The advantage of brief fMRI acquisition runs for multi-voxel pattern detection across runs
Coutanche, M.N., & Thompson-Schill, S. L. (In press) - NeuroImage
Functional magnetic resonance imaging (fMRI) studies are broken up into runs (or ‘sessions’), frequently selected to... more Functional magnetic resonance imaging (fMRI) studies are broken up into runs (or ‘sessions’), frequently selected to be long to minimize across-run signal variations. For investigations that use multi-voxel pattern analysis (MVPA), however, employing many short runs might improve a classifier’s ability to generalize across irrelevant pattern variations and detect condition-related activity patterns. We directly tested this hypothesis by scanning participants with both long and short runs and comparing MVPA performance using data from each set of runs. Every run included presentations of faces, places, man-made objects and fruit in a blocked 1-back design. MVPA performance significantly improved from using a large number of short runs, compared to several long runs, in across-run classifications with identical amounts of data. Superior classification was found across variations in the classifier employed, feature selection procedure and region of interest. Performance improvements also extended to an information brain mapping ‘searchlight’ procedure. These results suggest that investigators looking to maximize the detection of subtle multi-voxel patterns across runs might consider employing short fMRI runs.
Download (.pdf) Cortical thickness and oscillatory phase resetting: A proposed mechanism of salience network dysfunction in schizophrenia
Lena Palaniyappan MRCPsych, Kathrin Doege PhD, Pavan Mallikarjun MRCPsych, Elizabeth Liddle PhD, Peter Francis Liddle PhD MRCPsych.
Psychiatriki, 2012 (in press)
Abstract:
Background: Schizophrenia is characterised by both electrophysiological abnormalities and consistent... more
Abstract:
Background: Schizophrenia is characterised by both electrophysiological abnormalities and consistent changes in the structure of cortical grey matter. But the relationship between these two observations is largely unknown. Structural changes reported in schizophrenia include reduced grey matter volume, thickness and surface area in several cortical regions, but most frequently in the insula and anterior cingulate cortex. These two regions together constitute an intrinsic brain circuit known as the ‘Salience Network’, which has a key role in stimulus processing. During stimulus processing tasks, evoked activity is noted using electroencephalography (EEG). Phase resetting of ongoing oscillations contributes to this evoked activity.
Methods: In this study, we investigated the relationship between the cortical thickness in the Salience Network (measured using MRI) and the degree of phase resetting observed during an oddball task (measured using EEG) in 18 patients with schizophrenia and 20 healthy controls.
Results: In patients with schizophrenia the reduced thickness in the Salience Network was associated with the inefficient phase resetting of theta oscillations.
Conclusions: Our findings suggest that the grey matter reduction seen in the Salience Network in patients with schizophrenia has substantial functional consequences. In particular, the structural defect of the insula that is seen in schizophrenia is likely to be associated with less efficient recruitment of brain circuits for processing information. This implies a possible mechanism by which disruptions in the intrinsic Salience Network can result in a general disturbance in salience detection seen in schizophrenia.
Action anticipation beyond the action observation network: a functional magnetic resonance imaging study in expert basketball players
Published in ‘European Journal of Neuroscience’ (featured in the cover)
The ability to predict the actions of others is quintessential for effective social interactions, particularly in... more
The ability to predict the actions of others is quintessential for effective social interactions, particularly in competitive contexts (e.g. in sport) when knowledge about upcoming movements allows anticipating rather than reacting to opponents. Studies suggest that we predict what others are doing by using our own motor system as an internal forward model and that the fronto-parietal action observation network (AON) is fundamental for this ability. However, multiple-duty cells dealing with action perception and execution have been found in a variety of cortical regions. Here we used functional magnetic resonance imaging to explore, in expert basketball athletes and novices, whether the ability to make early predictions about the fate of sport-specific actions (i.e. free throws) is underpinned by neural regions beyond the classical AON. We found that, although involved in action prediction, the fronto-parietal AON was similarly activated in novices and experts. Importantly, athletes exhibited relatively greater activity in the extrastriate body
area during the prediction task, probably due to their expert reading of the observed action kinematics. Moreover, experts exhibited higher activation in the bilateral inferior frontal gyrus and in the right anterior insular cortex when producing errors, suggesting that they might become aware of their own errors. Correct action prediction induced higher posterior insular cortex activity in experts and higher orbito-frontal activity in novices, suggesting that body awareness is important for performance monitoring in experts, whereas novices rely more on higher-order decision-making strategies. This functional reorganization highlights the tight relationship between action anticipation, error awareness and motor expertise leading to body-related processing and differences in decision-making processes.
