51
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Maselli A. Allocentric and egocentric manipulations of the sense of self-location in full-body illusions and their relation with the sense of body ownership. Cogn Process 2016. [PMID: 26220702 DOI: 10.1007/s10339-015-0667-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Self-location refers to the experience of occupying a given position in the environment. Recent research has addressed the sense of self-location as one of the key components of self-consciousness, together with the experience of owning the physical body (ownership) (Blanke and Metzinger, Trends Cogn Sci 13:7-13 in 2009. doi: 10.1016/j.tics.2008.10.003 ). Experimentally controlled full-body illusions proved to be valuable research tools to study these components and their interaction, and to explore their underlying neural underpinning. The focus of this manuscript is to provide a close look into the nuances of different illusory experiences affecting the sense of self-location and to examine their relation to the concurrent experienced sense of body ownership. On the basis of previous reviewed studies, it is proposed that the sense of self-location may be regarded as the blending of two paralllel representations: the abstract allocentric coding of the position occupied in the environment, mainly associated with visual-perspective, and the egocentric mapping of somatosensory sensations into the external space, mainly associated with peripersonal space. Open questions to be addressed by future research are further addressed.
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Affiliation(s)
- Antonella Maselli
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation, Via Ardeatina 306, 00179, Roma, Italy,
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52
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Tribukait A, Eiken O. On the time course of short-term forgetting: a human experimental model for the sense of balance. Cogn Neurodyn 2016; 10:7-22. [PMID: 26834858 PMCID: PMC4722133 DOI: 10.1007/s11571-015-9362-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 10/09/2015] [Accepted: 10/22/2015] [Indexed: 12/18/2022] Open
Abstract
The primary aim of this study was to establish whether the decline of the memory of an angular displacement, detected by the semicircular canals, is best characterized by an exponential function or by a power function. In 27 subjects a conflict was created between the semicircular canals and the graviceptive systems. Subjects were seated, facing forwards, in the gondola of a large centrifuge. The centrifuge was accelerated from stationary to 2.5Gz. While the swing out of the gondola (66°) during acceleration constitutes a frontal plane angular-displacement stimulus to the semicircular canals, the graviceptive systems persistently signal that the subject is upright. During 6 min at 2.5Gz the perceived head and body position was recorded; in darkness the subject repeatedly adjusted the orientation of a luminous line so that it appeared to be horizontal. Acceleration of the centrifuge induced a sensation of tilt which declined with time in a characteristic way. A three-parameter exponential function (Y = Ae(-bt) + C) and a power function (Y = At(-b) + C) were fitted to the data points. The inter-individual variability was considerable. In the vast majority of cases, however, the exponential function provided a better fit (in terms of RMS error) than the power function. The mean exponential function was: y = 27.8e(-0.018t) + 0.5°, where t is time in seconds. Findings are discussed with connection to possible underlying neural mechanisms; in particular, the head-direction system and short-term potentiation and persistent action potential firing in the hippocampus are considered.
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Affiliation(s)
- Arne Tribukait
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, School of Technology and Health, Royal Institute of Technology, KTH, Berzelius väg 13, 171 65 Solna, Sweden
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, School of Technology and Health, Royal Institute of Technology, KTH, Berzelius väg 13, 171 65 Solna, Sweden
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53
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Evans T, Bicanski A, Bush D, Burgess N. How environment and self-motion combine in neural representations of space. J Physiol 2016; 594:6535-6546. [PMID: 26607203 DOI: 10.1113/jp270666] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/13/2015] [Indexed: 11/08/2022] Open
Abstract
Estimates of location or orientation can be constructed solely from sensory information representing environmental cues. In unfamiliar or sensory-poor environments, these estimates can also be maintained and updated by integrating self-motion information. However, the accumulation of error dictates that updated representations of heading direction and location become progressively less reliable over time, and must be corrected by environmental sensory inputs when available. Anatomical, electrophysiological and behavioural evidence indicates that angular and translational path integration contributes to the firing of head direction cells and grid cells. We discuss how sensory inputs may be combined with self-motion information in the firing patterns of these cells. For head direction cells, direct projections from egocentric sensory representations of distal cues can help to correct cumulative errors. Grid cells may benefit from sensory inputs via boundary vector cells and place cells. However, the allocentric code of boundary vector cells and place cells requires consistent head-direction information in order to translate the sensory signal of egocentric boundary distance into allocentric boundary vector cell firing, suggesting that the different spatial representations found in and around the hippocampal formation are interdependent. We conclude that, rather than representing pure path integration, the firing of head-direction cells and grid cells reflects the interface between self-motion and environmental sensory information. Together with place cells and boundary vector cells they can support a coherent unitary representation of space based on both environmental sensory inputs and path integration signals.
