Activation of the sensorimotor cortex with the use of a device for the mechanical stimulation of the plantar support zones

Studies of the control movements mechanisms have been performed in the interest of space medicine were the basis for the development of the concept about the leading role of the support afferent input in the regulation of postural-tonic system of mammals. Introduction of functional magnetic resonance imaging (fMRI) made it possible to investigate in-vivo brain mapping during stimulation of support afferent input. The aim of our study was to investigate brain activation due to mechanical support stimulation of the soles with the special device "Korvit". 12 healthy participants (6 women, 6 men; average age = 28.8 years) were scanned. fMRI protocol for each person consisted of 2 different blocked paradigms: soles stimulation in stance imitation (1) and slow walking imitation (2) modes. The results were analyzed with statistical program SPM5 for each person and then for the whole group. In all our paradigms there was significant (P(correct) < 0.05 for cluster level) activation of primary somatosensory, premotor and dorsolateral cortex, insula. During the stance imitation mode, extensive prefrontal cortex activation was observed; during the slow walking imitation mode there was activation of different primary and secondary sensorimotor cortex areas.     

Analysis for Distinctive Activation Patterns of Pain and Itchy in the Human Brain Cortex Measured Using Near Infrared Spectroscopy (NIRS)

Pain and itch are closely related sensations, yet qualitatively quite distinct. Despite recent advances in brain imaging techniques, identifying the differences between pain and itch signals in the brain cortex is difficult due to continuous temporal and spatial changes in the signals. The high spatial resolution of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) has substantially advanced research of pain and itch, but these are uncomfortable because of expensiveness, importability and the limited operation in the shielded room. Here, we used near infrared spectroscopy (NIRS), which has more conventional usability. NIRS can be used to visualize dynamic changes in oxygenated hemoglobin and deoxyhemoglobin concentrations in the capillary networks near activated neural circuits in real-time as well as fMRI. We observed distinct activation patterns in the frontal cortex for acute pain and histamine-induced itch. The prefrontal cortex exhibited a pain-related and itch-related activation pattern of blood flow in each subject. Although it looked as though that activation pattern for pain and itching was different in each subject, further cross correlation analysis of NIRS signals between each channels showed an overall agreement with regard to prefrontal area involvement. As a result, pain-related and itch-related blood flow responses (delayed responses in prefrontal area) were found to be clearly different between pain (τ = +18.7 sec) and itch (τ = +0.63 sec) stimulation. This is the first pilot study to demonstrate the temporal and spatial separation of a pain-induced blood flow and an itch-induced blood flow in human cortex during information processing.     

Specific activation of brain cortical areas in response to stimulation of the support receptors in healthy subjects and patients with focal lesions of the CNS

The space medicine data on the nature of motor disorders suggest an important role of the support inputs in the control of mammalian tonic and postural systems. Progress in functional magnetic resonance tomography (fMRT) makes it possible to perform in vivo analysis of various brain areas during stimulation of the support afferentation. Under these conditions, specific activation of the brain cortical areas was studied in 19 healthy subjects (with the mean age of 38 ± 15.13 years) and 23 patients (with the mean age of 53 ± 9.07 years) with focal CNS lesions (cortical-subcortical ischemic stroke). During scanning of subjects, the support areas of the soles of the feet were stimulated using a block design to simulate slow walking. In healthy subjects, significant activation was recorded (p < 0.05 at the cluster level) in the primary somatosensory cortex, premotor and dorsolateral prefrontal cortex, and insular lobe. In patients that had had a stroke, activation of the locomotion-controlling supraspinal systems clearly depended on the stage of the disease. In patients with a cortical-subcortical stroke, the pattern of contralateral activation of the sensorimotor locomotion predominated during motility rehabilitation.     

