4 Connections of the Visual Cortex Primary Visual Cortex (V1)Input from LGNOutput to all other levelsSecondary Visual Cortex (V2)After V2Output to the parietal lobe - Dorsal StreamOutput to the inferior temporal lobe - Ventral StreamOutput to the superior temporal sulcus (STS) - STS StreamDorsal StreamVisual Guidance of MovementsVentral StreamObject PerceptionSTSVisuospatial functions (bio movement)
7 Disorders of Visual Pathways 2. Monocular BlindnessLoss of sight in one eyeResults from destruction of the retina or optic nerve3. Bitemporal HemianopiaLoss of vision from both temporal fieldsResults from a lesion to the optic chiasm4. Nasal HemianopiaLoss of vision of one nasal fieldResults from a lesion of the lateral chiasm5. Homonymous HemianopiaBlindness of one entire visual fieldResults from a complete cut of the optic tract, LGN or V17. Macular sparingSparing of the central or macular region of the visual fieldResults from a lesion to the occipital lobe6. Quadrantoanopia or HemianopiaComplete loss of vision in one-quarter of the fovea or in one-half of the fovea
8 Disorders of Visual Pathways Field DefectsScotomas - small blind spotsResults from small lesions to the occipital lobe
9 Visual Agnosia Object Agnosia Apperceptive Agnosia Associative Agnosia Deficit in the ability to develop a percept of the structure of an object or objects (still see color, motion, acuity)SimultagnosiaUnable to perceive more than one object at a timeResults from bilateral damage to the lateral parts of the occipital lobesAssociative AgnosiaCan perceive objects, but cannot identify themResults from lesions to the anterior temporal lobes
10 Visual Agnosia Other Agnosias Prosopagnosia Alexia Cannot recognize facesCan recognize facial features, facial expressions, and tell human from nonhuman facesAlexiaInability to readForm of object agnosia - inability to construct perceptual wholes from parts orForm of associative agnosia - word memory is damaged or inaccessibleResults from damage to the left fusiform and lingual areas
11 Neuropsychological Tasks seemingly linked to Occipital lobe Benton task of Facial RecognitionFusiform gyrus (temporal lobe)Hooper Visual Organization Test (VOT)Dorsal stream (parietal lobe)Visual Motor Integration (VMI)Test of Visual-Perceptual Skills (TVPS)Not sure what region it tests and poor normative dataVisual Neglect (Bells Test)Simultagnosia (occipital) or contralateral neglect (parietal)?Wide Range Assessment of Visual Motor Abilities (WRAVMA)No links to brain structuresEmbedded Figures Task (EFT)
12 Benton Face Recognition History: “facial agnosia”/ prosopagnosiaPurpose: Measures visualoperceptual discrimination of unfamiliar faces (not recognition/memory)Associated with right hemisphere: parietal, occipitoparietal and occipitotemporal3 parts:Match identical front viewMatch front view with ¾ viewMatch front view with various lighting conditionsHistory: Loss of ability to recognize familiar faces 1st seen as neuropsych sympton in 1867 by 2 opthalmologists with 54 aphasic patient with hemiperisis and blindess after stroke. Aphasia and hemiperises gone within few daysand visual symptoms apparently slowly lessened until left with inability to recognize familiy pepople, trouble with color vison and poor spatial orientation. Diagnosed hemorrage in right hemisphere.Over time, researchers realized that people with agnosia also had “facial agnosia”/prosopagnosia and usually accompanied some other deficit associated with right hemisphere damage e.g., (left visual field defect).. Also found that seemed to be 2 different groups: some patients able to recognize unfamiliar faces when assessed while others unable to recognize unfamiliar faces but not familiar.Benton Purpose: measure ability to ID and discriminate unfamiliar human faces in photos (without memory demands)/visuoperceptual functions typically associated with right hemisphere structures, especially parietal, occipitoparietal, and