The well-worn route revisited: Striatal and hippocampal system contributions to route learning in human navigation

Parallel spatial memory systems theory posits that there are two types of memory system. One is a flexible, cognitive mapping system subserved by the hippocampal formation, and the other is a system centred on the striatum based on reinforcement learning principles where specific stimuli are associated with rewarded actions (O’Keefe & Nadel, 1978; White & McDonald, 2002). More recently, Khamassi & Humphries (2012) have argued that the division between model-based and model-free spatial learning is a better predictor of whether hippocampal or striatal systems will be recruited, with hippocampal systems associated with model-based responding and striatal systems with model-free responding. Model-free decision-making occurs when responding is based on average reward history associated with a particular cue-action pairing, whereas model-based decision-making allows knowledge of outcomes from previous learning history to be represented. We sought to test these theories by asking participants (N = 24) to navigate within a virtual environment through a previously learned, 9-junction route with distinctive landmarks at each junction, while undergoing functional magnetic resonance imaging. In critical conflict probe trials, a landmark was presented out of sequence such that following the usual sequence of actions would generate an opposite response to following the learned individual landmark-action association, now out of sequence. Participants that made sequence-based responses had higher parahippocampal activations relative to participants that made responses based on the individual landmark-action association, a result that would be predicted by the need to recruit model-based systems to make a sequence-based response. Parallel spatial memory systems theory would not predict hippocampal formation recruitment for either response in the conflict probe, because no cognitive mapping is required when following a prescribed route. In longer probe trials where participants were able to plan a sequence of responses, striatal systems were recruited (caudate and putamen) suggesting a role for striatum in action chunking

The development of hand-mouth coordination in early infancy

The aim of the thesis is to offer a comprehensive account of the developmental course of hand-mouth (HM) coordination from birth until a mature form of the coordination is attained. Questions relating both to the structure and function of the coordination were addressed. Three studies are reported. The method of observation was the same in each case; video records of two perpendicular views of the infant were obtained and a micro-analysis of movement structure was carried out. The main question addressed in study 1 was whether spontaneous HM contacts in newborns are related to hunger. HM contacts were compared before and after feeding in a group of newborn babies. There was no change in the relative distribution of locations of contacts on the mouth and face before and after feeding, but anticipatory mouth opening prior to HM contacts only occurred before feeding. Study 2 sought to obtain detailed measures of transitions taking place between 1-5 months in the structure of HM coordination, and to investigate what factors could be responsible for the changes observed. A longitudinal design was employed where babies were observed at monthly intervals. A small object was placed in the hands of infants to promote oral contacts. At 4 months of age, contacts began to be centred on the mouth (as opposed to other parts of the face) and the frequency of contacts was significantly higher when the object was present relative to the frequency of spontaneous contacts. Anticipatory mouth opening only occurred at 5 months of age, suggesting that this aspect of the coordination follows a U-shaped developmental trajectory. There was evidence that vision was playing a role in motivating HM contacts by 5 months of age. Consistent individual differences between babies were found in different aspects of HM coordination raising the possibility that more than one developmental route is followed in the achievement of mature HM coordination. Study 3 investigated HM coordination cross-sectionally between the ages of 5-9 months. The possibility that the development of reaching was influencing the development of HM coordination was investigated. Two situations were compared, one where the infant had to reach for an object prior to transportation to the mouth and another where the object was placed in the hand of the infant. Although HM coordination and reaching and grasping were already integrated at 5 months, the two coordinations appear to develop independently of each other. The development of HM coordination was found to be marked by motivational and structural shifts and apparent regressions. The results are interpreted within a dynamic systems view of development

Relations between psychological avoidance, symptom severity and embarrassment in essential tremor

