Multimodal Information Processing Research Articles

“High” cognitive emotions in language prosody: Commentary on “Emotional voices in context: A neurobiological model of multimodal affective information processing” by C. Brück, B. Kreifelts, & D. Wildgruber

“High” cognitive emotions in language prosody: Commentary on “Emotional voices in context: A neurobiological model of multimodal affective information processing” by C. Brück, B. Kreifelts, & D. Wildgruber

‘Emotion’ ‘The essence of Human communication – The processing of emotional information’: Comment on: Brück C, Kreifelts B, Wildgruber D. Emotional voices in context: a neurobiological model of multimodal affective information processing

‘Emotion’ ‘The essence of Human communication – The processing of emotional information’: Comment on: Brück C, Kreifelts B, Wildgruber D. Emotional voices in context: a neurobiological model of multimodal affective information processing

Is the medium the message?: Comment on “Emotional voices in context: A neurobiological model of multimodal affective information processing” by Brück et al.

Is the medium the message?: Comment on “Emotional voices in context: A neurobiological model of multimodal affective information processing” by Brück et al.

Multi-source information fusion applied to structural damage diagnosis

This study aims to import multi-source information fusion (MSIF) into structural damage diagnosis to improve its validity. Two structural damage identification methods based on MSIF are put forward, one of which is to fuse two or more structural damage detection methods by MSIF and another of which is the improved modal strain energy method by multi-mode information processing based on MSIF. Through a concrete plate experiment it is proved that, if two methods are integrated by character-level information fusion, structural initial damages can be more accurately identified than by a single method. In a simulation of a concrete box beam bridge, it is indicated that the improved modal strain energy method has a nice sensitivity to structural initial damages and a favorable robusticity to noise. These two structural damage diagnosis methods based on MSIF have good effects on structural damage identification and good practicability to actual structures.

Top-down and bottom-up modulation in processing bimodal face/voice stimuli

BackgroundProcessing of multimodal information is a critical capacity of the human brain, with classic studies showing bimodal stimulation either facilitating or interfering in perceptual processing. Comparing activity to congruent and incongruent bimodal stimuli can reveal sensory dominance in particular cognitive tasks.ResultsWe investigated audiovisual interactions driven by stimulus properties (bottom-up influences) or by task (top-down influences) on congruent and incongruent simultaneously presented faces and voices while ERPs were recorded. Subjects performed gender categorisation, directing attention either to faces or to voices and also judged whether the face/voice stimuli were congruent in terms of gender. Behaviourally, the unattended modality affected processing in the attended modality: the disruption was greater for attended voices. ERPs revealed top-down modulations of early brain processing (30-100 ms) over unisensory cortices. No effects were found on N170 or VPP, but from 180-230 ms larger right frontal activity was seen for incongruent than congruent stimuli.ConclusionsOur data demonstrates that in a gender categorisation task the processing of faces dominate over the processing of voices. Brain activity showed different modulation by top-down and bottom-up information. Top-down influences modulated early brain activity whereas bottom-up interactions occurred relatively late.

Large ion Coulomb crystals: A near-ideal medium for coupling optical cavity modes to matter

We present an investigation of the coherent coupling of various transverse field modes of an optical cavity to ion Coulomb crystals. The obtained experimental results, which include the demonstration of identical collective coupling rates for different transverse modes of a cavity field to ions in the same large Coulomb crystal, are in excellent agreement with theoretical predictions. The results furthermore suggest that Coulomb crystals in the future may serve as near-ideal media for highfidelity multi-mode quantum information processing and communication purposes, including the generation and storage of single photon qubits encoded in different transverse modes.

The Neuropsychological Connection Between Creativity and Meditation

Prior investigations into a creativity–meditation connection involving diverse meditation strategies, proficiency levels, and creativity measurement instruments presented mixed results. These results are explained through evidence (primarily from EEG studies) supporting the hypothesis that meditation training variously enhances creative incubation and illumination via transcendence and integration, neuropsychological mechanisms common to both processes. Transcendence surpasses informational limits; integration transforms informational boundaries. In this respect, increased low-alpha power reflects reduced cortical activity and detached witnessing of multimodal information processing; theta indicates an implicit affect-based orientation toward satisfaction and encoding of new information; delta reflects neural silence, signal matching and surprise, and gamma indicates heightened awareness, temporal-spatial binding, and salience. Cortical intra-interhemispheric synchronization, within these EEG spectral bands, is essential to effective creativity and meditation. The relative impact on creativity of various meditation strategies (mindfulness, concentrative and combined) is discussed. Sanyama, an ancient yogic attentional technique embodying both transcendence and integration, provides a unique neuropsychological explanation for extraordinary creativity.

