Midterm 1 Flashcards
Signals coming from ___ ____ project to MTL
Signals coming from IT cortex project to MTL
Medial temporal lobe (MTL) structures are extremely important for ____ (e.g. parahippocampal cortex, entorhinal cortex, hippocampus)
Medial temporal lobe (MTL) structures are extremely important for memory (e.g. parahippocampal cortex, entorhinal cortex, hippocampus)
Observations that developing expertise in something can lead to recruitment of the FFA for associated stimuli supports the ____ hypothesis, which is a counter to the idea that the FFA is intrinsically ‘hardwired’ to respond to faces, which some people have argued
Observations that developing expertise in something can lead to recruitment of the FFA for associated stimuli supports the expertise hypothesis, which is a counter to the idea that the FFA is intrinsically ‘hardwired’ to respond to faces, which some people have argued
fusiform face area (FFA)
has neurons which tend to respond best to faces
neurons in the ____ ____respond to more complex stimuli than neurons in ___
neurons in the inferotemporal (IT) cortex respond to more complex stimuli than neurons in V1
As a general principle, as the signal originating from the eye continues to get routed through various neural pathways, the complexity of what the neurons in those regions of the brain respond to ____
As a general principle, as the signal originating from the eye continues to get routed through various neural pathways, the complexity of what the neurons in those regions of the brain respond to increases
Ganel experiment was designed to demonstrate a separation of perception and action in ‘healthy’ subjects (i.e. without brain damage). There were 2 conditions: ____ length estimation vs ____ length estimation
Ganel experiment was designed to demonstrate a separation of perception and action in ‘healthy’ subjects (i.e. without brain damage). There were 2 conditions: passive length estimation vs grasping length estimation
patient D.F. demonstrated a ___ ____ as a result of damage in their ventral pathway in a gas leak, he was NOT able to match orientation of sample card (____) _____ (‘____’ condition) but WAS able to match orientation if ____ ____ ___ ______ (‘____’ condition)
patient D.F. demonstrated a double dissociation as a result of damage in their ventral pathway in a gas leak, he was not able to match orientation of sample card (held by the experimenter) while holding it in their hand (‘passive’ condition) but was able to match orientation if physically placing card in a slot (‘action’ condition)
Dorsal stream shows function for both ___ and for ___
Dorsal stream shows function for both location and for action
Both ventral and dorsal pathways:
- Originate in the ____ and continue through ____ different types of ganglion cells in the LGN (____ and ___, ____ neurons are more sensitive to colour and fine detail)
-Have some ___
-Receive ___ from ___ brain areas
Both ventral and dorsal pathways:
- Originate in the retina and continue through two different types of ganglion cells in the LGN (magnocellular and parvocellular, parvocellular neurons are more sensitive to colour and fine detail)
-Have some interconnections
-Receive feedback from higher brain areas
The dorsal and ventral pathways demonstrate a classic ___ ___: two functions that involve different mechanisms and operate independently
The dorsal and ventral pathways demonstrate a classic double dissociation: two functions that involve different mechanisms and operate independently
Removal of ____ lobe tissue resulted in problems with the landmark discrimination task (implicating the ___ pathway, or ___ stream), though not the ___ task
Removal of parietal lobe tissue resulted in problems with the landmark discrimination task (implicating the where pathway, or dorsal stream), though not the OD task
Removal of ____ lobe tissue resulted in problems with the object discrimination task (implicating the ____ pathway, or ___ stream), though not the ___ task
Removal of temporal lobe tissue resulted in problems with the object discrimination task (implicating the what pathway, or ventral stream), though not the LD task
for the landmark discrimination problem the monkey was trained to look for food ___ a specific object
for the landmark discrimination problem the monkey was trained to look for food next to a specific object
for the objection discrimination problem the monkey was trained to look for the food ____ a specific object
for the objection discrimination problem the monkey was trained to look for the food under a specific object
Lesioning or ablation experiments follow 4 steps…
- An animal is trained to indicate perceptual capacities
- A specific part of the brain is removed or destroyed
- The animal is retrained to determine which perceptual abilities remain
- The results reveal which portions of the brain are responsible for specific behaviours
Neuroimaging allows us to ___ ___ ____-___ ___ (which measure firing of individual neurons) and look at the distributed pattern of activity in the cortex in response to stimuli as a ___
Neuroimaging allows us to move beyond single-cell recordings (which measure firing of individual neurons) and look at the distributed pattern of activity in the cortex in response to stimuli as a whole
As active neurons ‘use up’ oxygen in the nearby supply of blood, this makes the hemoglobin more ___ and changes it’s response to the magnetic field. fMRI can estimate changes in the activity level of specific areas of the brain by ____ ___ in the ___ ___ of ____ to the ___ ___
As active neurons ‘use up’ oxygen in the nearby supply of blood, this makes the hemoglobin more magnetic and changes it’s response to the magnetic field. fMRI can estimate changes in the activity level of specific areas of the brain by detecting changes in the magnetic response of hemoglobin to the magnetic field.
