Eigenspectrum bounds for semirandom matrices with modular and spatial structure for neural networks

The eigenvalue spectrum of the matrix of directed weights defining a neural network model is informative of several stability and dynamical properties of network activity. Existing results for eigenspectra of sparse asymmetric random matrices neglect spatial or other constraints in determining entries in these matrices, and so are of partial applicability to cortical-like architectures. Here we examine a parameterized class of networks that are defined by sparse connectivity, with connection weighting modulated by physical proximity (i.e., asymmetric Euclidean random matrices), modular network partitioning, and functional specificity within the excitatory population. We present a set of analytical constraints that apply to the eigenvalue spectra of associated weight matrices, highlighting the relationship between connectivity rules and classes of network dynamics

Cortico-cerebellar interactions during goal-directed behavior

Preparatory activity is observed across multiple interconnected brain regions before goal-directed movement. Preparatory activity reflects discrete activity states representing specific future actions. It is unclear how this activity is mediated by multi-regional interactions. Recent evidence suggests that the cerebellum, classically associated with fine motor control, contributes to preparatory activity in the neocortex. We review recent advances and offer perspective on the function of cortico-cerebellar interactions during goal-directed behavior. We propose that the cerebellum learns to facilitate transitions between neocortical activity states. Transitions between activity states enable flexible and appropriately timed behavioral responses

The sensory representation of causally controlled objects

Intentional control over external objects is informed by our sensory experience of them. To study how causal relationships are learned and effected, we devised a brain machine interface (BMI) task using wide-field calcium signals. Mice learned to entrain activity patterns in arbitrary pairs of cortical regions to guide a visual cursor to a target location for reward. Brain areas that were normally correlated could be rapidly reconfigured to exert control over the cursor in a sensory-feedback-dependent manner. Higher visual cortex was more engaged when expert but not naive animals controlled the cursor. Individual neurons in higher visual cortex responded more strongly to the cursor when mice controlled it than when they passively viewed it, with the greatest response boosting as the cursor approached the target location. Thus, representations of causally controlled objects are sensitive to intention and proximity to the subject’s goal, potentially strengthening sensory feedback to allow more fluent control

Independent response modulation of visual cortical neurons by attentional and behavioral states

Sensory processing is influenced by cognitive and behavioral states, but how these states interact to modulate responses of individual neurons is unknown. We trained mice in a visual discrimination task wherein they attended to different locations within a hemifield while running or sitting still, enabling us to examine how visual responses are modulated by spatial attention and running behavior. We found that spatial attention improved discrimination performance and strengthened visual responses of excitatory neurons in the primary visual cortex whose receptive fields overlapped with the attended location. Although individual neurons were modulated by both spatial attention and running, the magnitudes of these influences were not correlated. While running-dependent modulation was stable across days, attentional modulation was dynamic, influencing individual neurons to different degrees after repeated changes in attentional states. Thus, despite similar effects on neural responses, spatial attention and running act independently with different dynamics, implying separable mechanisms for their implementation

Cortical feedback loops bind distributed representations of working memory

Working memory—the brain’s ability to internalize information and use it flexibly to guide behaviour—is an essential component of cognition. Although activity related to working memory has been observed in several brain regions, how neural populations actually represent working memory and the mechanisms by which this activity is maintained remain unclear. Here we describe the neural implementation of visual working memory in mice alternating between a delayed non-match-to-sample task and a simple discrimination task that does not require working memory but has identical stimulus, movement and reward statistics. Transient optogenetic inactivations revealed that distributed areas of the neocortex were required selectively for the maintenance of working memory. Population activity in visual area AM and premotor area M2 during the delay period was dominated by orderly low-dimensional dynamics that were, however, independent of working memory. Instead, working memory representations were embedded in high-dimensional population activity, present in both cortical areas, persisted throughout the inter-stimulus delay period, and predicted behavioural responses during the working memory task. To test whether the distributed nature of working memory was dependent on reciprocal interactions between cortical regions, we silenced one cortical area (AM or M2) while recording the feedback it received from the other. Transient inactivation of either area led to the selective disruption of inter-areal communication of working memory. Therefore, reciprocally interconnected cortical areas maintain bound high-dimensional representations of working memory

