceive them as different
Difference threshold
Definition
the change in a stimulus that is detectably different 50% of the time
Thresholds
Definition
a type of visual processing neuron in the mammalian cerebral cortex. They are defined by the property of end-stopping, which is a decrease in firing strength with increasingly larger stimuli
End-stopped cell
Define
Experience-dependent plasticity
the continuing process of the creation and organization of neuron connections that occurs as a result of a person’s life experiences
Definition
the name given to the relative deficiency in perceptual performance for oblique contours as compared to the performance for horizontal or vertical contours
Oblique effect
Definition
a population of neurons interconnected by synapses to carry out a specific function when activated
Neural circuits
Definition
the first stimulus relationship which relates stimuli to behavioural responses. This was the main relationship measured during the first 100 years of the scientific study of perception.
Stimulus-perception relationship
Define
Proximal stimulus
the pattern of energy impinging on the observer’s sensory receptors
Definition
the branch of psychology that deals with the relationships between physical stimuli and mental phenomena
Psychophysics
Why are simple circuits considered ineffecient?
Definition
the tools for measuring perception and performance. These tools are used to reveal basic perceptual processes, to assess observer performance, and to specify the required characteristics of a display
Psychophysical approach
Define
Amacrine cells
inhibitory neurons, and they project their dendritic arbors onto the inner plexiform layer (IPL), they interact with retinal ganglion cells and/or bipolar cells
Definition
movement of a cell’s membrane potential to a more negative value
Hyperpolarisation
Definition
the phase of the action potential caused by an influx of Na+
Rising phase of the action potential
Define
Rising phase of the action potential
the phase of the action potential caused by an influx of Na+