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Affiliation(s)
- Talfan Evans
- UCL Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, Gower Street, London, WC1E 6BT, UK.,UCL Institute of Cognitive Neuroscience, 17 Queen Square, London, WC1N 3AZ, UK.,UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.,UCL Department of Neuroscience, Physiology and Pharmacology, Gower Street, London, WC1E 6BT, UK
| | - Andrej Bicanski
- UCL Institute of Cognitive Neuroscience, 17 Queen Square, London, WC1N 3AZ, UK.,UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Daniel Bush
- UCL Institute of Cognitive Neuroscience, 17 Queen Square, London, WC1N 3AZ, UK.,UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Neil Burgess
- UCL Institute of Cognitive Neuroscience, 17 Queen Square, London, WC1N 3AZ, UK.,UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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54
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McKenzie S, Keene CS, Farovik A, Bladon J, Place R, Komorowski R, Eichenbaum H. Representation of memories in the cortical-hippocampal system: Results from the application of population similarity analyses. Neurobiol Learn Mem 2015; 134 Pt A:178-191. [PMID: 26748022 DOI: 10.1016/j.nlm.2015.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 12/08/2015] [Accepted: 12/24/2015] [Indexed: 01/07/2023]
Abstract
Here we consider the value of neural population analysis as an approach to understanding how information is represented in the hippocampus and cortical areas and how these areas might interact as a brain system to support memory. We argue that models based on sparse coding of different individual features by single neurons in these areas (e.g., place cells, grid cells) are inadequate to capture the complexity of experience represented within this system. By contrast, population analyses of neurons with denser coding and mixed selectivity reveal new and important insights into the organization of memories. Furthermore, comparisons of the organization of information in interconnected areas suggest a model of hippocampal-cortical interactions that mediates the fundamental features of memory.
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Affiliation(s)
- Sam McKenzie
- The Neuroscience Institute, NYU Langone Medical Center, United States
| | | | - Anja Farovik
- Center for Memory and Brain, Boston University, United States
| | - John Bladon
- Center for Memory and Brain, Boston University, United States
| | - Ryan Place
- Center for Memory and Brain, Boston University, United States
| | - Robert Komorowski
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, United States
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55
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Antonides A, Schoonderwoerd AC, Scholz G, Berg BM, Nordquist RE, van der Staay FJ. Pre-weaning dietary iron deficiency impairs spatial learning and memory in the cognitive holeboard task in piglets. Front Behav Neurosci 2015; 9:291. [PMID: 26578919 PMCID: PMC4626557 DOI: 10.3389/fnbeh.2015.00291] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/13/2015] [Indexed: 12/22/2022] Open
Abstract
Iron deficiency is the most common nutritional deficiency in humans, affecting more than two billion people worldwide. Early-life iron deficiency can lead to irreversible deficits in learning and memory. The pig represents a promising model animal for studying such deficits, because of its similarities to humans during early development. We investigated the effects of pre-weaning dietary iron deficiency in piglets on growth, blood parameters, cognitive performance, and brain histology later in life. Four to six days after birth, 10 male sibling pairs of piglets were taken from 10 different sows. One piglet of each pair was given a 200 mg iron dextran injection and fed a control milk diet for 28 days (88 mg Fe/kg), whereas the other sibling was given a saline injection and fed an iron deficient (ID) milk diet (21 mg Fe/kg). Due to severely retarded growth of two of the ID piglets, only eight ID piglets were tested behaviorally. After dietary treatment, all piglets were fed a balanced commercial pig diet (190-240 mg Fe/kg). Starting at 7.5 weeks of age, piglets were tested in a spatial cognitive holeboard task. In this task, 4 of 16 holes contain a hidden food reward, allowing measurement of working (short-term) memory and reference (long-term) memory (RM) simultaneously. All piglets received 40-60 acquisition trials, followed by a 16-trial reversal phase. ID piglets showed permanently retarded growth and a strong decrease in blood iron parameters during dietary treatment. After treatment, ID piglets' blood iron values restored to normal levels. In the holeboard task, ID piglets showed impaired RM learning during acquisition and reversal. Iron staining at necropsy at 12 weeks of age showed that ID piglets had fewer iron-containing cells in hippocampal regions CA1 and dentate gyrus (DG). The number of iron-containing cells in CA3 correlated positively with the average RM score during acquisition across all animals. Our results support the hypothesis that early-life iron deficiency leads to lasting cognitive deficits. The piglet as a model animal, tested in the holeboard, can be useful in future research for assessing long-term cognitive effects of early-life diets or diet-induced deficiencies.
