A new neural framework for visuospatial processing

A new neural framework for visuospatial processing Kravitz Saleem Baker Mishkin

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A new neural framework for visuospatial processing 2011 Nature Reviews Neuroscience 10.1038/nrn3008 Kravitz2011-a-new-neural-framework-for-visuospatial-proc Kravitz2011-a-new-neural-framework-for-visuospatial-proc.txt, the project's staged copy 2923a18c3f29b1a1e8ba4bb706192c7802efd138 not-redistributable neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them the cortical dorsal visual stream and what it actually comprises Quotation withheld because this record is not cleared for redistribution. whether the dorsal stream is best characterised as a Where pathway, a How pathway, or neither Quotation withheld because this record is not cleared for redistribution. replaces the single-purpose dorsal stream with three pathways - parieto-prefrontal, parieto-premotor and parieto-medial temporal - supporting spatial working memory, visually guided action and navigation Quotation withheld because this record is not cleared for redistribution. existence Quotation withheld because this record is not cleared for redistribution. dorsal-stream visuospatial processing Quotation withheld because this record is not cleared for redistribution. review review Quotation withheld because this record is not cleared for redistribution. mechanisms The three pathways acquire their different functions from their differing cortical targets rather than from their overlapping parietal sources — granular six-layered targets support perception while the agranular premotor target supports action status: the paper's own words: we suggest that Quotation withheld because this record is not cleared for redistribution. mechanisms Regional function is generated by the region's pattern of connectivity, so densely and reciprocally connected regions necessarily share functional properties and functions blend in gradients along a pathway Quotation withheld because this record is not cleared for redistribution. mechanisms The PCC and RSC sit mid-pathway and perform the conversion of egocentric parietal space codes into the allocentric codes used by the medial temporal lobe Quotation withheld because this record is not cleared for redistribution. the occipito-parietal circuit is the shared antecedent from which all three pathways diverge Quotation withheld because this record is not cleared for redistribution. posterior parietal representations are predominantly egocentric while medial temporal ones are mainly allocentric, with PCC and RSC coordinating between them Quotation withheld because this record is not cleared for redistribution. damage at different points along the pathway produces predictably different forms of topographic disorientation Quotation withheld because this record is not cleared for redistribution. a speculative anatomical account: the perception pathways target granular six-layered cortex while the action pathway targets agranular five-layered cortex Quotation withheld because this record is not cleared for redistribution. human resting-state functional connectivity reproduces the monkey tract-tracing circuit Quotation withheld because this record is not cleared for redistribution. No research directly compares the relative importance of the different functional properties within the same parietal region, so the proposed anatomical divisions are not yet functionally adjudicated. what this limits: comparisons between functional properties within a region: THERE HAS BEEN LITTLE RESEARCH THAT DIRECTLY COMPARES THE RELATIVE IMPORTANCE OF THESE DIFFERENT FUNCTIONAL PROPERTIES (FOR EXAMPLE, PERIPERSONAL VERSUS EXTRAPERSONAL CODING) WITHIN THE SAME REGION Quotation withheld because this record is not cleared for redistribution. Empirical data on the intermediate relay areas (PCC, RSC) of the proposed parieto-medial temporal pathway are sparse. what this limits: the intermediate areas of the pathway: THIS NEW FRAMEWORK ALSO HIGHLIGHTS THE PAUCITY OF EMPIRICAL DATA REGARDING THE INTERMEDIATE AREAS IN THE PARIETO-MEDIAL TEMPORAL PATHWAY Quotation withheld because this record is not cleared for redistribution. The trifurcation is not claimed to be exhaustive; further pathways may exist. what this limits: the trifurcation as a complete list: WE DO NOT MEAN TO IMPLY THAT THERE ARE THREE PATHWAYS ONLY, FOR THERE MAY WELL BE OTHERS Quotation withheld because this record is not cleared for redistribution. Scope is restricted to visuospatial processing, neglecting parietal contributions to spatial processing in other modalities. what this limits: other modalities, excluded by design: IN LIMITING THIS REVIEW TO VISUOSPATIAL PROCESSING, WE RECOGNIZE THAT WE HAVE LARGELY NEGLECTED THE ROLE THAT THE POSTERIOR PARIETAL CORTEX PLAYS IN SPATIAL PROCESSING IN OTHER MODALITIES Quotation withheld because this record is not cleared for redistribution. the framework's central premise - that function follows connectivity - is stated as a premise rather than demonstrated what this limits: everything the framework infers from anatomy: A MAJOR PREMISE IN THIS PERSPECTIVE IS THAT THE FUNCTION OF A REGION EMERGES FROM ITS PARTICULAR PATTERN OF CONNECTIVITY Quotation withheld because this record is not cleared for redistribution. the area-by-area exposition is described by the authors as purely didactic, with gradients assumed instead