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

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

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

The development of beacon use for spatial orientation in 6-8.5-month-old infants.

The overall aim of this research was to establish the youngest age at which use of beacons to aid spatial orientation could be demonstrated. Six- and 8.5-month-old infants were tested in a peekaboo paradigm in which they had to turn to a target location, either after displacement to a novel position and orientation (Study 1), or to a novel orientation only (Study 2). A beacon condition where there was a colourful landmark at the peekaboo location was contrasted with a non-beacon condition at each age. The 8.5-month-olds showed robust but modest gains in performance in the presence of a beacon, whereas the 6-month-old infants did not. A further study (Study 3) confirmed that performance was poor at 8.5 months in the absence of a beacon, even when displacements between training and test positions involved rotations only. This finding is contrary to that reported in earlier literature (Tyler and McKenzie, 1990). The possibility that onset of crawling (at a mean age of 8.5 months) could be linked both to the development of allocentric and egocentric spatial coding is left open by the relatively later age of competence found in the present series of studies

Use of configurational geometry for spatial orientation in human infants (homo sapiens).

Research with both rats and human infants has found that after inertial disorientation, the geometry of an enclosed environment is used in preference over distinctive featural information during goal localization. Infants (Homo sapiens, 18-24 months) were presented with a toy search task involving inertial disorientation in 1 of 2 conditions. In the identical condition, 4 identical hiding boxes in a rectangular formation were set within a circular enclosure. In the distinctive condition, 4 distinctive hiding boxes were used. Infants searched the goal box and its rotational equivalent significantly more than would be expected by chance in the identical condition, showing that they were sensitive to the geometric configuration of the array of boxes. Unlike the results of studies using a rectangular enclosure, however, in the distinctive condition, infants searched at the correct location significantly more than at other locations

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

The effects of spatial stability and cue type on spatial learning: Implications for theories of parallel memory systems

Some theories of spatial learning predict that associative rules apply under only limited circumstances. For example, learning based on a boundary has been claimed to be immune to cue competition effects because boundary information is the basis for the formation of a cognitive map, whilst landmark learning does not involve cognitive mapping. This is referred to as the cue type hypothesis. However, it has also been claimed that cue stability is a prerequisite for the formation of a cognitive map, meaning that whichever cue type was perceived as stable would enter a cognitive map and thus be immune to cue competition, while unstable cues will be subject to cue competition, regardless of cue type. In experiments 1 and 2 we manipulated the stability of boundary and landmark cues when learning the location of two hidden goals. One goal location was constant with respect to the boundary, and the other constant with respect to the landmark cues. For both cue types, the presence of distal orientation cues provided directional information. For half the participants the landmark cues were unstable relative to the boundary and orientation cues, whereas for the remainder of the participants the boundary was unstable relative to landmarks and orientation cues. In a second stage of training, all cues remained stable so that both goal locations could be learned with respect to both landmark and boundary information. According to the cue type hypothesis, boundary information should block learning about landmarks regardless of cue stability. According to the cue stability hypothesis, however, landmarks should block learning about the boundary when the landmarks appear stable relative to the boundary. Regardless of cue type or stability the results showed reciprocal blocking, contrary to both formulations of incidental cognitive mapping. Experiment 3 established that the results of Experiments 1 and 2 could not be explained in terms of difficulty in learning certain locations with respect to different cue types. In a final experiment, following training in which both landmarks and boundary cues signalled two goal locations, a new goal location was established with respect to the landmark cues, before testing with the boundary, which had never been used to define the new goal location. The results of this novel test of the interaction between boundary and landmark cues indicated that new learning with respect to the landmark had a profound effect on navigation with respect to the boundary, counter to the predictions of incidental cognitive mapping of boundaries

The symbolic method of network analysis based on topological methods

In the paper the regular skeleton of graph is defined and the generalized formula for evaluation of network determinants is presented. This reqiure explicit listing of the all regular multiskeletons of connected multigraph. The computer programs NTW001 and NTWTOOBV based on this methods will be presented