Anatomical substrates for the processing of multimodal information via the primary auditory cortex

Event Abstract Back to Event Anatomical substrates for the processing of multimodal information via the primary auditory cortex Eike Budinger1*, H. Scheich1 and F.W Ohl1 1 Leibniz Institute for Neurobiology, Germany It is still a popular view that primary sensory cortices are unimodal, but recent physiological and behavioral studies, including those from our laboratory, have shown that they can also be activated and modulated by multiple other modalities. Here, we will report about the anatomical substrate, which may underlie the processing of auditory but also multimodal information at the level of the primary auditory cortex (field AI), and which may, in turn, enable AI to influence other sensory and non-sensory systems. This issue was approached by means of the axonal transport of the sensitive bidirectional neuronal tracers fluorescein-labeled (FD) and tetramethylrhodamine-labeled dextran (TMRD), which were simultaneously injected into different frequency regions of the Mongolian gerbil’s AI. The location of retrogradely labeled cell bodies (i.e. cells of origin of direct projections to AI) and of anterogradely labeled axons and their terminations demonstrates, that AI has multiple connections with auditory, multisensory, non-auditory sensory, and non-sensory cortical and subcortical regions of the brain. As expected, the majority of AI connections, estimated by the number of retrogradely labeled cell bodies, exists with auditory structures like the other ipsilateral and contralateral auditory cortical fields (~57%) and the auditory thalamus (~23%). However, approx. 12% of the inputs to AI arise from multisensory cortical (e.g., posterior parietal cortex, claustrum) and subcortical areas (e.g., multisensory thalamic nuclei), 3% from other sensory (e.g., visual cortex and thalamus), and 5% from non-sensory structures (e.g., associative cortices, amygdala, neuromodulatory subcortical nuclei). The analysis of the topography of the FD- and TMRD-labeled cells of origin and axonal terminations, respectively, revealed that the connections between AI and the other auditory structures are usually topographically organized (i.e. frequency-specific, tonotop), whereas all other connections are non-topographic (i.e. frequency-unspecific, diffuse, non-tonotop). The laminar pattern of corticipetal (corticoafferent), corticocortical, and corticofugal (corticoefferent) connections suggests that AI receives primarily bottom-up-like inputs from the ascending auditory pathway and projects auditory information feedforward (bottom-up) to its cortical target areas. In turn, AI receives substantial cortical feedback inputs (top-down) and projects top-down-like to its subcortical targets. However, corticocortical and thalamo-cortico-thalamic feedback loops as well as several corticofugal and corticipetal modulatory connections make the classification of the AI connectivities increasingly complex. In conclusion, the present study supports the notion that AI as well as probably all other primary sensory cortices are not merely involved in sensory processing of their own modality, but also in multifaceted bottom-up and top-down processing of other sensory and non-sensory information. Supported by the SFB-TR 31 (DFG), BMBF and State Saxony-Anhalt, Germany. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Türkiye, 1 Sep - 5 Sep, 2008. Presentation Type: Oral Presentation Topic: Abstracts Citation: Budinger E, Scheich H and Ohl F (2008). Anatomical substrates for the processing of multimodal information via the primary auditory cortex. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.267 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Dec 2008; Published Online: 09 Dec 2008. * Correspondence: Eike Budinger, Leibniz Institute for Neurobiology, Magdeburg, Germany, budinger@lin-magdeburg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Eike Budinger H. Scheich F.W Ohl Google Eike Budinger H. Scheich F.W Ohl Google Scholar Eike Budinger H. Scheich F.W Ohl PubMed Eike Budinger H. Scheich F.W Ohl Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Guiding Visual Attention by Exploiting Crossmodal Spatial Links: An Application in Air Traffic Control