Altered Resting-State Functional Connectivity of the Frontal-Striatal Reward System in Social Anxiety Disorder

We investigated differences in the intrinsic functional brain organization (functional connectivity) of the human reward system between healthy control participants and patients with social anxiety disorder. Functional connectivity was measured in the resting-state via functional magnetic resonance imaging (fMRI). 53 patients with social anxiety disorder and 33 healthy control participants underwent a 6-minute resting-state fMRI scan. Functional connectivity of the reward system was analyzed by calculating whole-brain temporal correlations with a bilateral nucleus accumbens seed and a ventromedial prefrontal cortex seed. Patients with social anxiety disorder, relative to the control group, had (1) decreased functional connectivity between the nucleus accumbens seed and other regions associated with reward, including ventromedial prefrontal cortex; (2) decreased functional connectivity between the ventromedial prefrontal cortex seed and lateral prefrontal regions, including the anterior and dorsolateral prefrontal cortices; and (3) increased functional connectivity between both the nucleus accumbens seed and the ventromedial prefrontal cortex seed with more posterior brain regions, including anterior cingulate cortex. Social anxiety disorder appears to be associated with widespread differences in the functional connectivity of the reward system, including markedly decreased functional connectivity between reward regions and between reward regions and lateral prefrontal cortices, and markedly increased functional connectivity between reward regions and posterior brain regions.     

Auditory processing across the sleep-wake cycle: simultaneous EEG and fMRI monitoring in humans

We combined fMRI and EEG recording to study the neurophysiological responses associated with auditory stimulation across the sleep-wake cycle. We found that presentation of auditory stimuli produces bilateral activation in auditory cortex, thalamus, and caudate during both wakefulness and nonrapid eye movement (NREM) sleep. However, the left parietal and, bilaterally, the prefrontal and cingulate cortices and the thalamus were less activated during NREM sleep compared to wakefulness. These areas may play a role in the further processing of sensory information required to achieve conscious perception during wakefulness. Finally, during NREM sleep, the left amygdala and the left prefrontal cortex were more activated by stimuli having special affective significance than by neutral stimuli. These data suggests that the sleeping brain can process auditory stimuli and detect meaningful events.     

Mechanical stimulation of the support zones of soles: The method of noninvasive activation of the stepping movement generators in humans

The effects of mechanical stimulation of the soles’ support zones in the modes of slow and fast walking (75 and 120 steps per minute) were studied using the model of supportlessness (legs suspension). 20 healthy subjects participated in the study. EMG activity of hip and shin muscles was recorded. Kinematics of leg movements was assessed with the use of videoanalysis system. In 80% of cases support stimulation was followed by leg movements, in 69% of which they had characteristics of locomotions being accompanied by the burst-like electromyographic activities. The order of involvement of leg muscles and organization of antagonistic muscles activities were analogous to those of voluntary walking. The latencies of electromyographic activity in hip and shin muscles composed 5.17 ± 1.08 and 14.01 ± 2.82 s, respectively, the frequencies of bursts differed significantly depending on stimulation frequency. In 31% of cases the electromyographical activity following the stimulation of the soles’ support zones had not burst-like but uninterrupted pattern. Its amplitude rose smoothly reaching a certain level that was subsequently maintained. Results of the study showed that soles’ support zones stimulation in the mode of locomotion could activate a locomotor generator provoking the appearance of locomotion-like activity and that effect evoked by this stimulation includes not only rhythmical but also non-rhythmical (probably postural) components of walking.     

Influence of the structure of the support surface under the sole on vertical posture during standing with different body weight distributions between legs

