Internal representations of smell in the Drosophila brain

Recent advances in sensory neuroscience using Drosophila olfaction as a model system have revealed brain maps representing the external world. Once we understand how the brain's built-in capability generates the internal olfactory maps, we can then elaborate how the brain computes and makes decision to elicit complex behaviors. Here, we review current progress in mapping Drosophila olfactory circuits and discuss their relationships with innate olfactory behaviors

The subject at rest: novel conceptualizations of self and brain from cognitive neuroscience's study of the 'resting state'

The neuroscientific field of ‘resting state’ research has been described as heralding a paradigm shift in functional neuroimaging. As this new field has been central to the development of a cognitive neuroscientific theory of inner mental life, we here map and analyse its emergence and potential implications for conceptualizations of brain, self and subjectivity within and beyond the neurosciences. The article traces how the ‘resting state’ and ‘default mode’ became visible as objects of scientific enquiry through the yoking together of what were initially separate research endeavours addressing different neurophysiological and neuropsychological questions. In the process, ‘rest’ – as signifying the cessation of movement or labour – has been transformed: the brain, inner mental life – and potentially the self – are conceptualized by researchers in this field as perpetually productive and oriented towards the futur

Default positions: how neuroscience’s historical legacy has hampered investigation of the resting mind

The puzzle of the brain and mind at rest – their so-called default state – is strongly influenced by the historical precedents that led to its emergence as a scientific question. What eventually became the default-mode network (DMN) was inaugurated via meta-analysis to explain the observation that the baseline “at rest” condition was concealing a pattern of neural activations in anterior and posterior midline brain regions that were not commonly seen in external-task-driven experiments. One reason why these activations have puzzled scientists is because psychology and cognitive neuroscience have historically been focused on paradigms built around external tasks, and so lacked the scientific and theoretical tools to interpret the cognitive functions of the DMN. This externally-focused bias led to the erroneous assumption that the DMN is the primary neural system active at rest, as well as the assumption that this network serves non-goal-directed functions. Although cognitive neuroscience now embraces the need to decode the meaning of self-generated neural activity, a more deliberate and comprehensive framework will be needed before the puzzle of the wandering mind can be laid to rest

Toward a hierarchical model of social cognition: A neuroimaging meta-analysis and integrative review of empathy and theory of mind

Contains fulltext : 226714.pdf (Publisher’s version ) (Open Access)Along with the increased interest in and volume of social cognition research, there has been higher awareness of a lack of agreement on the concepts and taxonomy used to study social processes. Two central concepts in the field, empathy and Theory of Mind (ToM), have been identified as overlapping umbrella terms for different processes of limited convergence. Here, we review and integrate evidence of brain activation, brain organization, and behavior into a coherent model of social-cognitive processes. We start with a meta-analytic clustering of neuroimaging data across different social-cognitive tasks. Results show that understanding others' mental states can be described by a multilevel model of hierarchical structure, similar to models in intelligence and personality research. A higher level describes more broad and abstract classes of functioning, whereas a lower one explains how functions are applied to concrete contexts given by particular stimulus and task formats. Specifically, the higher level of our model suggests 3 groups of neurocognitive processes: (a) predominantly cognitive processes, which are engaged when mentalizing requires self-generated cognition decoupled from the physical world; (b) more affective processes, which are engaged when we witness emotions in others based on shared emotional, motor, and somatosensory representations; (c) combined processes, which engage cognitive and affective functions in parallel. We discuss how these processes are explained by an underlying principal gradient of structural brain organization. Finally, we validate the model by a review of empathy and ToM task interrelations found in behavioral studies.35 p

Functional Connectivity of Human Striatum: A Resting State fMRI Study

Item does not contain fulltextClassically regarded as motor structures, the basal ganglia subserve a wide range of functions, including motor, cognitive, motivational, and emotional processes. Consistent with this broad-reaching involvement in brain function, basal ganglia dysfunction has been implicated in numerous neurological and psychiatric disorders. Despite recent advances in human neuroimaging, models of basal ganglia circuitry continue to rely primarily upon inference from animal studies. Here, we provide a comprehensive functional connectivity analysis of basal ganglia circuitry in humans through a functional magnetic resonance imaging examination during rest. Voxelwise regression analyses substantiated the hypothesized motor, cognitive, and affective divisions among striatal subregions, and provided in vivo evidence of a functional organization consistent with parallel and integrative loop models described in animals. Our findings also revealed subtler distinctions within striatal subregions not previously appreciated by task-based imaging approaches. For instance, the inferior ventral striatum is functionally connected with medial portions of orbitofrontal cortex, whereas a more superior ventral striatal seed is associated with medial and lateral portions. The ability to map multiple distinct striatal circuits in a single study in humans, as opposed to relying on meta-analyses of multiple studies, is a principal strength of resting state functional magnetic resonance imaging. This approach holds promise for studying basal ganglia dysfunction in clinical disorders

Residual functional connectivity in the split-brain revealed with resting-state functional MRI

Item does not contain fulltextSplit-brain patients present a unique opportunity to address controversies regarding subcortical contributions to interhemispheric coordination. We characterized residual functional connectivity in a complete commissurotomy patient by examining patterns of low-frequency BOLD functional MRI signal. Using independent components analysis and region-of-interest-based functional connectivity analyses, we demonstrate bilateral resting state networks in a patient lacking all major cerebral commissures. Compared with a control group, the patient's interhemispheric correlation scores fell within the normal range for two out of three regions examined. Thus, we provide evidence for bilateral resting state networks in a patient with complete commissurotomy. Such continued interhemispheric interaction suggests that, at least in part, cortical networks in the brain can be coordinated by subcortical mechanisms