Stress and brain functional changes in patients with Crohn's disease: A functional magnetic resonance imaging study.

BACKGROUND: In Crohn's disease (CD) patients, stress is believed to influence symptoms generation. Stress may act via central nervous system pathways to affect visceral sensitivity and motility thus exacerbating gastrointestinal symptoms. The neural substrate underpinning these mechanisms needs to be investigated in CD. We conducted an explorative functional magnetic resonance imaging (fMRI) study in order to investigate potential differences in the brain stress response in CD patients compared to controls. METHODS: 17 CD patients and 17 healthy controls underwent a fMRI scan while performing a stressful task consisting in a Stroop color-word interference task designed to induce mental stress in the fMRI environment. KEY RESULTS: Compared to controls, in CD patients the stress task elicited greater blood oxygen level dependent (BOLD) signals in the midcingulate cortex (MCC). CONCLUSIONS & INFERENCES: The MCC integrate "high" emotional processes with afferent sensory information ascending from the gut. In light of these integrative functions, the stress-evoked MCC hyperactivity in CD patients might represent a plausible neural substrate for the association between stress and symptomatic disease. The MCC dysfunction might be involved in mechanisms of central disinhibition of nociceptive inputs leading to amplify the visceral sensitivity. Finally, the stress-evoked MCC hyperactivity might affect the regulation of intestinal motility resulting in exacerbation of disease symptoms and the autonomic and neuroendocrine regulation of inflammation resulting in enhanced inflammatory activity.

New insights into the brain involvement in patients with Crohn's disease: a voxel-based morphometry study.

BACKGROUND: Crohn's disease (CD) is a chronic intestinal disorder characterized by overproduction of inflammatory cytokines and recurrent abdominal pain. Recently, brain morphological abnormalities in the pain matrix were found in patients with chronic pain disorders including irritable bowel syndrome. To investigate potential structural brain changes associated with CD, we used magnetic resonance imaging (MRI). Furthermore, we tested whether in patients gray matter (GM) volumes correlated with disease duration. METHODS: Eighteen CD patients in remission and 18 healthy controls underwent structural MRI. Voxel-based morphometry (VBM) is a fully automated technique allowing identification of regional differences in the amount of GM enabling an objective analysis of the whole brain between groups of subjects. VBM was used for comparisons and correlation analysis. KEY RESULTS: With respect to controls, CD patients exhibited decreased GM volumes in portion of the frontal cortex and in the anterior midcingulate cortex. Disease duration was negatively correlated with GM volumes of several brain regions including neocortical and limbic areas. CONCLUSIONS & INFERENCES: Crohn's disease is associated with brain morphological changes in cortical and subcortical structures involved in nociception, emotional, and cognitive processes. Our findings provide new insight into the brain involvement in chronic inflammatory bowel disorders.

Impaired facial emotion recognition in early-onset right mesial temporal lobe epilepsy.

BACKGROUND: Anteromedial temporal lobe regions, particularly the amygdala, participate in the recognition of emotions from facial expressions. The authors studied the ability of facial emotion recognition (ER) in subjects with symptomatic epilepsy, evaluating whether mesial temporal lobe damage is related to an impairment in the recognition of specific emotions and whether the onset of seizures in a critical period of life could prevent the development of ER. METHODS: Groups included patients with temporal lobe epilepsy (TLE) with MRI evidence of mesial temporal sclerosis (MTS) (n = 33); patients with TLE with MRI evidence of temporal lobe lesions other than MTS (n = 30); and patients with extratemporal epilepsy (n = 33). Healthy volunteers (n = 50) served as controls. ER was tested by matching a facial expression with the name of one of the following basic emotions: happiness, sadness, fear, disgust, and anger. A face-matching task was used to control visuoperceptual abilities with face stimuli. RESULTS: No subject showed deficits in the face-matching task. ER was impaired in patients with right MTS, especially for fearful faces. Patients presenting left MTS, right or left temporal lobe lesions other than MTS, or extratemporal seizure foci showed ER performances similar to controls. In all subjects with right TLE, the degree of emotion recognition impairment was related to age at first seizure (febrile or afebrile) and age at epilepsy onset. CONCLUSIONS: Early-onset right-sided mesial temporal lobe epilepsy is the key substrate determining a severe deficit in recognizing emotional facial expressions, especially fear.

Grasp with hand and mouth: a kinematic study on healthy subjects.