The vertical posture was studied during standing with fееt on the support surfaces of different structures. The movements of the center of pressure (CP) of each leg and the common CP (CCP) were recorded while the subject stood with a support on a smooth floor and with the support of one foot on a spike mat (SM) with different load distributions between the legs. When the body weight was transferred to one leg during standing under ordinary conditions on a smooth floor, the CP of the loaded leg moved more than the CP of the unloaded leg; i.e., the posture sway was compensated mainly due to the activity of the loaded leg, which created a larger torque. When the subject stood with one foot on the SM, the CP movement of this leg did not depend on the leg load and was about 60% of the CP movement of the leg on the smooth floor. Apparently, the CP displacement of the unloaded leg on smooth support was larger than the CP displacement of the loaded leg creating the torque necessary for compensating the body sway. Thus, maintaining the vertical posture was carried out mainly by the leg standing on the smooth support. It is assumed that additional stimulation of different surface and deep receptors of the foot caused by foot support on the SM hampered the perception of its CP position, and the vertical posture was maintained mainly by the leg afferent signals from which more precisely reflected the CP position.     

Neural Basis of Anticipatory Anxiety Reappraisals

Reappraisal is a well-known emotion regulation strategy. Recent neuroimaging studies suggest that reappraisal recruits both medial and lateral prefrontal brain regions. However, few studies have investigated neural representation of reappraisals associated with anticipatory anxiety, and the specific nature of the brain activity underlying this process remains unclear. We used functional magnetic resonance imaging (fMRI) to investigate neural activity associated with reappraisals of transient anticipatory anxiety. Although transient anxiety activated mainly subcortical regions, reappraisals targeting the anxiety were associated with increased activity in the medial and lateral prefrontal regions (including the orbitofrontal and anterior cingulate cortices). Reappraisal decreased fear circuit activity (including the amygdala and thalamus). Correlational analysis demonstrated that reductions in subjective anxiety associated with reappraisal were correlated with orbitofrontal and anterior cingulate cortex activation. Reappraisal recruits medial and lateral prefrontal regions; particularly the orbitofrontal and anterior cingulate cortices are associated with successful use of this emotion regulation strategy.     

Intrinsic connectivity reveals functionally distinct cortico-hippocampal networks in the human brain

Episodic memory depends on interactions between the hippocampus and interconnected neocortical regions. Here, using data-driven analyses of resting-state functional magnetic resonance imaging (fMRI) data, we identified the networks that interact with the hippocampus—the default mode network (DMN) and a “medial temporal network” (MTN) that included regions in the medial temporal lobe (MTL) and precuneus. We observed that the MTN plays a critical role in connecting the visual network to the DMN and hippocampus. The DMN could be further divided into 3 subnetworks: a “posterior medial” (PM) subnetwork comprised of posterior cingulate and lateral parietal cortices; an “anterior temporal” (AT) subnetwork comprised of regions in the temporopolar and dorsomedial prefrontal cortex; and a “medial prefrontal” (MP) subnetwork comprised of regions primarily in the medial prefrontal cortex (mPFC). These networks vary in their functional connectivity (FC) along the hippocampal long axis and represent different kinds of information during memory-guided decision-making. Finally, a Neurosynth meta-analysis of fMRI studies suggests new hypotheses regarding the functions of the MTN and DMN subnetworks, providing a framework to guide future research on the neural architecture of episodic memory.

Episodic memory depends on interactions between the hippocampus and interconnected neocortical regions. This study uses network analyses of intrinsic brain networks at rest to identify and characterize brain networks that interact with the hippocampus and have distinct functions during memory-guided decision making.     

研究报告: 大鼠感觉运动系统静息态脑网络研究

为了理解啮齿类动物的脑功能连接,本文利用9.4T fMRI获得轻度麻醉状态下大鼠静息状态及刺激激活的数据,通过互相关分析构建节点之间的相关系数矩阵并计算相应的网络参数．结果发现：给予前爪电刺激时,刺激对侧初级感觉皮层(S1)、丘脑(Tha)有较强的正激活,双侧尾状壳核(CPu)有较强的负激活．静息状态时大鼠感觉/运动皮层内部、丘脑内部的连接性较强,而感觉/运动皮层与丘脑之间的连接较弱,双侧感觉运动系统之间存在较强的同步低频振荡,感觉运动系统在静息态时的脑网络具有小世界属性．结果提示,啮齿类动物在大脑信息处理中的功能分离和整合可能与人类存在某些相似性,支持哺乳动物中枢神经系统的基本功能存在遗传保守性的观点．     

