Term
| Marr's Three Levels of Analysis |
|
Definition
| Computational, Representation, & Hardware |
|
|
Term
|
Definition
| What is the goal of the computation? Why is it appropriate and what is the logic of the strategy by which it can be carried out? |
|
|
Term
|
Definition
| What is the method for this computation and representation? In particular, what is the representation for the input and output, and what is the algorithm for the transformation? |
|
|
Term
|
Definition
| What are the mans to implement the computation? How can the representation and algorithm be realized physically? |
|
|
Term
| law of mass action (Karl Lashley, 1930s) |
|
Definition
| Ran rats down mazes, took out different bits of brain from different locations, disruption seemingly depended on the mass removed, not the location. The mass-action principle stated that the reduction in learning is proportional to the amount of tissue destroyed, and the more complex the learning task, the more disruptive the lesions are. Lashley's research was an attempt to find the parts of the brain that were responsible for learning and memory traces or engrams. He trained rats to perform specific tasks (seeking a food reward), then lesioned varying portions of the rat cortex, either before or after the animals received the training depending upon the experiment. The amount of cortical tissue removed had specific effects on acquisition and retention of knowledge, but the location of the removed cortex had no effect on the rats' performance in the maze. This led Lashley to conclude that memories are not localized but widely distributed across the cortex |
|
|
Term
|
Definition
| Computerized Tomography (X-ray based), creates 3D pictures |
|
|
Term
|
Definition
| (Position Emission Tomography - using radioactive tracers, position-emitting)reasonably good spatial….bad temporal resolution (how quickly events take place) |
|
|
Term
|
Definition
| Magnetic Resonance Imaging - atoms align based magnetic fields |
|
|
Term
|
Definition
| electroencephalography - put electrode on the head, electrical waves, fast, but difficult to know where the signal comes from |
|
|
Term
|
Definition
| excellent resolution, but slow. is based on blood oxygen level, an indirect measure of neural activity, more neural activity, more blood oxygen, stronger FMI signal |
|
|
Term
|
Definition
| Magnetoencephalography (MEG) is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, fast, good resolution |
|
|
Term
|
Definition
| Patient X can perform task 1, but not task 2. Patient Y can perform task 2, but not task 1. This suggests that different and independent parts are involved in task 1 and task 2 (examples: language production vs. comprehension, recognizing faces vs. recognizing objects, seeing motion and seeing color) |
|
|
Term
|
Definition
| the part of a cell that contains the nucleus and surrounding cytoplasm, there is an electrical voltage difference between the outside and inside of the cell |
|
|
Term
|
Definition
| receive and integrate information |
|
|
Term
|
Definition
| decide and send information |
|
|
Term
| all-or-none spike (action potential) |
|
Definition
| If you receive enough signal, it generates an action potential; the signal gets transmitted through the axon to the next neuron |
|
|
Term
|
Definition
| is the process whereby one neuron (nerve cell) communicates with other neurons or effectors , such as a muscle cell, at a synapse. Input neurons release neurotransmitters; the neurotransmitters cross the synaptic gap |
|
|
Term
|
Definition
| Spikes are the language of cells. Output spike frequency reflects summation of excitation and inhibition |
|
|
Term
|
Definition
| the message is the pattern of cells which are firing, not the pattern of firing of each cell |
|
|
Term
|
Definition
| cell bodies, surface of the brain |
|
|
Term
|
Definition
| the axons or connections look whitish because of the fatty wrapping, |
|
|
Term
|
Definition
| mixture of cell bodies and axons |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| based on the axon connections, |
|
|
Term
|
Definition
| Penfield stimulation-function - in the penfield stimulation-function, you can see that there is disproportionate area of the somatic sensory cortex devoted to different parts of the body |
|
|
Term
|
Definition
| based on cellular composition. It was very detailed work. This map is still used today. Broadman's map is somewhat modified |
|
|
Term
|
Definition
| outer layers of the brain |
|
|
Term
|
Definition
| on the same side of the body |
|
|
Term
|
Definition
|
|
Term
|
Definition
| is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci (sl. sulcus). |
|
|
Term
|
Definition
| is a depression or fissure in the surface of the brain |
|
|
Term
| Folding of cortical surface |
|
Definition
| enables more surface area to be packed into a fixed volume. Van Essen’s idea about cortical folding: areas that interact alot needs more connections, folding pattern reflect this connectio |
|
|
Term
| Hebbian learning (fire together, connect together) |
|
Definition