what this limits: the area-by-area presentation: THIS APPROACH IS PURELY DIDACTIC. IN FACT, WE ASSUME THAT THERE ARE GRADIENTS OF FUNCTION WITHIN AND BETWEEN areas Quotation withheld because this record is not cleared for redistribution. how the reference-frame transformations are actually performed remains unclear what this limits: the reference-frame account: IT IS STILL UNCLEAR HOW THESE TRANSFORMATIONS BETWEEN REFERENCE FRAMES occur Quotation withheld because this record is not cleared for redistribution. there may be more than three pathways; the trifurcation is not claimed to be exhaustive duplicate of: limitations[2] · what this limits: the same scope as limitations[2] - the trifurcation is not claimed to be exhaustive Quotation withheld because this record is not cleared for redistribution. the granular versus agranular account is explicitly left for future research what this limits: the granular-versus-agranular explanation: WHETHER OR NOT THESE DIFFERENCES IN THE MAKEUP OF THEIR CORTICAL TARGETS HELP TO ACCOUNT FOR THE STRIKING DIFFERENCES IN THE FUNCTIONAL CHARACTERISTICS IS A MATTER FOR FUTURE RESEARCH Quotation withheld because this record is not cleared for redistribution. navigation evidence does not exclude other visuospatial functions for the pathway what this limits: the navigation account of the pathway: THE EXISTENCE OF THESE MULTIPLE [routes] leaves other visuospatial functions available to it Quotation withheld because this record is not cleared for redistribution. the claim that the parahippocampal place area tracks layout over semantic content has published opposing views what this limits: the layout-over-semantics claim about PPA, which is contested: SEE REFS 173, 174 FOR OPPOSING VIEWS Quotation withheld because this record is not cleared for redistribution. the single-patient dissociation in D.F., which grounded the How account of the whole dorsal stream Quotation withheld because this record is not cleared for redistribution. functional connectivity in humans, used to corroborate a circuit established by tract tracing in monkeys Quotation withheld because this record is not cleared for redistribution. dorsal stream dorsal stream Quotation withheld because this record is not cleared for redistribution. the same anatomical stream has carried three successive names - Where, How, and now a trifurcated framework - and each name IS a functional theory rather than a label Quotation withheld because this record is not cleared for redistribution. dorsal stream is explicitly REDEFINED here: originally the pathway from striate cortex to the posterior inferior parietal lobule, now a widespread system across frontal, temporal and limbic lobes Quotation withheld because this record is not cleared for redistribution. egocentric and allocentric are the two reference frames whose transformation is the pathway's proposed job, and the mechanism of transformation is stated to be unknown Quotation withheld because this record is not cleared for redistribution. topographic disorientation is not one syndrome but a family, subdivided by which part of the pathway is damaged Quotation withheld because this record is not cleared for redistribution. claim_type: critique a second reading DIFFERING from the recorded value. Recorded: existence — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. method: review of monkey tract-tracing anatomy, primate and human functional data, and human lesion syndromes, organised around a proposed trifurcation a second reading DIFFERING from the recorded value. Recorded: review — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. phenomenon: visuospatial processing across cortex a second reading DIFFERING from the recorded value. Recorded: dorsal-stream visuospatial processing — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. builds-on → Milner and Goodale's 'How' account of the dorsal stream Quotation withheld because this record is not cleared for redistribution. contradicts → the hypothesis (from patient D.F.) that the dorsal stream serves only non-conscious action and that only the ventral stream yields conscious representations Quotation withheld because this record is not cleared for redistribution. builds-on → Margulies and colleagues (ref. 51), human/monkey functional connectivity of medial parietal areas Quotation withheld because this record is not cleared for redistribution. contradicts → the characterisation of the dorsal stream as either a perceptual Where or a motoric How pathway Quotation withheld because this record is not cleared for redistribution. qualifies → the claim that only the ventral stream produces representations accessible to consciousness Quotation withheld because this record is not cleared for redistribution. extends → the original two-stream anatomy of Ungerleider and Mishkin Quotation withheld because this record is not cleared for redistribution. supports → the parieto-medial temporal pathway, previously not well characterised in primates Quotation withheld because this record is not cleared for redistribution. dorsal stream —contrasted-with→ ventral stream dorsal stream ventral stream strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. egocentric —contrasted-with→ allocentric egocentric allocentric differs in: THE AXIS IS THE REFERENCE FRAME, AND BOTH SIDES ARE HEDGED. 