Processing Of Different Aspects Research Articles

Different facets of object-use pantomime: online TMS evidence on the role of the supramarginal gyrus.

A key question in apraxia research is which specific cognitive processes in pantomiming the parietal cortex supports. The manipulation-based hypothesis and the technical-reasoning hypothesis ascribe different roles to the inferior parietal lobule (IPL). We elucidated the role of the left supramarginal gyrus (SMG, i.e., part of IPL) during the processing of different aspects of object-use pantomime. Thirty-one healthy participants matched pantomimes with the corresponding object (PO) or the corresponding situation (PS) during online transcranial magnetic stimulation (TMS) interference applied to left SMG, compared to a control stimulation (vertex). Notably, the object corresponding to a given pantomime was explicitly not shown in the PS task, excluding the possibility to analyse a physical object. Matching an object to the corresponding situation (OS) served as a control task. TMS interference with left SMG significantly affected response times for both investigated pantomime tasks (PO and PS); the effect in the PO task significantly correlated with that in the PS task. As expected, no TMS effect was observed in the control task (OS). Left SMG does not only establish a link between pantomime and a manipulable object but is also involved in pantomime recognition and comprehension. That TMS interfered with both pantomime tasks supports the manipulation-based hypothesis, assuming that the IPL recruits stored gesture engrams whenever pantomimes are processed.

Phase-Sensitive Measurements of Depth-Dependent Signal Transduction in the Inner Plexiform Layer.

Non-invasive spatially resolved functional imaging in the human retina has recently attracted considerable attention. Particularly functional imaging of bipolar and ganglion cells could aid in studying neuronal activity in humans, including an investigation of processes of the central nervous system. Recently, we imaged the activity of the inner neuronal layers by measuring nanometer-size changes of the cells within the inner plexiform layer (IPL) using phase-sensitive optical coherence tomography (OCT). In the IPL, there are connections between the neuronal cells that are dedicated to the processing of different aspects of the visual information, such as edges in the image or temporal changes. Still, so far, it was not possible to assign functional changes to single cells or cell classes in living humans, which is essential for studying the vision process. One characteristic of signal processing in the IPL is that different aspects of the visual impression are only processed in specific sub-layers (strata). Here, we present an investigation of these functional signals for three different sub-layers in the IPL with the aim to separate different properties of the visual signal processing. Whereas the inner depth-layer, closest to the ganglion cells, exhibits an increase in the optical path length, the outer depth-layer, closest to the bipolar cell layer, exhibits a decrease in the optical path length. Additionally, we found that the central depth is sensitive to temporal changes, showing a maximum response at a stimulation frequency of around 12.5 Hz. The results demonstrate that the signals from different cell types can be distinguished by phase-sensitive OCT.

Attentional Weighting in the Face Processing Network: A Magnetic Response Image-guided Magnetoencephalography Study Using Multiple Cyclic Entrainments.

We recorded magnetoencephalography using a neural entrainment paradigm with compound face stimuli that allowed for entraining the processing of various parts of a face (eyes, mouth) as well as changes in facial identity. Our magnetic response image-guided magnetoencephalography analyses revealed that different subnodes of the human face processing network were entrained differentially according to their functional specialization. Whereas the occipital face area was most responsive to the rate at which face parts (e.g., the mouth) changed, and face patches in the STS were mostly entrained by rhythmic changes in the eye region, the fusiform face area was the only subregion that was strongly entrained by the rhythmic changes in facial identity. Furthermore, top-down attention to the mouth, eyes, or identity of the face selectively modulated the neural processing in the respective area (i.e., occipital face area, STS, or fusiform face area), resembling behavioral cue validity effects observed in the participants' RT and detection rate data. Our results show the attentional weighting of the visual processing of different aspects and dimensions of a single face object, at various stages of the involved visual processing hierarchy.

