Editing Spatial memory (section)

==Physiology==

===Hippocampus===
[[File:Hippocampus small.gif|thumb|left|alt=rotating 3D animation of the human hippocampus in skull.|Hippocampus shown in red]]

The [[hippocampus]] provides animals with a spatial map of their environment.<ref>{{cite journal | last1 = O'Keefe | first1 = J. | last2 = Dostrovsky | first2 = J. | year = 1971 | title = The hippocampus as a spatial map. Preliminary evidence from unit activity in the freely-moving rat | journal = Brain Research | volume = 34 | issue = 1| pages = 171–175 | doi = 10.1016/0006-8993(71)90358-1 | pmid = 5124915 }}</ref> It stores information regarding non-egocentric space (egocentric means in reference to one's body position in space) and therefore supports viewpoint independence in spatial memory.<ref name=memory_and_hippo>{{cite journal | last1 = Squire | first1 = L. R. | year = 1992 | title = Memory and the hippocampus: A synthesis from findings with rats, monkeys, and humans | journal = Psychological Review | volume = 99 | issue = 2| pages = 195–231 | doi = 10.1037/0033-295X.99.2.195 | pmid = 1594723 }}</ref> This means that it allows for viewpoint manipulation from memory. It is important for long-term spatial memory of allocentric space (reference to external cues in space).<ref>{{cite journal | last1 = Ramos | first1 = J. M. J. | year = 2000 | title = Long-term spatial memory in rats with hippocampal lesions | journal = European Journal of Neuroscience | volume = 12 | issue = 9| pages = 3375–3384 | doi = 10.1046/j.1460-9568.2000.00206.x | pmid = 10998120 }}</ref> Maintenance and retrieval of memories are thus relational or [[Context-dependent memory|context dependent]].<ref>{{cite journal | last1 = Winocur | first1 = G. | last2 = Moscovitch | first2 = M. | last3 = Caruana | first3 = D. A. | last4 = Binns | first4 = M. A. | year = 2005 | title = Retrograde amnesia in rats with lesions to the hippocampus on a test of spatial memory | journal = Neuropsychologia | volume = 43 | issue = 11| pages = 1580–1590 | doi = 10.1016/j.neuropsychologia.2005.01.013 | pmid = 16009240 }}</ref> The hippocampus makes use of reference and working memory and has the important role of processing information about spatial locations.<ref name="the_effects_of_excitotoxic"/>

Blocking [[Neuroplasticity|plasticity]] in this region results in problems in goal-directed navigation and impairs the ability to remember precise locations.<ref>{{cite journal | last1 = Hebert | first1 = A. E. | last2 = Dash | first2 = P. K. | year = 2004 | title = Nonredundant roles for hippocampal and entorhinal cortical plasticity in spatial memory storage | journal = Pharmacology Biochemistry and Behavior | volume = 79 | issue = 1| pages = 143–153 | doi = 10.1016/j.pbb.2004.06.016 | pmid = 15388294 }}</ref> [[Amnesic]] patients with damage to the hippocampus cannot learn or remember spatial layouts, and patients having undergone hippocampal removal are severely impaired in spatial navigation.<ref name=memory_and_hippo/><ref name=place_navigation>{{cite journal |vauthors = Morris RG, Garrud P, Rawlins JN, O'Keefe J |year=1982 |title=Place navigation impaired in rats with hippocampal lesions |journal=[[Nature (journal)|Nature]] |volume=297 |issue= 5868|pages=681–683 |pmid=7088155 |bibcode=1982Natur.297..681M |doi=10.1038/297681a0 }}</ref>

