Cortical state dynamics and selective attention define the spatial pattern of correlated variability in neocortex

Correlated activity fluctuations in the neocortex influence sensory responses and behavior. Neural correlations reflect anatomical connectivity but also change dynamically with cognitive states such as attention. Yet, the network mechanisms defining the population structure of correlations remain unknown. We measured correlations within columns in the visual cortex. We show that the magnitude of correlations, their attentional modulation, and dependence on lateral distance are explained by columnar On-Off dynamics, which are synchronous activity fluctuations reflecting cortical state. We developed a network model in which the On-Off dynamics propagate across nearby columns generating spatial correlations with the extent controlled by attentional inputs. This mechanism, unlike previous proposals, predicts spatially non-uniform changes in correlations during attention. We confirm this prediction in our columnar recordings by showing that in superficial layers the largest changes in correlations occur at intermediate lateral distances. Our results reveal how spatially structured patterns of correlated variability emerge through interactions of cortical state dynamics, anatomical connectivity, and attention.

Neural Readout of a Latency Code in the Active Electrosensory System

The latency of spikes relative to a stimulus conveys sensory information across modalities. However, in most cases it remains unclear whether and how such latency codes are utilized by postsynaptic neurons. In the active electrosensory system of mormyrid fish, a latency code for stimulus amplitude in electroreceptor afferent nerve fibers (EAs) is hypothesized to be read out by a central reference provided by motor corollary discharge (CD). Here we demonstrate that CD enhances sensory responses in postsynaptic granular cells of the electrosensory lobe, but is not required for reading out EA input. Instead, diverse latency and spike count tuning across the EA population gives rise to graded information about stimulus amplitude that can be read out by standard integration of converging excitatory synaptic inputs. Inhibitory control over the temporal window of integration renders two granular cell subclasses differentially sensitive to information derived from relative spike latency versus spike count.

Multisensory stimuli shift perceptual priors to facilitate rapid behavior

Multisensory stimuli speed behavioral responses, but the mechanisms subserving these effects remain disputed. Historically, the observation that multisensory reaction times (RTs) outpace models assuming independent sensory channels has been taken as evidence for multisensory integration (the “redundant target effect”; RTE). However, this interpretation has been challenged by alternative explanations based on stimulus sequence effects, RT variability, and/or negative correlations in unisensory processing. To clarify the mechanisms subserving the RTE, we collected RTs from 78 undergraduates in a multisensory simple RT task. Based on previous neurophysiological findings, we hypothesized that the RTE was unlikely to reflect these alternative mechanisms, and more likely reflected pre-potentiation of sensory responses through crossmodal phase-resetting. Contrary to accounts based on stimulus sequence effects, we found that preceding stimuli explained only 3–9% of the variance in apparent RTEs. Comparing three plausible evidence accumulator models, we found that multisensory RT distributions were best explained by increased sensory evidence at stimulus onset. Because crossmodal phase-resetting increases cortical excitability before sensory input arrives, these results are consistent with a mechanism based on pre-potentiation through phase-resetting. Mathematically, this model entails increasing the prior log-odds of stimulus presence, providing a potential link between neurophysiological, behavioral, and computational accounts of multisensory interactions.

Emotional responses to different flavoured popcorns on watching different types of movies

The emotional responses to five flavoured popcorns (butter, cheese, caramel, barbecue and Thai spicy) compared to ‘not eat anything’ on watching each genre of five digital video disk (DVD) movies (action, comedy, fantasy, romance and horror movies) were measured by 100 voluntary audiences. They were recruited to participate in the sensory laboratory set as a theatre. After five minutes of watching each movie, they had to taste each of the flavoured popcorns for 25 g serving with 250 mL of drinking water than their 39 emotional and 2 sensory responses were recorded. Analysis of variance (ANOVA) and emotional ratio profiling of all flavoured popcorns on watching each movie were analysed. The results revealed that the mean overall liking score for each flavoured popcorn was not different, but the mean emotional scores that responded to each flavoured popcorn on watching each movie were different significantly (p < 0.01). During watching the action movie, butter and cheese flavoured popcorns seemed to significantly evoke most emotions on ‘daring’ and ‘pleasant’ (p < 0.01). While watching the horror movie, caramel flavoured popcorn undoubtedly evoked the most emotional responses among other flavoured popcorns. These emotional responses to each of flavoured popcorns on each of variety DVD movies might be used for movie theatre strategic promotion and advertisement to add value and distinction for the flavoured popcorn products in all cases.

Give me a pain that I am used to: distinct habituation patterns to painful and non-painful stimulation

Pain habituation is associated with a decrease of activation in brain areas related to pain perception. However, little is known about the specificity of these decreases to pain, as habituation has also been described for other responses like spinal reflexes and other sensory responses. Thus, it might be hypothesized that previously reported reductions in activation are not specifically related to pain habituation. For this reason, we performed a 3 T fMRI study using either painful or non-painful electrical stimulation via an electrode attached to the back of the left hand. Contrasting painful vs. non-painful stimulation revealed significant activation clusters in regions well-known to be related to pain processing, such as bilateral anterior and posterior insula, primary/secondary sensory cortices (S1/S2) and anterior midcingulate cortex (aMCC). Importantly, our results show distinct habituation patterns for painful (in aMCC) and non-painful (contralateral claustrum) stimulation, while similar habituation for both types of stimulation was identified in bilateral inferior frontal gyrus (IFG) and contralateral S2. Our findings thus distinguish a general habituation in somatosensory processing (S2) and reduced attention (IFG) from specific pain and non-pain related habituation effects where pain-specific habituation effects within the aMCC highlight a change in affective pain perception.