occipitotemporal structures.3 parts:Matching identical front view photos by pointing or saying its number)- 6 itemsMatching fromt view with ¾ view photos- 12 items on short form, 24 on long formMatching of front view under various lighting conditions: shown face in full lighting view and then asked to find same face in different lighting conditions- 9 items on short form, 24 longAdmin: Subjects can hold notebook. Present stimulus item and array at same time.1-7:“you see this yong woman? Show me where she is on this picture”7-13: you see this young woman? She is shown three times on this picture. Show me where she is. Find three pictures of her”Scoring: see scoring formLong form54 scorable responses. 1 point per correct response. Effective range =25-54Short formShort form effective range =11-27Findinsg with Brain DiseaseThere is consistent evidence that FRT performance, which is properly described as “visuoperceptual discrimination of unfamiliar faces” (and not facial “recognition”), is related to right hemisphere processing. Within the hemisphere, there is some indication that the posterior sector is more critical, but there is actually not much empirical evidence for this. There is an inkling that the left hemisphere makes a non-negligible contribution, and for the simpler aspects of the test (front-view and three-quarter view matching), may perhaps even be of comparable competence as the right hemisphere.Specific temporal lobe findingsPatients undergoing left (n = 81) or right (n = 77) anterior temporal lobectomy were administered tests of object recognition (facial recognition) and spatial localization (line orientation) preoperatively and 6 mo postoperatively to determine the effects on the what and where visual systems. Postoperatively there was significant loss in facial recognition ability and concomitant improvement in line orientation performance. The pattern of performance was similar for both groups. The findings suggest that anterior temporal lobectomy had a specific effect on the occipitotemporal object recognition system while leaving the occipitoparietal spatial localization system unaffected. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
13 Hooper Visual Organization Test (VOT) Test of the ability to conceptually rearrange disarranged picturesPosterior parietal lobe (dorsal visual stream)30 items, total # correctAnswers at end of Occipital Lobe section
14 Visual Motor Integration (VMI) 3 parts: VMI, Visual Perception, Motor Coordination.VMI: Copy a developmental sequence of geometric formsVisual Perception: ID the exact match for as many of the 27 stimuli as possible in 3 minutes.Motor: Trace the stimulus forms with a pencil without going outside double-lined paths in 5 min.Two versions (short and long form)- ages 2-18)Short only ages 2-8Long form for ages 9-18 takes minutesLong form is all about integration, that’s why you would want to add supplemental Visual perception and Motor coordination components- Allows you to see where the breakdown is occuring: motor, perception or the integration of the 2Perceptual Motor Impairment and Academic Achievement/LearningVM measures originally designed for use with adults with brain injuriesVM assessment now a part of evaluations due to correlations with specific learning problemsEx. Written expressionEx. Reading and math disorders- attention is usually associated; kids that skipping words when reading will often skip parts when reproducing figures in visual motor assessment.
15 Test of Visual-Perceptual Skills (TVPS) Visual-spatial relationshipsVisual closureVisual memory(response page)Visual sequential memory(stimulus page)Using 7 subtests, in theory, assesses visual processing of form, but limited dataVisual discriminationVisual form constancyVisual figure ground
17 Visual Neglect (Bells Test) Visual field defects and hemianopia impact performance minimally.This is about right parietal lesions not the occipital lobe.
