Intrinsic Frame Of Reference Research Articles

The use of front–back arrays by young children to code locations

Research suggests that during the first 2years of life, children use an egocentric reference system and an extrinsic reference frame, the latter being one allocentric reference system, to encode locations. However, little is known about children’s use of an object’s intrinsic structure, another allocentric reference system. The current study focused on the role of the front–back relationship, one of the simplest intrinsic reference frames, in children’s location encoding. Children (3- to 5-year-olds) participated in a hide-and-find game with one of three different intrinsic front–back array conditions: a facet-induced front–back array, a motion-induced front–back array, or no array. The results showed that whereas the ability to use a facet-induced front–back array began by 3years of age, children used a motion-induced front–back array to encode locations at 4years of age. These results provide evidence that the developmental trajectories of using an intrinsic reference frame to encode locations vary and depend on the specific spatial array involved.

Language supports young children’s use of spatial relations to remember locations

Two experiments investigated the role of language in children’s spatial recall performance. In particular, we assessed whether selecting an intrinsic reference frame could be improved through verbal encoding. Selecting an intrinsic reference frame requires remembering locations relative to nearby objects independent of one’s body (egocentric) or distal environmental (allocentric) cues, and does not reliably occur in children under 5years of age (Nardini, Burgess, Breckenridge, & Atkinson, 2006). The current studies tested the relation between spatial language and 4-year-olds’ selection of an intrinsic reference frame in spatial recall. Experiment 1 showed that providing 4-year-olds with location-descriptive cues during (Exp. 1a) or before (Exp. 1b) the recall task improved performance both overall and specifically on trials relying most on an intrinsic reference frame. Additionally, children’s recall performance was predicted by their verbal descriptions of the task space (Exp. 1a control condition). Non-verbally highlighting relations among objects during the recall task (Exp. 2) supported children’s performance relative to the control condition, but significantly less than the location-descriptive cues. These results suggest that the ability to verbally represent relations is a potential mechanism that could account for developmental changes in the selection of an intrinsic reference frame during spatial recall.

Spatial Language and Culture: Cardinal Directions in Negev Arabic

Negev Arabic displays a unique spatial system characterized by referential complementarity: Intrinsic, Relative, and Absolute frames of reference serve all speakers and are selected according to properties of the Ground. The Absolute frame of reference, employing cardinal directions, represents the lateral axis of all Ground-objects and serves as a default frame for problematic cases, such as modern, culturally alien objects; this frame of reference largely replaces right and left and serves, e.g., as a means to locate Figures in non-prototypical axial positions or in relation to modern Ground-objects. As in other Arabic dialects, cardinal directions also encode cultural, metaphorical, and symbolic meanings—especially east and west; north and south have not developed cultural salience.

Four-Year-Olds Use a Mixture of Spatial Reference Frames.

Keeping track of unseen objects is an important spatial skill. In order to do this, people must situate the object in terms of different frames of reference, including body position (egocentric frame of reference), landmarks in the surrounding environment (extrinsic frame reference), or other attached features (intrinsic frame of reference). Nardini et al. hid a toy in one of 12 cups in front of children, turned the array when they were not looking, and then asked them to point to the cup with the toy. This forced children to use the intrinsic frame (information about the array of cups) to locate the hidden toy. Three-year-olds made systematic errors by using the wrong frame of reference, 4-year-olds were at chance, and only 5- and 6-year-olds were successful. Can we better understand the developmental change that takes place at four years? This paper uses a modelling approach to re-examine the data and distinguish three possible strategies that could lead to the previous results at four years: (1) Children were choosing cups randomly, (2) Children were pointing between the egocentric/extrinsic-cued location and the correct target, and (3) Children were pointing near the egocentric/extrinsic-cued location on some trials and near the target on the rest. Results heavily favor the last possibility: 4-year-olds were not just guessing or trying to combine the available frames of reference. They were using the intrinsic frame on some trials, but not doing so consistently. These insights suggest that accounts of improving spatial performance at 4 years need to explain why there is a mixture of responses. Further application of the selected model also suggests that children become both more reliant on the correct frame and more accurate with any chosen frame as they mature.

Motor adaptation and generalization of reaching movements using motor primitives based on spatial coordinates.