Digital Integration and Automated Assessment of Eye-Tracking and Emotional Response Data Using the BioSensory App to Maximize Packaging Label Analysis

New and emerging non-invasive digital tools, such as eye-tracking, facial expression and physiological biometrics, have been implemented to extract more objective sensory responses by panelists from packaging and, specifically, labels. However, integrating these technologies from different company providers and software for data acquisition and analysis makes their practical application difficult for research and the industry. This study proposed a prototype integration between eye tracking and emotional biometrics using the BioSensory computer application for three sample labels: Stevia, Potato chips, and Spaghetti. Multivariate data analyses are presented, showing the integrative analysis approach of the proposed prototype system. Further studies can be conducted with this system and integrating other biometrics available, such as physiological response with heart rate, blood, pressure, and temperature changes analyzed while focusing on different label components or packaging features. By maximizing data extraction from various components of packaging and labels, smart predictive systems can also be implemented, such as machine learning to assess liking and other parameters of interest from the whole package and specific components.

Progressive Numbness, Burning Pain, Imbalance, and Dryness

A 65-year-old woman was evaluated for progressive numbness and tingling involving different body parts. Onset was with her right foot. Numbness and paresthesia progressed to her left hand and then left foot. Numbness and tingling of her right hand also developed. Progressive gait instability also developed, leading to frequent falls. She started using a cane to walk. She also reported severe dry eyes and mouth and noticed an inability to sweat in hot weather. Her neurologic examination showed pseudoathetosis with eye closure and sensory gait ataxia. She had profound vibration and proprioceptive loss in all extremities (lower extremities greater than upper extremities). She also had asymmetric reduction in pinprick sensation in her hands and feet distally. She had minimal distal weakness involving her toes and upper extremities. Her deep tendon reflexes were reduced in the upper limbs and absent in the lower limbs. Toes were downgoing to plantar stimulation. Nerve conduction studies demonstrated asymmetric, sensory-predominant, axonal peripheral neuropathy with absent left median and ulnar sensory responses and relatively preserved (reduced) right median and ulnar sensory responses. Bilateral sural sensory responses were absent. Motor responses were relatively preserved. Cerebrospinal fluid analysis showed mildly increased protein concentration, and 5 cerebrospinal fluid-restricted oligoclonal bands. Thermoregulatory sweat testing showed anhidrosis involving the proximal limbs and the trunk and hypohidrosis of the forehead and distal extremities. Serum laboratory investigations identified an increased erythrocyte sedimentation rate. Serologic testing was remarkable for positive antinuclear antibody, rheumatoid factor, and Sjögren syndrome-A antibody. Chest computed tomography showed a nonspecific solitary nodule in the right upper lobe but was otherwise normal. The patient was diagnosed with Sjögren sensory ganglionopathy (or neuronopathy). The patient received a 12-week course of intravenous methylprednisolone. She was also started on mycophenolate mofetil. Two weeks later, the mycophenolate mofetil dose was increased. At follow-up 4 months later, she reported improvement in neuropathic pain, but the sensory loss and ataxia continued to be treatment refractory. The presence of sicca symptoms (dry eyes and mouth), polyarthralgias, morning stiffness, and anti-Ro antibody seropositivity were supportive of a Sjögren syndrome diagnosis. Sjögren syndrome has been associated with various neuropathic presentations. Sensory ganglionopathy in Sjögren syndrome usually presents with asymmetrical sensory loss, neuropathic pain, sensory ataxia, and sometimes pseudoathetosis, which were presenting features in this case patient.

Balancing memory fidelity and representational stability in the female mouse accessory olfactory bulb

Sensory systems must balance the value of efficient coding schemes against the need to update specific memorized representations without perturbing other memories. Here we describe a unique solution to this challenge that is implemented by the vomeronasal system (VNS) to encode and remember multiple conspecific individuals as part of the Bruce Effect (BE). In the BE, exposure of a pregnant female mouse to the odors of an unfamiliar male leads to failure of the pregnancy (pregnancy block) via the VNS. Following mating and sensory exposure, however, the female becomes protected from a pregnancy block by the stud individual. While this form of natural learning has been proposed to depend on changes in the representation of his odors in her accessory olfactory bulb (AOB), a key VNS structure, there are no direct comparisons of in vivo sensory responses before and after imprinting. It has further been suggested that these changes simply render the AOB insensitive to stud odors. However, the combinatorial odor code used by the AOB and the significant overlap in the odor composition of different males means that silencing responses to one individual is likely to degrade responses to others, posing potential problems for more general sensory encoding. To identify the neuronal correlates of learning in the context of the BE, we recorded extracellular responses of AOB neurons in vivo in mated and unmated female mice upon controlled presentation of urinary chemosignals, including urine from both the stud and males of a distinct strain. We find that while initial sensory responses in the AOB (within a timescale required to guide social interactions) remain stable, responses to extended stimulation (as required for eliciting the pregnancy block) display selective attenuation of stud-responsive neurons. Based on our results, we propose a model that reconciles the formation of strong, selective memories with the need to sustain robust representational bandwidth by noting a distinction between the representations of brief and extended stimuli. This temporal disassociation allows attenuation of slow-acting endocrine processes in a stimulus-specific manner, without compromising consistent ongoing representations of stimuli that guide behavior.