Parieto-frontal mechanisms underlying observation of complex hand-object manipulation

The observation of actions performed by others is believed to activate the Action Observation Network (AON). Previous evidence suggests that subjects with a specific motor skill show increased activation of the AON during observation of the same skill. The question arises regarding which modulation of the AON occurs during observation of novel complex manipulative actions that are beyond the personal motor repertoire. To address this issue, we carried out a functional MRI study in which healthy volunteers without specific hand motor skills observed videos displaying hand-object manipulation executed by an expert with high manual dexterity, by an actor with intermediate ability or by a naïve subject. The results showed that the observation of actions performed by a naïve model produced stronger activation in a dorso-medial parieto-premotor circuit including the superior parietal lobule and dorsal premotor cortex, compared to observation of an expert actor. Functional connectivity analysis comparing the observation of the naïve model with that of the expert model, revealed increased connectivity between dorsal areas of the AON. This suggests a possible distinction between ventral and dorsal brain circuits involved in the processing of different aspects of action perception, such as kinematics and final action goal.

Distribution of calcium-binding proteins, parvalbumin and calbindin, in the midbrain auditory center (MLd) of a pigeon.

Immunohistochemical distribution of calcium-binding proteins, parvalbumin (PV) and calbindin (CB), has been studied in the mesencephalic auditory center (MLd) of pigeon (Columba livia). In the central region of the MLd (core, ICC), an overlap in distribution of the PVand CB-immunopositive (ip) neurons and neuropil has been observed, with different patterns in the central and peripheral parts. In the peripheral region of the MLd (belt, ICS, and ICX), both neurons and neuropil contained only CB. A selective CB chemospecificity of the belt, ICS, and ICX is an evolutionary conserved feature characteristic of all avian species. Interspecies differences in the distribution of PV and CB immunoreactivity in the ICC are a result of adaptive functional specialization, which provides specific processing of different aspects of the auditory information.

Cerebral representation of non-verbal emotional perception: fMRI reveals audiovisual integration area between voice- and face-sensitive regions in the superior temporal sulcus

Successful social interaction relies on multimodal integration of non-verbal emotional signals. The neural correlates of this function, along with those underlying the processing of human faces and voices, have been linked to the superior temporal sulcus (STS) in previous neuroimaging studies. Yet, recently it has been demonstrated that this structure consists of several anatomically defined sections, including a trunk section as well as two separate terminal branches, and exhibits a pronounced spatial variability across subjects. Using functional magnetic resonance imaging (fMRI), we demonstrated that the neural representations of the audiovisual integration of non-verbal emotional signals, voice sensitivity and face sensitivity are located in different parts of the STS with maximum voice sensitivity in the trunk section and maximum face sensitivity in the posterior terminal ascending branch. The audiovisual integration area for emotional signals is located at the bifurcation of the STS at an overlap of voice- and face-sensitive regions. In summary, our findings evidence a functional subdivision of the STS into modules subserving the processing of different aspects of social communication, here exemplified in human voices and faces and audiovisual integration of emotional signals from these sources and suggest a possible interaction of the underlying voice- and face-sensitive neuronal populations during the formation of the audiovisual emotional percept.

Acute effects of alcohol on the development of intrusive memories

Post-traumatic stress disorder is characterised by repeated intrusive imagery of the traumatic event. Despite alcohol's impairing effect on memory and frequent involvement in real-life trauma, virtually nothing is known of the interaction between alcohol and trauma memory. We aimed to investigate the acute alcohol effects on spontaneous memories following a trauma film as well as explicit memory for the film. Utilising an independent-group double-blind design, 48 healthy volunteers were randomly allocated to receive alcohol of 0.4 or 0.8 g/kg or a matched placebo drink. A stressful film was viewed post-drink. Skin conductance was monitored throughout and mood and dissociative symptoms were indexed. Volunteers recorded their spontaneous memories of the film daily in an online diary over the following week. Their explicit memory for both gist and details of the film was tested on day 7. Intriguingly, an inverted 'U' alcohol dose-response was observed on intrusive memories with a low dose of alcohol increasing memory intrusions while a high dose decreased intrusions. In contrast, explicit memory performance after 7 days showed a linear dose-response effect of alcohol with both recall and recognition decreasing as dose increased. These findings highlight a striking differential pattern of alcohol's effects on spontaneous memories as compared with explicit memories. Alcohol's effect on spontaneous memories may reflect a dose-dependent impairment of two separate memory systems integral to the processing of different aspects of a traumatic event.