Adolescent impulsivity phenotypes characterized by distinct brain networks
Nature Neuroscience. doi:10.1038/nn.3092
Robert Whelan, Patricia J Conrod, Jean-Baptiste Poline, Anbarasu Lourdusamy, Tobias Banaschewski, Gareth J Barker, Mark A Bellgrove, Christian Büchel, Mark Byrne, Tarrant D R Cummins, Mira Fauth-Bühler, Herta Flor, Jürgen Gallinat, Andreas Heinz, Bernd Ittermann, Karl Mann, Jean-Luc Martinot, Edmund C Lalor, Mark Lathrop, Eva Loth, Frauke Nees, Tomas Paus, Marcella Rietschel, Michael N Smolka, Rainer Spanagel, David N Stephens, Maren Struve, Benjamin Thyreau, Sabine Vollstaedt-Klein, Trevor W Robbins, Gunter Schumann, Hugh Garavan & the IMAGEN Consortium
The impulsive behavior that is often characteristic of adolescence may reflect underlying neurodevelopmental... more The impulsive behavior that is often characteristic of adolescence may reflect underlying neurodevelopmental processes. Moreover, impulsivity is a multi-dimensional construct, and it is plausible that distinct brain networks contribute to its different cognitive, clinical and behavioral aspects. As these networks have not yet been described, we identified distinct cortical and subcortical networks underlying successful inhibitions and inhibition failures in a large sample (n = 1,896) of 14-year-old adolescents. Different networks were associated with drug use (n = 1,593) and attention-deficit hyperactivity disorder symptoms (n = 342). Hypofunctioning of a specific orbitofrontal cortical network was associated with likelihood of initiating drug use in early adolescence. Right inferior frontal activity was related to the speed of the inhibition process (n = 826) and use of illegal substances and associated with genetic variation in a norepinephrine transporter gene (n = 819). Our results indicate that both neural endophenotypes and genetic variation give rise to the various manifestations of impulsive behavior.
Brain vs Behavior: An Effect Size Comparison of Neuroimaging and Cognitive Studies of Genetic Risk for Schizophrenia
Emma Jane Rose and Gary Donohoe. Schizophrenia Bulletin (in press)
Genetic variants associated with increased risk for schizophrenia (SZ) are hypothesized to be more penetrant at the... more Genetic variants associated with increased risk for schizophrenia (SZ) are hypothesized to be more penetrant at the level of brain structure and function than at the level of behavior. However, to date the relative sensitivity of imaging vs cognitive measures of these variants has not been quantified. We considered effect sizes associated with cognitive and imaging studies of 9 robust SZ risk genes (DAOA, DISC1, DTNBP1, NRG1, RGS4, NRGN, CACNA1C, TCF4, and ZNF804A) published between January 2005–November 2011. Summary data was used to calculate estimates of effect size for each significant finding. The mean effect size for each study was categorized as small, medium, or large and the relative frequency of each category was compared between modalities and across genes. Random effects meta-analysis was used to consider the impact of experimental methodology on effect size. Imaging studies reported mostly medium or large effects, whereas cognitive investigations commonly reported small effects. Meta-analysis confirmed that imaging studies were associated with larger effects. Effect size estimates were negatively correlated with sample size but did not differ as a function of gene nor imaging modality. These observations support the notion that SZ risk variants show larger effects, and hence greater penetrance, when characterized using indices of brain structure and function than when indexed by cognitive measures. However, it remains to be established whether this holds true for individual risk variants, imaging modalities, or cognitive functions, and how such effects may be mediated by a relationship with sample size and other aspects of experimental variability.
Identifying abnormal connectivity in patients using dynamic causal modeling of FMRI responses
Functional imaging studies of brain damaged patients offer a unique opportunity to understand how sensorimotor and... more Functional imaging studies of brain damaged patients offer a unique opportunity to understand how sensorimotor and cognitive tasks can be carried out when parts of the neural system that support normal performance are no longer available. In addition to knowing which regions a patient activates, we also need to know how these regions interact with one another, and how these inter-regional interactions deviate from normal. Dynamic causal modeling (DCM) offers the opportunity to assess task-dependent interactions within a set of regions. Here we review its use in patients when the question of interest concerns the characterization of abnormal connectivity for a given pathology. We describe the currently available implementations of DCM for fMRI responses, varying from the deterministic bilinear models with one-state equation to the stochastic non-linear models with two-state equations. We also highlight the importance of the new Bayesian model selection and averaging tools that allow different plausible models to be compared at the single subject and group level. These procedures allow inferences to be made at different levels of model selection, from features (model families) to connectivity parameters. Following a critical review of previous DCM studies that investigated abnormal connectivity we propose a systematic procedure that will ensure more flexibility and efficiency when using DCM in patients. Finally, some practical and methodological issues crucial for interpreting or generalizing DCM findings in patients are discussed.