Characterization of the cerebral cortical representation of heartburn in GERD patients

Although symptoms arising from the esophagus such as heartburn and pain can at times become challenging clinical problems, esophageal viscerosensation, especially with regard to chemical stimulation in humans, is incompletely understood. Our aims were 1) to characterize and ascertain the reproducibility of cerebral cortical registration of heartburn and 2) to elucidate the differences between these findings and those of esophageal subliminal acid stimulation in asymptomatic controls. We studied 11 gastroesophageal reflux disease (GERD) patients (9 males, 30-55 yr) and 15 healthy controls (8 males, 21-49 yr). Cerebral cortical functional magnetic resonance imaging (fMRI) activity was recorded twice in each subject, during two 5-min intervals of 0.1 N HCl, separated by 5 min of NaCl perfusion. Time from onset of acid perfusion to instant of fMRI signal increase and first report of heartburn averaged 1.60 +/- 0.80 and 1.85 +/- 0.60 min, respectively. Average maximum percent signal increase in the GERD patients (16.3 +/- 3.5%) was significantly greater than that of healthy controls (3.8 +/- 0.9%; P < 0.01). Temporal fMRI signal characteristics during heartburn were significantly different from those of subliminal acid stimulation in controls (P < 0.01). Activated cortical regions included sensory/motor, parieto-occipital, cingulate and prefrontal regions, and the insula. There was 92% concordance between the activated Brodmann areas in repeated studies of GERD patients. Cortical activity associated with perceived and unperceived esophageal acid exposure in GERD patients and healthy controls, respectively, involves multiple brain regions but occurs more rapidly and with greater intensity in GERD patients than the activity in response to subliminal acid exposure in healthy controls. The cortical pain-processing pathway seems to be involved in perception of esophageal acid exposure and could explain the variations encountered in clinical practice defining this sensation.     

Aging alters regional multichemical profile of the human brain: an in vivo 1H-MRS study of young versus middle-aged subjects

Age-related differences in the multichemical proton magnetic resonance spectroscopy (1H-MRS) profile of the human brain have been reported for several age groups, and most consistently for ages from neonates to 16-year-olds. Our recent 1H-MRS study demonstrated a significant age-related increase of total chemical concentration (relative to creatine) in the prefrontal and sensorimotor cortices within young adulthood (19-31-year-olds). In the present study we test the hypothesis that the level of brain chemicals in the same cortices, which show increased chemical levels during normal development, are reduced with normal aging after young adulthood. The multichemical 1H-MRS profile of the brain was compared between 19 young and 16 middle-aged normal subjects across multiple brain regions for all chemicals of 1H-MRS spectra. Chemical concentrations were measured relative to creatine. Over all age groups the total relative chemical concentration was highest in the prefrontal cortex. Middle-aged subjects demonstrated a significant decrease of total relative chemical concentration in the dorsolateral prefrontal (F = 54.8, p < 10(-7), ANOVA), orbital frontal (F = 3.7, p < 0.05) and sensorimotor (F = 15.1, p < 0.0001) cortices, as compared with younger age. Other brain regions showed no age-dependent differences. The results indicate that normal aging alters multichemical 1H-MRS profile of the human brain and that these changes are region-specific, with the largest changes occuring in the dorsolateral prefrontal cortex. These findings provide evidence that the processes of neuronal maturation of the human brain, and neurotransmitters and other chemical changes as the marker of these neuronal changes are almost finished by young adulthood and then reduced during normal aging toward middle age period of life. The present data also support the notion of heterochronic regressive changes of the aging human brain, where the multichemical brain regional profile seems to inversely recapitulate cortical chemical maturation within normal development.     

