Spatial Goals Research Articles

Planning for Rural Housing in the Republic of Ireland: From National Spatial Strategies to Development Plans

This paper examines the role of spatial planning as a policy framework for managing rural housing within an integrated territorial development strategy. The paper focuses on the Republic of Ireland, which provides a useful case for analysing spatial planning and rural housing relationships, due to the State's recent shift towards spatial planning (formalized with the publication of the Irish National Spatial Strategy), as well as the level of housing construction that has been observed in an increasingly post-productivist countryside (triggered by counter-urbanization flows, increased affluence and demands for second holiday homes, etc.). The paper reviews all policy instruments that have been used to manage rural housing at various scales (from national strategies to local level development plans). It is argued that while spatial planning adopts an integrative vocabulary, as policy moves down the spatial scale hierarchy, multi-dimensional spatial goals are implemented through traditional, narrow land-use regulation. This often leads to rural housing being addressed in isolation from its wider social and economic context, disconnecting housing from wider rural community issues and ultimately failing to deliver a coordinated and coherent spatial policy for managing rural settlements.

Resuming after Interruption: Exploring the Roles of Spatial and Goal Memory

Interruptions research has generally focused on the factors that make interruptions more or less disruptive to primary task performance, the ways in which people engage the interruption as they disengage from a primary task, and the role of environmental context/cues in primary task resumption. However, little research has focused on investigating the processes by which a person reorients to and resumes the primary task following an interruption. This research explores the potential roles of spatial location and goal memory in the process of resumption. The experiment reported uses a new paradigm in which, following an interruption, a person can be returned to a different task and/or a different location. We found that both goal memory and spatial memory play a role in resuming the primary task following an interruption. However, there is still not a clear picture of how the two interact, and it may be that individual differences play an important role in how people deal with interruptions.

A Property Rights Approach to Externality Problems: Planning Based on Compensation Rules

Most European countries have implemented some kind of land use planning based on exclusionary zoning principles to achieve spatial goals. This paper argues that, to reduce externality problems, regulatory planning is not always the best planning solution. Therefore, an alternative planning approach, which makes use of compensation rules, is suggested in this paper. This compensatory planning approach is based on property rights theory and refers to recent applications of this theory to planning practice. To illustrate the usefulness of such an approach, it is applied to the planning of out-of-town retail development in The Netherlands. The paper aims to demonstrate how deficiencies in the property rights regime can be repaired to deal with externality problems, achieving a more socially acceptable outcome of out-of-town retail development. The paper concludes with a discussion of the value of spontaneous order solutions for planning practice, by introducing four pragmatic rules on how to choose between different types of government interventions.

Between-person effects on attention and action: Joe and Fred revisited

Previous study indicates that target-target inhibition of return (IOR) is not restricted to a single nervous system. Specifically, watching another person perform a goal-directed aiming movement engages similar inhibitory processes on a subsequent aiming attempt as if having performed the preceding movement oneself. This between-person effect has been attributed to the mirror neuron system. In the study reported here, we replicated this finding and examined the relative importance of automatic stimulus alerting events and action-observation by dissociating these two influences. This was done by having two people alternately perform sets of two aiming trials to the same equally probable targets. Under some experimental conditions, one or both of the performers moved to a non-illuminated target. In this way, we dissociated the stimulus and observed event under some between-person conditions. Although IOR was greatest when the stimulus and observed events were compatible, both contributed to the between-person inhibitory processes slowing the responses (Experiment 1). The impact of observing another person perform an aiming movement appears to have more to do with realizing a particular spatial goal than seeing the biological motion associated with achieving that goal (Experiment 2). Findings that both the illumination of a visual target signal and the observation of another person's action engage similar attention-action processes are consistent with action-based accounts of visual selective attention.

