scholarly journals Task-dependent mixed selectivity in the subiculum

2020 ◽  
Author(s):  
Debora Ledergerber ◽  
Claudia Battistin ◽  
Jan Sigurd Blackstad ◽  
Richard J. Gardner ◽  
Menno P. Witter ◽  
...  
Keyword(s):  
Spatial Navigation ◽  
Brain Regions ◽  
Head Direction ◽  
Running Speed ◽  
Downstream Targets ◽  
Mixed Representation ◽  
Efficient Transmission

SummaryCA1 and subiculum (SUB) connect the hippocampus to numerous output regions. Cells in both areas have place-specific firing fields, although they are more dispersed in SUB. Weak responses to head direction and running speed have been reported in both regions. However, how such information is encoded in CA1 and SUB, and the resulting impact on downstream targets, is poorly understood. Here we estimate the tuning of simultaneously recorded CA1 and SUB cells to position, head direction, and speed. Individual neurons respond conjunctively to these covariates in both regions but the degree of mixed representation is stronger in SUB, and more so during goal-directed spatial navigation than free foraging. Each navigational variable could be decoded with higher precision, from a similar number of neurons, in SUB than CA1. The findings point to a possible contribution of mixed-selective coding in SUB to efficient transmission of hippocampal representations to widespread brain regions.

scholarly journals Attractor-like spatial representations in the Subicular Complex network

2020 ◽  
Author(s):  
Apoorv Sharma ◽  
Indrajith R. Nair ◽  
Yoganarasimha Doreswamy
Keyword(s):  
Spatial Information ◽  
Spatial Navigation ◽  
Critical Role ◽  
Brain Regions ◽  
Spatial Representations ◽  
Head Direction ◽  
Neural Representations ◽  
Attractor Dynamics ◽  
Reference Map ◽  
Cue Conflict

AbstractDistinct computations are performed at multiple brain regions during encoding of the spatial environments. Neural representations in the hippocampal, entorhinal and head direction (HD) networks during spatial navigation have been clearly documented, while the representational properties of the Subicular Complex (SC) network is rather unexplored, even though it has extensive anatomical connections with various brain regions involved in spatial information processing. Here, we report a global cue controlled highly coherent representation of the cue-conflict environment in the SC network, along with strong coupling between HD cells and Spatial cells. We propose that the attractor dynamics in the SC network might play a critical role in orientation of the spatial representations, thus providing a “reference map” of the environment for further processing at other networks.

scholarly journals Spatially structured inhibition defined by polarized parvalbumin interneuron axons promotes head direction tuning

2021 ◽  
Vol 7 (25) ◽  
pp. eabg4693
Author(s):  
Yangfan Peng ◽  
Federico J. Barreda Tomas ◽  
Paul Pfeiffer ◽  
Moritz Drangmeister ◽  
Susanne Schreiber ◽  
...  
Keyword(s):  
Spatial Organization ◽  
Pyramidal Cells ◽  
Brain Regions ◽  
Head Direction ◽  
Spatial Connectivity ◽  
Parvalbumin Interneurons ◽  
Parvalbumin Interneuron ◽  
Network Simulations ◽  
Fast Spiking ◽  
Direction Tuning

In cortical microcircuits, it is generally assumed that fast-spiking parvalbumin interneurons mediate dense and nonselective inhibition. Some reports indicate sparse and structured inhibitory connectivity, but the computational relevance and the underlying spatial organization remain unresolved. In the rat superficial presubiculum, we find that inhibition by fast-spiking interneurons is organized in the form of a dominant super-reciprocal microcircuit motif where multiple pyramidal cells recurrently inhibit each other via a single interneuron. Multineuron recordings and subsequent 3D reconstructions and analysis further show that this nonrandom connectivity arises from an asymmetric, polarized morphology of fast-spiking interneuron axons, which individually cover different directions in the same volume. Network simulations assuming topographically organized input demonstrate that such polarized inhibition can improve head direction tuning of pyramidal cells in comparison to a “blanket of inhibition.” We propose that structured inhibition based on asymmetrical axons is an overarching spatial connectivity principle for tailored computation across brain regions.

scholarly journals The Role of Hp-NCL Network in Goal-Directed Routing Information Encoding of Bird: A Review