Monkeys with lesions to this area cannot learn object-place associations and rats also display spatial deficits by not reacting to spatial change.<ref name=memory_and_hippo/><ref name="Save, E. 1992">{{cite journal | last1 = Save | first1 = E. | last2 = Poucet | first2 = B. | last3 = Foreman | first3 = N. | last4 = Buhot | first4 = M. | year = 1992 | title = Object exploration and reactions to spatial and nonspatial changes in hooded rats following damage to parietal cortex or hippocampal formation | journal = Behavioral Neuroscience | volume = 106 | issue = 3| pages = 447–456 | doi = 10.1037/0735-7044.106.3.447 | pmid = 1616611 }}</ref> In addition, rats with hippocampal lesions were shown to have temporally ungraded (time-independent) [[retrograde amnesia]] that is resistant to recognition of a learned platform task only when the entire hippocampus is lesioned, but not when it is partially lesioned.<ref>{{cite journal | last1 = Martin | first1 = S. J. | last2 = de Hozl | first2 = L. | last3 = Morris | first3 = R. G. M. | year = 2005 | title = Retrograde amnesia: neither partial nor complete hippocampal lesions in rats result in preferential sparing of remote spatial memory, even after reminding | journal = Neuropsychologia | volume = 43 | issue = 4| pages = 609–624 | doi = 10.1016/j.neuropsychologia.2004.07.007 | pmid = 15716151 }}</ref> Deficits in spatial memory are also found in spatial discrimination tasks.<ref name= place_navigation/>
[[File:Brainmaps-macaque-hippocampus.jpg|thumb|alt=Brain slice showing areas CA1 and CA3 in hippocampus.|Brain slice showing areas CA1 and CA3 in the hippocampus]]

Large differences in spatial impairment are found among the [[Dorsum (anatomy)|dorsal]] and [[Anatomical terms of location#Dorsal and ventral|ventral]] hippocampus. Lesions to the ventral hippocampus have no effect on spatial memory, while the dorsal hippocampus is required for retrieval, processing short-term memory and transferring memory from the short term to longer delay periods.<ref>{{cite journal | last1 = Bannerman | first1 = D. M. | last2 = Deacon | first2 = R. M. J. | last3 = Offen | first3 = S. | last4 = Friswell | first4 = J. | last5 = Grubb | first5 = M. | last6 = Rawlins | first6 = J. N. P. | year = 2002 | title = Double dissociation of function within the hippocampus: Spatial memory and hyponeophagia | journal = Behavioral Neuroscience | volume = 116 | issue = 5| pages = 884–901 | doi = 10.1037/0735-7044.116.5.884 | pmid = 12369808 }}</ref><ref>{{cite journal | last1 = Moser | first1 = M. | last2 = Moser | first2 = E. I. | year = 1998 | title = Distributed encoding and retrieval of spatial memory in the hippocampus | journal = The Journal of Neuroscience | volume = 18 | issue = 18| pages = 7535–7542 | pmid = 9736671 | pmc = 6793256 | doi = 10.1523/JNEUROSCI.18-18-07535.1998 }}</ref><ref name="Lee, I. 2003">{{cite journal | last1 = Lee | first1 = I. | last2 = Kesner | first2 = R. P. | year = 2003 | title = Time-dependent relationship between the dorsal hippocampus and the prefrontal cortex in spatial memory | journal = The Journal of Neuroscience | volume = 23 | issue = 4| pages = 1517–1523 | pmid = 12598640 | pmc = 6742248 | doi = 10.1523/JNEUROSCI.23-04-01517.2003 }}</ref> Infusion of [[amphetamine]] into the dorsal hippocampus has also been shown to enhance memory for spatial locations learned previously.<ref>{{cite journal | last1 = McGaugh | first1 = J. L. | year = 2000 | title = Memory—a century of consolidation | journal = Science | volume = 287 | issue = 5451| pages = 248–251 | doi = 10.1126/science.287.5451.248 | pmid = 10634773 |bibcode = 2000Sci...287..248M }}</ref> These findings indicate that there is a [[Dissociation (neuropsychology)|functional dissociation]] between the dorsal and ventral hippocampus. {{cn|date=March 2025}}

Hemispheric differences within the hippocampus are also observed. A study on [[London]] taxi drivers, asked drivers to recall complex routes around the city as well as famous [[landmark]]s for which the drivers had no knowledge of their spatial location. This resulted in an activation of the right hippocampus solely during recall of the complex routes which indicates that the right hippocampus is used for navigation in large scale spatial environments.<ref>{{cite journal | last1 = Maguire | first1 = E. A. | last2 = Frackowiak | first2 = R. S. J. | last3 = Frith | first3 = C. D. | year = 1997 | title = Recalling routes around London: Activation of the right hippocampus in taxi drivers | journal = The Journal of Neuroscience | volume = 17 | issue = 18| pages = 7103–7110 | pmid = 9278544 | pmc = 6573257 | doi = 10.1523/JNEUROSCI.17-18-07103.1997 }}</ref>

