Eye-hand coordination when the body moves: Dynamic egocentric and exocentric sensory encoding

We investigated whether the human brain encodes and memorizes object orientations with respect to external references, such as gravity and visual landmarks, or whether it uses egocentric representations of the task. To this end, we applied a new analysis to a previously reported experiment on a reach-to-grasp-like movement, in which we used sensory conflict to identify how the CNS encodes target and hand orientation. Whereas in the preceding study deviations of responses provoked by the conflict provided evidence for the simultaneous use of visual and kinesthetic representations of target and hand (Tagliabue and McIntyre, 2011 [20]), here we used an analysis of response variability in the presence of conflict to test for ego- versus exo-centric encoding within each sensory modality. Our results show an increase of response variability with the amplitude of the head rotation, indicative of errors that accumulate when updating egocentric representations during head movements. In addition, the effect of conflict on error accumulation showed that the brain selects different information about the head movement for the updating, depending on the modality of the egocentric representation (visual or kinesthetic) that is retained. In particular, the CNS appears to privilege the sensory information about head movement that can most easily be combined with each internal representation. Moreover, a combined analysis of response variability and response deviations induced by the conflict suggests the coexistence of independent ego- and exo-centered internal representations within each sensory modality.     

Selectivity of voluntary finger flexion during ischemic nerve block of the hand

During ischemic nerve block of an extremity the cortical representations of muscles proximal to the block are known to expand, increasing the overlap of different muscle representations. Such reorganization mimics that seen in actual amputees. We investigated whether such changes degrade voluntary control of muscles proximal to the block. Nine subjects produced brief, isometric flexion force selectively with each fingertip before, during, and after ischemic block at the wrist. We recorded the isometric force exerted at the distal phalanx of each digit, along with electromyographic (EMG) activity from intrinsic and extrinsic finger muscles. Despite paralysis of the intrinsic hand muscles, and associated decrements in the flexion forces exerted by the thumb, index, and little fingers, the selectivity of voluntary finger flexion forces and of EMG activity in the extrinsic finger muscles that generated these forces remained unchanged. Our observations indicate that during ischemic nerve block reorganization does not eliminate or degrade motor representations of the temporarily deafferented and paralyzed fingers.     

Illness beliefs and self-management in children and young people with chronic illness: a systematic review

To review the extent to which illness representations, based on Leventhal's Common Sense Model, relate to self-management in children and young people with chronic physical health conditions. A systematic literature review was carried out to identify relevant studies and each included paper was assessed for risk of bias. Fifteen papers met criteria for inclusion within the review. The majority of studies were cross-sectional, and small sample sizes for some studies made it difficult to generalise findings. The method of measuring both illness representations and outcomes varied. Timeline, identity, control and consequences beliefs were the most frequently assessed domains of illness representations included within the studies. While there is variability, there are indications that control beliefs, specifically treatment control beliefs, are more consistently and strongly associated with self-management than other representation domains. Control beliefs should be targeted for intervention in studies trying to improve adolescent self-management. In addition, the relationship between illness representations and self-management needs to be considered within both developmental and systemic contexts. It is likely that the variation in self-management will be more fully explained in future research that explores the combined effects of individual representations and the influence of wider contexts.     

Illness representations and psychological adjustment of Greek couples dealing with a recently-diagnosed cancer: dyadic,interaction and perception-dissimilarity effects

The aim was to examine the impact of the dyadic, interaction and dissimilarity effects of the illness representations on the psychological health of recently diagnosed cancer patients and spouses in Greece. The sample consisted of 298 individuals nested in 149 couples. Effects were examined with the Actor–Partner Interdependence Model. Both actor (i.e., within person) and partner (i.e., between partners) effects were detected for both patients’ and spouses’ psychological symptoms. The negative association of patients’ psychological symptoms with their representations of illness coherence was weak at the higher and medium levels, and stronger at the lower levels of spouse corresponding representations. Patient–partner discrepancy in perceived illness consequences was associated with more psychological symptoms in patients. Adaptation to cancer is a dyadic process within the context of which patient and partner psychological well-being is affected by each other’s understanding of illness. Thus, the parallel examination of the illness representations of both partners is needed from the early phases of the illness trajectory.     

