Evidence for allocentric boundary and goal direction information in the human entorhinal cortex and subiculum

Abstract

2In rodents, cells in the medial entorhinal cortex (EC) and subiculum code for 3 the allocentric direction to environment boundaries, which is an important 4 prerequisite for accurate positional coding. Although in humans boundary-5 related signals have been reported, there is no evidence that they contain 6 allocentric direction information. Furthermore, it has not been possible to 7 separate boundary versus goal direction signals in the EC/subiculum. To 8 address these important questions, participants learned a virtual environment 9 containing four unique boundaries, after which they underwent fMRI scanning 10where they made judgments about the allocentric direction of a cue object. 11Using multivariate decoding, we found information regarding allocentric 12 boundary direction in posterior EC and subiculum, whereas in anterior EC and 13 subiculum we could decode allocentric goal direction. These data provide the 14 first evidence of allocentric boundary coding in humans, and are consistent 15 with recent conceptualisations of a division of labour within the EC. 16 17 18 19 20 21 22 23 24 25Recent evidence of spatial coding in the rodent LEC, however, has led to 43 modifications of this model in which the MEC is proposed to support neural 44 populations involved in spatial navigation (e.g., grid cells), whereas the LEC 45 codes for external sensory inputs (e.g., landmarks or prominent objects in the 46 environment) 8 . 47

Behavior-dependent directional tuning in the human visual-navigation network

“…Directional representations in the human brain Our observations emphasize the central role of scene processing and navigation regions in spatial cognition (Bicanski and Burgess, 2018;Byrne et al, 2007;Clark et al, 2018;Epstein and Baker, 2019;Epstein et al, 2017;Mitchell et al, 2018;Nau et al, 2018a;Vann et al, 2009) and are consistent with previous work on directional representations in the human brain (Baumann and Mattingley, 2010;Bellmund et al, 2016;Chadwick et al, 2015;Doeller et al, 2010;Indovina et al, 2013;Jacobs et al, 2010;Kim and Maguire, 2019;Marchette et al, 2014;Shine et al, 2016Shine et al, , 2019Vass and Epstein, 2013). They are also consistent with lesion studies showing that damage to regions like the RSC can impair the ability to orient oneself relative to landmarks (Aguirre, 1999).…”

“…A critical challenge the brain needs to solve to map the environment is keeping track of our own direction as we move. Previous studies revealed directional representations and activity related to heading perception in several areas including the medial parietal lobe and retrosplenial cortex (Baumann and Mattingley, 2010;Chadwick et al, 2015;Marchette et al, 2014;Shine et al, 2016), the parahippocampal gyrus (Bellmund et al, 2016;Doeller et al, 2010;Kim and Maguire, 2019;Marchette et al, 2014;Epstein, 2013, 2016), the entorhinal/subicular region (Chadwick et al, 2015;Doeller et al, 2010;Jacobs et al, 2010;Shine et al, 2019;Vass and Epstein, 2016), the thalamus (Shine et al, 2016) and the superior parietal cortex (Gourtzelidis et al, 2005;Schindler and Bartels, 2013). Also, hippocampal and parahippocampal activity encodes heading in the horizontal plane (Indovina et al, 2013).…”

Behavior-dependent directional tuning in the human visual-navigation network

“…A critical challenge the brain needs to solve to map the environment is keeping track of our own direction as we move. Previous studies revealed directional representations and activity related to heading perception in several areas, including the medial parietal lobe and retrosplenial cortex [15][16][17][18] , the parahippocampal gyrus 17,[19][20][21][22][23] , the entorhinal/subicular cortex region 16,[22][23][24][25] , the thalamus 18 , and the superior parietal cortex 26,27 . Most of these studies used dedicated and constrained directional judgment-and mental imagery tasks, and often examined direction in a self-centered frame of reference.…”

Homologous laminar organization of the mouse and human subiculum

“…Based on this rotation, the mouse dorsal SUB is generally believed to be homologous to the human posterior SUB and mouse ventral SUB is homologous to anterior human SUB. Functional evidence supports this view as the mouse dorsal SUB and human posterior SUB are involved in visuospatial navigation 10,[17][18][19] . In contrast, the mouse ventral SUB and human anterior SUB are related to limbic emotional processing and social behaviors 12,20,21 .…”