Recent research on multimodal information processing has provided evidence for the existence of crossmodal links in spatial attention between vision, audition, and touch. The present study examined whether these links can be exploited to support attention allocation in workplaces that involve competing task demands and the potential for visual data overload. In particular, the effectiveness of tactile cues for guiding visual attention to the location of a critical event was tested in the context of an air traffic control simulation. Participants monitored a display depicting the flight paths of 40 aircraft and were presented with tactile cues indicating either just the occurrence, or both the occurrence and display location, of an event requiring a participant response. Tactile cuing, especially when combined with location information, resulted in significantly higher detection rates and faster response times to these events. These findings indicate that tactile cuing is a promising means of directing visual attention in a data-driven manner.

Neuro-cognitively inspired haptic user interfaces

Haptic systems and devices are a recent addition to multimodal systems. These devices have widespread applications such as surgical simulations, medical and procedural training, scientific visualizations, assistive and rehabilitative devices for individuals who have physical or neurological impediments and assistive devices for individuals who are blind. While the potential of haptics in natural human machine interaction is undisputable, the realization of such means is still a long way ahead. There are considerable research challenges to development of natural haptic interfaces. The study of human tactile abilities is a recent endeavor and many of the available systems still do not incorporate the domain knowledge of psychophysics, biomechanics and neurological elements of haptic perception. Development of smart and effective haptic interfaces and devices requires extensive studies that link perceptual phenomena with measurable parameters and incorporation of such domain knowledge in the engineering of haptic interfaces. This paper presents design, development and usability testing of a neuro-cognitively inspired haptic user interface for individuals who are blind. The proposed system design is inspired by neuro-cognitive basis of haptic perception and incorporates the computational aspects and requirements of multimodal information processing system. Usability testing of the system suggests that a biologically inspired haptic user interfaces may form a powerful paradigm for haptic user interface design.

Non-sensory cortical and subcortical connections of the primary auditory cortex in Mongolian gerbils: Bottom-up and top-down processing of neuronal information via field AI

In the present study, we will provide further anatomical evidence that the primary auditory cortex (field AI) is not only involved in sensory processing of its own modality, but also in complex bottom-up and top-down processing of multimodal information. We have recently shown that AI in the Mongolian gerbil ( Meriones unguiculatus) has substantial connections with non-auditory sensory and multisensory brain structures [Budinger, E., Heil, P., Hess, A., Scheich, H., 2006. Multisensory processing via early cortical stages: Connections of the primary auditory cortical field with other sensory systems. Neuroscience 143, 1065–1083]. Here we will report about the direct connections of AI with non-sensory cortical areas and subcortical structures. We approached this issue by means of the axonal transport of the sensitive bidirectional neuronal tracers fluorescein-labelled (FD) and tetramethylrhodamine-labelled dextran (TMRD), which were simultaneously injected into different frequency regions of the gerbil's AI. Of the total number of retrogradely labelled cell bodies found in non-sensory brain areas, which identify cells of origin of direct projections to AI, approximately 24% were in cortical areas and 76% in subcortical structures. Of the cell bodies in the cortical areas, about 4.4% were located in the orbital, 11.1% in the infralimbic medial prefrontal (areas DPC, IL), 18.2% in the cingulate (3.2% in CG1, 2.9% in CG2, 12.1% in CG3), 9.5% in the frontal association (area Fr2), 12.0% in the insular (areas AI, DI), 10.8% in the retrosplenial, and 34.0% in the perirhinal cortex. The cortical regions with retrogradely labelled cells, as well as the entorhinal cortex, also contained anterogradely labelled axons and their terminations, which means that they are also target areas of direct projections from AI. The laminar pattern of corticocortical connections indicates that AI receives primarily cortical feedback-type inputs and projects in a feedforward manner to its target areas. The high number of double-labelled somata, the non-topographic distribution of single FD- and TMRD-labelled somata, and the overlapping spatial distribution of FD- and TMRD-labelled axonal elements suggest rather non-tonotopic connections between AI and the multimodal cortices. Of the labelled cell bodies in the subcortical structures, about 38.8% were located in the ipsilateral basal forebrain (10.6% in the lateral amygdala LA, 11.5% in the globus pallidus GP, 3.7% in the ventral pallidum VPa, 13.0% in the nucleus basalis NB), 13.1% in the ipsi- and contralateral diencephalon (6.4% in the posterior paraventricular thalamic nuclei, 6.7% in the hypothalamic area), and 48.1% in the midbrain (20.0% in the ipsilateral substantia nigra, 9.8% in the ipsi- and contralateral ventral tegmental area, 5.0% in the ipsi- and contralateral locus coeruleus, 13.3% the ipsi- and contralateral dorsal raphe nuclei). Thus, the majority of subcortical inputs to AI was related to different neurotransmitter systems. Anterograde labelling was only found in some ipsilateral basal forebrain structures, namely, the LA, basolateral amygdala, GP, VPa, and NB. As for the cortex, the proportion and spatial distribution of single FD-, TMRD-, and double-labelled neuronal elements suggests rather non-tonotopic connections between AI and the neuromodulatory subcortical structures.