Attachment in mental health institutions: A critical review of assumptions,clinical implications,and research strategies

Attachment is relevant to institutionalized treatment and the therapeutic process in three identifiable ways: (1) patients bring their mental representations of previous and existing attachment relationships to the treatment; (2) attachment is relevant to the extent to which a therapeutic alliance is established and maintained, both in terms of the mental representations of attachment in the patient and in the therapist and how these influence interactive behaviour and expectations in each partner to the therapeutic work; (3) the outcome of the treatment may be related to attachment; for example, when institutional experiences have an enduring impact on attachment representations and the future attachment behaviour of the patient. However, this brief review of attachment concepts reveals that several theoretical, conceptual and empirical questions remain to be answered before evidence-based clinical attachment guidelines can be formulated concerning patient-staff relationships.     

The organization of the human cerebellum estimated by intrinsic functional connectivity

The cerebral cortex communicates with the cerebellum via polysynaptic circuits. Separate regions of the cerebellum are connected to distinct cerebral areas, forming a complex topography. In this study we explored the organization of cerebrocerebellar circuits in the human using resting-state functional connectivity MRI (fcMRI). Data from 1,000 subjects were registered using nonlinear deformation of the cerebellum in combination with surface-based alignment of the cerebral cortex. The foot, hand, and tongue representations were localized in subjects performing movements. fcMRI maps derived from seed regions placed in different parts of the motor body representation yielded the expected inverted map of somatomotor topography in the anterior lobe and the upright map in the posterior lobe. Next, we mapped the complete topography of the cerebellum by estimating the principal cerebral target for each point in the cerebellum in a discovery sample of 500 subjects and replicated the topography in 500 independent subjects. The majority of the human cerebellum maps to association areas. Quantitative analysis of 17 distinct cerebral networks revealed that the extent of the cerebellum dedicated to each network is proportional to the network's extent in the cerebrum with a few exceptions, including primary visual cortex, which is not represented in the cerebellum. Like somatomotor representations, cerebellar regions linked to association cortex have separate anterior and posterior representations that are oriented as mirror images of one another. The orderly topography of the representations suggests that the cerebellum possesses at least two large, homotopic maps of the full cerebrum and possibly a smaller third map.     

Dynamic circuitry for updating spatial representations. II. Physiological evidence for interhemispheric transfer in area LIP of the split-brain macaque

With each eye movement, a new image impinges on the retina, yet we do not notice any shift in visual perception. This perceptual stability indicates that the brain must be able to update visual representations to take our eye movements into account. Neurons in the lateral intraparietal area (LIP) update visual representations when the eyes move. The circuitry that supports these updated representations remains unknown, however. In this experiment, we asked whether the forebrain commissures are necessary for updating in area LIP when stimulus representations must be updated from one visual hemifield to the other. We addressed this question by recording from LIP neurons in split-brain monkeys during two conditions: stimulus traces were updated either across or within hemifields. Our expectation was that across-hemifield updating activity in LIP would be reduced or abolished after transection of the forebrain commissures. Our principal finding is that LIP neurons can update stimulus traces from one hemifield to the other even in the absence of the forebrain commissures. This finding provides the first evidence that representations in parietal cortex can be updated without the use of direct cortico-cortical links. The second main finding is that updating activity in LIP is modified in the split-brain monkey: across-hemifield signals are reduced in magnitude and delayed in onset compared with within-hemifield signals, which indicates that the pathways for across-hemifield updating are less effective in the absence of the forebrain commissures. Together these findings reveal a dynamic circuit that contributes to updating spatial representations.     

Attachment in mental health institutions: a critical review of assumptions, clinical implications, and research strategies

Attachment is relevant to institutionalized treatment and the therapeutic process in three identifiable ways: (1) patients bring their mental representations of previous and existing attachment relationships to the treatment; (2) attachment is relevant to the extent to which a therapeutic alliance is established and maintained, both in terms of the mental representations of attachment in the patient and in the therapist and how these influence interactive behaviour and expectations in each partner to the therapeutic work; (3) the outcome of the treatment may be related to attachment; for example, when institutional experiences have an enduring impact on attachment representations and the future attachment behaviour of the patient. However, this brief review of attachment concepts reveals that several theoretical, conceptual and empirical questions remain to be answered before evidence-based clinical attachment guidelines can be formulated concerning patient-staff relationships.     