The hippocampus is known to contain two separate memory circuits. One circuit is used for recollection-based place recognition memory and includes the [[Apical dendrite#Hippocampus|entorhinal-CA1 system]],<ref>{{cite journal | last1 = Brun | first1 = V. H. | last2 = Otnaess | first2 = M. K. | last3 = Molden | first3 = S. | last4 = Steffenach | first4 = H. | last5 = Witter | first5 = M. P. | last6 = Moser | first6 = M. | last7 = Moser | first7 = E. I. | year = 2002 | title = Place cells and place recognition maintained by direct entorhinal-hippocampal circuitry | journal = Science | volume = 296 | issue = 5576| pages = 2243–2246 | doi = 10.1126/science.1071089 | pmid = 12077421 |bibcode = 2002Sci...296.2243B }}</ref> while the other system, consisting of the hippocampus [[trisynaptic loop]] (entohinal-dentate-CA3-CA1) is used for place recall memory<ref name="pmid18298245">{{cite journal |vauthors=Goodrich-Hunsaker NJ, Hunsaker MR, Kesner RP | title = The interactions and dissociations of the dorsal hippocampus subregions: how the dentate gyrus, CA3, and CA1 process spatial information. | journal = Behav. Neurosci. | volume = 122 | issue = 1 | pages = 16–26 | year = 2008 | pmid = 18298245 | doi=10.1037/0735-7044.122.1.16}}</ref> and facilitation of plasticity at the entorhinal-dentate synapse in mice is sufficient to enhance place recall.<ref name="pmid19755107">{{cite journal |vauthors=Saab BJ, Georgiou J, Nath A, Lee FJ, Wang M, Michalon A, Liu F, Mansuy IM, Roder JC | title = NCS-1 in the dentate gyrus promotes exploration, synaptic plasticity, and rapid acquisition of spatial memory | journal = Neuron | volume = 63 | issue = 5 | pages = 643–56 | year = 2009 | pmid = 19755107 | doi = 10.1016/j.neuron.2009.08.014 | doi-access = free }}</ref>

[[Place cell]]s are also found in the hippocampus.

===Posterior parietal cortex===
[[File:Parietal lobe animation.gif|thumb|left|110px|alt=rotating 3D animation of the parietal lobe in human skull.|Parietal lobe shown in red]]

The [[Parietal lobe|parietal cortex]] encodes spatial information using an egocentric frame of reference. It is therefore involved in the transformation of sensory information coordinates into action or effector coordinates by updating the spatial representation of the body within the environment.<ref>{{cite journal | last1 = Colby | first1 = C. L. | last2 = Goldberg | first2 = M. E. | year = 1999 | title = Space and attention in parietal cortex | journal = Annual Review of Neuroscience | volume = 22 | pages = 319–349 | doi = 10.1146/annurev.neuro.22.1.319 | pmid = 10202542 }}</ref> As a result, lesions to the parietal cortex produce deficits in the acquisition and retention of egocentric tasks, whereas minor impairment is seen among allocentric tasks.<ref>{{cite journal | last1 = Save | first1 = E. | last2 = Moghaddam | first2 = M. | year = 1996 | title = Effects of lesions of the associative parietal cortex on the acquisition and use of spatial memory in egocentric and allocentric navigation tasks in the rat | journal = Behavioral Neuroscience | volume = 110 | issue = 1| pages = 74–85 | doi = 10.1037/0735-7044.110.1.74 | pmid = 8652075 }}</ref>

Rats with lesions to the [[Anatomical terms of location#Anterior and posterior|anterior]] region of the [[posterior parietal cortex]] reexplore displaced objects, while rats with lesions to the [[Anatomical terms of location#Anterior and posterior|posterior]] region of the posterior parietal cortex displayed no reaction to spatial change.<ref name="Save, E. 1992"/>

Parietal cortex lesions are also known to produce temporally ungraded [[retrograde amnesia]].<ref name="Cho, Y. H. 1996">{{cite journal | last1 = Cho | first1 = Y. H. | last2 = Kesner | first2 = R. P. | year = 1996 | title = Involvement of entorhinal cortex or parietal cortex in long-term spatial discrimination memory in rats: Retrograde amnesia | journal = Behavioral Neuroscience | volume = 110 | issue = 3| pages = 436–442 | doi = 10.1037/0735-7044.110.3.436 | pmid = 8888988 }}</ref>