The brain processes sensory and motor information in a wide range of coordinate systems, ranging from retinal coordinates in vision to body-centered coordinates in areas that control musculature. Here we focus on the coordinate system used in the motor cortex to guide actions and examine physiological and psychophysical evidence for an allocentric reference frame based on spatial coordinates. When the equations of motion governing reaching dynamics are expressed as spatial vectors, each term is a vector cross product between a limb-segment position and a velocity or acceleration. We extend this computational framework to motor adaptation, in which the cross-product terms form adaptive bases for canceling imposed perturbations. Coefficients of the velocity- and acceleration-dependent cross products are assumed to undergo plastic changes to compensate the force-field or visuomotor perturbations. Consistent with experimental findings, each of the cross products had a distinct reference frame, which predicted how an acquired remapping generalized to untrained location in the workspace. In response to force field or visual rotation, mainly the coefficients of the velocity- or acceleration-dependent cross products adapted, leading to transfer in an intrinsic or extrinsic reference frame, respectively. The model further predicted that remapping of visuomotor rotation should under- or overgeneralize in a distal or proximal workspace. The cross-product bases can explain the distinct patterns of generalization in visuomotor and force-field adaptation in a unified way, showing that kinematic and dynamic motor adaptation need not arise through separate neural substrates.

Three-Dimensional Vibration of the Malleus and Incus in the Living Gerbil

In previous studies, 3D motion of the middle-ear ossicles in cat and human was explored, but models for hearing research have shifted in the last few decades to smaller mammals, and gerbil, in particular, has become a popular hearing model. In the present study, we have measured with an optical interferometer the 3D motion of the malleus and incus in anesthetized gerbil for sound of moderate intensity (90-dB sound pressure level) over a broad frequency range. To access the ossicles, the pars flaccida was removed exposing the neck and head of the malleus and the incus from the malleus-incus joint to the plate of the lenticular process. Vibration measurements were done at six to eight points per ossicle while the angle of observation was varied over approximately 30° to enable calculation of the 3D rigid-body velocity components. These components were expressed in an intrinsic reference frame, with one axis along the anatomical suspension axis of the malleus-incus block and a second axis along the stapes piston direction. Another way of describing the motion that does not assume an a priori rotation axis is to calculate the instantaneous rotation axis (screw axis) of the malleus/incus motion. Only at frequencies below a few kilohertz did the screw axis have a maximum rotation in a direction close to that of the ligament axis. A slight slippage in the malleus-incus joint developed with increasing frequency. Our findings are useful in determining the sound transfer characteristics through the middle ear and serve as a reference for validation of mathematical middle-ear models. Last but not least, comparing our present results in gerbil with those of previously measured species (human and cat) exposes similarities and dissimilarities among them.

Effector-independent motor sequence representations exist in extrinsic and intrinsic reference frames.

Many daily activities rely on the ability to produce meaningful sequences of movements. Motor sequences can be learned in an effector-specific fashion (such that benefits of training are restricted to the trained hand) or an effector-independent manner (meaning that learning also facilitates performance with the untrained hand). Effector-independent knowledge can be represented in extrinsic/world-centered or in intrinsic/body-centered coordinates. Here, we used functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis to determine the distribution of intrinsic and extrinsic finger sequence representations across the human neocortex. Participants practiced four sequences with one hand for 4 d, and then performed these sequences during fMRI with both left and right hand. Between hands, these sequences were equivalent in extrinsic or intrinsic space, or were unrelated. In dorsal premotor cortex (PMd), we found that sequence-specific activity patterns correlated higher for extrinsic than for unrelated pairs, providing evidence for an extrinsic sequence representation. In contrast, primary sensory and motor cortices showed effector-independent representations in intrinsic space, with considerable overlap of the two reference frames in caudal PMd. These results suggest that effector-independent representations exist not only in world-centered, but also in body-centered coordinates, and that PMd may be involved in transforming sequential knowledge between the two. Moreover, although effector-independent sequence representations were found bilaterally, they were stronger in the hemisphere contralateral to the trained hand. This indicates that intermanual transfer relies on motor memories that are laid down during training in both hemispheres, but preferentially draws upon sequential knowledge represented in the trained hemisphere.