Although we cannot directly measure cognitive activity, blood flow provides a correlate that can be used to make inferences about ___ ___ (e.g. increased blood flow = increased ___)
Although we cannot directly measure cognitive activity, blood flow provides a correlate that can be used to make inferences about neural activation (e.g. increased blood flow = increased activation)
Cortical magnification
a small area of the fovea is represented by a large area on the visual cortex
The organization of V1 represents an ‘electronic map’ of the retina which is ___ : two points that are ___ ___ on an object (and thus are also ___ ___ on the retinal image formed by looking at the object) are also represented in parts of the cortex that are ___ ___
The organization of V1 represents an ‘electronic map’ of the retina which is retinotopic : two points that are close together on an object (and thus are also close together on the retinal image formed by looking at the object) are also represented in parts of the cortex that are close together
Because horizontal and vertical lines are more common in our environment, this should promote the development of ___ ___ ___ that respond to those kinds of stimuli
Because horizontal and vertical lines are more common in our environment, this should promote the development of more feature detectors that respond to those kinds of stimuli
oblique effect
vertical and horizontal lines are more easily identified than oblique lines by most humans
In theory, neurons that respond to whatever stimuli are present in the environment will become more ___ due to ____ ___
In theory, neurons that respond to whatever stimuli are present in the environment will become more predominate due to neural plasticity
Selective rearing
raising animals in environments that contain only certain types of stimuli (while depriving exposure to other kinds)
The orientation that is most affected by selective adaptation is ___
The orientation that is most affected by selective adaptation is vertical
The general experimental procedure for testing selective adaptation:
1) Measure ___ to range of one stimulus property (e.g. orientation), which can be taken as your ‘___’ response
2) ___ neurons with extended ___ of stimuli that have the property being tested
3) ____ the ____ to range of that same stimulus property
The general experimental procedure for testing selective adaptation:
1) Measure sensitivity to range of one stimulus property (e.g. orientation), which can be taken as your ‘baseline’ response
2) Adapt neurons with extended exposures of stimuli that have the property being tested
3) Remeasure the sensitivity to range of that same stimulus property
To test for contrast gratings difference in ____ can be changed
To test for contrast gratings difference in intensity can be changed
To test for sensitivity to orientation the gratings ___ relative to vertical is changed
To test for sensitivity to orientation the gratings angle relative to vertical is changed
the typical stimuli used for selective adaption are called ___ and are made of ____ ___ and ___ bars
the typical stimuli used for selective adaption are called gratings and are made of alternating light and dark bars
Fatigue or adaptation to stimulus causes a decrease in both:
- ____ firing of those neurons
- the response of those neurons to ___ ___ of the ___ they have been adapted to
Fatigue or adaptation to stimulus causes a decrease in both:
- baseline firing of those neurons
- the response of those neurons to repeated presentations of the stimuli they have been adapted to
Selective Adaptation
a phenomenon in which neurons tuned to specific stimuli properties fatigue with prolonged exposure to stimuli containing those properties
Method of limits
used to determine absolute thresholds
Absolute Threshold
smallest amount of energy needed to detect a stimulus
Simple cortical cells
excitatory and inhibitory areas arranged side by side. Responds best to bars of a particular orientation
Complex cortical cells
respond best to movement across the receptive field of particularly oriented bar
Orientation tuning curves
plot the response of a simple cortical cell to line stimuli of varying orientations
The major types of feature detectors in the V1 are….