18 Wide Range Assessment of Visual Motor Abilities (WRAVMA) Measure of visual motor, visual spatial and fine motor skills3 partsDrawing Test: Visual Motor AbilityMatching Test: Visual Spatial abilityPegboard Test: Fine motor abilityDesigned for referrals in which kids with handwriting difficulties performed WNL on traditional visuomotor assessments.Measure of visual motor, visual spatial and fine motor skills with separate norms for each.Drawing test: measures integrated visual motor ability (which would lead to question if a visual issue, motor or both, so administered additional subtests) (5-10 min)Matching test: visual spatial ability (5-10 min)Pegboard test: measures fine motor ability (insert as many pegs as can in 90 seconds into a waffled pegboard. First with dominant hand (score is based on this), then with nondominant hand (may be useful in quantifiying impact of nerve damage, unilateral frontal brain injury or hemiplegia. (4 min)Administration:#1) We are going to do some drawing. This man has 2 balloons and they need some strings. I’ll make this one (model). Now you do this one” (acceptable versus unacceptable examples om page 13 of manual)
19 Embedded Figures Task (EFT) Cognitive “style” measureTask= Find simple target shape within complex designScoring: Average time in secondsHigher score= greater difficulty analyzing a parts separate from whole/tendency to perceive complete patterns instead of separate partsSometiems referred to as a measure of cog styile rather than cog ability. Cognitive style or "thinking style" is a term used in cog psych to describe HOW people think, percieve and remember info. Different from cog ability/intelligence. There is some controversy over real meaning of cog style and it’s dimension in human personality.The EFT is a standardized measure of cognitive style and analytical ability. the subject is shown a complex design, and then is asked to find a target (simple) shape within the complex.The score is the average time in seconds to detect the simple forms. Thus, higher scores reflect greater difficulty in analyzing a part separately from a wider pattern. (Or, viewed more positively, a greater tendency to perceive complete patterns rather than their separate components.)The EFT is closely associated with other perceptual measures which require the participant to analyze part of an organized field independently of the These include tests of perception of orientation to the vertical (the rod-and-frame test and the body adjustment test); of certain illusions and reversible perspective; of similar auditory and tactile disembedding tasks; and of problem-solving which requires ``disembedding'' a part from its current environment.Previous work in 80’s suggests children with autism show superior performance (in relation to their general mental age) on the EFT. Frith interprets this as showing that they have “weak central coherence”. BUT Brian and Bryson and Ozonoff, Pennington and Rogers (1991) both attempted to replicate the Shah and Frith (1983) finding of autistic superiority on the EFT, but found no differences to matched controls. Baron cohen responded to this difference by attemptign to replicate and found that individuals with Aspergers and ASD were significantly faster on the EFT than age and IQ matched normal controls. This replicates the finding of superior performance reported by Shah and Frith (1983), and extends it by demonstrating this in terms of speed, on a more challenging adult-level test, and finding it in adults of normal intelligence who have either autism or Asperger Syndrome (AS). There were no significant group differences in terms of accuracy on the EFT, and this replicates the study by Ozonoff, Pennington and Rogers (1991). So- it is important to collecting response time (RT) data, rather than simply accuracy data. (Baron Cohen- 1997). There is continued discussion of WHY these differences exist.Sex differences- 1st grade boys performed better than 1st grade girls at pre test. However, after short period of instruction and exposure, gap disappeared. Boys and girls both benefited from instruction….calls into question causation of sex differences in visual-spatial type abilities. ane Marantz Connor, Maxine Schackman and Lisa A. Serbin Child DevelopmentVol. 49, No. 1 (Mar., 1978), pp
20 Answers to Hooper Visual Organization Test (VOT)
22 The Parietal Lobes Postcentral Gyrus Superior Parietal Lobule Brodmann’s areas 1,2, and 3Superior Parietal LobuleBrodmann’s areas 5 and 7Parietal OperculumBrodmann’s area 43Supramarginal GyrusBrodmann’s area 40Angular GyrusBrodmann’s area 39Process and integrate somatosensory and visual informationPart of the Dorsal StreamFunctional zonesAnterior zone - 1,2,3, and 43Somatosensory cortexPosterior zone - remaining areasPosterior parietal cortexVisual processing areasIntraparietal sulcus (cIPS)Control of saccadic eye movementsSaccade - involuntary abrupt and rapid small movements made by the eyes when changing the fixation pointVisual control of graspingParietal reach regions (PRR) area 7Visually guided grasping movementsAnterior zones - process somatic sensations and perceptionsPosterior zones - integrate information from vision with somatosensory information for movementInferior Parietal Lobule