Processing of Frequency-Modulated Sounds in the Lateral Auditory Belt Cortex of the Rhesus Monkey

Single neurons were recorded from the lateral belt areas, anterolateral (AL), mediolateral (ML), and caudolateral (CL), of nonprimary auditory cortex in 4 adult rhesus monkeys under gas anesthesia, while the neurons were stimulated with frequency-modulated (FM) sweeps. Responses to FM sweeps, measured as the firing rate of the neurons, were invariably greater than those to tone bursts. In our stimuli, frequency changed linearly from low to high frequencies (FM direction "up") or high to low frequencies ("down") at varying speeds (FM rates). Neurons were highly selective to the rate and direction of the FM sweep. Significant differences were found between the 3 lateral belt areas with regard to their FM rate preferences: whereas neurons in ML responded to the whole range of FM rates, AL neurons responded better to slower FM rates in the range of naturally occurring communication sounds. CL neurons generally responded best to fast FM rates at a speed of several hundred Hz/ms, which have the broadest frequency spectrum. These selectivities are consistent with a role of AL in the decoding of communication sounds and of CL in the localization of sounds, which works best with broader bandwidths. Together, the results support the hypothesis of parallel streams for the processing of different aspects of sounds, including auditory objects and auditory space.

The Faces of Development: A Review of Early Face Processing over Childhood

The understanding of the adult proficiency in recognizing and extracting information from faces is still limited despite the number of studies over the last decade. Our knowledge on the development of these capacities is even more restricted, as only a handful of such studies exist. Here we present a combined reanalysis of four ERP studies in children from 4 to 15 years of age and adults (n = 424, across the studies), which investigated face processing in implicit and explicit tasks. We restricted these analyses to what was common across studies: early ERP components and upright face processing across all four studies and the inversion effect, investigated in three of the studies. These data demonstrated that processing faces implicates very rapid neural activity, even in young children--at the P1 component--with protracted age-related change in both P1 and N170, that were sensitive to the different task demands. Inversion produced latency and amplitude effects on the P1 from the youngest group, but on N170 only starting in mid childhood. These developmental data suggest that there are functionally different sources of the P1 and N170, related to the processing of different aspects of faces.

Effects of Sentential Context on the Processing of Unambiguous Words by the Two Cerebral Hemispheres

The effect of sentence context on the processing of different aspects of meaning of unambiguous nouns by the two cerebral hemispheres was examined. Participants performed a lexical decision task on target words following two primes, an unambiguous noun preceded by an incomplete sentence. Priming sentences were consistent with either the dominant or the subordinate aspect of meaning of their final unambiguous word. Short and long SOAs were used. A principal finding of this study was that, when compared to unrelated aspects of meaning, for both the short and the long SOAs, the dominant and subordinate aspects of meaning of the unambiguous words were activated regardless of context in both hemispheres. However, the activation of the subordinate aspect of meaning of unambiguous words appears to be more sensitive to sentential context, especially when the unambiguous word is being processed by the left hemisphere.

Surgical Treatment of Mental Illness: Impact of Imaging

Surgical Treatment of Mental Illness: Impact of Imaging

An electrophysiological index of stimulus unfamiliarity

This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they were deviant, target, or background stimuli, evoked larger N2 responses than their simple, familiar counterparts. N2 elicited by an unusual background stimulus was larger than that evoked by simple, deviant stimuli, a pattern opposite that exhibited by the subsequent P3. Deviance from immediate context had limited influence over N2 amplitude. The results suggest that novelty N2 and novelty P3 reflect the processing of different aspects of "novel" visual stimuli. The novelty P3 is particularly sensitive to deviation from immediate context. In contrast, the novelty N2 is sensitive to deviation from long-term context that renders a stimulus unfamiliar and difficult to encode.

Developmental Aspects of Verbal Fluency and Confrontation Naming in Children

Developmental changes in children's verbal fluency and confrontation naming were explored in this study. One hundred and sixty children (ages 5 years and 11 months to 11 years and 4 months) completed two verbal fluency tasks (phonemic and semantic) and the Boston Naming Test (BNT). Normative data were compiled for the BNT and the phonemic and semantic fluency tasks. With the exception of the phonemic fluency task, all tests showed a linear increase from year-groups I to V, with a significant increase between year-groups I and II. Principal Component Factor Analysis was conducted to determine whether the tests evaluated similar or different functions. Two factors emerged: the first involving all of the measurements and the second explaining exclusively the phonemic fluency. These results make it possible to conclude that children also seem to have different subsystems responsible for the analysis and processing of different aspects of language.