Spatial and Effector Processing in the Human Parietofrontal Network for Reaches and Saccades

It is generally accepted that interactions between parietal and frontal cortices subserve the visuomotor processing for eye and hand movements. Here, we used a sequential-instruction paradigm in 3-T functional MRI to test the processing of effector and spatial signals, as well as their interaction, as a movement is composed and executed in different stages. Subjects prepared either a saccade or a reach following two successive visual instruction cues, presented in either order. One cue instructed which effector to use (eyes, right hand); the other signaled the spatial goal (leftward vs. rightward target location) of the movement. During the first phase of the prepared movement, after cueing of either goal or effector information, we found significant spatial goal selectivity but no effector specificity along the parietofrontal network. During the second phase of the prepared movement, when both goal and effector information were available, we found a large overlap in the neural circuitry involved in the planning of eye and hand movements. Gradually distributed along this network, we observed clear spatial goal selectivity and limited, but significant, effector specificity. Regions in the intraparietal sulcus and the dorsal premotor cortex were selective to both goal location and motor effector. Taken together, our results suggest that the relative weight of spatial goal and effector selectivity changes along the parietofrontal network, depending on the status of the movement plan.

Practice makes bimanual interference imperfect – On the way to the generation of bimanual motion primitives

Simultaneously manipulating the two hands is central to human daily life, from a simple action such as tying one’s shoes to the proficiency of building and using tools. While using both hands in order to reach a common goal does not require extensive effort and is even done automatically, the concurrent generation of two independent movements with different spatiotemporal patterns results often in an increased time to initiate the movements (reaction time – RT) compared to conditions in which only one movement is performed at a time (Walter and Swinnen, 1990; Heuer, 1996; Vangheluwe et al., 2004). Furthermore, when different spatiotemporal patterns must be simultaneously produced, such as drawing a circle with one hand and drawing a rectangle with the second hand, spatial similarity effects take place between the two trajectories (Kelso et al., 1983; Konzem, 1987; Swinnen and Walter, 1998). The phenomenon was termed bimanual interference and was studied extensively over the last three decades. Psychological and imaging studies conducted on split brain patients (Franz et al., 1996; Eliassen et al., 1999; Kennerley et al., 2002) have shown that interference based on the spatial characteristics of the movements arises through callosally mediated interactions suggesting that the spatial goals are established at a high, cortical level. Studies employing discrete incompatible actions for the two hands, such as pointing in different directions and/or different amplitudes have shown that bimanual interference could be reduced when the target movements were cued directly by the onset of the target locations rather than symbolically by letters (Diedrichsen et al., 2001; Hazeltine et al., 2003). This finding indicates that directly cued actions can be programmed in parallel for the two hands, challenging the hypothesis that the cost to initiate non-symmetrical movements derives from spatial interference at the motorprogramming stage. Rather, the cost appears to be related to stimulus identification, processing of symbolic cues and selection of an appropriate response, or both. Another way to reduce bimanual interference is practice, as shown recently by Albert and Ivry (2009). Although several studies have previously shown that bimanual practice can suppress directional interference (Swinnen et al., 1991; Schumacher et al., 1999; Puttemans et al., 2003) the study of Albert and Ivry, based on a drawing task first introduced by Franz et al. (1996), is unique as it calls for the bimanual generation of sequential discrete movements rather than a continuous movement, which allows the assessment of bimanual interference and its modulation by practice both by the analysis of the reaction time needed to plan each segment and the characteristics of the spatiotemporal attributes of the trajectories generated by each hand. Thus, the novelty of the work is in its ability to study the evolution of the interaction and interference between the unimanual and bimanual representation of the task emerging throughout practice. Furthermore, as target movements in the paradigm used by Albert and Ivry are directly cued, an ability to transfer to unvisited configurations should imply the conceptualization of the stimuli as defining a common goal which operates at an abstract level of representation. Albert and Ivry (2009) show that prolonged practice on incongruent patterns (e.g., one hand moving forward, one sideways) resulted in reduced bimanual interference which was manifested by shorter RTs and increased number of correct patterns by both hands. As the effect of congruency on movement reaction times was larger than the effect on movement time it may be that the main outcome of training was the evolution of a bimanual representation of the task which allowed for shorter planning times as was shown to