===Entorhinal cortex===
[[File:Medial surface of cerebral cortex - entorhinal cortex.png|thumb|120px|alt=medial view of the right cerebral hemisphere showing the entorhinal cortex near the base of the temporal lobe.|Medial view of the right cerebral hemisphere showing the entorhinal cortex in red at the base of the temporal lobe]]

The dorsalcaudal medial [[entorhinal cortex]] (dMEC) contains a topographically organized map of the spatial environment made up of [[grid cell]]s.<ref>{{cite journal | last1 = Hafting | first1 = T. | last2 = Fyhn | first2 = M. | last3 = Molden | first3 = S. | last4 = Moser | first4 = M. | last5 = Moser | first5 = E. I. | year = 2005 | title = Microstructure of a spatial map in the entorhinal cortex | journal = Nature | volume = 436 | issue = 7052| pages = 801–806 | doi = 10.1038/nature03721 | pmid = 15965463 |bibcode = 2005Natur.436..801H }}</ref> This brain region thus transforms sensory input from the environment and stores it as a durable allocentric representation in the brain to be used for [[path integration]].<ref>{{cite journal | last1 = Fyhn | first1 = M. | last2 = Molden | first2 = S. | last3 = Witter | first3 = M. P. | last4 = Moser | first4 = E. I. | last5 = Moser | first5 = M. | year = 2004 | title = Spatial representation in the entorhinal cortex | journal = Science | volume = 305 | issue = 5688| pages = 1258–1264 | doi = 10.1126/science.1099901 | pmid = 15333832 |bibcode = 2004Sci...305.1258F | doi-access = free }}</ref>

The entorhinal cortex contributes to the processing and integration of geometric properties and information in the environment.<ref name="Parron, C. 2004">{{cite journal | last1 = Parron | first1 = C. | last2 = Save | first2 = E. | year = 2004 | title = Comparison of the effects of entorhinal and retrosplenial cortical lesions on habituation, reaction to spatial and non-spatial changes during object exploration in the rat | journal = [[Neurobiology of Learning and Memory]] | volume = 82 | issue = 1| pages = 1–11 | doi = 10.1016/j.nlm.2004.03.004 | pmid = 15183166 }}</ref> Lesions to this region impair the use of [[Anatomical terms of location#Proximal and distal|distal]] but not [[Anatomical terms of location#Proximal and distal|proximal]] landmarks during navigation and produces a delay-dependent deficit in spatial memory that is proportional to the length of the delay.<ref>{{cite journal | last1 = Parron | first1 = C. | last2 = Poucet | first2 = B. | last3 = Save | first3 = E. | year = 2004 | title = Entorhinal cortex lesions impair the use of distal but not proximal landmarks during place navigation in the rat | journal = Behavioural Brain Research | volume = 154 | issue = 2| pages = 345–352 | doi = 10.1016/j.bbr.2004.03.006 | pmid = 15313022 }}</ref><ref>{{cite journal | last1 = Nagahara | first1 = H. A. | last2 = Otto | first2 = T. | last3 = Gallagher | first3 = M. | year = 1995 | title = Entorhinal-perirhinal lesions impair performance of rats on two versions of place learning in the Morris water maze | journal = Behavioral Neuroscience | volume = 109 | issue = 1| pages = 3–9 | doi = 10.1037/0735-7044.109.1.3 | pmid = 7734077 }}</ref> Lesions to this region are also known to create retention deficits for tasks learned up to 4 weeks but not 6 weeks prior to the lesions.<ref name="Cho, Y. H. 1996"/>

[[Memory consolidation]] in the entorhinal cortex is achieved through extracellular signal-regulated [[kinase]] activity.<ref>{{cite journal | last1 = Hebert | first1 = A. E. | last2 = Dash | first2 = P. K. | year = 2002 | title = Extracellular signal-regulated kinase activity in the entorhinal cortex is necessary for long-term spatial memory | journal = [[Learning & Memory]] | volume = 9 | issue = 4| pages = 156–166 | doi = 10.1101/lm.48502 | pmc = 182586 | pmid=12177229}}</ref>