Resolving response, decision, and strategic control: Evidence for a functional topography in dorsomedial prefrontal cortext
Venkatraman, V., Rosati, A.G., Taren, A.A., & Huettel, S.A. (2009). Journal of Neuroscience
The dorsomedial prefrontal cortex (DMPFC) plays a central role in aspects of cognitive control and decision making.... more The dorsomedial prefrontal cortex (DMPFC) plays a central role in aspects of cognitive control and decision making. Here, we provide evidence for an anterior-to-posterior topography within the DMPFC using tasks that evoke three distinct forms of control demands— response, decision, and strategic— each of which could be mapped onto independent behavioral data. Specifically, we identify three spatially distinct regions within the DMPFC: a posterior region associated with control demands evoked by multiple incompatible responses, a middle region associated with control demands evoked by the relative desirability of decision options, and an anterior region that predicts control demands related to deviations from an individual’s preferred decision-making strategy. These results provide new insight into the functional organization of DMPFC and suggest how recent controversies about its role in complex decision making and response mapping can be reconciled.
Multimodal analyses identify linked functional and white matter abnormalities within the working memory network in schizophrenia
Sugranyes G, Kyriakopoulos M, Dima D, O'Muircheartaigh J, Corrigall R, Pendelbury G, Hayes D, Calhoun VD, Frangou S
Schizophr
BACKGROUND: Dysconnectivity between brain regions is thought to underlie the cognitive abnormalities that characterise... more
BACKGROUND: Dysconnectivity between brain regions is thought to underlie the cognitive abnormalities that characterise schizophrenia (SZ). Consistent with this notion functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) studies in SZ have reliably provided evidence of abnormalities in functional integration and in white matter connectivity. Yet little is known about how alterations at the functional level related to abnormalities in anatomical connectivity.
METHODS: We obtained fMRI data during the 2-back working memory task from 25 patients with SZ and 19 healthy controls matched for age, sex and IQ. DTI data were also acquired in the same session. In addition to conventional unimodal analyses we extracted "features" [contrast maps for fMRI and fractional anisotropy (FA) for DTI] that were subjected to joint independent component analysis (JICA) in order to examine interactions between fMRI and DTI data sources.
RESULTS: Conventional unimodal analyses revealed both functional and structural deficits in patients with SZ. The JICA identified regions of joint, multimodal brain sources that differed in patients and controls. The fMRI source implicated regions within the anterior cingulate and ventrolateral prefrontal cortex and in the cuneus where patients showed relative hypoactivation and within the frontopolar cortex where patients showed relative hyperactivation. The DTI source localised reduced FA in patients in the splenium and posterior cingulum.
CONCLUSIONS: This study promotes our understanding of structure-function relationships in SZ by characterising linked functional and white matter changes that contribute to working memory dysfunction in this disorder.
Evolving Signal Processing for Brain-Computer Interface
by Zhilin Zhang
Scott Makeig, Christian Kothe, Tim Mullen, Nima Bigdely-Shamlo, Zhilin Zhang, Kenneth Kreutz-Delgado, to appear in Proceedings of the IEEE, May, 2012
Because of the increasing portability and wearability of noninvasive electrophysiological systems that record and... more Because of the increasing portability and wearability of noninvasive electrophysiological systems that record and process electrical signals from the human brain, automated systems for assessing changes in user cognitive state, intent, and response to events are of increasing interest. Brain-computer interface (BCI) systems can make use of such knowledge to deliver relevant feedback to the user or to an observer, or within a human–machine system to increase safety and enhance overall performance. Building robust and useful BCI models from accumulated biological knowledge and available data is a major challenge, as are technical problems associated with incorporating multimodal physiological, behavioral, and contextual data that may in the future be increasingly ubiquitous. While performance of current BCI modeling methods is slowly increasing, current performance levels do not yet support widespread uses. Here we discuss the current neuroscientific questions and data processing challenges facing BCI designers and outline some promising current and future directions to address them.