Research with community- and clinic-based samples of essential tremor (ET) sufferers has identified embarrassment as a common consequence of the condition, leading to social anxiety and avoidance. We sought to ascertain whether psychological avoidance was related to embarrassment in ET, and whether any such relation was independent of symptom severity. Establishing whether psychological avoidance is related to embarrassment in ET would be a first indicator that mindfulness-based therapeutic approaches may be appropriate for sufferers of ET. Ninety-two participants were recruited through online support groups run by the International Tremor Foundation and the UK National Tremor Foundation, with the self-reported inclusion criteria being a clinical diagnosis of ET. Participants completed 3 validated questionnaires concerning ET-related embarrassment, ET symptom severity and psychological avoidance. Females had slightly higher embarrassment scores than males, and symptom severity and psychological avoidance made significant moderate (each accounting for 10-15% of variance approx.), but independent contributions to embarrassment scores. These results suggest that to address the potentially debilitating effects of embarrassment in ET, both symptom severity and psychological avoidance need to be targeted, with intervention research being required

Social cognition in children with epilepsy in mainstream education

AIM To establish whether deficits in social cognition are present in children with generalised or focal epilepsy in mainstream education, and whether any relation exists between social cognition, communication, and behaviour measures. METHOD In a cross-sectional study, children with an epilepsy-only diagnoses in mainstream education (n=20 with generalized epilepsy; eight males, 12 females; mean age 11y 6mo, SD 2y 6mo; and n=27 with focal epilepsy; 12 males, 15 females; mean age 11y 8mo, SD 2y 2mo) and comparison participants (n=57; 28 males, 29 females; mean age 11y 2mo, SD 2y 4mo) were administered the Strange Stories task and the Mind in the Eyes task, as well as an IQ assessment. Parents completed the Children’s Communication Checklist-2 and the Child Behavior Checklist (CBCL). RESULTS Both groups of children with epilepsy performed more poorly than control children on the Mental Stories component of the Strange Stories task, F(2,101)=3.2, p<0.001. Performance on Mental Stories was related to pragmatic communication, but only in the generalized epilepsy group (r=0.51, p=0.03, 95% CI=0.2–0.8). There were no differences between epilepsy groups or control participants in the Mind in the Eyes task, F(2,101)=0.4, p=0.4. INTERPRETATION Children with ‘epilepsy only’ are at risk of deficits in social cognition and may require appropriate support

The well‐worn route revisited: Striatal and hippocampal system contributions to familiar route navigation

Classic research has shown a division in the neuroanatomical structures that support flexible (e.g., short‐cutting) and habitual (e.g., familiar route following) navigational behavior, with hippocampal–caudate systems associated with the former and putamen systems with the latter. There is, however, disagreement about whether the neural structures involved in navigation process particular forms of spatial information, such as associations between constellations of cues forming a cognitive map, versus single landmark‐action associations, or alternatively, perform particular reinforcement learning algorithms that allow the use of different spatial strategies, so‐called model‐based (flexible) or model‐free (habitual) forms of learning. We sought to test these theories by asking participants (N = 24) to navigate within a virtual environment through a previously learned, 9‐junction route with distinctive landmarks at each junction while undergoing functional magnetic resonance imaging (fMRI). In a series of probe trials, we distinguished knowledge of individual landmark‐action associations along the route versus knowledge of the correct sequence of landmark‐action associations, either by having absent landmarks, or “out‐of‐sequence” landmarks. Under a map‐based perspective, sequence knowledge would not require hippocampal systems, because there are no constellations of cues available for cognitive map formation. Within a learning‐based model, however, responding based on knowledge of sequence would require hippocampal systems because prior context has to be utilized. We found that hippocampal–caudate systems were more active in probes requiring sequence knowledge, supporting the learning‐based model. However, we also found greater putamen activation in probes where navigation based purely on sequence memory could be planned, supporting models of putamen function that emphasize its role in action sequencing

Carer evaluations of paediatric epilepsy services with and without Epilepsy Specialist Nurse provision