2020 ◽  
Vol 10 (9) ◽  
pp. 617
Author(s):  
Mengmeng Li ◽  
Zhigang Shang ◽  
Kun Zhao ◽  
Shuguan Cheng ◽  
Hong Wan
Keyword(s):  
Spatial Navigation ◽  
Neural Mechanism ◽  
Brain Regions ◽  
Current Situation ◽  
Cooperative Interaction ◽  
Local Network ◽  
Avian Brain ◽  
Information Encoding ◽  
Goal Directed Behavior

Goal-directed navigation is a crucial behavior for the survival of animals, especially for the birds having extraordinary spatial navigation ability. In the studies of the neural mechanism of the goal-directed behavior, especially involving the information encoding mechanism of the route, the hippocampus (Hp) and nidopallium caudalle (NCL) of the avian brain are the famous regions that play important roles. Therefore, they have been widely concerned and a series of studies surrounding them have increased our understandings of the navigation mechanism of birds in recent years. In this paper, we focus on the studies of the information encoding mechanism of the route in the avian goal-directed behavior. We first summarize and introduce the related studies on the role of the Hp and NCL for goal-directed behavior comprehensively. Furthermore, we review the related cooperative interaction studies about the Hp-NCL local network and other relevant brain regions supporting the goal-directed routing information encoding. Finally, we summarize the current situation and prospect the existing important questions in this field. We hope this paper can spark fresh thinking for the following research on routing information encoding mechanism of birds.

scholarly journals Oscillatory synchrony between head direction cells recorded bilaterally in the anterodorsal thalamic nuclei

2017 ◽  
Vol 117 (5) ◽  
pp. 1847-1852 ◽  
Author(s):  
William N. Butler ◽  
Jeffrey S. Taube
Keyword(s):  
High Frequency ◽  
Brain Regions ◽  
High Frequency Oscillation ◽  
Head Direction ◽  
Thalamic Nuclei ◽  
Head Direction Cells ◽  
Oscillatory Pattern ◽  
Cross Correlations ◽  
Left And Right ◽  
The Cross

The head direction (HD) circuit is a complex interconnected network of brain regions ranging from the brain stem to the cortex. Recent work found that HD cells corecorded ipsilaterally in the anterodorsal nucleus (ADN) of the thalamus displayed coordinated firing patterns. A high-frequency oscillation pattern (130–160 Hz) was visible in the cross-correlograms of these HD cell pairs. Spectral analysis further found that the power of this oscillation was greatest at 0 ms and decreased at greater lags, and demonstrated that there was greater synchrony between HD cells with similar preferred firing directions. Here, we demonstrate that the same high-frequency synchrony exists in HD cell pairs recorded contralaterally from one another in the bilateral ADN. When we examined the cross-correlograms of HD cells that were corecorded bilaterally, we observed the same high-frequency (~150- to 200-Hz) oscillatory relationship. The strength of this synchrony was similar to the synchrony seen in ipsilateral HD cell pairs, and the degree of synchrony in each cross-correlogram was dependent on the difference in tuning between the two cells. Additionally, the frequency rate of this oscillation appeared to be independent of the firing rates of the two cross-correlated cells. Taken together, these results imply that the left and right thalamic HD network are functionally related despite an absence of direct anatomical projections. However, anatomical tracing has found that each of the lateral mammillary nuclei (LMN) project bilaterally to both of the ADN, suggesting the LMN may be responsible for the functional connectivity observed between the two ADN. NEW & NOTEWORTHY This study used bilateral recording electrodes to examine whether head direction cells recorded simultaneously in both the left and right thalamus show coordinated firing. Cross-correlations of the cells’ spike trains revealed a high-frequency oscillatory pattern similar to that seen in cross-correlations between pairs of ipsilateral head direction cells, demonstrating that the bilateral thalamic head direction signals may be part of a single unified network.

scholarly journals Multiple spatial codes for navigating 2-D semantic spaces

2020 ◽  
Author(s):  
Simone Viganò ◽  
Valerio Rubino ◽  
Antonio Di Soccio ◽  
Marco Buiatti ◽  
Manuela Piazza
Keyword(s):  
Physical Space ◽  
Semantic Space ◽  
Brain Regions ◽  
Head Direction ◽  
Word Meanings ◽  
Neuronal Coding ◽  
Coding Schemes ◽  
Direction Of Movement ◽  
Human Participants ◽  
The Right