BRAIN SURFACE ANATOMY IN ADULTS WITH AUTISM: THE RELATIONSHIP BETWEEN SURFACE AREA, CORTICAL THICKNESS AND AUTISTIC SYMPTOMS
C Ecker*, C Ginestet, Y Feng, P Johnston, MV Lombardo, MC Lai, J Suckling , L Palaniyappan, E Daly, CM Murphy, SC Williams, ET Bullmorec, S Baron- Cohen, M Brammer, the MRC AIMS Consortium, and DGM Murphy
Archives of General Psychiatry (in press)
"Behavioural manifestations of third ventricular colloid cysts"
by Robert Winer
Journal of Neurology, Neurosurgery, and Psychiatry 1985;48:847
This case calls to attention behavioral manifestations associated with colloid cyst of the third ventricle without... more
This case calls to attention behavioral manifestations associated with colloid cyst of the third ventricle without hydrocephalus.
In general, it is the impression of my neurosurgical colleagues in the United States that in the absence of hydrocephalus, removal of a colloid cyst is not mandatory.
It is my hope that reports of cases such as this will raise the awareness of behavioral manifestations in colloid cysts of third ventricle without hydrocephalus.
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Functional neuroimaging in anorexia nervosa: A clinical approach.
Pietrini F, Castellini G, Ricca V, Polito C, Pupi A, Faravelli C. Functional
neuroimaging in anorexia nervosa: a clinical approach. Eur Psychiatry. 2011
Apr;26(3):176-82. Epub 2010 Oct 8. Review. PubMed PMID: 20934859.
AIMS: To provide a review of the available literature about the functional
neuroimaging of anorexia nervosa, and... more
AIMS: To provide a review of the available literature about the functional
neuroimaging of anorexia nervosa, and to summarize the possible role of
neurobiological factors in its pathogenesis.
METHODS: A systematic review of the literature was performed using PubMed and
Medline electronic database (1950-September 2009). Eligible studies were
restricted to those involving the main parameters of cerebral activity and
functional neuroimaging techniques. Findings of the reviewed studies have been
grouped on a diagnostic subtype basis, and their comparison has been interpreted
in terms of concordance.
RESULTS: We found a high level of concordance among available studies with regard
to the presence of frontal, parietal and cingulate functional disturbances in
both anorexia nervosa restricting and binge/purging subtypes. Concordance among
studies conducted regardless of the anorexia nervosa subtypes suggests an
alteration in temporal and parietal functions and striatal metabolism.
CONCLUSIONS: The most consistent alterations in anorexia nervosa cerebral
activity seem to involve the dorsolateral prefrontal cortex, the inferior
parietal lobule, the anterior cingulate cortex and the caudate nucleus. They may
affect different neural systems such as the frontal visual system, the attention
network, the arousal and emotional processing systems, the reward processing
network, and the network for the body schema.
Copyright © 2010 Elsevier Masson SAS. All rights reserved.
PMID: 20934859 [PubMed - indexed for MEDLINE]
Neuroimaging and neurobiology of social anxiety.
Pietrini F, Godini L, Lazzeretti L, Benni L, Pracucci C, Talamba GA, Faravelli
C. [Neuroimaging and neurobiology of social anxiety]. Riv Psichiatr. 2010
Nov-Dec;45(6):349-60. Review. Italian. PubMed PMID: 21328822.
AIM: Social Anxiety Disorder (SAD) represents one of the most frequent
psychiatric disorders. The results of a... more
AIM: Social Anxiety Disorder (SAD) represents one of the most frequent
psychiatric disorders. The results of a systematic review of the literature
published until January 2010 on the neurobiology of SAD are reported, giving
prominence to functional neuroimaging (fNI) findings.
METHODS: A literature search of neuroimaging and neurobiology studies of SAD was
conducted on PubMed and Medline electronic archives and by canvassing
English-language and other European languages publications. Eligible studies were
restricted to those on adult population (age 16 to 65) and using DSM and ICD
criteria.
RESULTS: The 19 reviewed fNI studies on SAD agree in identifying a dysfunction of
five main cerebral areas: the amygdala, the medial prefrontal cortex, the insula,
the hippocampus and the dorsolateral prefrontal cortex. Those findings strongly
suggest the presence, in this disorder, of functional alterations in the neural
systems involved in the genesis of fear, in the processing of emotional stimuli,
in the "self" perception and in the evaluation of others' intentions.