New visuomotor maps are immediately available to the opposite limb

Humans can learn to make accurate movements when the required map between vision and motor commands changes, but can visuomotor maps obtained through experience with one limb benefit the other? Complete transfer would require new maps to be both fully compatible and accessible between limbs. However, when this question is addressed by providing subjects with rotated visual feedback during reaching, transfer is rarely apparent in the first few trials with the unpracticed limb and is sometimes absent altogether. Partial transfer might be explained by limited accessibility to remapped brain circuits, since critical visuomotor transformations mediating unilateral movements appear to be lateralized. Alternatively, if adaptation involves movement representations associated with both extrinsic (i.e., direction of motion in space) and intrinsic (i.e., joint or muscle based) frames of reference, new visuomotor maps might be incompatible with opposite limb use when visual distortions have opposite effects for the two limbs in intrinsic coordinates. Here we addressed this issue when subjects performed an isometric aiming task with the index finger. We manipulated the alignment of visuomotor distortion for the two hands in different reference frames by altering body posture relative to the orientation of the finger and the visual display. There was strong, immediate transfer of adaptation between limbs only when visuomotor distortion had identical effects in eye- and joint-based coordinates bilaterally. This implies that new visuomotor maps are encoded in neural circuits associated with both intrinsic and extrinsic movement representations and are available to both limbs.

Reading spike timing without a clock: intrinsic decoding of spike trains

The precise timing of action potentials of sensory neurons relative to the time of stimulus presentation carries substantial sensory information that is lost or degraded when these responses are summed over longer time windows. However, it is unclear whether and how downstream networks can access information in precise time-varying neural responses. Here, we review approaches to test the hypothesis that the activity of neural populations provides the temporal reference frames needed to decode temporal spike patterns. These approaches are based on comparing the single-trial stimulus discriminability obtained from neural codes defined with respect to network-intrinsic reference frames to the discriminability obtained from codes defined relative to the experimenter's computer clock. Application of this formalism to auditory, visual and somatosensory data shows that information carried by millisecond-scale spike times can be decoded robustly even with little or no independent external knowledge of stimulus time. In cortex, key components of such intrinsic temporal reference frames include dedicated neural populations that signal stimulus onset with reliable and precise latencies, and low-frequency oscillations that can serve as reference for partitioning extended neuronal responses into informative spike patterns.

Insight into others’ minds: spatio-temporal representations by intrinsic frame of reference

Recent research has seen a growing interest in connections between domains of spatial and social cognition. Much evidence indicates that processes of representing space in distinct frames of reference (FOR) contribute to basic spatial abilities as well as sophisticated social abilities such as tracking other’s intention and belief. Argument remains, however, that belief reasoning in social domain requires an innately dedicated system and cannot be reduced to low-level encoding of spatial relationships. Here we offer an integrated account advocating the critical roles of spatial representations in intrinsic frame of reference. By re-examining the results from a spatial task (Tamborello etal., 2012) and a false-belief task (Onishi and Baillargeon, 2005), we argue that spatial and social abilities share a common origin at the level of spatio-temporal association and predictive learning, where multiple FOR-based representations provide the basic building blocks for efficient and flexible partitioning of the environmental statistics. We also discuss neuroscience evidence supporting these mechanisms. We conclude that FOR-based representations may bridge the conceptual as well as the implementation gaps between the burgeoning fields of social and spatial cognition.

Influences of indigenous language on spatial frames of reference in Aboriginal English

The Aboriginal English spoken by Indigenous children in remote communities in the Northern Territory of Australia is influenced by the home languages spoken by themselves and their families. This affects uses of spatial terms used in mathematics such as ‘in front’ and ‘behind.’ Speakers of the endangered Indigenous Australian language Iwaidja use the intrinsic frame of reference in contexts where speakers of Standard Australian English use the relative frame of reference. Children speaking Aboriginal English show patterns of use that parallel the Iwaidja contexts. This paper presents detailed examples of spatial descriptions in Iwaidja and Aboriginal English that demonstrate the parallel patterns of use. The data comes from a study that investigated how an understanding of spatial frame of reference in Iwaidja could assist teaching mathematics to Indigenous language-speaking students. Implications for teaching mathematics are explored for teachers without previous experience in a remote Indigenous community.

Intrinsic frames of reference in haptic spatial learning

It has been proposed that spatial reference frames with which object locations are specified in memory are intrinsic to a to-be-remembered spatial layout (intrinsic reference theory). Although this theory has been supported by accumulating evidence, it has only been collected from paradigms in which the entire spatial layout was simultaneously visible to observers. The present study was designed to examine the generality of the theory by investigating whether the geometric structure of a spatial layout (bilateral symmetry) influences selection of spatial reference frames when object locations are sequentially learned through haptic exploration. In two experiments, participants learned the spatial layout solely by touch and performed judgments of relative direction among objects using their spatial memories. Results indicated that the geometric structure can provide a spatial cue for establishing reference frames as long as it is accentuated by explicit instructions (Experiment 1) or alignment with an egocentric orientation (Experiment 2). These results are entirely consistent with those from previous studies in which spatial information was encoded through simultaneous viewing of all object locations, suggesting that the intrinsic reference theory is not specific to a type of spatial memory acquired by the particular learning method but instead generalizes to spatial memories learned through a variety of encoding conditions. In particular, the present findings suggest that spatial memories that follow the intrinsic reference theory function equivalently regardless of the modality in which spatial information is encoded.