Cerebral Inefficient Activation in Schizophrenia Patients and Their Unaffected Parents during the N-Back Working Memory Task: A Family fMRI Study

Background

It has been suggested that working memory deficits is a core feature of symptomatology of schizophrenia, which can be detected in patients and their unaffected relatives. The impairment of working memory has been found related to the abnormal activity of human brain regions in many functional magnetic resonance imaging (fMRI) studies. This study investigated how brain region activation was altered in schizophrenia and how it was inherited independently from performance deficits.

Method

The authors used fMRI method during N-back task to assess working memory related cortical activation in four groups (N = 20 in each group, matching task performance, age, gender and education): schizophrenic patients, their unaffected biological parents, young healthy controls for the patients and older healthy controls for their parents.

Results

Compared to healthy controls, patients showed an exaggerated response in the right dorsolateral prefrontal cortex (brodmann area [BA] 46) and bilateral ventrolateral prefrontal cortex, and had reduced activation in bilateral dorsolateral prefrontal cortex (BA 9). In the conjunction analysis, the effect of genetic risk (parents versus older control) shared significantly overlapped activation with effect of disease (patients versus young control) in the right middle frontal gyrus (BA 46) and left inferior parietal gyrus (BA 40).

Conclusions

Physiological inefficiency of dorsal prefrontal cortex and compensation involvement of ventral prefrontal cortex in working memory function may one physiological characteristics of schizophrenia. And relatively inefficient activation in dorsolateral prefrontal cortex probably can be a promising intermediate phenotype for schizophrenia.     

A biphasic and brain-region selective down-regulation of cyclic adenosine monophosphate concentrations supports object recognition in the rat

Background

We aimed to further understand the relationship between cAMP concentration and mnesic performance.

Methods and Findings

Rats were injected with milrinone (PDE3 inhibitor, 0.3 mg/kg, i.p.), rolipram (PDE4 inhibitor, 0.3 mg/kg, i.p.) and/or the selective 5-HT4R agonist RS 67333 (1 mg/kg, i.p.) before testing in the object recognition paradigm. Cyclic AMP concentrations were measured in brain structures linked to episodic-like memory (i.e. hippocampus, prefrontal and perirhinal cortices) before or after either the sample or the testing phase. Except in the hippocampus of rolipram treated-rats, all treatment increased cAMP levels in each brain sub-region studied before the sample phase. After the sample phase, cAMP levels were significantly increased in hippocampus (1.8 fold), prefrontal (1.3 fold) and perirhinal (1.3 fold) cortices from controls rat while decreased in prefrontal cortex (∼0.83 to 0.62 fold) from drug-treated rats (except for milrinone+RS 67333 treatment). After the testing phase, cAMP concentrations were still increased in both the hippocampus (2.76 fold) and the perirhinal cortex (2.1 fold) from controls animals. Minor increase were reported in hippocampus and perirhinal cortex from both rolipram (respectively, 1.44 fold and 1.70 fold) and milrinone (respectively 1.46 fold and 1.56 fold)-treated rat. Following the paradigm, cAMP levels were significantly lower in the hippocampus, prefrontal and perirhinal cortices from drug-treated rat when compared to controls animals, however, only drug-treated rats spent longer time exploring the novel object during the testing phase (inter-phase interval of 4 h).

Conclusions

Our results strongly suggest that a “pre-sample” early increase in cAMP levels followed by a specific lowering of cAMP concentrations in each brain sub-region linked to the object recognition paradigm support learning efficacy after a middle-term delay.     

Different Brain Activation under Left and Right Ventricular Stimulation: An fMRI Study in Anesthetized Rats

Background

Myocardial ischemia in the anterior wall of the left ventricule (LV) and in the inferior wall and/or right ventricle (RV) shows different manifestations that can be explained by the different innervations of cardiac afferent nerves. However, it remains unclear whether information from different areas of the heart, such as the LV and RV, are differently processed in the brain. In this study, we investigated the brain regions that process information from the LV or RV using cardiac electrical stimulation and functional magnetic resonance imaging (fMRI) in anesthetized rats because the combination of these two approaches cannot be used in humans.