Purpose To compare paediatric epilepsy services with and without Epilepsy Specialist Nurse (ESN) provision on measures of carer satisfaction and accessibility of service. Methods In Study 1, carers in Northern England (n = 69 with an ESN, n = 27 without an ESN), completed the Parent Report of Psychosocial Care Scale to measure satisfaction with service provision. A measure of accessibility of service was also included. In Study 2, in depth semi-structured interviews with 58 carers (51 of whom had also participated in Study 1) were examined for talk related to accessibility of service. Results In Study 1, Satisfaction with service levels were high across all areas, (ESN areas Mdn = 9.04, IQR = 1.48, non-ESN areas Mdn = 8.29, IQR = 2.41; maximum score = 10), but with carers from ESN areas over 3 times more likely to endorse scores at the median or above relative to non-ESN areas (OR = 3.28). For accessibility, carers in ESN areas were over 5 times more likely to have a median score or higher (ESN areas Mdn = 10, IQR = 0.45, non-ESN areas Mdn = 8.4, IQR = 5, OR = 5.43). In study 2 a majority of all carers reported having made at least one attempt to contact services between appointments, for a wide range of reasons, with timely resolution reported in ESN areas, but more variable resolution occurring in non-ESN areas. Conclusion Paediatric ESNs provide a critical and timely service to children with epilepsy and their carers

Looking beyond the boundaries: Time to put landmarks back on the cognitive map?

Since the proposal of Tolman (1948) that mammals form maplike representations of familiar environments, cognitive map theory has been at the core of debates on the fundamental mechanisms of animal learning and memory. Traditional formulations of cognitive map theory emphasize relations between landmarks and between landmarks and goal locations as the basis of the map. More recently, several models of spatial coding have taken the boundaries of an environment as the basis of the cognitive map, with landmark relations being processed through alternative, operant learning mechanisms. In this review, the evidence for this proposed dichotomy is analyzed. It is suggested that 2 factors repeatedly confound efforts to compare spatial coding based on landmark arrays, formed by 2 or more landmarks, and that based on the boundaries of an environment. The factors are the perceived stability of the landmark arrays and their placement relative to the larger environment. Although the effects of landmark stability and of placement on spatial navigation have been studied extensively, the implications of this work for debates concerning the role of boundaries in cognitive map formation have not been fully realized. It is argued that when these 2 factors are equated between landmark arrays and bounded environments, current evidence supports a commonality of spatial coding mechanism rather than a dichotomy. The analysis places further doubt on the existence of a dedicated geometric module for reorientation and is consistent with models of navigation containing mapping and operant learning components, both taking as input local views (Sheynikhovich et al., 2009)

The effects of hunger on hand-mouth coordination in newborn infants

The spontaneous hand–mouth (HM) behavior of a group of newborn infants was analyzed before and after feeding to examine the hypothesis that there is a link between hunger and HM coordination. There was no difference in the relative distribution of contacts on the mouth compared with other parts of the face as a result of feeding. However, significantly more mouth opening before contacts to the mouth than those to the face occurred before but not after feeding. It was suggested that HM coordination was linked to feeding, but because of involuntary general movements infants might not be able to determine the final location of a movement. However, they are able to predict where a movement will land and anticipate this, if motivated to do so

Disorientation inhibits landmark use in 12-18-month-old infants.

Recent research has indicated that, particularly under conditions of inertial disorientation, mammals may be sensitive to landmark configuration geometry at the expense of individual featural information when locating hidden goals. The current study sought to establish whether landmark use could be demonstrated in 12–18-month-old infants with and without a disorientation procedure, and with geometrically ambiguous landmark configurations. A peekaboo paradigm was employed in which infants learned to anticipate a peekaboo event after a cue from two locations within a circular arena, followed by a test trial from a novel position in which no peekaboo occurred after the cue. In all conditions, an isosceles triangle arrangement of landmarks was used, with peekaboo occurring between the landmarks of one of the two equal “sides”, thus being geometrically ambiguous. In two conditions, the landmarks were distinctive, and in two further conditions, they were identical. In one of the distinctive conditions and one of the identical landmark conditions, infants underwent a disorientation procedure in between training and test trials. Only oriented infants with distinctive landmarks were successful in test trials, thus suggesting that infants are able to use the individual features of landmarks to locate a goal, but can only do so if oriented