SummaryWhen mammals navigate in the physical environment, specific neurons such as grid-cells, head-direction cells, and place-cells activate to represent the navigable surface, the faced direction of movement, and the specific location the animal is visiting. Here we test the hypothesis that these codes are also activated when humans navigate abstract language-based representational spaces. Human participants learnt the meaning of novel words as arbitrary signs referring to specific artificial audiovisual objects varying in size and sound. Next, they were presented with sequences of words and asked to process them semantically while we recorded the activity of their brain using fMRI. Processing words in sequence was conceivable as movements in the semantic space, thus enabling us to systematically search for the different types of neuronal coding schemes known to represent space during navigation. By applying a combination of representational similarity and fMRI-adaptation analyses, we found evidence of i) a grid-like code in the right postero-medial entorhinal cortex, representing the general bidimensional layout of the novel semantic space; ii) a head-direction-like code in parietal cortex and striatum, representing the faced direction of movements between concepts; and iii) a place-like code in medial prefrontal, orbitofrontal, and mid cingulate cortices, representing the Euclidean distance between concepts. We also found evidence that the brain represents 1-dimensional distances between word meanings along individual sensory dimensions: implied size was encoded in secondary visual areas, and implied sound in Heschl’s gyrus/Insula. These results reveal that mentally navigating between 2D word meanings is supported by a network of brain regions hosting a variety of spatial codes, partially overlapping with those recruited for navigation in physical space.

scholarly journals Local microcircuitry of parasubiculum shows distinct and common features of excitatory and inhibitory connectivity

2020 ◽  
Author(s):  
Rosanna P Sammons ◽  
Alexandra Tzilivaki ◽  
Dietmar Schmitz
Keyword(s):  
Random Network ◽  
Spatial Navigation ◽  
Border Cells ◽  
Head Direction ◽  
Grid Cells ◽  
Medial Entorhinal Cortex ◽  
Common Features ◽  
Layer 2 ◽  
Firing Properties ◽  
Local Circuitry

The parasubiculum is located within the parahippocampal region, where it is thought to be involved in the processing of spatial navigational information. It contains a number of functionally specialised neuron types including grid cells, head direction cells and border cells, and provides input into layer 2 of the medial entorhinal cortex where grid cells are abundantly located. The local circuitry within the parasubiculum remains so far undefined but may provide clues as to the emergence of spatially tuned firing properties of neurons in this region. We used simultaneous patch-clamp recordings to determine the connectivity rates between the three major groups of neurons found in the parasubiculum. We find high rates of interconnectivity between the pyramidal class and interneurons, as well as features of pyramid to pyramid interactions indicative of a non-random network. The microcircuit that we uncover shares both similarities and divergences to those from other parahippocampal regions also involved in spatial navigation.

scholarly journals A thalamic reticular circuit for head direction cell tuning and spatial navigation

2019 ◽  
Author(s):  
Gil Vantomme ◽  
Zita Rovó ◽  
Romain Cardis ◽  
Elidie Béard ◽  
Georgia Katsioudi ◽  
...  
Keyword(s):  
Spatial Navigation ◽  
Sensory Information ◽  
Search Strategies ◽  
Retrosplenial Cortex ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Head Direction ◽  
Thalamic Nuclei

SummaryTo navigate in space, an animal must refer to sensory cues to orient and move. Circuit and synaptic mechanisms that integrate cues with internal head-direction (HD) signals remain, however, unclear. We identify an excitatory synaptic projection from the presubiculum (PreS) and the multisensory-associative retrosplenial cortex (RSC) to the anterodorsal thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. In vitro, projections to TRN involved AMPA/NMDA-type glutamate receptors that initiated TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei. In vivo, chemogenetic anterodorsal TRN inhibition modulated PreS/RSC-induced anterior thalamic firing dynamics, broadened the tuning of thalamic HD cells, and led to preferential use of allo-over egocentric search strategies in the Morris water maze. TRN-dependent thalamic inhibition is thus an integral part of limbic navigational circuits wherein it coordinates external sensory and internal HD signals to regulate the choice of search strategies during spatial navigation.

scholarly journals Neurophysiological coding of space and time in the hippocampus, entorhinal cortex, and retrosplenial cortex

2020 ◽  
Vol 4 ◽  
pp. 239821282097287
Author(s):  
Andrew S. Alexander ◽  
Jennifer C. Robinson ◽  
Holger Dannenberg ◽  
Nathaniel R. Kinsky ◽  
Samuel J. Levy ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Entorhinal Cortex ◽  
Neuronal Response ◽  
Retrosplenial Cortex ◽  
Movement Direction ◽  
Head Direction ◽  
Time Intervals ◽  
Running Speed ◽  
Space And Time ◽  
Spatiotemporal Trajectories