Methodology/Principal Findings

An electrical stimulation catheter was inserted into the LV or RV (n = 12 each). Brain fMRI scans were recorded during LV or RV stimulation (9 Hz and 0.3 ms width) over 10 blocks consisting of alternating periods of 2 mA for 30 sec followed by 0.2 mA for 60 sec. The validity of fMRI signals was confirmed by first and second-level analyses and temporal profiles. Increases in fMRI signals were observed in the anterior cingulate cortex and the right somatosensory cortex under LV stimulation. In contrast, RV stimulation activated the right somatosensory cortex, which was identified more anteriorly compared with LV stimulation but did not activate the anterior cingulate cortex.

Conclusion/Significance

This study provides the first evidence for differences in brain activation under LV and RV stimulation. These different brain processes may be associated with different clinical manifestations between anterior wall and inferoposterior wall and/or RV myocardial ischemia.     

Dorsal striatum and its limbic connectivity mediate abnormal anticipatory reward processing in obesity

Obesity is characterized by an imbalance in the brain circuits promoting reward seeking and those governing cognitive control. Here we show that the dorsal caudate nucleus and its connections with amygdala, insula and prefrontal cortex contribute to abnormal reward processing in obesity. We measured regional brain glucose uptake in morbidly obese (n = 19) and normal weighted (n = 16) subjects with 2-[18F]fluoro-2-deoxyglucose ([¹⁸F]FDG) positron emission tomography (PET) during euglycemic hyperinsulinemia and with functional magnetic resonance imaging (fMRI) while anticipatory food reward was induced by repeated presentations of appetizing and bland food pictures. First, we found that glucose uptake rate in the dorsal caudate nucleus was higher in obese than in normal-weight subjects. Second, obese subjects showed increased hemodynamic responses in the caudate nucleus while viewing appetizing versus bland foods in fMRI. The caudate also showed elevated task-related functional connectivity with amygdala and insula in the obese versus normal-weight subjects. Finally, obese subjects had smaller responses to appetizing versus bland foods in the dorsolateral and orbitofrontal cortices than did normal-weight subjects, and failure to activate the dorsolateral prefrontal cortex was correlated with high glucose metabolism in the dorsal caudate nucleus. These findings suggest that enhanced sensitivity to external food cues in obesity may involve abnormal stimulus-response learning and incentive motivation subserved by the dorsal caudate nucleus, which in turn may be due to abnormally high input from the amygdala and insula and dysfunctional inhibitory control by the frontal cortical regions. These functional changes in the responsiveness and interconnectivity of the reward circuit could be a critical mechanism to explain overeating in obesity.     

APOE Status Modulates the Changes in Network Connectivity Induced by Brain Stimulation in Non-Demented Elders

Behavioral consequences of a brain insult represent an interaction between the injury and the capacity of the rest of the brain to adapt to it. We provide experimental support for the notion that genetic factors play a critical role in such adaptation. We induced a controlled brain disruption using repetitive transcranial magnetic stimulation (rTMS) and show that APOE status determines its impact on distributed brain networks as assessed by functional MRI (fMRI).Twenty non-demented elders exhibiting mild memory dysfunction underwent two fMRI studies during face-name encoding tasks (before and after rTMS). Baseline task performance was associated with activation of a network of brain regions in prefrontal, parietal, medial temporal and visual associative areas. APOE ε4 bearers exhibited this pattern in two separate independent components, whereas ε4-non carriers presented a single partially overlapping network. Following rTMS all subjects showed slight ameliorations in memory performance, regardless of APOE status. However, after rTMS APOE ε4-carriers showed significant changes in brain network activation, expressing strikingly similar spatial configuration as the one observed in the non-carrier group prior to stimulation. Similarly, activity in areas of the default-mode network (DMN) was found in a single component among the ε4-non bearers, whereas among carriers it appeared disaggregated in three distinct spatiotemporal components that changed to an integrated single component after rTMS.Our findings demonstrate that genetic background play a fundamental role in the brain responses to focal insults, conditioning expression of distinct brain networks to sustain similar cognitive performance.     