Ipsilateral wrist–ankle movements in the sagittal plane encoded in extrinsic reference frame

When performing oscillatory movements of two joints in the sagittal plane, there is a directional constraint for performing such movements. Previous studies could not distinguish whether the directional constraint reflected movement direction encoded in the extrinsic (outside the body) reference frame or in the intrinsic (the participants’ torso/head) reference frame since participants performed coordinated movements in a sitting position where the torso/head was stationary relative to the external world. In order to discern the reference frame in the present study, participants performed paced oscillatory movements of the ipsilateral wrist and ankle in the sagittal plane in a standing position so that the torso/head moved relative to the external world. The coordinated movements were performed in one of two modes of coordination, moving the hand upward concomitant with either ankle plantarflexion or ankle dorsiflexion. The same directional mode relative to extrinsic space was more stable and accurate as compared with the opposite directional mode. When forearm position was changed from the pronated position to the supinated position, similar results were obtained, indicating that the results were independent of a particular coupling of muscles. These findings suggest that the directional constraint on ipsilateral joints movements in the sagittal plane reflects movement direction encoded in the extrinsic reference frame.

Application of the sextic oscillator with a centrifugal barrier and the spheroidal equation for some X(5) candidate nuclei

The eigenvalue equation associated with the Bohr–Mottelson Hamiltonian is considered in the intrinsic reference frame and amended by replacing the harmonic oscillator potential in the β variable with a sextic oscillator potential with centrifugal barrier plus a periodic potential for the γ variable. After the separation of variables, the β equation is quasi-exactly solved, while the solutions for the γ equation are just the angular spheroidal functions. An anharmonic transition operator is used to determine the reduced E2 transition probabilities. The formalism is conventionally called the sextic and spheroidal approach (SSA) and applied for several X(5) candidate nuclei: 176, 178, 180, 188, 190Os, 150Nd, 170W, 156Dy and 166, 168Hf. The SSA predictions are in good agreement with the experimental data of the mentioned nuclei. The comparison of the SSA results with those yielded by other models, such as X(5) (Iachello 2001 Phys. Rev. Lett.87052502), infinite square well (Raduta et al 2009 Nucl. Phys.A 81946) and Davidson like potential (Raduta et al) for the β, otherwise keeping the spheroidal functions for the γ , and the coherent state model (Raduta et al 1981 Phys. Lett. B 99 444, Raduta et al 1982 Nucl. Phys.A 381 253, Raduta et al 1987 Phys. Rev. C 36 2111, Raduta et al 1983 Z. Phys. A 313 69, Raduta et al 1997 Phys. Rev. C 55 1747, Raduta et al 2002 Phys. Rev. C 65 064322, Raduta and Sabac 1983 Ann. Phys., NY 148 1, Raduta 2004 Recent Research Developments in Nuclear Physics vol 1) respectively, suggests that SSA represents a good approach to describe nuclei achieving the critical point of the U(5)→SU(3) shape phase transition.

Motor memory is encoded as a gain-field combination of intrinsic and extrinsic action representations.

Actions can be planned in either an intrinsic (body-based) reference frame or an extrinsic (world-based) frame, and understanding how the internal representations associated with these frames contribute to the learning of motor actions is a key issue in motor control. We studied the internal representation of this learning in human subjects by analyzing generalization patterns across an array of different movement directions and workspaces after training a visuomotor rotation in a single movement direction in one workspace. This provided a dense sampling of the generalization function across intrinsic and extrinsic reference frames, which allowed us to dissociate intrinsic and extrinsic representations and determine the manner in which they contributed to the motor memory for a trained action. A first experiment showed that the generalization pattern reflected a memory that was intermediate between intrinsic and extrinsic representations. A second experiment showed that this intermediate representation could not arise from separate intrinsic and extrinsic learning. Instead, we find that the representation of learning is based on a gain-field combination of local representations in intrinsic and extrinsic coordinates. This gain-field representation generalizes between actions by effectively computing similarity based on the (Mahalanobis) distance across intrinsic and extrinsic coordinates and is in line with neural recordings showing mixed intrinsic-extrinsic representations in motor and parietal cortices.