Movement preparation and working memory: a behavioural dissociation

We can cross temporal sensorimotor contingencies by remembering sensory events or by anticipating motor responses. Here we tested the hypothesis that sensory and motor representations can be accessed according to different temporal dynamics. We predicted that the manipulation of movement representations would lead to a performance independent from the length of a delay interposed between sensory instructions and behavioural responses. Conversely, we expected a delay-dependent performance whenever temporary storage of sensory information was necessary to solve the task. We have measured reaction times and error rate in subjects performing a delayed non-matching to sample task. Task contingencies rather than explicit instructions ensured that either sensory or motor representations were used to cross the delay period on each trial. We tested our hypothesis by manipulating the length of the delays between stimulus presentation and behavioural response. We found that carrying sensory material over temporal gaps affects performance as a non-linear function of time, whereas movement representations remain robust over a wide range of delays. This novel behavioural paradigm might prove effective in dissociating the neural bases of preparatory and mnestic processes in normal human subjects, as well as their disorders in neurological patients.     

Semantic memory is an amodal, dynamic system: Evidence from the interaction of naming and object use in semantic dementia

Classic neurological accounts and some contemporary theories of semantic memory assume that concepts are acquired through a learning process that draws together information experienced in each of our verbal and nonverbal modalities. These accounts embody three critical assumptions: semantic representations are amodal; the mapping between surface form and meaning varies for different modalities; and the representations are dynamic. The influence of these three factors was revealed in data collected over a 4-year longitudinal period in two patients with semantic dementia. Semantic assessment revealed a parallel decline in verbal and nonverbal aspects of conceptual knowledge, reflecting a gradual degradation of a single amodal semantic system. As expected, when the patients' semantic impairment was mild, they presented with profound anomia but relatively preserved object use. Over time, performance on all semantic tasks including object use declined. High item-by-item consistency across these tasks was observed in all testing sessions. The impact of dynamic semantic representations was revealed by a striking clinical finding. Although unable to name many of the objects in isolation, their performance was significantly facilitated if they were asked to name while they demonstrated the use of each object. These results are discussed in the context of contemporary models of semantic memory.     

Individual differences in adult attachment are systematically related to dream narratives

Self-reported individual differences in attachment insecurities (anxiety and avoidance) are sometimes assumed to tap only conscious mental processes, although many studies have found correlations between such measures and responses to the Thematic Apperception Test, the Rorschach Inkblot Test, and diverse laboratory measures of unconscious mental processes. Dreams offer another route into the unconscious, as Freud famously claimed: a route found useful in psychotherapy. In this study, approximately 1000 dreams reported by 68 young adults who kept dream diaries for a month were analyzed using the Core Conflictual Relationships Theme method, and the themes were examined in relation to (a) scores on the Experiences in Close Relationships measure of attachment anxiety and avoidance and (b) stress experienced the day before each dream. In line with attachment theory and previous research, attachment-related avoidance predicted avoidant wishes and negative representations of other people in dreams. Attachment anxiety predicted wishes for interpersonal closeness, especially in dreams following stressful days, and negative representations of self and both positive and negative representations of others, with negative representations being more common in dreams following stressful days.     

Sparse odor representation and olfactory learning

Sensory systems create neural representations of environmental stimuli and these representations can be associated with other stimuli through learning. Are spike patterns the neural representations that get directly associated with reinforcement during conditioning? In the moth Manduca sexta, we found that odor presentations that support associative conditioning elicited only one or two spikes on the odor's onset (and sometimes offset) in each of a small fraction of Kenyon cells. Using associative conditioning procedures that effectively induced learning and varying the timing of reinforcement relative to spiking in Kenyon cells, we found that odor-elicited spiking in these cells ended well before the reinforcement was delivered. Furthermore, increasing the temporal overlap between spiking in Kenyon cells and reinforcement presentation actually reduced the efficacy of learning. Thus, spikes in Kenyon cells do not constitute the odor representation that coincides with reinforcement, and Hebbian spike timing-dependent plasticity in Kenyon cells alone cannot underlie this learning.     

Semantic memory is an amodal,dynamic system: Evidence from the interaction of naming and object use in semantic dementia

Classic neurological accounts and some contemporary theories of semantic memory assume that concepts are acquired through a learning process that draws together information experienced in each of our verbal and nonverbal modalities. These accounts embody three critical assumptions: semantic representations are amodal; the mapping between surface form and meaning varies for different modalities; and the representations are dynamic. The influence of these three factors was revealed in data collected over a 4‐year longitudinal period in two patients with semantic dementia. Semantic assessment revealed a parallel decline in verbal and nonverbal aspects of conceptual knowledge, reflecting a gradual degradation of a single amodal semantic system. As expected, when the patients' semantic impairment was mild, they presented with profound anomia but relatively preserved object use. Over time, performance on all semantic tasks including object use declined. High item‐by‐item consistency across these tasks was observed in all testing sessions. The impact of dynamic semantic representations was revealed by a striking clinical finding. Although unable to name many of the objects in isolation, their performance was significantly facilitated if they were asked to name while they demonstrated the use of each object. These results are discussed in the context of contemporary models of semantic memory.     