If two neurons fire together, they will wire together
This explains why some parts are closer together |
|
|
Term
|
Definition
| failure to attend to or represent sensory information from one side, a type of unilateral neglect, neglect is typically on the left side |
|
|
Term
|
Definition
| a type of unilateral neglect, directional hypokinesia, failure to execute movements fully in or towards (usually the contralateral) hempispace, not really "neglect" in the true sense, some patients show a "neglect like" problem > but their problems are more in the motor system |
|
|
Term
|
Definition
| detection ok when stimulus is presented in isolation, when two stimuli are presented simultaneously, one is ignored |
|
|
Term
|
Definition
| (seen in Balint syndrome): people are only attending to one object at a time, usually in central fovea, like “tunnel vision”. Simultanagnosia: inability to recognize more than one object, shown at the same time |
|
|
Term
|
Definition
| optic ataxia (inability to move the hand to an object by using vision), occular apraxia (inability to voluntarily control the gaze), simultanagnosia (inability to recognize more than one object shown at the same time) |
|
|
Term
| Peri-personal vs. extra-personal |
|
Definition
| This makes sense because your hands are beneath your eyes. Your visual resolution is better in the lower visual space. There is evidence for a double dissociation, suggesting that they are indepedent |
|
|
Term
| Perceptual deficit not sufficient to explain neglect: effect of temporal gap between cue and target |
|
Definition
| In Walker et al (1991), it was shown that neglect patients performed much better in the +100ms gap condition. It is helpful if the participant has time to fixate & cue their attention. This provided evidence that a perceptual deficit is not sufficient to explain neglect. This study helped to conclude that neglect is not just about a defect field. |
|
|
Term
| Neglect as a Deficit in Representation: imagine a familiar scene, from opposite viewpoints |
|
Definition
|
|
Term
| Neglect as a Defict in Attention |
|
Definition
| nefficient in disengagement from the current attentional focus. Posner study showed that you can “cue” attention. Posner paradigm > you can cue attention to the left or right side. Invalid Cue > cue to the right side…but the stimulus presented to the left side. This results in "poor performance" D’Erme et al. (1992): neutral cueing study -- initial magnetic attraction of to the right Neglect patients naturally have a bias to the right. When the cue is on the right > leads to more bias “ |
|
|
Term
| Neglect as a Defict in Attention |
|
Definition
| nefficient in disengagement from the current attentional focus. Posner study showed that you can “cue” attention. Posner paradigm > you can cue attention to the left or right side. Invalid Cue > cue to the right side…but the stimulus presented to the left side. This results in "poor performance" D’Erme et al. (1992): neutral cueing study -- initial magnetic attraction of to the right Neglect patients naturally have a bias to the right. When the cue is on the right > leads to more bias “ |
|
|
Term
| left hemisphere - for detailed information; right hemisphere -- for global configuration. |
|
Definition
| Damage to the left and damage to the right have different implications. The right side is more attuned to global info. If it is damaged > the global form will not be continued. The left side is more attuned to detailed info. If it is damaged > detail will be disrupted. But the global info might be per served. |
|
|
Term
| “Burning House”: implicit processing for the unattended side |
|
Definition
| A picture of a house shows a “burning house” on the left side. Is this information lost because neglect patients don’t report seeing it? No > it seems like it still affects decision-making. They are less likely to want to live in a house that is “burning” The difference seems to be registered in the brain somewhere |
|
|
Term
| D’Erme et al. (1992): neutral cueing study - |
|
Definition
| Neglect patients naturally have a bias to the right. When the cue is on the right > leads to more bias |
|
|
Term
| Attention: Posner et al.(1982): valid vs. invalid cueing study |
|
Definition
| inefficient in disengagement from the current attentional focus. Posner study showed that you can “cue” attention. Posner paradigm > you can cue attention to the left or right side. Invalid Cue > cue to the right side…but the stimulus presented to the left side. This results in "poor performance" |
|
|
Term
| Neglect as a Deficit in Representation: imagine a familiar scene, from opposite viewpoints |
|
Definition
| Bisiach & Luzzati (1978) has people imagine a familiar scene (square of Milan) from opposite view points. When you have patients facing in one direction, they tend to ignore the buildings on the left side. But if you have them turn around, then they will ignore the buildings from the new perspective. In the mind, the perspective changes. The "mental map" has changed. Not a deficit in representation |