Neurophysiological recordings in behaving rodents demonstrate neuronal response properties that may code space and time for episodic memory and goal-directed behaviour. Here, we review recordings from hippocampus, entorhinal cortex, and retrosplenial cortex to address the problem of how neurons encode multiple overlapping spatiotemporal trajectories and disambiguate these for accurate memory-guided behaviour. The solution could involve neurons in the entorhinal cortex and hippocampus that show mixed selectivity, coding both time and location. Some grid cells and place cells that code space also respond selectively as time cells, allowing differentiation of time intervals when a rat runs in the same location during a delay period. Cells in these regions also develop new representations that differentially code the context of prior or future behaviour allowing disambiguation of overlapping trajectories. Spiking activity is also modulated by running speed and head direction, supporting the coding of episodic memory not as a series of snapshots but as a trajectory that can also be distinguished on the basis of speed and direction. Recent data also address the mechanisms by which sensory input could distinguish different spatial locations. Changes in firing rate reflect running speed on long but not short time intervals, and few cells code movement direction, arguing against path integration for coding location. Instead, new evidence for neural coding of environmental boundaries in egocentric coordinates fits with a modelling framework in which egocentric coding of barriers combined with head direction generates distinct allocentric coding of location. The egocentric input can be used both for coding the location of spatiotemporal trajectories and for retrieving specific viewpoints of the environment. Overall, these different patterns of neural activity can be used for encoding and disambiguation of prior episodic spatiotemporal trajectories or for planning of future goal-directed spatiotemporal trajectories.

scholarly journals Interacting networks of brain regions underlie human spatial navigation: a review and novel synthesis of the literature

2017 ◽  
Vol 118 (6) ◽  
pp. 3328-3344 ◽  
Author(s):  
Arne D. Ekstrom ◽  
Derek J. Huffman ◽  
Michael Starrett
Keyword(s):  
Cognitive Processes ◽  
Posterior Parietal Cortex ◽  
Spatial Navigation ◽  
Neural Model ◽  
Brain Regions ◽  
Cognitive Components ◽  
Current Task ◽  
Posterior Parietal ◽  
Interacting Networks ◽  
Multimodal Process

Navigation is an inherently dynamic and multimodal process, making isolation of the unique cognitive components underlying it challenging. The assumptions of much of the literature on human spatial navigation are that 1) spatial navigation involves modality independent, discrete metric representations (i.e., egocentric vs. allocentric), 2) such representations can be further distilled to elemental cognitive processes, and 3) these cognitive processes can be ascribed to unique brain regions. We argue that modality-independent spatial representations, instead of providing exact metrics about our surrounding environment, more often involve heuristics for estimating spatial topology useful to the current task at hand. We also argue that egocentric (body centered) and allocentric (world centered) representations are better conceptualized as involving a continuum rather than as discrete. We propose a neural model to accommodate these ideas, arguing that such representations also involve a continuum of network interactions centered on retrosplenial and posterior parietal cortex, respectively. Our model thus helps explain both behavioral and neural findings otherwise difficult to account for with classic models of spatial navigation and memory, providing a testable framework for novel experiments.

scholarly journals Human brain dynamics in active spatial navigation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tien-Thong Nguyen Do ◽  
Chin-Teng Lin ◽  
Klaus Gramann
Keyword(s):  
Human Brain ◽  
Cognitive Process ◽  
Spatial Navigation ◽  
Brain Dynamics ◽  
Head Direction ◽  
Brain Areas ◽  
Present Evidence ◽  
Healthy Humans ◽  
Starting Location ◽  
Proprioceptive Inputs

AbstractSpatial navigation is a complex cognitive process based on multiple senses that are integrated and processed by a wide network of brain areas. Previous studies have revealed the retrosplenial complex (RSC) to be modulated in a task-related manner during navigation. However, these studies restricted participants’ movement to stationary setups, which might have impacted heading computations due to the absence of vestibular and proprioceptive inputs. Here, we present evidence of human RSC theta oscillation (4–8 Hz) in an active spatial navigation task where participants actively ambulated from one location to several other points while the position of a landmark and the starting location were updated. The results revealed theta power in the RSC to be pronounced during heading changes but not during translational movements, indicating that physical rotations induce human RSC theta activity. This finding provides a potential evidence of head-direction computation in RSC in healthy humans during active spatial navigation.

Sign in / Sign up

Export Citation Format

Share Document