Experience-dependent specialization of receptive field surround for selective coding of natural scenes

At eye opening, neurons in primary visual cortex (V1) are selective for stimulus features, but circuits continue to refine in an experience-dependent manner for some weeks thereafter. How these changes contribute to the coding of visual features embedded in complex natural scenes remains unknown. Here we show that normal visual experience after eye opening is required for V1 neurons to develop a sensitivity for the statistical structure of natural stimuli extending beyond the boundaries of their receptive fields (RFs), which leads to improvements in coding efficiency for full-field natural scenes (increased selectivity and information rate). These improvements are mediated by an experience-dependent increase in the effectiveness of natural surround stimuli to hyperpolarize the membrane potential specifically during RF-stimulus epochs triggering action potentials. We suggest that neural circuits underlying surround modulation are shaped by the statistical structure of visual input, which leads to more selective coding of features in natural scenes

Mesoscale cortical dynamics reflect the interaction of sensory evidence and temporal expectation during perceptual decision-making

How sensory evidence is transformed across multiple brain regions to influence behavior remains poorly understood. We trained mice in a visual change detection task designed to separate the covert antecedents of choices from activity associated with their execution. Wide-field calcium imaging across the dorsal cortex revealed fundamentally different dynamics of activity underlying these processes. Although signals related to execution of choice were widespread, fluctuations in sensory evidence in the absence of overt motor responses triggered a confined activity cascade, beginning with transient modulation of visual cortex and followed by sustained recruitment of the secondary and primary motor cortex. Activation of the motor cortex by sensory evidence was modulated by animals’ expectation of when the stimulus was likely to change. These results reveal distinct activation timescales of specific cortical areas by sensory evidence during decision-making and show that recruitment of the motor cortex depends on the interaction of sensory evidence and temporal expectation

Hur upplever och värderar personer med ångest- depression och psykossjukdom sin empowerment och vårdkvalitet vid fysioterapeutisk behandling? En kvantitativ tvärsnittstudie om arbete med psykisk ohälsa i Region Skånes öppenvård

Titel: Hur upplever och värderar personer med ångest- depression- och psykossjukdom sin empowerment och vårdkvalitet vid fysioterapeutisk behandling? -En kvantitativ tvärsnittsstudie om arbete med psykisk ohälsa i Region Skånes öppenvård. Bakgrund: Diagnos inom psykisk ohälsa är den vanligaste sjukdomen för kvinnor i Sverige och näst vanligast för befolkningen i övrigt. Psykisk ohälsa kan ha många orsaker och återhämtningsprocessen är ofta komplex. Många studier har beskrivit återhämtning från psykisk ohälsa men få har fokus på fysioterapi. Av de studier som gjorts beskrivs god vårdkvalité och empowerment som viktiga komponenter för en god återhämtning. Syfte/frågeställningar: Att beskriva upplevd vårdkvaliet och självskattad empowerment då patienter med psykos-, ångest- och depressionssjukdom behandlas hos fysioterapeut. Att beskriva skillnader i upplevd vårdkvalitet beroende på självskattad empowerment. Att undersöka om det finns aspekter inom vårdkvalitet man särskilt bör beakta som behandlande fysioterapeut åt denna patientkategori. Studiedesign: Kvantitativ enkätstudie. Material och metoder: Patienter som behandlas inom Region Skånes öppenvård med diagnoser inom depression-, ångest- och psykossjukdomar svarade på en enkät innehållande KUPP (kvalitet ur patientens perspektiv) och empowermentskalan “Att fatta beslut”. Etik: Studien är godkänd av etikprövningsnämnden i Lund. Resultat 40 personer inkluderades i studien. Patienterna var nöjda med sin vårdkvalité och skattade sin medelempowerment som högre än mitten av skalan. Aspekter som delaktighet, information och respektfullt bemötande skattades högre än tidigare utvärdering. Slutsats: Patienter med ångest-, depression- och/eller psykossjukdomar som behandlas inom Region Skåne av fysioterapeuter är nöjda med sin vård och empowered. De behöver behandlas med respekt och ett holistiskt synsätt där de tillåts vara ledare för sin egen återhämtning