Reversal of Bimanual Feedback Responses With Changes in Task Goal

We show that fast bimanual coordinative feedback responses can be reversed with changes in task goals. Participants moved a flexible virtual object across a finish line with an upward movement of both hands. In one condition, the middle of the object had to be aligned with a spatial goal at the end of the movement. In the second condition, the object had to be kept at a specific length. During the movement, a velocity-dependent force field was applied randomly to one of the hands to the left or to the right. Depending on the task condition, the unperturbed hand showed fast feedback corrections, either in or against the direction of the force field on the other hand. In the object-length condition we found evidence for a mixture of task goals: early in the movement the correction of the unperturbed hand was aimed at stabilizing object length; later in the movement, the correction reversed direction to reach a symmetric body posture in the end of the movement. The observed differences in feedback responses between task conditions also influenced the covariance structure of unperturbed movements and the adaptation when a specific force field was applied repeatedly to one of the hands. The results are congruent with the notion that coordination is established flexibly through a representation of the task-relevant controlled variables, rather than through a direct interaction between motor commands.

Transient Neuronal Correlations Underlying Goal Selection and Maintenance in Prefrontal Cortex

We reported previously that as monkeys used abstract response strategies to choose spatial goals, 1 population of prefrontal cortex neurons encoded future goals (F cells), whereas a largely separate population encoded previous goals (P cells). Here, to better understand the mechanisms of goal selection and maintenance, we studied correlated activity among pairs of these neurons. Among the 3 possible types of pairs, F-F and F-P pairs often exhibited significant correlations when and after monkeys selected future goals but P-P pairs rarely did. These correlations were stronger when monkeys shifted from a previous goal than when they stayed with that goal. In addition, members of F-F pairs usually preferred the same goal and thus shared both prospective coding and spatial tuning properties. In contrast, cells composing F-P pairs usually had different spatial preferences and thus shared neither coding nor spatial tuning properties. On the assumption that the neurons composing a pair send convergent outputs to target neurons, their correlated activity could enhance their efficacy in context-dependent goal selection, goal maintenance, and the transformation of goal choices into action.

Keeping the goal in mind: Prefrontal contributions to spatial navigation

Keeping the goal in mind: Prefrontal contributions to spatial navigation

Encoding problem‐solving strategies in prefrontal cortex: activity during strategic errors

The primate prefrontal cortex (PF) plays a central role in choosing goals and strategies. To better understand its mechanisms, we recorded from PF neurons as monkeys used abstract response strategies to select a spatial goal. A visual cue, selected randomly from a set of three cues, appeared on each trial. All three cues were novel when neuronal recording commenced. From trial to trial, the cue could have either been repeated or changed from the previous trial; these were called repeat trials and change trials, respectively. On repeat trials, the monkeys used a Repeat-stay strategy to gain a reward by choosing the same spatial goal as on the previous trial; on change trials, they used a Change-shift strategy to reject the previous goal in favour of an alternative. We reported previously that when monkeys performed the task correctly, many PF neurons had activity encoding one of these two strategies. The monkeys sometimes chose the incorrect strategy, however. Strategy coding was weak or absent during the cue period of error trials which was, for correct trials, the time when the monkeys used a strategy to choose a future goal. By contrast, later in the trial, after the chosen goal had been attained and the monkeys awaited feedback, strategy coding was present and it reflected the strategy used, whether correct or incorrect. The weak cue-period strategy signal could, whatever its cause, have contributed to the errors made, whereas the activity prior to feedback suggests a role in monitoring task performance.

The role of ventromedial prefrontal cortex in navigation: A case of impaired wayfinding and rehabilitation

A patient with ventromedial prefrontal damage, LG, is described who had a severe difficulty in wayfinding in his home town, despite intact knowledge for landmarks and routes in town. Although able to recall his spatial goals, LG often headed to familiar, “attractor” locations while navigating, losing his way in the process. Both a laboratory and an ecological study showed that spatial navigation improved when the patient was periodically reminded of, or asked to recall, the goal destination along his route. It is suggested that the ventromedial prefrontal cortex is necessary to maintain actively the goal destination in working memory, for use in navigation.