|
|
Term
| Neglect as a Deficit in Representation: imagine a familiar scene, from opposite viewpoints |
|
Definition
| Bisiach & Luzzati (1978) has people imagine a familiar scene (square of Milan) from opposite view points. When you have patients facing in one direction, they tend to ignore the buildings on the left side. But if you have them turn around, then they will ignore the buildings from the new perspective. In the mind, the perspective changes. The "mental map" has changed. Not a deficit in representation |
|
|
Term
| Perceptual deficit not sufficient to explain neglect: effect of temporal gap between cue and target |
|
Definition
| In Walker et al (1991), it was shown that neglect patients performed much better in the +100ms gap condition. It is helpful if the participant has time to fixate & cue their attention. This provided evidence that a perceptual deficit is not sufficient to explain neglect. This study helped to conclude that neglect is not just about a defect field. |
|
|
Term
|
Definition
| patients only read rightward potion of words |
|
|
Term
| Space or object-centered neglect |
|
Definition
| By in large, it is neglect based on space. Overall, it is strongly biased in an "egocentric direction" |
|
|
Term
|
Definition
| Patients refuse to acknowledge the symptom (left side paralysis); denial can be extended to other. A certain proportion of right-hemisphere stroke patients who have left-sided hemiplegia will vehemently deny their paralysis, even though they may be mentally quite lucid in other respects |
|
|
Term
| A simplified model of face recognition |
|
Definition
| Visual strucutral processing (expression analysis, facial speech analysis, face recognition, person identification, name generation |
|
|
Term
| Behavioral studies of face recognition |
|
Definition
| evidence that a face is more than just a summation of parts |
|
|
Term
| Inversion effect (upside-down faces) |
|
Definition
| For inverted faces, the processing is less global. When they are upright, the brain processes them as a whole. We are very good at judging if a stimulus is a face or not, when they are upright. But, we are slower when the face is tilted, and even slower when it is inverted. |
|
|
Term
| McGurk effect/illusion (a video that says “ba, ba”): |
|
Definition
| The McGurk effect is a perceptual phenomenon which demonstrates an interaction between hearing and vision in speech perception. It suggests that speech perception is multimodal, that is, that it involves information from more than one sensory modality. The syllable /ba-ba/ is spoken over the lip movements of /ga-ga/, and the perception is of /da-da/. |
|
|
Term
| Grandmother cells/tuning properties of face-sensitive cells. |
|
Definition
| some cells respond seemingly to an individual identiy of the person, regardless of the view. |
|
|
Term
| Prototype referenced encoding (face adaptation) |
|
Definition
|
|
Term
|
Definition
| The grandmother cell is a hypothetical neuron that represents a complex but specific concept or object.[1] It activates when a person's brain "sees, hears, or otherwise sensibly discriminates"[2] a specific entity, such as his or her grandmother |
|
|
Term
| Grandmother cells/tuning properties of face-sensitive cells. |
|
Definition
| some cells respond seemingly to an individual identity of the person, regardless of the view, There are certain views that respond to particular people (it will respond to whatever view of the person)….but there are some that will prefer a specific viewpoint |
|
|
Term
| Perception” pathway (temporal pathway), |
|
Definition
| The ventral stream (also known as the "what pathway") travels to the temporal lobe and is involved with object identification |
|
|
Term
|
Definition
| Inferotemporal (IT) is placed below the middle temporal sulcus, and is connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface of the temporal lobe, where it is limited by the inferior sulcus. This region is one of the higher levels of the ventral stream of visual processing, associated with the representation of complex object features, such as global shape. It may also be involved in face perception |
|
|
Term
|
Definition
| After initial visual analysis, the info travels along two pathways. STS (superior temporal sulcus) is a region that is highly sensitive to faces. The other area is the FFA (inferotemporal gyrus). STS specializes in expression, mood, emotion analyses, as well as the variant aspects of the face. FFA is more involved in recognition, regardless of expression. |
|
|
Term
|
Definition
| Cell response better to upside-down faces, mooney faces, better to unblocked faces than partially bloocked faces, better for face itself than for features of the face, better to a front-facing face, regardless of lighting direction, and some cells respond better to certain views than others, some cells like all of the views of given face |
|
|
Term
|
Definition