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Affiliation(s)
- Alexandra Antonides
- Emotion and Cognition Group, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands ; Brain Center Rudolf Magnus, Utrecht University Utrecht, Netherlands
| | - Anne C Schoonderwoerd
- Emotion and Cognition Group, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands ; Brain Center Rudolf Magnus, Utrecht University Utrecht, Netherlands
| | - Gabi Scholz
- Faculty of Technique and Life Sciences, Institute of Applied Sciences, Professional University HAN (Hogeschool Arnhem & Nijmegen) Arnhem, Netherlands
| | - Brian M Berg
- Department of Global Discovery, Mead Johnson Pediatric Nutrition Institute Evansville, IN, USA ; Division of Nutritional Sciences, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Rebecca E Nordquist
- Emotion and Cognition Group, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands ; Brain Center Rudolf Magnus, Utrecht University Utrecht, Netherlands
| | - Franz Josef van der Staay
- Emotion and Cognition Group, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands ; Brain Center Rudolf Magnus, Utrecht University Utrecht, Netherlands
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56
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Lee SA, Ferrari A, Vallortigara G, Sovrano VA. Boundary primacy in spatial mapping: Evidence from zebrafish (Danio rerio). Behav Processes 2015; 119:116-22. [DOI: 10.1016/j.beproc.2015.07.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 07/21/2015] [Accepted: 07/22/2015] [Indexed: 12/16/2022]
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57
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Environmental stability modulates the role of path integration in human navigation. Cognition 2015; 142:96-109. [DOI: 10.1016/j.cognition.2015.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 05/10/2015] [Accepted: 05/11/2015] [Indexed: 11/19/2022]
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58
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Abstract
In celebration of the 2014 Nobel Prize in Physiology or Medicine, this issue of Hippocampus includes a collection of commentaries from a broad range of perspectives on the significance of position coding neurons in the hippocampal region. From the perspective of this student of hippocampal physiology, it is argued that place cells and grid cells reflect the outcome of experiments that strongly select the information available and correspondingly observe singular "trigger features" of these neurons. Notably, however, in more naturalistic situations where multiple dimensions of information are available, hippocampal neurons have mixed selectivity wherein population-firing patterns reflect the organization of many features of experience. Thus, while discoveries on position coding were major breakthroughs in penetrating the hippocampal code, future studies exploring more complex behaviors hold the promise of revealing the full contribution of the hippocampal region to cognition and memory.
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Affiliation(s)
- Howard Eichenbaum
- Center for Memory and Brain, Boston University, Boston, Massachusetts
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59
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Synaptic diversity enables temporal coding of coincident multisensory inputs in single neurons. Nat Neurosci 2015; 18:718-27. [PMID: 25821914 PMCID: PMC4413433 DOI: 10.1038/nn.3974] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/12/2015] [Indexed: 02/08/2023]
Abstract
The ability of the brain to rapidly process information from multiple pathways is critical for reliable execution of complex sensory-motor behaviors, yet the cellular mechanisms underlying a neuronal representation of multimodal stimuli are poorly understood. Here we explored the possibility that the physiological diversity of mossy fiber (MF) to granule cell (GC) synapses within the mouse vestibulocerebellum may contribute to the processing of coincident multisensory information at the level of individual GCs. We found that the strength and short-term dynamics of individual MF-GC synapses can act as biophysical signatures for primary vestibular, secondary vestibular and visual input pathways. The majority of GCs receive inputs from different modalities, which when co-activated, produced enhanced GC firing rates and distinct first spike latencies. Thus, pathway-specific synaptic response properties permit temporal coding of correlated multisensory input by single GCs, thereby enriching sensory representation and facilitating pattern separation.
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61
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A computational theory of hippocampal function, and tests of the theory: New developments. Neurosci Biobehav Rev 2015; 48:92-147. [DOI: 10.1016/j.neubiorev.2014.11.009] [Citation(s) in RCA: 226] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 10/24/2014] [Accepted: 11/12/2014] [Indexed: 01/01/2023]
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62
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Dissociating position and heading estimations: Rotated visual orientation cues perceived after walking reset headings but not positions. Cognition 2014; 133:553-71. [DOI: 10.1016/j.cognition.2014.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 11/19/2022]
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63
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Functional heterogeneity of the limbic thalamus: From hippocampal to cortical functions. Neurosci Biobehav Rev 2014; 54:120-30. [PMID: 25446945 DOI: 10.1016/j.neubiorev.2014.11.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 10/22/2014] [Accepted: 11/12/2014] [Indexed: 12/31/2022]
Abstract
Today, the idea that the integrity of the limbic thalamus is necessary for normal memory functions is well established. However, if the study of thalamic patients emphasized the anterior and the mediodorsal thalamus as the critical thalamic loci supporting cognitive functions, clinical studies have so far failed to attribute a specific role to each of these regions. In view of these difficulties, we review here the experimental data conducted in rodents harboring specific lesions of each thalamic region. These data clearly indicate a major functional dissociation within the limbic thalamus. The anterior thalamus provides critical support for hippocampal functions due to its cardinal location in the Papez circuit, while the mediodorsal thalamus may signal relevant information in a circuit encompassing the basolateral amygdala and the prefrontal cortex. Interestingly, while clinical studies have suggested that diencephalic pathologies may disconnect the medial temporal lobe from the cortex, experimental studies conducted in rodent show how this may differently affect distinct temporo-thalamo-cortical circuits, sharing the same general organization but supporting dissociable functions.
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