Exploiting spatial descriptions in visual scene analysis

The reliable automatic visual recognition of indoor scenes with complex object constellations using only sensor data is a nontrivial problem. In order to improve the construction of an accurate semantic 3D model of an indoor scene, we exploit human-produced verbal descriptions of the relative location of pairs of objects. This requires the ability to deal with different spatial reference frames (RF) that humans use interchangeably. In German, both the intrinsic and relative RF are used frequently, which often leads to ambiguities in referential communication. We assume that there are certain regularities that help in specific contexts. In a first experiment, we investigated how speakers of German describe spatial relationships between different pieces of furniture. This gave us important information about the distribution of the RFs used for furniture-predicate combinations, and by implication also about the preferred spatial predicate. The results of this experiment are compiled into a computational model that extracts partial orderings of spatial arrangements between furniture items from verbal descriptions. In the implemented system, the visual scene is initially scanned by a 3D camera system. From the 3D point cloud, we extract point clusters that suggest the presence of certain furniture objects. We then integrate the partial orderings extracted from the verbal utterances incrementally and cumulatively with the estimated probabilities about the identity and location of objects in the scene, and also estimate the probable orientation of the objects. This allows the system to significantly improve both the accuracy and richness of its visual scene representation.

Spatial Reasoning With Multiple Intrinsic Frames of Reference

Establishing and updating spatial relationships between objects in the environment is vital to maintaining situation awareness and supporting many socio-spatial tasks. In a complex environment, people often need to utilize multiple reference systems that are intrinsic to different objects (intrinsic frame of reference, IFOR), but these IFORs may conflict with each other in one or more ways. Current spatial cognition theories do not adequately address how people handle multi-IFOR reasoning problems. Two experiments manipulated relative orientations of two task-relevant objects with intrinsic axes of orientation as well as their relative task salience. Response times (RTs) decreased with increasing salience of the targeted IFOR. In addition, RTs increased as a consequence of intrinsic orientation conflict, but not by amount of orientation difference. The results suggest that people encounter difficulties when they have to process two conflicting IFOR representations, and that they seem to prioritize processing of each IFOR by salience.

Ocular vestibular evoked myogenic potentials: the missing link

Stabilization of oculomotor and postural responses results from a complex multisensory integration, which can be defined as the process of matching multiple internal representations of an external event (head and trunk rotations), obtained from different sensory modalities (visual, vestibular and proprioceptive), into a single intrinsic frame of reference, in which appropriate motor commands can be coded. Several characteristics of the stabilizing synergies make them a unique model to study how sensorimotor transformations are implemented by the central nervous system. Firstly, these synergies have a purpose, which is well defined and requires the computation of an equally well-understood quantity, i.e. self-motion. Secondly, the input (velocity of the visual world detected by the eyes, velocity of the head detected by the vestibular system, etc.) as well as the static and dynamic motor responses to these inputs (eye and head movements, change in the skeletal geometry) is quantifiable with precision. Thirdly, the stabilizing synergies have been shown to display plasticity in adult humans and animals either under the pressure of environmental changes (prism adaptation, repetitive stimulation) or pathological changes (vestibular neuritis, unilateral labyrinthectomy, vestibular neurectomy). Consequently, the neural networks implementing the sensorimotor transformations underlying gaze and postural control have been intensively studied for the past sixty years and they are well described. It remains that despite its plasticity, gaze and postural stabilization can be disturbed by senescence and several pathologies; in an ageing population, vertigo, perception of instability and falls have become of great concern. Falls are the leading cause of both non-fatal and fatal injuries among the over-65 age group (Sleet et al. 2008). With that perspective, several tests were developed to probe the function of the vestibulo-ocular and vestibulo-spinal synergies, in order to detect vestibular deficits in due time. The vestibulo-ocular reflexes of semicircular canal origin can be tested by using caloric and rotatory stimuli and the head impulse test. The cervical and ocular vestibular evoked myogenic potentials (oVEMPs) are used to test the saccular and utricular functions, respectively. A common denominator of these clinical tests is that they rely for their interpretation on electrophysiological studies performed in animal models. That is, their validity relies on the fact that the activation of a given sensor and the resulting motor behaviour was demonstrated to be similar in patients and in the animal models where the neuronal vestibulo-ocular and vestibulo-spinal networks could be described. In that context, oVEMP recordings were recently proposed as a new and increasingly popular technique to clinically test otolith function (Todd et al. 2007). oVEMPs are evoked by bone-conducted sound and vibrations stimuli to probe the vestibulo-ocular pathways and are thought to result mainly from utricular stimulation (Chiarovani et al. 2011). In animal models, selective utricular nerve stimulations evoke excitatory and inhibitory responses in the contralateral superior oblique motoneuron pool and the ipsilateral inferior oblique motoneuron pool (Uchino et al. 1996). However, it remained to ascertain the muscle of origin of the oVEMP when tested in humans. This is precisely what Weber et al. (2012) elegantly succeeded in demonstrating in an article in this issue of The Journal of Physiology, by recording single motor unit activity in human extra-ocular muscles. Reviving a heroic tradition from the first days of physiology of testing on themselves a quite invasive procedure, the authors recorded their own inferior oblique (IO) and inferior rectus (IR) muscle activity with concentric needle electrodes, following bursts of 500 Hz skull vibration and sound – two otolith stimuli. After bone vibration of the midline forehead, highly synchronous excitation of the IO and the IR muscles was recorded, with a reciprocal activation pattern after a short latency. Sound stimulation of one ear produced short-latency excitation of the contralateral IO muscle. Simultaneous needle and surface recordings proved the IO to be responsible for the oVEMP. By using oVEMP to investigate eye muscle activity during the translational vestibular ocular reflex in humans, not only did Weber and colleagues (2012) confirm a crucial physiological hypothesis, they also reopened a wide field for future research, much beyond the peculiar setting of self-experimentation. Needle electromyography of extra-ocular muscles in humans has slowly declined after its golden age in the 1960's, although technical advances now allow for more refined single motor unit recordings. While this technique is less frequently used for clinical purposes in the era of molecular genetics (Finsterer 2008), it remains essential for physiological studies, as it is the only way to help bridge the many existing gaps between animal experimentation and novel clinical tests or findings.