Neurons involved in grasp preparation with hand and mouth were previously recorded in the premotor cortex of monkey. The aim of the present kinematic study was to determine whether a unique planning underlies the act of grasping with hand and mouth in humans as well. In a set of four experiments, healthy subjects reached and grasped with the hand an object of different size while opening the mouth (experiments 1 and 3), or extending the other forearm (experiment 4), or the fingers of the other hand (experiment 5). In a subsequent set of three experiments, subjects grasped an object of different size with the mouth, while opening the fingers of the right hand (experiments 6-8). The initial kinematics of mouth and finger opening, but not of forearm extension, was affected by the size of the grasped object congruently with the size effect on initial grasp kinematics. This effect was due neither to visual presentation of the object, without the successive grasp motor act (experiment 2) nor to synchronism between finger and mouth opening (experiments 3, 7, and 8). In experiment 9 subjects grasped with the right hand an object of different size while pronouncing a syllable printed on the target. Mouth opening and sound production were affected by the grasped object size. The results of the present study are discussed according to the notion that in an action each motor act is prepared before the beginning of the motor sequence. Double grasp preparation can be used for successive motor acts on the same object as, for example, grasping food with the hand and ingesting it after bringing it to the mouth. We speculate that the circuits involved in double grasp preparation might have been the neural substrate where hand motor patterns used as primitive communication signs were transferred to mouth articulation system. This is in accordance with the hypothesis that Broca's area derives phylogenetically from the monkey premotor area where hand movements are controlled.

Influence of stimulus color on the control of reaching-grasping movements.

This kinematic study aimed to determine whether color is a stimulus property involved in the control of reaching-grasping movements. Subjects reached and grasped a target-object, located either on the right or on the left of the subject's midline. A distractor, placed along the subject's midline, could be randomly presented. The colors, i.e., both chromaticity (red and green stimuli were presented) and lightness, of the target and distractor were varied in experiment 1. Only stimulus lightness and only stimulus chromaticity were varied in experiments 2 and 3, respectively. In experiment 4 subjects matched with their thumb and index finger the size of the target-stimuli presented in experiment 1. Chromaticity (experiments 1 and 3) of the target and distractor influenced grasp, but not reach. Maximal finger aperture was larger during grasping the red than the green target. Data collected in the matching task (experiment 4) confirmed a trend to overestimate the red target and to underestimate the green one. During grasp, hand shaping was influenced by distractor chromaticity when it was different from target chromaticity. Distractor lightness affected reach, but not grasp (experiments 1 and 2). Reach was slower when the distractor was lighter and arm trajectory veered away from it. The results of the present study suggest that color, that is the ensemble of chromaticity and lightness, is a stimulus property involved in the control of reaching-grasping. The different effects of target color on reach and grasp support the notion that intrinsic object properties, such as color, affect grasp more than reach. In addition, the different effects of distractor chromaticity and lightness on reach and grasp confirm that target-objects are visually extracted from surrounding cues by means of different processes, according to the required motor response.

Visual illusions and the control of children arm movements.

The aim of the present study was to determine whether children like adults (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni I. Visual illusion and action. Neuropsychologia 1996;34:369-76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position tunes the contribution of allocentric and egocentric information to target localisation in human goal directed arm movements. Neurosci Lett 1997;222:123-6) are influenced by visual illusions when they transform visual information in motor command. Children and adults pointed to a shaft extremity of the Müller-Lyer configurations, as well as to an extremity of a control configuration. Movements were executed in two experimental conditions. In the vision condition subjects saw both the stimulus and their hand before and during movement. In the no vision (memory) condition subjects saw the stimulus and their hand before, but not during movement. Movement started 5 s after vision was precluded. The Müller-Lyer illusion affected pointing kinematics of both children and adults. As found previously (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni I. Visual illusion and action. Neuropsychologia 1996;34:369-76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position tunes the contribution of allocentric and egocentric information to target localisation in human goal directed arm movements. Neurosci Lett 1997;222:123-6), subjects undershot and overshot the shaft extremity of the closed and of the open configuration, respectively. The illusion effect was greater in the no vision than in the vision condition. These results show that in children like in adults the system underlying visual perception in an object-centered frame of reference and that involved in motor control functionally interact with each other. Although the processes of target localisation were the same, the transformation of target position information in a sequence of motor patterns was different in children from that in adults. Even if both children and adults lengthened duration of the deceleration phase in the vision condition, only adults shortened duration of the acceleration phase in order to maintain constant movement time (Viviani P, Schneider R. A developmental study of the relationship between geometry and kinematics in drawing movements. J Exp Psychol 1991;17:198-218). This result suggests that children are yet unable to co-ordinate temporally acceleration with deceleration phase.

Language and motor control.