simple cortical cells, complex cortical cells and end-stopped cortical cells
Feature detectors are oriented __ ___ __ different from the ____ receptive fields seen in the retina and ____
Feature detectors are oriented side-by-side different from the centre-surround receptive fields seen in the retina and LGN
Feature detectors have receptive fields with ___ ____ ___ ___ ___
Feature detectors have receptive fields with both inhibitory and excitatory areas
Neurons that fire in response to specific features of a stimulus are called ___ ___
Neurons that fire in response to specific features of a stimulus are called feature detectors
LGN ___ more information from the cortex than it ___ to the cortex, suggesting a backward flow of information that may constitute a ___ mechanism
LGN receives more information from the cortex than it sends to the cortex, suggesting a backward flow of information that may constitute a feedback mechanism
More ‘___’ (a larger signal) is sent from the eye to the LGN, as compared to what is passed along from the __ to ___ (suggesting the LGN may ___, or ___, what information is passed along to ___)
More ‘information’ (a larger signal) is sent from the eye to the LGN, as compared to what is passed along from the LGN to V1 (suggesting the LGN may regulate, or filter, what information is passed along to V1)
LGN cells have ___ receptive fields
LGN cells have centre-surround receptive fields
LGN accounts for ___ nerve fibres leaving the eye
LGN accounts for ~90% nerve fibres leaving the eye
Superior colliculus receives signals from the eye and is important for ___ ___
Superior colliculus receives signals from the eye and is important for controlling eye-movements
Signals from the retina exit the eye through the ___ ____and then…
- Arrive first at the ____ ____ ____ (___)
- Are then sent along to the primary visual receiving area in the occipital lobe (the ___ ___, beginning with area ___)
- Are then sent through two pathways to the ___ lobe and the ___ lobe (the ___ and ___ streams)
- Finally arrive at the ___ lobe
Signals from the retina exit the eye through the optic nerve and then…
- Arrive first at the lateral geniculate nucleus (LGN)
- Are then sent along to the primary visual receiving area in the occipital lobe (the striate cortex, beginning with area V1)
- Are then sent through two pathways to the temporal lobe and the parietal lobe (the dorsal and ventral streams)
- Finally arrive at the frontal lobe
Output of centre-surround receptive fields changes depending on area stimulated…
_____ response when only the excitatory area is stimulated, _____ responses when both areas are stimulated (centre-surround antagonism) and _____ response when only the inhibitory area is stimulated
Output of centre-surround receptive fields changes depending on area stimulated…
highest response when only the excitatory area is stimulated, intermediate responses when both areas are stimulated (centre-surround antagonism) and lowest response when only the inhibitory area is stimulated
2 basic forms of receptive fields
1) excitatory-centre-inhibitory surround
2) inhibitory-centre-excitatory surround
visual receptive fields can be determined by monitoring __ ___ ___
visual receptive fields can be determined by monitoring single cell responses
Visual receptive fields
the retinal region over which a given cell in the visual system can be influenced (excited or inhibited) by light
Rods have worse acuity because two patterns of stimuli result in the firing of ___ ganglion cells connected to rods, which results in the neural system not being able to distinguish any difference
Rods have worse acuity because two patterns of stimuli result in the firing of one ganglion cells connected to rods, which results in the neural system not being able to distinguish any difference
Cones have better acuity because two patterns of stimuli result in the firing of ___ ganglion cells connected to cones, allowing the system to discriminate between the two stimulus examples
Cones have better acuity because two patterns of stimuli result in the firing of different ganglion cells connected to cones, allowing the system to discriminate between the two stimulus examples
the trade-off for cones having ___ convergence is that they need ___ light to respond than rods
the trade-off for cones having less convergence is that they need more light to respond than rods
Cones have better acuity because they have ___ cones that are connected to any one ganglion cell i.e. have ___ convergence
Cones have better acuity because they have fewer cones that are connected to any one ganglion cell i.e. have less convergence
All-___ foveal vision results in ___ visual acuity
All-cone foveal vision results in high visual acuity
___ convergence of ___= better acuity
less convergence of cones= better acuity
___ convergence of __ = more sensitive
more convergence of rods = more sensitive
Because rods have greater convergence than cones, the trade-off is that ___ ___ distinguish ____ as well
Because rods have greater convergence than cones, the trade-off is that rods cannot distinguish detail as well
Greater convergence results in ___ of the inputs of many rods into ganglion cells, ____ the likelihood of a response
Greater convergence results in summation of the inputs of many rods into ganglion cells, increasing the likelihood of a response
Rods as compared to cones are ___ sensitive to light, take ___ light to respond and have ___ convergence
Rods as compared to cones are more sensitive to light, take less light to respond and have greater convergence
Purkinje shift results in ___ ‘seeming’ ___ to a __-adapted eye, as compared to how it appears to a ___-adapted eye
Purkinje shift results in blue ‘seeming’ brighter to a dark-adapted eye, as compared to how it appears to a light-adapted eye
Purkinje shift
enhanced sensitivity to short wavelengths during dark adaptation when the shift from cone to rod vision occurs
Cone pigments absorb best at __ nm, __ nm, and __ nm
Cone pigments absorb best at 419nm, 531nm, and 558nm
The difference in spectral sensitivity across rods/cones is due to a difference in their ___ ___ of visual pigments
The difference in spectral sensitivity across rods/cones is due to a difference in their absorption spectra of visual pigments
Cones are most sensitive at ___ nm.