A Model of Partial Reference Frame Transforms Through Pooling of Gain-Modulated Responses

In multimodal integration and sensorimotor transformation areas of the posterior parietal cortex (PPC), neural responses often appear encoded in spatial reference frames that are intermediate to the intrinsic sensory reference frames, for example, eye-centered for visual or head-centered for auditory stimulation. Many sensory responses in these areas are also modulated by direction of gaze. We demonstrate that certain types of mixed-frame responses can be generated by pooling gain-modulated responses--similar to how complex cells in the visual cortex are thought to pool the responses of simple cells. The proposed model simulates 2 types of mixed-frame responses observed in the PPC: in particular, sensory responses that shift differentially with gaze in horizontal and vertical dimensions and sensory responses that shift differentially for different start and end points along a single dimension of gaze. We distinguish these 2 types of mixed-frame responses from a third type in which sensory responses shift a partial yet approximately equal amount with each gaze shift. We argue that the empirical data on mixed-frame responses may be caused by multiple mechanisms, and we adapt existing reference-frame measures to distinguish between the different types. Finally, we discuss how mixed-frame responses may be revealing of the local organization of presynaptic responses.

Tracking Down Abstract Linguistic Meaning: Neural Correlates of Spatial Frame of Reference Ambiguities in Language

This functional magnetic resonance imaging (fMRI) study investigates a crucial parameter in spatial description, namely variants in the frame of reference chosen. Two frames of reference are available in European languages for the description of small-scale assemblages, namely the intrinsic (or object-oriented) frame and the relative (or egocentric) frame. We showed participants a sentence such as “the ball is in front of the man”, ambiguous between the two frames, and then a picture of a scene with a ball and a man – participants had to respond by indicating whether the picture did or did not match the sentence. There were two blocks, in which we induced each frame of reference by feedback. Thus for the crucial test items, participants saw exactly the same sentence and the same picture but now from one perspective, now the other. Using this method, we were able to precisely pinpoint the pattern of neural activation associated with each linguistic interpretation of the ambiguity, while holding the perceptual stimuli constant. Increased brain activity in bilateral parahippocampal gyrus was associated with the intrinsic frame of reference whereas increased activity in the right superior frontal gyrus and in the parietal lobe was observed for the relative frame of reference. The study is among the few to show a distinctive pattern of neural activation for an abstract yet specific semantic parameter in language. It shows with special clarity the nature of the neural substrate supporting each frame of spatial reference.