23 Use of Spatial Information Spatial information can be used :Object recognitionViewer centered object identificationDetermines the location, location orientation and motion of an objectPosterior parietal cortexGuidance of MovementSensitive to eye movementsSensorimotor TransformationNeural calculations of the relative position of the body with respect to sensory feedback from movements being made and planned
24 Use of Spatial Information Spatial NavigationCognitive spatial mapRoute knowledge, unconscious knowledge of how to reach a destinationMental transformations are carried out by the posterior parietal cortexOther functions of parietal lobes:Aspects of mathAspects of languageMovement sequencingAcalculiaInability to do arithmeticNoted in parietal lobe patientsMight result from the spatial properties of addition and subtractionTwo digit number occupy different spaces“Borrowing” during subtractionLanguageWords have spatial organization“tap” vs. “pat”Movement SequencingIndividual elements of the movement have a spatial organization
25 Somatosensory Symptoms of Parietal-Lobe Lesions Lesions to the postcentral gyrus produce:Abnormally high sensory thresholdsImpaired position senseDeficits in stereognosis, or tactile perceptionAfferent paresisClumsy finger movements due to lack of feedback about finger position
26 Somatoperceptual Disorders AstereognosisInability to recognize an object by touchSimultaneous ExtinctionTwo stimuli are applied simultaneously to opposite sides of the bodyA failure to report a stimulus on one side is referred to as extinctionBlind TouchCannot feel stimuli, but can report their location
27 Somatoperceptual Disorders AgnosiasAsomatognosiaLoss of knowledge or sense of one’s own bodyAnosognosiaUnawareness or denial of illnessAnosodiaphoriaIndifference to illnessAsymbolia for painAbsence of normal reactions to painFinger AgnosiaUnable to point to the fingers or show them to the examinerAgnosia: partial or complete inability to recognize sensory stimuli, unexplained by a defect in elementary sensation or by reduced attention
28 Symptoms of Posterior Parietal Lobe Damage Contralateral NeglectNeglect for visual, auditory, and somesthetic stimulation on one side of the body or spaceLesion most often in the right inferior parietal lobeRight intraparietal sulcus and the right angular gyrusDefective sensation or perceptionDefective attention or orientation
29 Left Parietal Symptoms Disturbed Language FunctionApraxiaMovement disorder in which the loss of movement is not caused by weakness, inability to move, abnormal muscle tone, intellectual deterioration, poor comprehension, or other disorders of movementDyscalculiaDifficulties with arithmeticPoor recallInability to discriminate left from rightRight hemianopiaDyscalculia has to do with complex mental manipulations (subtraction which requires borrowing) not a problem, but is.
30 Apraxia and the Parietal Lobe Ideomotor ApraxiaCannot copy serial movementsMore likely to be associated with left parietal lesionsConstructional ApraxiaCannot copy pictures, build puzzles, or copy a series of facial movementsAssociated with right and left parietal lesions
31 Symptoms of Posterior Parietal Lobe Damage Deficits in drawing appear after damage to the right parietal lobeSpatial AttentionFunction of the parietal lobe to selectively attend to different stimuliDisengagementShifting attention from one stimulus to the next
32 Disorders of Spatial Cognition Mental rotation requires:Mental imaging of the stimulusManipulation of the imageLeft hemisphere deficit associated with the inability to generate the imageRight hemisphere deficit associated with the inability to manipulate the imageInability to use topographic information is associated with right hemisphere damage
34 Neuropsychological Tasks linked to Parietal lobe Two Point DiscriminationSeguin-Goddard Form Board/Tactual Performance TestLine bisectionIncomplete FiguresMooney ClosureRight-left differentiation
35 Two point discrimination Sharp, two point calipers2.85 cm, 2.7, 2.54….At each distance, touch either 1 or 2 points, , etcExaminee indicates one or 2 touches.Linked to contralateral postcentral gyrus (BA1, 2, & 3).
36 Seguin-Goddard Form Board/Tactual Performance Test Formboard, pieces, blindfoldRepeat for left, right, and both handsTotal time to place pieces in formboard for each trial.Remove formboard, provide paperExaminee draws formboard and places the shape in the outline of the formboard.Contralateral parietal lesions (PE, PF) for tactile and PG for drawing part
37 Line bisection Mark the middle of each line. Contralateral neglect With right parietal lesion, the lines to the left side of the page would be left blank.