Spelling and dysgraphia

Early cognitive models of spelling assumed that orthographic word representations are linear, ordered sequences of abstract letter identities (graphemes), activated only by word meaning information, and in some cases proposed that activating phonological information is a necessary stage of the spelling process. Over the past 20 years, studies on dysgraphia have shown that orthographic representations are autonomous from phonological representations and, just like the latter, are directly activated from semantics. The selection of an orthographic form for output relies on the convergence of activation from lexical-semantic information and from sublexical phoneme-grapheme conversion procedures. In addition, it is increasingly clear that orthographic representations are multidimensional objects that separately represent the graphosyllabic structure (or perhaps the nucleus/non-nucleus positions) of the target, and the identity, the CV status, and the quantity (doubling) of each grapheme. In spelling, the structure of orthographic knowledge and the mechanisms involved in processing serial order interact in complex ways and constrain performance accuracy. Further research is needed to clarify some critical issues: We need to specify in greater detail the mechanisms involved in the interaction between meaning and sublexical information; we must consider the possibility that orthographic representations have texture, in addition to structure; we must provide explicit hypotheses on the mechanisms that process orthographic knowledge; and we must gain a better understanding of the interaction between structure and serial order.     

The illness representations of multiple sclerosis and their relations to outcome

Objectives: The main aims of the present study were to explore the illness representations of individuals with multiple sclerosis (MS) and investigate the relationship of these beliefs to outcome. Based on Leventhal et al.'s self‐regulation model, the commonly accepted generic five‐component structure of illness representations including identity, time‐line, consequences, cause, and cure/controllability was used. Design: A cross‐sectional, correlational design was employed for the study. Interrelationships among the illness representation components and the relationships between the components and outcome were explored using Pearson's r. To determine the contribution of the illness representation components to the explained variance in outcome, a series of stepwise multiple regression analyses was used. Method: A total of 99 participants took part in the study. A series of measures were completed to assess (1) illness representations and (2) five specific areas of outcome. Results: Participants' illness representations of MS were consistent with the medical nature and understanding of this illness indicating that they held the perceptions of a strong illness identity, chronic time‐line, no particular cause and no cure. Beliefs in the serious consequences of MS and limited control were also reported. Some important interrelationships among the illness representation components were demonstrated where a strong illness identity, chronic time‐line view and perception of low control were related to more serious consequences. Overall, evidence was provided to suggest that illness representations contribute to outcome. The consequences component was associated with, and contributed to, the explained variance for each of the five outcome areas, indicating that the perception that MS has many negative effects on an individual's life was associated with greater levels of difficulty in all of the outcome areas. In addition, for each of the outcome variables, different combinations of illness representation components explained their variance. For example, higher levels of depression were associated with perceptions of a stronger illness identity, more serious consequences, acute time‐line, and low control. Conclusion: Overall support is provided for the application of the five‐component structure of illness representations to MS and the likely contribution of such beliefs to outcome. The concept of illness representations therefore provides a useful framework for understanding the psychosocial effects of this illness.     

Distribution of corticopontine neurons in visual areas of the middle suprasylvian sulcus: quantitative studies in the cat

This study deals with the distribution of corticopontine neurons in four of the lateral suprasylvian visual areas, the anteromedial, anterolateral, posteromedial and posterolateral areas. Following large injections of horseradish peroxidase-wheat germ agglutinin in the pontine nuclei, labelled cells were quantitatively mapped. The borders of the four areas were determined cyto- and myeloarchitectonically or from standard retinotopic maps presented in frontal sections (Tusa et al., 1981). Flat maps were constructed of each area showing the distribution of retrogradely labelled neurons. Maps of the retinotopic organization in the lateral suprasylvian visual areas (Palmer et al., 1978; Tusa et al., 1981) were transferred to the flat maps. Thus, the density and number of labelled cells within each area and within smaller zones representing different visual field blocks could be determined. The average cell density (average number of labelled cells per mm2 of flattened cortex) is highest in the anteromedial area. The average density in this area is higher than in areas 17, 18 and 19. The total number of labelled cells is highest in the posteromedial area. The lateral syprasylvian visual areas together have a stronger pontine projection in terms of actual number of cells than each of areas 17, 18 and 19. [Data on areas 17, 18 and 19 from Bjaalie and Brodal (1983) and Bjaalie (1985)]. The four areas investigated have different internal distribution of corticopontine cells. The posteromedial and posterolateral areas have lower densities of labelled cells in the representations of the retinal central area than in the representations of the visual periphery. However, due to the enlarged cortical representations of central vision, the actual number of corticopontine cells per visual field block is higher in the cortex representing the central area; i.e. the central visual field region is moderately over-represented in the corticopontine projection from these areas. In the anteromedial and anterolateral areas, unlike in all other areas so far investigated, the cortical representations of the central visual field contain higher densities of corticopontine cells than the representations of the lower visual periphery. However, since the central area is only very weakly over-represented compared to the lower visual periphery in terms of cortical volume in these areas, the over-representation in the corticopontine projection of central vision compared to the lower visual periphery is fairly moderate.(ABSTRACT TRUNCATED AT 400 WORDS)     