'Quotation withheld' Note 'predominantly' and 'mainly' on either side: the division is a tendency, not a partition, and a join that treats it as a partition will find counterexamples in both regions and call them contradictions. · strength of the relation: 1 · note: and the mechanism converting one to the other is stated to be unknown Quotation withheld because this record is not cleared for redistribution. spatial working memory —distinct-from→ visually guided action spatial working memory visually guided action strength of the relation: 1 · note: the two functions the old single dorsal stream had to carry at once Quotation withheld because this record is not cleared for redistribution. The dorsal stream is shown to trifurcate beyond parietal cortex into parieto-prefrontal, parieto-premotor and parieto-medial temporal pathways, the last running through posterior cingulate and retrosplenial cortex to the medial temporal lobe. Quotation withheld because this record is not cleared for redistribution. Because each of the three pathways serves a different class of visuospatial function, neither the 'Where' nor the 'How' characterisation of the dorsal stream is adequate. Quotation withheld because this record is not cleared for redistribution. The site of damage along the parieto-medial temporal pathway predicts which specific form of topographic disorientation a patient shows. Quotation withheld because this record is not cleared for redistribution. Human resting-state fMRI connectivity between IPL, PCC, RSC and parahippocampal cortex converges with the monkey tract-tracing evidence for the proposed pathway. Quotation withheld because this record is not cleared for redistribution. Within the IPL, only the rostral part (area 7b) is specialized for guiding action in peripersonal space. Quotation withheld because this record is not cleared for redistribution. The dorsal stream is reconceived as a widespread visuospatial system across frontal, temporal and limbic cortex, contributing to both spatial perception and non-conscious spatial processing. Quotation withheld because this record is not cleared for redistribution. The review suggests, as one potential answer, the MTL as a major point of convergence and perceptual integration for the ventral stream and the parieto-medial temporal pathway. Quotation withheld because this record is not cleared for redistribution. the dorsal stream trifurcates beyond parietal cortex into prefrontal, premotor and medial temporal pathways Quotation withheld because this record is not cleared for redistribution. resting-state fMRI time courses correlate strongly among IPL, PCC, RSC and parahippocampal cortex Quotation withheld because this record is not cleared for redistribution. damage at different points along the pathway yields predictably different topographic disorientations Quotation withheld because this record is not cleared for redistribution. landmark agnosia leaves orientation and map-making intact but destroys landmark recognition Quotation withheld because this record is not cleared for redistribution. anterograde topographic disorientation leaves patients unable to form representations of new environments Quotation withheld because this record is not cleared for redistribution. the parahippocampal place area responds equally to furnished and emptied rooms, tracking layout rather than content Quotation withheld because this record is not cleared for redistribution. patient D.F. can reach accurately for objects she cannot consciously perceive Quotation withheld because this record is not cleared for redistribution. but D.F. can also make conscious depth judgments that probably depend on the dorsal stream Quotation withheld because this record is not cleared for redistribution. parieto–medial temporal pathway parieto–medial temporal pathway Quotation withheld because this record is not cleared for redistribution. retrosplenial complex retrosplenial complex Quotation withheld because this record is not cleared for redistribution. head-direction cells head-direction cells Quotation withheld because this record is not cleared for redistribution. place cells place cells Quotation withheld because this record is not cleared for redistribution. allocentric spatial view cells allocentric spatial view cells Quotation withheld because this record is not cleared for redistribution. heading disorientation heading disorientation Quotation withheld because this record is not cleared for redistribution. landmark agnosia landmark agnosia Quotation withheld because this record is not cleared for redistribution. anterograde topographic disorientation anterograde topographic disorientation Quotation withheld because this record is not cleared for redistribution. cross-modal extinction cross-modal extinction Quotation withheld because this record is not cleared for redistribution. parahippocampal place area parahippocampal place area Quotation withheld because this record is not cleared for redistribution. dorsal stream dorsal stream Quotation withheld because this record is not cleared for redistribution. dorsal stream dorsal stream Quotation withheld because this record is not cleared for redistribution. three pathways, not claimed to be exhaustive — the proposed trifurcation, with the authors noting there may well be others Quotation withheld because this record is not cleared for redistribution. reference frame reference frame Quotation withheld because this record is not cleared for redistribution.

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