===Prefrontal cortex===
[[File:Ptsd-brain.png|thumb|left|120px|alt=medial view of the right cerebral hemisphere showing the location of the prefrontal cortex at the front of the brain and more specifically the medial prefrontal cortex and ventromedial prefrontal cortex.|Medial view of the cerebral hemisphere showing the location of the prefrontal cortex and more specifically the medial and ventromedial prefrontal cortex in purple]]

The medial [[prefrontal cortex]] processes egocentric spatial information. It participates in the processing of short-term spatial memory used to guide planned search behavior and is believed to join spatial information with its [[motivation]]al significance.<ref name="Lee, I. 2003"/><ref>{{cite journal | last1 = Pratt | first1 = W. E. | last2 = Mizumori | first2 = S. J. Y. | year = 2001 | title = Neurons in rat medial prefrontal cortex show anticipatory rate changes to predictable differential rewards in a spatial memory task | journal = Behavioural Brain Research | volume = 123 | issue = 2| pages = 165–183 | doi = 10.1016/S0166-4328(01)00204-2 | pmid = 11399329 }}</ref> The identification of neurons that anticipate expected [[Reinforcement|rewards]] in a spatial task support this hypothesis. The medial prefrontal cortex is also implicated in the temporal organization of information.<ref>{{cite journal | last1 = Kesner | first1 = R. P. | last2 = Holbrook | first2 = T. | year = 1987 | title = Dissociation of item and order spatial memory in rats following medial prefrontal cortex lesions | journal = Neuropsychologia | volume = 25 | issue = 4| pages = 653–664 | doi = 10.1016/0028-3932(87)90056-X | pmid = 3658148 }}</ref>

Hemisphere specialization is found in this brain region. The left prefrontal cortex preferentially processes categorical spatial memory including source memory (reference to spatial relationships between a place or event), while the right prefrontal cortex preferentially processes coordinate spatial memory including item memory (reference to spatial relationships between features of an item).<ref>{{cite journal | last1 = Slotnick | first1 = S. D. | last2 = Moo | first2 = L. R. | year = 2006 | title = Prefrontal cortex hemispheric specialization for categorical and coordinate visual spatial memory | journal = Neuropsychologia | volume = 44 | issue = 9| pages = 1560–1568 | doi = 10.1016/j.neuropsychologia.2006.01.018 | pmid = 16516248 }}</ref>

Lesions to the medial prefrontal cortex impair the performance of rats on a previously trained radial arm maze, but rats can gradually improve to the level of the controls as a function of experience.<ref>{{cite journal | last1 = Becker | first1 = J. T. | last2 = Walker | first2 = J. A. | last3 = Olton | first3 = D. S. | year = 1980 | title = Neuroanatomical bases of spatial memory | journal = Brain Research | volume = 200 | issue = 2| pages = 307–320 | doi = 10.1016/0006-8993(80)90922-1 | pmid = 7417818 }}</ref> Lesions to this area also cause deficits on delayed nonmatching-to-positions tasks and impairments in the acquisition of spatial memory tasks during training trials.<ref>{{cite journal | last1 = Aggleton | first1 = J. P. | last2 = Neave | first2 = N. | last3 = Nagle | first3 = S. | last4 = Sahgal | first4 = A. | year = 1995 | title = A comparison of the effects of medial prefrontal, cingulate cortex, and cingulum bundle lesions on tests of spatial memory: Evidence of a double dissociation between frontal and cingulum bundle contributions | journal = The Journal of Neuroscience | volume = 15 | issue = 11| pages = 7270–7281 | pmid = 7472481 | pmc = 6578066 | doi = 10.1523/JNEUROSCI.15-11-07270.1995 }}</ref><ref>{{cite journal | last1 = Lacroix | first1 = L. | last2 = White | first2 = I. | last3 = Feldon | first3 = J. | year = 2002 | title = Effect of excitotoxic lesions of rat medial prefrontal cortex on spatial memory | journal = Behavioural Brain Research | volume = 133 | issue = 1| pages = 69–81 | doi = 10.1016/S0166-4328(01)00442-9 | pmid = 12048175 }}</ref>