Cones are most sensitive at 560 nm.
Rods are ____ sensitive to short-wavelength light (most sensitivity at ___ nm) than cones.
Rods are more sensitive to short-wavelength light (most sensitivity at 500 nm) than cones.
Rods and cones differ in their ___ ___.
Rods and cones differ in their spectral sensitivity.
Humans are most sensitive to the ___ part of the visible spectrum (greenish/yellow light). This corresponds to the part of the spectrum that they have the lowest ___ for.
Humans are most sensitive to the middle part of the visible spectrum (greenish/yellow light). This corresponds to the part of the spectrum that they have the lowest threshold for.
Threshold and sensitivity mean something similar but are essentially ____ concepts (1/___ = ___)
Threshold and sensitivity mean something similar but are essentially reciprocal concepts (1/threshold = sensitivity)
Spectral sensitivity
refers to the sensitivity of rods and cones to different parts of the visible spectrum
Along similar lines (but in the opposite direction), the gradual ____ that we experience as we dark adapt has a lot to do with pigments being ___ at a ___ rate than they’re being used
Along similar lines (but in the opposite direction), the gradual improvement that we experience as we dark adapt has a lot to do with pigments being regenerated at a faster rate than they’re being used
Pigment bleaching accounts for being temporarily ‘blinded’ by a bright light (e.g. camera flash) because your ___ ___ of pigments is ___ and must regenerate before ___ can occur again
Pigment bleaching accounts for being temporarily ‘blinded’ by a bright light (e.g. camera flash) because your entire supply of pigments is depleted and must regenerate before transduction can occur again
Process needed for transduction:
- Retinal molecule ___ ___
- Opsin molecule ____
- The retina shows visual pigment ____
- Retinal and opsin must then recombine in a process called ____, in order to be capable of responding to light again
Process needed for transduction:
- Retinal molecule changes shape
- Opsin molecule separates
- The retina shows visual pigment bleaching
- Retinal and opsin must then recombine in a process called regeneration, in order to be capable of responding to light again
The dark adaptation curve can be determined using the following general approach:
(1) An observer starts in a lit room and becomes ‘___’
(2) The lights are then turned off, at which point the observer adjusts the intensity of a test light until it is just barely visible. This determines_____
(3) As time passes, they continue to readjust the intensity of the test light (again, until it is just barely visible) to plot the ____
The dark adaptation curve can be determined using the following general approach:
(1) An observer starts in a lit room and becomes ‘light adapted’
(2) The lights are then turned off, at which point the observer adjusts the intensity of a test light until it is just barely visible. This determines their sensitivity at the beginning of the dark adaptation curve
(3) As time passes, they continue to readjust the intensity of the test light (again, until it is just barely visible) to plot the change in sensitivity across time
Dark adaption refers to the process of ___ visual sensitivity after switching from ___ to __-level lighting conditions
Dark adaption refers to the process of increasing visual sensitivity after switching from high to low-level lighting conditions
A chain reaction occurs when a __ __ absorbs a __ ____ __ ___. Each visual pigment molecule activates hundreds more molecules, which each activate ~ 1000 more molecules
A chain reaction occurs when a visual pigment absorbs a single photon of light. Each visual pigment molecule activates hundreds more molecules, which each activate ~ 1000 more molecules
Visual transduction occurs when the ___ absorbs one photon, causing it to ___ ___ (a process referred to as isomerization)
Visual transduction occurs when the retinal absorbs one photon, causing it to change shape (a process referred to as isomerization)
Opsin
a large protein
Retinal
a light sensitive molecule
The outer segments of receptors contain visual pigment molecules, which consist of two components, ___ and ____.
The outer segments of receptors contain visual pigment molecules, which consist of two components, retinal and opsin.
Presbyopia is caused by the ____ of the lens and ___ of the ciliary muscles
Presbyopia is caused by the hardening of the lens and weakening of the ciliary muscles