| There are inhibitory regions and excitatory regions. Only responds to some orientations. They are very specific. Cell response better to upside-down faces, mooney faces, better to unblocked faces than partially bloocked faces, better for face itself than for features of the face, better to a front-facing face, regardless of lighting direction, and some cells respond better to certain views than others, some cells like all of the views of given face. |
|
|
Term
| Apperceptive Prosopagnosia (Apperceptive Visual Agnosia): |
|
Definition
| Apperceptive prosopagnosia is thought to be a disorder of some of the earliest processes in the face perception system. People with this disorder cannot make any sense of faces and are unable to make same-different judgments when they are presented with pictures of different faces. They may also be unable to work out attributes such as age or gender from a face. However, they may be able to recognize people based on non-face clues such as their clothing, hairstyle or voice. |
|
|
Term
| Associative Prosopagnosia |
|
Definition
| Associative prosopagnosia is thought to be an impairment to the links between early face perception processes and the semantic information we hold about people in our memories. People with this form of the disorder may be able to say whether photos of people's faces are the same or different and derive the age and gender from a face (suggesting they can make sense of some face information) but may not be able to subsequently identify the person or provide any information about them such as their name, occupation, or when they were last encountered. They may be able to recognize and produce such information based on non-face information such as voice, hair, or even particularly distinctive facial features (such as a distinctive moustache) that do not require the structure of the face to be understood. Typically such people do not report that 'faces make no sense' but simply that they do not look distinctive in any way. They seem to have trouble with the specific object name…..the guy also has trouble with the semantic meaning. It's not about finding the name |
|
|
Term
|
Definition
| (Greek: "prosopon" = "face", "agnosia" = "not knowing") is a disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intac |
|
|
Term
|
Definition
| in the fusiform cortex, there is a small area that shows high degree responsitivity to faces. |
|
|
Term
|
Definition
| in the fusiform cortex, there is a small area that shows high degree responsitivity to faces. |
|
|
Term
| Face identification or identification at the more specific category (subordinate) level?: |
|
Definition
| The Gauthier et al studies show that faces are processed at a subordinate, individual level. With other subjects, our analyses default to the basic (sort of cateogroical) level. The studies trained subjects to faces and greebles. After training, subjects became more responsive to certain object in the same brain location. |
|
|
Term
|
Definition
a set of neurons that are selective to representing faces
In a distributed network, you look at t he pattern of responses, but just the individual response. Looked at the spatial correlation
-Do objects stimulate neurons? Do they stimulate the same neurons (have high correlations?) |
|
|
Term
| Covert facial recognition |
|
Definition
|
|
Term
|
Definition
| The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centers of the brain through the fibers of the optic nerve,We can form images on the back of the eye, on the retina… |
|
|
Term
|
Definition
| A photoreceptor cell is a specialized type of neuron found in the eye's retina that is capable of phototransduction. The great biological importance of photoreceptors is that they convert light (electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential, in the center of the fovea, we don't have any photoreceptors |
|
|
Term
|
Definition
| The fovea centralis, also generally known as the fovea (the term fovea comes from the Latin, meaning pit or pitfall), is a part of the eye, located in the center of the macula region of the retina. [1] [2] The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for reading, watching television or movies, driving, and any activity where visual detail is of primary importance. |
|
|
Term
|
Definition
| The optic disc or optic nerve head is the location where ganglion cell axons exit the eye to form the optic nerve. There are no light sensitive rods or cones to respond to a light stimulus at this point. This causes a break in the visual field called "the blind spot" or the "physiological blind spot". The optic disc represents the beginning of the optic nerve (second cranial nerve) and is the point where the axons of retinal ganglion cells come together. |
|
|
Term
| *From eye to V1 (geniculo-striate pathway) |
|
Definition
| Optic nerve, Optic Chiasm, LGN, Primary Visual Cortex (V1) |
|
|
Term
| Other input pathways: Superior Colliculus (SC) |
|
Definition