Multimodal information presentation: Design guidance and research challenges

Multimodal interfaces have gained considerable interest in recent years. This trend can be expected to continue as designers try to address challenges like data overload, the need for improved performance of recognition-based systems, a greater sense of immersion in virtual-reality environments, and support for time sharing and attention management in a variety of complex real-world domains. To ensure the robustness and effectiveness of multimodal interfaces, a number of design guidelines have been proposed. The present paper will review guidelines that focus on multimodal information presentation (as opposed to multimodal system input), and it will discuss important research needs in this area, including the exploration of possible uses and benefits of rarely used sensory channels (such as touch and olfaction), the consideration of crossmodal links in attention, the top–down modulation of multimodal information processing, and the need for adaptive and adaptable multimodal interfaces. Relevance to industry Multimodal interfaces will likely find their way into an increasing number of complex data-rich environments. It is critical for engineers and designers to be aware of benefits, requirements, and constraints associated with the design of multimodal displays to ensure their effectiveness and avoid pitfalls of this approach to information presentation.

Mechanisms of Memory

Back to table of contents Previous article Next article Book Forum: GENETICS AND NEUROSCIENCEFull AccessMechanisms of MemoryLAURA A. FLASHMAN, Ph.D., LAURA A. FLASHMANSearch for more papers by this author, Ph.D., Lebanon, N.H.Published Online:1 Nov 2005https://doi.org/10.1176/appi.ajp.162.11.2201AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail In the introduction to this book, Larry Squire, Ph.D., points out that the first book called Mechanisms of Memory, by the neuroscientist E. Roy John, was published in 1967 (1). Squire highlights the considerable progress that has been made in understanding memory systems, including a host of new tools, ideas, and discoveries, by comparing the foundation from which Dr. John wrote with the state of the field in the 2000s. Dr. John’s book was based on localization of function, information provided by assemblies of neurons, and electrophysiological correlates of learning and memory. The current volume is based on the development of animal model systems for studying the genetics and synaptic changes underlying behavioral memory, the discovery of long-term potentiation, the concept of multiple memory systems, and delineation of both cellular and molecular contributions to neural plasticity.The book is organized in a way that provides a foundation for thinking about the molecular and cellular underpinnings of synaptic plasticity and information storage, with particular emphasis on the hippocampus and its role in declarative and spatial learning. Examples from other anatomical and behavioral systems are also included. Dr. Sweatt progresses from well-established facts and background, to a description of current work and thinking in each area, to a final section he clearly indicates should be considered “speculation.” Thus, after a brief introduction to the basics of learning and memory at the psychological level, chapters focus on rodent behavioral learning and memory models (chapter 2), the role of the hippocampus in multimodal information processing and memory consolidation (chapter 3), aspects of long-term potentiation (chapters 4–6 and 9), biochemical mechanisms for short- and long-term information storage at the cellular level (chapters 7 and 8), inherited and acquired disorders of memory (chapters 10 and 11), and the chemistry of perpetual memory (chapter 12). Thus, the reader goes from a basic background of learning theory and synaptic physiology, to a detailed discussion of the biochemical mechanisms of long-term changes in synaptic function and information storage, to consideration of the molecular basis of learning and memory disorders.The intended users of this book include advanced undergraduates, graduate students, and researchers interested in learning, and it is well designed as a textbook to be used in psychology, biology, and neuroscience programs. Dr. Sweatt’s goal that the book be targeted to active researchers in the fields of learning and memory, at all stages of their career development, may be somewhat ambitious. One unique aspect of this book is that it surveys learning and memory from a molecular level through complex behavioral levels, but this means that it is best viewed as a survey tool. Dr. Sweatt provides an organizational framework for thinking about synaptic plasticity and memory that incorporates biochemical complexity into our conceptualization and understanding. He clearly articulates throughout the book why an understanding of the molecular basis of memory is important to those of us working in the field, since all biological processes are subserved by biochemical phenomena.The book is well written and includes interesting and illustrative text inserts as well as colorful figures with detailed explanations. Mechanisms of Memory is a successful integration of recent discoveries and technological advances applied to learning and memory at many different levels that will appeal to its target audience of advanced undergraduates and graduates across a number of disciplines.By J. David Sweatt, Ph.D. New York, Elsevier Academic Press, 2003, 400 pp., $79.95.Reference1. John ER: Mechanisms of Memory. New York, Academic Press, 1967Google Scholar FiguresReferencesCited byDetailsCited byNone Volume 162Issue 11 November 2005Pages 2201-2201 Metrics PDF download History Published online 1 November 2005 Published in print 1 November 2005