DISCUSSION: Neurobiology research on SAD is still relatively young and, up to
today, available findings are still not exhaustive. Nonetheless, a growing
evidence from different lines of research seems to suggest that SAD patients may
present a distinct biologic background compared to control subjects. Until now,
however, no specific neurobiological aspect has been proposed for the SAD only.
Per contra, results from fNI studies seem to indicate the presence of a common
pattern of neural dysfunction in all the major anxiety disorders.
PMID: 21328822 [PubMed - indexed for MEDLINE]
Toward a second-person neuroscience
Schilbach L and* Timmermans B, Reddy V, Costall A, Bente G, Schlicht T, & Vogeley K. Toward a second-person neuroscience. Behavioral and Brain Sciences, target article accepted for publication. *equal contributions
In spite of the remarkable progress made in the burgeoning field of social neuroscience, the neural mechanisms that... more In spite of the remarkable progress made in the burgeoning field of social neuroscience, the neural mechanisms that underlie social encounters are only beginning to be studied and could —paradoxically— be seen as representing the ‘dark matter’ of social neuroscience. Recent conceptual and empirical developments consistently indicate the need for investigations, which allow the study of real-time social encounters in a truly interactive manner. This suggestion is based on the premise that social cognition is fundamentally different when we are in interaction with others rather than merely observing them. In this article, we outline the theoretical conception of a second-person approach to other minds and review evidence from neuroimaging, psychophysiological studies and related fields to argue for the development of a second-person neuroscience, which will help neuroscience to really go social; this may also be relevant for our understanding of psychiatric disorders construed as disorders of social cognition.
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Dissociable Morphometric Differences of the Inferior Parietal Lobule in Schizophrenia
Lena Palaniyappan and Peter F. Liddle
European Archives of Psychiatry & Clinical Neurosciences
Abstract
Objectives: Inferior Parietal Lobule (IPL) forms an integral part of a critical frontoparietal... more
Abstract
Objectives: Inferior Parietal Lobule (IPL) forms an integral part of a critical frontoparietal network, which has been implicated in various clinical symptoms and cognitive deficits seen in schizophrenia. Despite its functional relevance, the relatively few studies that have investigated the structural changes in the IPL report inconsistent findings concerning the nature and localization of these changes.
Methods: We employed a blinded, automated labeling procedure to measure cortical thickness, surface area and the degree of cortical folding of the two distinct subregions of the IPL (Angular Gyrus and Supramarginal Gyrus) in 57 patients with schizophrenia and 41 controls using high resolution magnetic resonance imaging.
Results: Within the IPL, we observed more pronounced morphological changes in supramarginal gyrus compared to angular gyrus in schizophrenia. While supramarginal gyrus in patients showed reduced gyrification, contracted surface area and thinning, the morphometric changes in angular gyrus were largely confined to a reduction in surface area. Significant hemispheric asymmetry was observed in the gyrification of the supramarginal gyrus.
Conclusions: Our findings suggest that in addition to abnormalities in the neurodevelopmental processes that contribute to regional surface area and cortical thickness, a specific defect in cortical folding, especially affecting the left hemisphere is likely to occur in schizophrenia.
Neurobiological narratives: Experiences of mood disorder through the lens of neuroimaging
Co-authored with Emily Borgelt, Louise Whiteley, and Judy Illes. Sociology of Health and Illness, in press.
Many scientists, healthcare providers, policymakers and patients are awaiting in anticipation the application of... more Many scientists, healthcare providers, policymakers and patients are awaiting in anticipation the application of biomedical technologies such as functional neuroimaging for the prediction, diagnosis and treatment of mental disorders. The potential efficacy of such applications is controversial, and functional neuroimaging is not yet routinely used in psychiatric clinics. However, commercial ventures and enthusiastic reporting indicate a pressing need to engage with the social and ethical issues raised by clinical translation. There has been little investigation of how individuals living with mental illness view functional neuroimaging, or of the potential psychological impacts of its clinical use. We conducted 12 semi-structured interviews with adults diagnosed with major depression or bipolar disorder, probing their experiences with mental health care and their perspectives on the prospect of receiving neuroimaging for prediction, diagnosis and planning treatment. The participants discussed the potential role of neuroimages in (i) mitigating stigma; (ii) supporting morally loaded explanations of mental illness due to an imbalance of brain chemistry; (iii) legitimising psychiatric symptoms, which may have previously been de-legitimised since they lacked objective representation, through objective representations of disorder; and (iv) reifying DSM-IV-TR disorder categories and links to identity. We discuss these anticipated outcomes in the context of participant lived experience and attitudes to biologisation of mental illness, and argue for bringing these voices into upstream ethics discussion.