Factors influencing maltreated children's early adjustment in foster care

Internal representations of self and primary attachment figures may be one mechanism by which maltreatment affects children's interpersonal behavior and relationships with others. Research on the continuity and influence of maltreated children's attachment representations, however, has not included youngsters removed from abusive or neglectful home environments. This paper examines the influence of maltreated children's maternal and self-representations on subsequent relationships with foster mothers and behavioral adjustment in foster care. Participants included 32 children, ages 9-13 years, who entered foster placement for the first time after a sustained relationship with a maltreating biological mother. Upon initially entering foster care, children's maternal and self-representations were significantly related to each other and to severity of maltreatment history but not to other factors believed to influence the quality of parent-child relationship (e.g., maternal mental health, partner stability). In addition, these representations significantly predicted children's subsequent views of their relationships with foster mothers. Finally, children's behavior in their foster homes was associated with maltreatment severity, internal representations assessed at entry into foster care, and to concurrent perceptions of their new foster mothers. These findings advance our understanding of foster placement's role in maltreated children's development and provide preliminary insight into the processes associated with the formation of potentially compensatory relationships.     

The orbitofrontal cortex and beyond: from affect to decision-making

The orbitofrontal cortex represents the reward or affective value of primary reinforcers including taste, touch, texture, and face expression. It learns to associate other stimuli with these to produce representations of the expected reward value for visual, auditory, and abstract stimuli including monetary reward value. The orbitofrontal cortex thus plays a key role in emotion, by representing the goals for action. The learning process is stimulus-reinforcer association learning. Negative reward prediction error neurons are related to this affective learning. Activations in the orbitofrontal cortex correlate with the subjective emotional experience of affective stimuli, and damage to the orbitofrontal cortex impairs emotion-related learning, emotional behaviour, and subjective affective state. With an origin from beyond the orbitofrontal cortex, top-down attention to affect modulates orbitofrontal cortex representations, and attention to intensity modulates representations in earlier cortical areas of the physical properties of stimuli. Top-down word-level cognitive inputs can bias affective representations in the orbitofrontal cortex, providing a mechanism for cognition to influence emotion. Whereas the orbitofrontal cortex provides a representation of reward or affective value on a continuous scale, areas beyond the orbitofrontal cortex such as the medial prefrontal cortex area 10 are involved in binary decision-making when a choice must be made. For this decision-making, the orbitofrontal cortex provides a representation of each specific reward in a common currency.     

Encoding,storage, and response preparation—Distinct EEG correlates of stimulus and action representations in working memory

Working memory (WM) allows for the active storage of stimulus- and higher level representations, such as action plans. This electroencephalography (EEG) study investigated the specific electrophysiological correlates dissociating action-related from stimulus-related representations in WM using three different experimental conditions based on the same stimulus material. In the experiment, a random sequence of single numbers (from 1 to 6) was presented and participants had to indicate whether the current number (N0 condition), the preceding number (N-1 condition), or the sum of the current and the preceding number (S-1 condition) was odd or even. Accordingly, participants had to store a stimulus representation in S-1 and an action representation in N-1 until the onset of the next stimulus. In the EEG, the storage of stimulus representations (S-1) was reflected by a fronto-central slow wave indicating the rehearsal of information that was required for the response in the following trial. In contrast, the storage of action representations (N-1) went along with a posterior positive slow wave, suggesting that the action plan was actively stored in WM until the presentation of the next stimulus. Crucially, preparing for the next response in N-1 was associated with increased contralateral mu/beta suppression, predicting the response time in the given trial. Our findings, thus, show that the WM processes for stimulus- and action representations can be clearly dissociated from each other with a distinct sequence of EEG correlates for encoding, storage, and response preparation.