Building the central complex of the grasshopper Schistocerca gregaria: temporal topology organizes the neuroarchitecture of the w, x, y, z tracts

The central complex is a brain specific structure involved in multimodal information processing and in coordinating motor behaviour. It possesses a highly organized neuroarchitecture, which is remarkably conserved across insect species. A prominent feature of this neuroarchitecture is the stereotypic projection of axons from clusters of neurons in the pars intercerebralis to the central body via the so-called w, x, y and z tracts. Despite extensive analyses of this neuroarchitecture in adults, little is known about its ontogeny in any insect. In this paper we use the expression pattern of the segment polarity gene engrailed to identify those neuroblasts belonging to the protocerebrum of the early embryonic brain of the grasshopper Schistocerca gregaria. We present a new map for this brain region in which the 95 protocerebral neuroblasts in each hemisphere are organized into seven rows, as they are in the neuromeres of the ventral nerve cord. We then identify a subset of four of these neuroblasts as being the progenitor cells for four clusters of neurons, some of whose axons we show project via discrete tracts (w, x, y, z) into the central complex. These tracts begin to form prior to 39% of embryogenesis. We show further, that the cells from one of these clusters (the Z cluster) are organized according to age, and direct axons topologically according to age into the appropriate z tract. This pattern is repeated in each of the other three clusters, thus establishing a clonally based modular system of fibre tracts consistent with the model proposed for this brain region in the adult.

New evidence for involvement of the entorhinal region in schizophrenia: a combined MRI volumetric and DTI study

Postmortem examinations and magnetic resonance imaging (MRI) studies suggest involvement of the entorhinal cortex (EC) in schizophrenic psychoses. However, the extent and nature of the possible pathogenetical process underlying the observed alterations of this limbic key region for processing of multimodal sensory information remains unclear. Three-dimensional high-resolution MRI volumetry and evaluation of the regional diffusional anisotropy based on diffusion tensor imaging (DTI) were performed on the EC of 15 paranoid schizophrenic patients and 15 closely matched control subjects. In schizophrenic patients, EC volumes showed a slight, but not significant, decrease. However, the anisotropy values, expressed as inter-voxel coherences (COH), were found to be significantly decreased by 17.9% (right side) and 12.5% (left side), respectively, in schizophrenics. Reduction of entorhinal diffusional anisotropy can be hypothesized to be functionally related to disturbances in the perforant path, the principal efferent EC fiber tract supplying the limbic system with neuronal input from multimodal association centers. Combinations of different MRI modalities are a promising approach for the detection and characterization of subtle brain tissue alterations.