===Retrosplenial cortex===
The [[Retrosplenial region|retrosplenial cortex]] is involved in the processing of allocentric memory and [[Geometry|geometric properties]] in the environment.<ref name="Parron, C. 2004"/> Inactivation of this region accounts for impaired navigation in the dark and it may be involved in the process of [[path integration]].<ref>{{cite journal | last1 = Cooper | first1 = B. G. | last2 = Manka | first2 = T. F. | last3 = Mizumori | first3 = S. J. Y. | year = 2001 | title = Finding your way in the dark: The retrosplenial cortex contributes to spatial memory and navigation without visual cues | journal = Behavioral Neuroscience | volume = 115 | issue = 5| pages = 1012–1028 | doi = 10.1037/0735-7044.115.5.1012 | pmid = 11584914 }}</ref>

Lesions to the retrosplenial cortex consistently impair tests of allocentric memory, while sparing egocentric memory.<ref>{{cite journal | last1 = Vann | first1 = S. D. | last2 = Aggleton | first2 = J. P. | year = 2002 | title = Extensive cytotoxic lesions of the rat retrosplenial cortex reveal consistent deficits on tasks that tax allocentric spatial memory | journal = Behavioral Neuroscience | volume = 116 | issue = 1| pages = 85–94 | doi = 10.1037/0735-7044.116.1.85 | pmid = 11895186 }}</ref> Animals with lesions to the caudal retrosplenial cortex show impaired performance on a radial arm maze only when the maze is rotated to remove their reliance on intramaze cues.<ref>{{cite journal | last1 = Vann | first1 = S. D. | last2 = Wilton | first2 = L. A. | last3 = Muir | first3 = J. L. | last4 = Aggleton | first4 = J. P. | year = 2003 | title = Testing the importance of the caudal retrosplenial cortex for spatial memory in rats | journal = Behavioural Brain Research | volume = 140 | issue = 1–2| pages = 107–118 | doi = 10.1016/S0166-4328(02)00274-7 | pmid = 12644284 }}</ref> [[File:Gray727-Brodman.png|thumb|120px|alt=medial surface of the cerebral hemisphere indicating locations of Brodmann's areas.|Medial view of the cerebral hemisphere. The retrosplenial cortex encompasses Brodmann areas 26, 29, and 30. The perirhinal cortex contains Brodmann area 35 and 36 (not shown)]]

In humans, damage to the retrosplenial cortex results in topographical disorientation. Most cases involve damage to the right retrosplenial cortex and include Brodmann area 30. Patients are often impaired at learning new routes and at navigating through familiar environments.<ref name=the_retrosplenial_contribution>{{cite journal | last1 = Maguire | first1 = E. A. | year = 2001 | title = The retrosplenial contribution to human navigation: A review of lesion and neuroimaging findings | journal = [[Scandinavian Journal of Psychology]] | volume = 42 | issue = 3| pages = 225–238 | doi = 10.1111/1467-9450.00233 | pmid = 11501737 }}</ref> However, most patients usually recover within 8 weeks.

The retrosplenial cortex preferentially processes spatial information in the right hemisphere.<ref name=the_retrosplenial_contribution/>

===Perirhinal cortex===
The [[perirhinal cortex]] is associated with both spatial reference and spatial working memory.<ref name=the_effects_of_excitotoxic>{{cite journal | last1 = Liu | first1 = P. | last2 = Bilkey | first2 = D. K. | year = 2001 | title = The effect of excitotoxic lesions centered on the hippocampus or perirhinal cortex in object recognition and spatial memory tasks | journal = Behavioral Neuroscience | volume = 115 | issue = 1| pages = 94–111 | doi = 10.1037/0735-7044.115.1.94 | pmid = 11256456 }}</ref> It processes relational information of environmental cues and locations. {{cn|date=March 2025}}

Lesions in the perirhinal cortex account for deficits in reference memory and working memory, and increase the rate of [[forgetting]] of information during training trials of the Morris water maze.<ref>{{cite journal | last1 = Liu | first1 = P. | last2 = Bilkey | first2 = D. K. | year = 1998 | title = Perirhinal cortex contributions to performance in the Morris water maze | journal = Behavioral Neuroscience | volume = 112 | issue = 2| pages = 304–315 | doi = 10.1037/0735-7044.112.2.304 | pmid = 9588480 }}</ref> This accounts for the impairment in the initial acquisition of the task. Lesions also cause impairment on an object location task and reduce habituation to a novel environment.<ref name=the_effects_of_excitotoxic/>