Interpreting deactivations in neuroimaging
by dave hayes
Hayes DJ and Huxtable AG (2012) Interpreting deactivations in neuroimaging. Front. Psychology 3:27.
Asymmetric cortical surface area and morphology changes in mesial temporal lobe epilepsy with hippocampal sclerosis
Saud Alhusaini1, 2, Colin P Doherty3, Lena Palaniyappan4, Cathy Scanlon2, 5, Sinead Maguire6, Paul Brennan6, Norman Delanty1, 7, Mary Fitzsimons2, Gianpiero L Cavalleri1
Epilepsia, in press
1 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin.2, Ireland.
2 Brain Morphometry Laboratory, Neurophysics Department, Beaumont Hospital, Dublin.9, Ireland.
3 Neurology Department, St. James’s Hospital, Dublin.8, Ireland.
4 Division of Psychiatry, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom
5 Clinical Neuroimaging Laboratory, Department of Psychiatry, National University of Ireland, Galway, Ireland.
6 Radiology Department, Beaumont Hospital, Dublin.9, Ireland.
7 Neurology Department, Beaumont Hospital, Dublin.9, Ireland
Aberrant Cortical Gyrification in Schizophrenia: A Surface Based Morphometry Study
Palaniyappan, L & Liddle PF
Journal of Psychiatry and Neuroscience. In press
Abstract
Background: Schizophrenia is considered to be a disorder of cerebral connectivity associated with... more
Abstract
Background: Schizophrenia is considered to be a disorder of cerebral connectivity associated with disturbances of cortical development. Disturbances in cortical connectivity at an early period of cortical maturation can result in widespread defects in cortical gyrification. Investigating the anatomical distribution of gyrification defects can provide important information about neurodevelopment in schizophrenia.
Methods: We undertook an automated surface based morphometric assessment of gyrification on 3-dimensionally reconstructed cortical surfaces across multiple vertices that cover the entire cortex. We studied 57 patients (50 males) with schizophrenia and 41 healthy controls in whom we have previously tested a specific hypothesis regarding presence of both hypo- and hypergyria in prefrontal cortex using a frontal region-of-interest approach.
Results: Regions with significant reductions in gyrification (hypogyria) were seen predominantly in the left hemisphere, involving the insula and several regions of the multimodal association cortex. Although the prefrontal hypergyria documented earlier did not survive the statistical correction required for a whole brain search (cluster inclusion at p=0.0001), significant hypergyric frontal clusters emerged when the threshold was lowered (cluster inclusion at p=0.05). In insula, a reduction in gyrification was related to reduced cortical thickness in patients.
Limitations: We studied a sample of patients taking antipsychotics, which could have confounded the results. Our sample was predominantly male, limiting the generalisability.
Conclusions: Our observations suggest that the disturbances in cortical gyrification seen in schizophrenia might be related to a disrupted interaction between the paralimbic and the multimodal association cortex and thus contribute to the pathogenesis of the illness.
Visual aspects of reaching represented in primary motor cortex
K.P. Miyapuram (2012) Current Science 102(4):549-550
comment on Eisenberg, M., Shmuelof, L., Vaadia, E., and Zohary, E., The representation of visual and motor aspects of reaching movements in the human motor cortex. J. Neurosci., 2011, 31, 34:12377-84.
Visuomotor skills enrich our behavioural repertoire. In everyday life, visual information is used to guide motor... more Visuomotor skills enrich our behavioural repertoire. In everyday life, visual information is used to guide motor actions. For example, the mouse pointer on a computer screen guides the manipulation of the mouse by hand. The transformation of visual cues into motor actions in this case bears a systematic spatial relationship. The movements of the hand in the horizontal plane translate into vertical movement of the pointer on the screen. Hence the visual and motor aspects of a reaching movement are intricately related to each other. Separating the cognitive aspects pertaining to perception of visual input from the generation of motor output is critical for understanding the mechanisms underlying reaching movements. In a recent brain imaging study, Eisenberg et al.1 designed a clever task to isolate the visual and motor aspects of reaching movements. Their results show that the primary motor cortex represents both visual and motor aspects of reaching movements. However, visual aspects alone, when decoupled from their motor consequences, are not represented in the primary motor cortex.