Guidelines for multimodal user interface design

JMUI (Journal on Multimodal User Interfaces), Special issue “Best of affective computing and intelligent Guidelines for multimodal user interface design. support, human multi-modal information processing. characteristics to the design of a user-oriented and guidelines of multimodal interface design. Artifact lifecycle management, Consumer and user, Interfaces in Automated.Aug 2 Aug 7Los Angeles, CA, USAThursday, 6 August 2015 / HCI International 20152015.hci.international/thursday​CachedDefining and Optimizing User Interfaces Information Complexity for AI Design and Development of Multimodal Applications: A Vision on Key Issues and Traditional Heuristics and Industry Guidelines to Evaluate Multimodal Digital Artifacts

Parcellation of cortical afferents to three distinct sectors in the parahippocampal gyrus of the rhesus monkey: an anatomical and neurophysiological study.

The posterior parahippocampal gyrus (PHG) of the rhesus monkey (Macaca mulatta) is comprised of three distinct cortical areas based on cytoarchitecture, connectivity, and neurophysiological response properties. Fluorescent retrograde tracers placed in each PHG area demonstrated unique patterns of cortical afferent input to areas TH, TL, and TF. Area TF receives inputs from the multimodal cortices of the superior temporal sulcus including areas PGa, TPO, and MST, from the visuospatial parietal area PG-Opt, and from visual areas V3A and dorsal V4. Area TL receives afferents from the inferotemporal region including visual areas TE1 and TE2 as well as from areas TEa, IPa, and FST in the lower bank and depth of the superior temporal sulcus. In contrast, the input to area TH is from the rostral part of superior temporal gyrus, including the auditory association areas TS1-3, and from the middle sector of area TPO in the superior temporal sulcus. Frontal and cingulate areas also project to the PHG in largely differential patterns. To further investigate this a correlative electrophysiological study of the three PHG areas resulted in a confirmation of these differential cortical inputs such that visually responsive neurons were found in areas TF and TL, auditory responsive neurons or bimodal auditory/visual-responsive neurons in area TH, and somatosensory-responsive neurons at the TF/TL border. Since each PHG area also receives differential hippocampal input, these data suggest that the processing of unimodal or multimodal information may be related to memory processing functions that are largely segregated within areas TH, TL, and TF.

Evidence for training-induced crossmodal reorganization of cortical functions in trumpet players.

The aim of this study was to compare multimodal information processing in the somatosensory and auditory cortices and related multimodal areas in musicians (trumpet players) and non-musicians. Magnetoencephalographic activity (MEG) was recorded in response to five stimulus conditions from 10 professional trumpet players and nine musically untrained control subjects. Somatosensory and auditory stimuli were presented alone or in combination. Our data suggest that musicians, in general, process multisensory stimuli differently to the control group. When stimulating the lip in professional trumpet players, a multimodal interaction (expressed as difference between the multimodal response and the sum of unimodal responses) in the corresponding somatosensory cortex showed a positive peak at 33 ms, which was not found in the control group. Conversely, the control group shows a significant interaction of opposite polarity around 60-80 ms. We suggest that training-induced reorganization in musicians leads to a qualitatively different way to process multisensory information. It favors an early stage of cortical processing, which is modified by the connections between multimodal and auditory neurons from thalamus to primary somatosensory area.

Hippocampus as comparator: role of the two input and two output systems of the hippocampus in selection and registration of information.