The use of cellular automaton approach in forest planning

This study presents an optimization method based on cellular automaton (CA) for solving spatial forest planning problems. The CA maximizes stand-level and neighbourhood objectives locally, i.e., separately for different stands or raster cells. Global objectives are dealt with by adding a global part to the objective function and gradually increasing its weight until the global targets are met to a required degree. The method was tested in an area that consisted of 2500 (50 × 50) hexagons 1 ha in size. The CA was used with both parallel and sequential state-updating rules. The method was compared with linear programming (LP) in four nonspatial forest planning problems where net present value (NPV) was maximized subject to harvest constraints. The CA solutions were within 99.6% of the LP solutions in three problems and 97.9% in the fourth problem. The CA was compared with simulated annealing (SA) in three spatial problems where a multiobjective utility function was maximized subject to periodical harvest and ending volume constraints. The nonspatial goal was the NPV and the spatial goals were old forest and cutting area aggregation as well as dispersion of regeneration cuttings. The CA produced higher objective function values than SA in all problems. Especially, the spatial objective variables were better in the CA solutions, whereas differences in NPV were small. There were no major differences in the performance of the parallel and sequential cell state-updating modes of the CA.

Different Learned Coordinate Frames for Planning Trajectories and Final Positions in Reaching

We previously reported that the kinematics of reaching movements reflect the superimposition of two separate control mechanisms specifying the hand's spatial trajectory and its final equilibrium position. We now asked whether the brain maintains separate representations of the spatial goals for planning hand trajectory and final position. One group of subjects learned a 30 degrees visuomotor rotation about the hand's starting point while performing a movement reversal task ("slicing") in which they reversed direction at one target and terminated movement at another. This task required accuracy in acquiring a target mid-movement. A second group adapted while moving to -- and stabilizing at -- a single target ("reaching"). This task required accuracy in specifying an intended final position. We examined how learning in the two tasks generalized both to movements made from untrained initial positions and to movements directed toward untrained targets. Shifting initial hand position had differential effects on the location of reversals and final positions: Trajectory directions remained unchanged and reversal locations were displaced in slicing whereas final positions of both reaches and slices were relatively unchanged. Generalization across directions in slicing was consistent with a hand-centered representation of desired reversal point as demonstrated previously for this task whereas the distributions of final positions were consistent with an eye-centered representation as found previously in studies of pointing in three-dimensional space. Our findings indicate that the intended trajectory and final position are represented in different coordinate frames, reconciling previous conflicting claims of hand-centered (vectorial) and eye-centered representations in reach planning.

オランダの事前協議プロセスにおける空間的な目標像の共有化に関する研究 : 都市デザインマスタープランと決定プロセス要綱を通して

オランダの事前協議プロセスにおける空間的な目標像の共有化に関する研究 : 都市デザインマスタープランと決定プロセス要綱を通して

Preparatory Delay Activity in the Monkey Parietal Reach Region Predicts Reach Reaction Times

To acquire something that we see, visual spatial information must ultimately result in the activation of the appropriate set of muscles. This sensory to motor transformation requires an interaction between information coding target location and information coding which effector will be moved. Activity in the monkey parietal reach region (PRR) reflects both spatial information and the effector (arm or eye) that will be used in an upcoming reach or saccade task. To further elucidate the functional role of PRR in visually guided movement tasks and to obtain evidence that PRR signals are used to drive arm movements, we tested the hypothesis that increased neuronal activity during a preparatory delay period would lead to faster reach reaction times but would not be correlated with saccade reaction times. This proved to be the case only when the type of movement and not the spatial goal of that movement was known in advance. The correlation was strongest in cells that showed significantly more activity on arm reach compared with saccade trials. No significant correlations were found during delay periods in which spatial information was provided in advance. These data support the idea that PRR constitutes a bottleneck in the processing of spatial information for an upcoming arm reach. The lack of a correlation with saccadic reaction time also supports the idea that PRR processing is effector specific, that is, it is involved in specifying targets for arm movements but not targets for eye movements.