We investigated the possible influence of automatic word reading on processes of visuo-motor transformation. Subjects reached and grasped an object on which the following Italian words were printed: "VICINO" (near) or "LONTAN" (far) on an object either near or far from the agent (experiments 1, 2); PICCOLO (small) or "GRANDE" (large) on either a small or a large object (experiment 4); and "ALTO" (high) or "BASSO" (low) on either a high or a low object (experiment 5). The kinematics of the initial phase of reaching-grasping was affected by the meaning of the printed words. Namely, subjects automatically associated the meaning of the word with the corresponding property of the object and activated a reach and/or a grasp motor program influenced by the word. No effect on initial reach kinematics was observed for words related to object properties not directly involved in reach control (experiment 3). Moreover, in all the experiments, the presented words poorly influenced perceptual judgement of object properties. In experiments 5-7, the effects of the Italian adjectives "ALTO" (high) and "BASSO" (low) on reaching-grasping control were compared with those of the Italian adverbs "SOPRA" (up) and "SOTTO" (down). Adjectives influenced visual analysis of target-object properties, whereas adverbs more directly influenced the control of the action. We suggest that these effects resemble the structure of a sentence, where adjectives are commonly referred to nouns, and adverbs to verbs. In other words, class of words and, in a broad sense, grammar influenced motor control. The results of the present study show that cognitive functions such as language can affect visuo-motor transformation. They are discussed according to the notion that a strict relation between language and motor control exists, and that the frontal cortex can be involved in interactions between automatic word reading and visuo-motor transformation.

Impaired control of an action after supplementary motor area lesion: a case study.

The kinematics of the action formed by reaching-grasping an object and placing it on a second target was studied in a patient who suffered from an acute vascular left brain lesion, which affected the Supplementary Motor Area proper (SMA-proper) (Matelli M, Luppino G. Thalamic input to mesial and superior area 6 in the macaque monkey. Journal of Comparative Neurology 1996;372:59-87, Matelli M, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the macaque monkey. Journal of Comparative Neurology 1989;280:468-488), and in five healthy control subjects. The reach kinematics of the controls was affected by the positions of both the reaching-grasping and the placing targets (Gentilucci M, Negrotti A, Gangitano M. Planning an action. Experimental Brain Research 1997;115:116-28). In contrast, the reach kinematics of the patient was affected only by the position of the reaching-grasping target. By comparing these results with those previously found in Parkinson's disease patients executing the same action (Gentilucci M, Negrotti A. Planning and executing an action in Parkinson's disease patients. Movement Disorders 1999;1:69-79, Gentilucci M, Negrotti A. The control of an action in Parkinson's disease. Experimental Brain Research 1999;129:269-277), we suggest that the anatomical "motor" circuit formed by SMA-proper (see above), Basal Ganglia (BG) and Thalamus (Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends in the Neurosciences 1990;13:266-271, Hoover JE, Strick PL. Multiple output channels in the basal ganglia. Nature 1993;259:819-821) may be involved in the control of actions: SMA-proper assembles the sequence of the action, whereas BG updates its parameters and stores them.

Recognising a hand by grasp.

The present study aimed to demonstrate that motor representations are used to recognise biological stimuli. In three experiments subjects were required to judge laterality of hands and forearms presented by pictures. The postures of the hands were those assumed when holding a small, medium and large sphere. In experiment 1, the sphere held in hand was presented, whereas in experiment 2 it was absent. In experiment 3, the same images, showing holding-a-sphere hands, as in experiment 1 were presented, but without forearm. In all experiments one finger of each hand could be absent. In experiment 1 recognition time was longer for those hand postures for which the corresponding grasping motor acts required more accuracy. This was confirmed by a control experiment (experiment 4), in which subjects actually grasped the spheres. Absence of fingers did not influence right-left hand recognition. However, the absence of target object in experiment 2, and of forearm in experiment 3 reduced the effects of the type of holding on hand laterality recognition. The results of the present study indicate that grasp representations are used to recognise hand laterality. In particular, the visual description of how hand and object interact in space (the opposition space [M.A. Arbib, Programs, schemas and neural networks for control of hand movement: beyond the RS frameworks, in: M. Jeannerod (Ed.), Attention and Performance XIII: Motor Representation and Control, Lawrence Erlbaum, Hillsdale, NJ, 1990, 111-138; M.A. Arbib, T. Iberall, D. Lyons, Coordinated control programs for movements of the hand, in: A.W. Goodman, I. Darian-Smith (Eds.), Hand function and the neocortex, Springer, Berlin, 1985, pp. 135-170]) and the anchoring of the hand to the agent are the features of the grasp representations used in hand-recognition processes. The data are discussed according to the more general notion that motor representations are automatically extracted in the process of intuiting situations, or people's intentions. These motor representations, which are compared with those of other people, contain concrete information on the actions (the motor program) by which a situation is created and on the aim of the agents executing those actions.