Low Message Sensation Health Promotion Videos Are Better Remembered and Activate Areas of the Brain Associated with Memory Encoding

Greater sensory stimulation in advertising has been postulated to facilitate attention and persuasion. For this reason, video ads promoting health behaviors are often designed to be high in “message sensation value” (MSV), a standardized measure of sensory intensity of the audiovisual and content features of an ad. However, our previous functional Magnetic Resonance Imaging (fMRI) study showed that low MSV ads were better remembered and produced more prefrontal and temporal and less occipital cortex activation, suggesting that high MSV may divert cognitive resources from processing ad content. The present study aimed to determine whether these findings from anti-smoking ads generalize to other public health topics, such as safe sex. Thirty-nine healthy adults viewed high- and low MSV ads promoting safer sex through condom use, during an fMRI session. Recognition memory of the ads was tested immediately and 3 weeks after the session. We found that low MSV condom ads were better remembered than the high MSV ads at both time points and replicated the fMRI patterns previously reported for the anti-smoking ads. Occipital and superior temporal activation was negatively related to the attitudes favoring condom use (see Condom Attitudes Scale, Methods and Materials section). Psychophysiological interaction (PPI) analysis of the relation between occipital and fronto-temporal (middle temporal and inferior frontal gyri) cortices revealed weaker negative interactions between occipital and fronto-temporal cortices during viewing of the low MSV that high MSV ads. These findings confirm that the low MSV video health messages are better remembered than the high MSV messages and that this effect generalizes across public health domains. The greater engagement of the prefrontal and fronto-temporal cortices by low MSV ads and the greater occipital activation by high MSV ads suggest that that the “attention-grabbing” high MSV format could impede the learning and retention of public health messages.     

The planning of action: can one separate attention from intention?

Attention and motor preparation are two intimately linked processes. However, they can be dissociated in the laboratory in order to study their neuronal basis. Behavioral neurophysiology has thus shown that neurons that discharge in relation with attention or with motor preparation (or intention) exist in a variety of brain regions in the monkey, especially the prefrontal and premotor cortices. When examined more carefully, these two regions appear different in both the proportion of cells that respond during attention versus intention, and in the information coded in the so-called "preparatory activity". This activity reflects sensory selection in the prefrontal cortex (spatial attention/memory), motor selection in the premotor cortex. Furthermore, two regions in the dorsal aspect of premotor cortex can be distinguished on the basis of their relative involvement in attention: a rostral (anterior) region, functionally close to prefrontal cortex, and a caudal one, which appears functionally close to motor cortex. Using an experimental design derived from monkey experiments, a functional magnetic resonance imaging (fMRI) study recently indicated that the functional specialization within the premotor cortex is similar in monkey and man.     

Functional magnetic resonance study of deliberate deception

The goal of the study was analysis of the cerebral mechanisms of deliberate deception. The eventrelated functional magnetic resonance (ER fMRI) imaging technique was used to assess the changes in the functional brain activity by means of recording the blood oxygen level-dependent (BOLD) signal. Twelve right-handed healthy volunteers aged 19–44 years participated in the study. The BOLD images were obtained during three experimental trials: deliberate deception, manipulative honest and control truthful trials (catch trials). The deliberate deception and manipulative honest actions were characterized by a BOLD signal increase in the anterior cingulate (Brodmann’s area (BA) 32), frontal (BAs 9/10, 6), and parietal (BA 40) cortices as compared with a truthful response. Comparison of the ER fMRI data with the results of earlier studies where event-related potentials (ERPs) were recorded under similar conditions indicates the involvement of the brain mechanism of error detection in deliberate deception.