Representation of Spatial Goals in Rat Orbitofrontal Cortex

The orbitofrontal cortex (OFC) is thought to participate in making and evaluating goal-directed decisions. In rodents, spatial navigation is a major mode of goal-directed behavior, and anatomical and lesion studies implicate the OFC in spatial processing, but there is little direct evidence for coding of spatial or motor variables. Here, we recorded from ventrolateral and lateral OFC in an odor-cued two-alternative choice task requiring orientation and approach to spatial goal ports. In this context, over half of OFC neurons encoded choice direction or goal port location. A subset of neurons was jointly selective for the trial outcome and port location, information useful for the selection or evaluation of spatial goals. These observations show that the rodent OFC not only encodes information relating to general motivational significance, as shown previously, but also encodes spatiomotor variables needed to define specific behavioral goals and the locomotor actions required to attain them.

Representation of Future and Previous Spatial Goals by Separate Neural Populations in Prefrontal Cortex

The primate prefrontal cortex plays a central role in choosing goals, along with a wide variety of additional functions, including short-term memory. In the present study, we examined neuronal activity in the prefrontal cortex as monkeys used abstract response strategies to select one of three spatial goals, a selection that depended on their memory of the most recent previous goal. During each trial, the monkeys selected a future goal on the basis of events from the previous trial, including both the symbolic visual cue that had appeared on that trial and the previous goal that the monkeys had selected. When a symbolic visual cue repeated from the previous trial, the monkeys stayed with their previous goal as the next (future) goal; when the cue changed, the monkeys shifted from their previous goal to one of the two remaining locations as their future goal. We found that prefrontal neurons had activity that reflected either previous goals or future goals, but only rarely did individual cells reflect both. This finding suggests that essentially separate neural networks encode these two aspects of spatial information processing. A failure to distinguish previous and future goals could lead to two kinds of maladaptive behavior. First, wrongly representing an accomplished goal as still pending could cause perseveration or compulsive checking, two disorders commonly attributed to dysfunction of the prefrontal cortex. Second, mistaking a pending goal as already accomplished could cause the failures of omission that occur commonly in dementia.

Saccadic lateropulsion in Wallenberg syndrome: a window to access cerebellar control of saccades?

Saccadic lateropulsion is characterized by an undershoot of contralaterally directed saccades, an overshoot of ipsilaterally directed saccades and an ipsilateral deviation of vertical saccades. In Wallenberg syndrome, it is thought to result from altered signals in the olivo-cerebellar pathway to the oculomotor cerebellar network. In the current study we aimed to determine whether saccadic lateropulsion results from a cerebellar impairment of motor related signals or visuo-spatial related signals. We studied the trajectory, the accuracy, the direction and the amplitude of a variety of vertical and oblique saccades produced by five patients and nine control subjects. Some results are consistent with previous data suggesting altered motor related signals. Indeed, the horizontal error of contralesional saccades in patients increased with the desired horizontal saccade size. Furthermore, the initial directional error measured during the saccadic acceleration phase was smaller than the global directional error, suggesting that the eye trajectory curved progressively. However, some other results suggest that the processes that specify the horizontal spatial goal of the saccades might be impaired in the patients. Indeed, the horizontal error of ipsilesional saccades in patients did not change significantly with the desired horizontal saccade size. In addition, when comparing saccades with similar intended direction, it was found that the directional error was inversely related to the vertical saccade amplitude. Thus we conclude that the cerebellum might be involved both in controlling the motor execution of saccades and in determining the visuo-spatial information about their goal.