| The superior colliculi form the rostral two bumps (one on each side) on the dorsal aspect of the midbrain. The caudal two bumps are the inferior colliculi and together they (inferior and superior colliculi) comprise the TECTUM or roof of the midbrain. In contrast to the inferior colliculus, which is an AUDITORY structure, the superior colliculus is usually described as a VISUAL reflex center. It is a highly laminated (layered) structure. The top or dorsal-most three layers receive visual information primarily from two sources, i.e., the retina (retinocollicular) and the visual cortex (area 17; corticotectal). In contrast to the exclusively visual nature of the superficial layers, the intermediate and deep layers receive projections from many functionally different areas of the brain. These inputs are both “motor” and “sensory”. Since the latter category includes visual, auditory and somatosensory inputs, you can see that the superior colliculus is not exclusively related to visual function. Instead, it plays a role in helping orient the head and eyes to all types of sensory stimuli. |
|
|
Term
|
Definition
| The lateral and inferior pulvinar have widespread connections with visual cortical association areas. |
|
|
Term
| What vs. Where (Ungerleider and Mishkin) |
|
Definition
Ventral Stream: What
Dorsal Stream: Where |
|
|
Term
|
Definition
|
|
Term
|
Definition
| damage retina or optic nerve; damage V1, damage other extra striate area |
|
|
Term
| Different forms of blindness |
|
Definition
There are different ways that people can become blind. If the damage is earlier in the pathway, you might really be blind. If your damage occurs later in the pathway, the person might feel blind, but there is a potential for some "blindsight" If you damage LGN or visual cortex…it's more likely that you'll damage one side…. Half of the visual field feels blind. You can observe "blindsight" in this …
If you damage V1, V2, V3…these situations are more complicated….they might lose more specific visual abilities (i.e. they cannot discriminate between colors) |
|
|
Term
|
Definition
Vision in a monkey….removed the primary visual cortex…the monkey ended up blind…. The monkey gradually regained a lot of the visual functions over time….the information was not as precise, but the monkey learned how to grab the chocolate
The visual information appears to not be that crude, the monkey was receiving the information. |
|
|
Term
|
Definition
| Monkey who had bilateral lesions of V1, had some ability to do blindsight |
|
|
Term
|
Definition
| pointing, gazing to target, determine whether present/absent, reasonable visual acuity, motion, orientation, some form (maybe based on orientation), sign of contrast, subjective self verbal report of guessing |
|
|
Term
|
Definition
Could be an artifact of stray light. Stray light could go into a sighted field area and provide additional information. They also checked what happens when you present light tot the blind spot vs. to the scotoma……
At the natural blind spot(where there would be a lot of stray light bouncing), they performed poorly.
So there seems to be no good evidence that suggests that stravy light is why people can see is NOT RIGHT |
|
|
Term
|
Definition
| A second objection rasied by Campion was the visual abilities demonstrated by blindsight studies were not hte product of non-striate visual mechanims, but instead represented |
|
|
Term
| gross anatomy, symmentry & asymmentry |
|
Definition
| Right hemisphere is slightly larger, left has more grey matter. Sylvian fissure slope difference (left more gentle, right steeper) |
|
|
Term
| within hemisphere difference |
|
Definition
| many different areas, cell type difference between areas, richer dendritic branching pattern in Broca's area than elsewhere |
|
|
Term
|
Definition
| is a lay term to describe the result when the corpus callosum connecting the two hemispheres of the brain is severed to some degree. The surgical operation to produce this condition is called corpus callosotomy (not to be confused with colostomy) and is usually used as a last resort to treat otherwise intractable epilepsy. Initially, partial callosotomies are performed; if this operation does not succeed, a complete callosotomy is performed to mitigate the risk of accidental physical injury by reducing the severity and violence of epileptic seizures. Prior to callosotomies, epilepsy is treated through pharmaceutical means. |
|
|
Term
|
Definition
| A patient with a split brain, when shown an image in his or her left visual field (the left half of what both eyes take in, see optic tract), will be unable to vocally name what he or she has seen. This is because the speech-control center is in the left side of the brain in most people, and the image from the left visual field is sent only to the right side of the brain (those with the speech control center in the right side will experience similar symptoms when an image is presented in the right visual field). Since communication between the two sides of the brain is inhibited, the patient cannot name what the right side of the brain is seeing. The person can, however, pick up and show recognition of an object (one within the left overall visual field) with their left hand, since that hand is controlled by the right side of the brain. |
|
|