Processing of multimodal sensory information by the morphological subdivisions of the hippocampus and its input and output structures was investigated in unanesthetized rabbits by extracellular recording of neuronal activity. Analysis shows principal differences between CA3 neurons with uniform multimodal, mainly inhibitory, rapidly habituating sensory responses, and CA1-subicular neurons, substantial parts of which have phasic reactions and patterned on-responses, depending on the characteristics of the stimuli. These differences result from the organization of the afferent inputs to CA1 and CA3. Analysis of neuronal responses in sources of hippocampal inputs, their electrical stimulation, and chronic disconnection show the greater functional significance of the brain-stem reticular input for tonic responses characteristic of CA3. This input signal before entering the hippocampus is additionally preprocessed at the MS-DB relay, where it becomes more uniform and frequency-modulated in the range of theta-rhythm. It is shown that the new sensory stimuli produce inhibitory reset, after which synchronized theta-modulation is triggered. Other stimuli, appearing at the background of the ongoing theta, do not evoke any responses of the hippocampal neurons. Thus, theta-modulation can be regarded as a mechanism of attention, which prolongs response to a selected stimulus and simultaneously protects its processing against interference. The cortical input of the hippocampus introduces highly differentiated information analyzed at the highest levels of the neocortex through the intermediary of the entorhinal cortex and presubiculum. However, only CA1-subiculum receives this information directly; before its entrance into CA3, it is additionally preprocessed at the FD relay, where the secondary simplification of signals occurs. As a result, CA3 receives by its two inputs (MS-DB and FD) messages just about the presence and level of input signals in each of them, and performs relatively simple functions of determination of match/mismatch of their weights. For this comparator system, the presence of signal only in the reticulo-septal input is equivalent to quality of novelty. The cortical signal appears with some delay, after its analysis in the neocortex and shaping in the prehippocampal structures; besides, it is gradually increased due to LTP-like incremental changes in PP and mossy fiber synapses. The CA3 neurons with potentiated synapses of cortical input do not respond to sensory stimuli; that is, the increased efficacy of the cortical signals can be regarded as "familiarity" of a signal, terminating the reactive state of the CA3 neurons. The integrity of both inputs is necessary for gradual habituation of sensory responses in the hippocampus. The output signals of CA3 following in the precommissural fornix to the output relay-LS nucleus and to the brain-stem structures have strong regulatory influence on the level of brain activity (arousal), which is an important condition for processing and registration of information. The primary targets of this output signal are raphe nuclei, which suppress activity of the ascending excitatory RF. In the background state, activity of the CA3 neurons through the intermediary of raphe keeps RF under tonic inhibitory control. Inhibition of the majority of CA3 pyramidal neurons during a novel stimulus action decreases the volume of its output signal to raphe and releases RF from tonic inhibition (increase in level of activity of the forebrain, arousal). When the responses of CA3 neurons habituate, the initial high background activity is reinstated, as well as tonic suppression of RF. Analysis of the second output of CA3 (by Schaffer's collaterals to CA1) shows that activity in this pathway can block access of cortical signals from PP to CA1 neurons by action upon the local system of inhibitory neurons, or by shunting the propagation of signals in apical dendrites. Thus, CA3 can act as a filter controlling the information transmission by CA1; such transmission at any given moment is allowed only in those CA1 neurons which receive SC from CA3 neurons, responding to the sensory stimulus by suppression of their activity. Disconnection of the CA3 output fibers results in disappearance of habituation in all its target structures (raphe, RF, CA1). The output signal of CA1-subiculum follows by postcommissural fornix to the chain of structures of the main limbic circuit: mammillary bodies (medial nucleus), anterior thalamic nuclei (mainly antero-ventral nucleus), and cingulate limbic cortex (mainly posterior area). In each of these links, the signal is additionally processed. Habituation is nearly absent in these structures; instead, st

Neurons with dopamine-like immunoreactivity target mushroom body Kenyon cell somata in the brain of some hymenopteran insects

The mushroom bodies of the insect brain are centers for olfactory and multimodal information processing and they are involved in associative olfactory learning. They are comprised of numerous (340,000 in the bee brain), small (3–8 μm soma diameter) local interneurons, the Kenyon cells. In the brain of honeybees ( Apis mellifera) of all castes (worker bees, drones and queens), wasps ( Vespula germanica) and hornets ( Vespa crabro) immunostaining revealed fibers with dopamine-like immunoreactivity projecting from the pedunculus and the lip neuropil of the mushroom bodies into the Kenyon cell perikaryal layer. These fibers terminate with numerous varicosities, mainly around the border between medial and lateral Kenyon cell soma groups. Visualization of immunostained terminals in the transmission electron microscope showed that they directly contact the somata of the Kenyon cells and contain presynaptic elements. The somata of the Kenyon cells are clearly non-immunoreactive. Synaptic contacts at the somata are unusual for the central nervous systems of insects and other arthropods. This finding suggests that the somata of the Kenyon cells of Hymenoptera may serve an integrative role, and not merely a supportive function.