Evidence for the Encoding of a Motion's Goal in the Monkey Brain

From cooking to playing the piano, our activities consist of simple motions that we string together for specific purposes. When we learn a new recipe or piano sonata, we memorize the elemental gestures of the trade as well as the precise order in which they must occur to produce a coq au vin or “Moonlight Sonata.” And when we start cooking or playing, we somehow summon the sequence of movements that will lead to our goal. Scientists have long wondered how the brain stores in memory a sequence of movements. Ultimately, such memories result from connections that brain cells (neurons) establish among themselves and with the relevant muscles during the learning period. But precisely how the information is organized in the brain remains largely mysterious. A model called “associative chaining” proposes that a memory cell representing an early motion activates memory cells representing later motions in the sequence. In this model, a memory cell recalls at once the type of motion and its order of appearance in the sequence. But in a new study, Mark H. Histed and Earl K. Miller show that they can uncouple the memories for a sequence's components and for their serial order by manipulating a subset of cells in the brain of monkeys. Their observations suggest the existence of abstract forms of memory that store the goal of a sequence of movements. The researchers focused on a small area near the surface of the brain's frontal lobe called the supplementary eye field (SEF). Within the SEF are cells that control small voluntary eye movements called saccades that animals use to track bright objects near the periphery of their field of vision. Stimulation of individual SEF neurons triggers saccades to separate locations, and SEF neurons have been found to fire sequentially while monkeys made serial saccades to visual targets, as if the cells controlled the saccade succession. The SEF therefore appeared like a logical place to look for neurons that harbor memories of learned saccade sequences. Histed and Miller first trained two monkeys to saccade to successive locations on a screen. While the monkeys focused on a bright central spot, two additional spots (cues) would appear at random one after the other and disappear after half a second. The monkeys had to wait one more second before saccading to the two cued locations in the order of the cues' appearance. The task therefore required memorizing both the cues' location and order. The monkeys were rewarded each time they accomplished a saccade sequence correctly, and they eventually performed with a near-perfect score. In an experimental session, the researchers would stimulate various sites in the SEF with microelectrodes during the one-second delay period, and record the effect of these stimulations on the monkeys' performance. Out of 55 SEF locations tested, the researchers found 25 that disrupted the monkeys' performance. The pattern of errors was always the same: the monkeys saccaded to the correct locations, but in incorrect order. For instance, if the sequence consisted of a cue at a 1 o'clock location followed by a cue at 3 o'clock, the monkeys would saccade to 3 o'clock first and then 1 o'clock. However, they never saccaded to 5 o'clock or 11 o'clock, or to any other wrong location. Therefore, the monkeys seem able to keep the memory of visual cues intact even when they forget the order of the cues' appearance, which shows that memories for the order versus the components of a sequence are held separately in the monkey's brain. More specifically, these results indicate that the SEF can reorganize a series of saccades. Strong stimulation of the SEF can elicit eye movements. If you vertically divide the visual world in half, stimulating the right SEF causes saccades to the left field, and vice versa. But the stimuli Histed and Miller applied to the SEF were too weak to produce saccades. Nevertheless, their effects were similarly biased: they reordered saccade sequences such that the monkeys always seemed to aim for left field when receiving a stimulus in the right SEF, and to right field when receiving a left stimulus. The researchers conclude that rather than precisely ordering a sequence of saccades, the SEF codes for a spatial goal (left field or right field), regardless of whether it takes one or more saccades to reach that goal. The implication of these results is that the brain might store complex sequences of movements in two forms: one for the sequence's goal and one for the details of its execution.

Coding for spatial goals in the prelimbic/infralimbic area of the rat frontal cortex

Finding one's way in space requires a distributed neural network to support accurate spatial navigation. In the rat, this network likely includes the hippocampus and its place cells. Although such cells allow the organism to locate itself in the environment, an additional mechanism is required to specify the animal's goal. Here, we show that firing activity of neurons in medial prefrontal cortex (mPFC) reflects the motivational salience of places. We recorded mPFC neurons from rats performing a place navigation task, and found that a substantial proportion of cells in the prelimbic/infralimbic area had place fields. A much smaller proportion of cells with such properties was found in the dorsal anterior cingulate area. Furthermore, the distribution of place fields in prelimbic/infralimbic cells was not homogeneous: goal locations were overrepresented. Because such locations were spatially dissociated from rewards, we suggest that mPFC neurons might be responsible for encoding the rat's goals, a process necessary for path planning.