Activity In Superior Colliculus Research Articles

Face-related activity in superior colliculus and temporal cortex of primates

Face-related activity in superior colliculus and temporal cortex of primates

A distinct circuit for biasing visual perceptual decisions and modulating superior colliculus activity through the mouse posterior striatum.

The basal ganglia play a key role in visual perceptual decisions. Despite being the primary target in the basal ganglia for inputs from the visual cortex, the posterior striatum's (PS) involvement in visual perceptual behavior remains unknown in rodents. We reveal that the PS direct pathway is largely segregated from the dorsomedial striatum (DMS) direct pathway, the other major striatal target for visual cortex. We investigated the role of the PS in visual perceptual decisions by optogenetically stimulating striatal medium spiny neurons in the direct pathway (D1-MSNs) of mice performing a visual change-detection task. PS D1-MSN activation robustly biased visual decisions in a manner dependent on visual context, timing, and reward expectation. We examined the effects of PS and DMS direct pathway activation on neuronal activity in the superior colliculus (SC), a major output target of the basal ganglia. Activation of either direct pathway rapidly modulated SC neurons, but mostly targeted different SC neurons and had opposite effects. These results demonstrate that the PS in rodents provides an important route for controlling visual decisions, in parallel with the better known DMS, but with distinct anatomical and functional properties.

Sex differences in dorsolateral prefrontal cortical and superior colliculus activities support the impact of alcohol use severity and sleep deficiency on two-back memory.

Working memory refers to a process of temporary storage and manipulation of information to support planning, decision-making, and action. Frequently comorbid alcohol misuse and sleep deficiency have both been associated with working memory deficits. However, how alcohol misuse and sleep deficiency interact to impact working memory remains unclear. In this study, we aim to investigate the neural processes inter-relating alcohol misuse, sleep deficiency and working memory. We curated the Human Connectome Project (HCP) dataset and investigated the neural correlation of working memory in link with alcohol use severity and sleep deficiency in 991 young adults (521 women). The two were indexed by the first principal component (PC1) of principal component analysis of all drinking metrics and Pittsburgh Sleep Quality Index (PSQI) score, respectively. We processed the imaging data with published routines and evaluated the results with a corrected threshold. We used path model to characterize the inter-relationship between the clinical, behavioral, and neural measures, and explored sex differences in the findings. In whole-brain regression, we identified β estimates of dorsolateral prefrontal cortex response (DLPFC β) to 2- vs. 0-back in correlation with PC1. The DLPFC showed higher activation in positive correlation with PC1 across men and women (r=0.16, P<0.001). Path analyses showed the model PC1 → DLPFC β → differences in reaction time (2- minus 0-back; RT2-0) of correct trials → differences in critical success index (2- minus 0-back; CSI2-0) with the best fit. In women alone, in addition to the DLPFC, a cluster in the superior colliculus (SC) showed a significant negative correlation with the PSQI score (r=-0.23, P<0.001), and the path model showed the inter-relationship of PC1, PSQI score, DLPFC and SC β's, and CSI2-0 in women. Alcohol misuse may involve higher DLPFC activation in functional compensation, whereas, in women only, sleep deficiency affects 2-back memory by depressing SC activity. In women only, path model suggests inter-related impact of drinking severity and sleep deficiency on 2-back memory. These findings suggest potential sex differences in the impact of drinking and sleep problems on working memory that need to be further investigated.

Stimulus-dependent differences in cortical versus subcortical contributions to visual detection in mice

The primary visual cortex (V1) and the superior colliculus (SC) both occupy stations early in the processing of visual information. They have long been thought to perform distinct functions, with the V1 supporting the perception of visual features and the SC regulating orienting to visual inputs. However, growing evidence suggests that the SC supports the perception of many of the same visual features traditionally associated with the V1. To distinguish V1 and SC contributions to visual processing, it is critical to determine whether both areas causally contribute to the detection of specific visual stimuli. Here, mice reported changes in visual contrast or luminance near their perceptual threshold while white noise patterns of optogenetic stimulation were delivered to V1 or SC inhibitory neurons. We then performed a reverse correlation analysis on the optogenetic stimuli to estimate a neuronal-behavioral kernel (NBK), a moment-to-moment estimate of the impact of V1 or SC inhibition on stimulus detection. We show that the earliest moments of stimulus-evoked activity in the SC are critical for the detection of both luminance and contrast changes. Strikingly, there was a robust stimulus-aligned modulation in the V1 contrast-detection NBK but no sign of a comparable modulation for luminance detection. The data suggest that behavioral detection of visual contrast depends on both V1 and SC spiking, whereas mice preferentially use SC activity to detect changes in luminance. Electrophysiological recordings showed that neurons in both the SC and V1 responded strongly to both visual stimulus types, while the reverse correlation analysis reveals when these neuronal signals actually contribute to visually guided behaviors.

Inhibitory tagging both speeds and strengthens saccade target selection in the superior colliculus during visual search.

It has been suggested that, during difficult visual search tasks involving time pressure and multiple saccades, inhibitory tagging helps to facilitate efficient saccade target selection by reducing responses to objects in the scene once they have been searched and rejected. The superior colliculus (SC) is a midbrain structure involved in target selection, and recent findings suggest an influence of inhibitory tagging on SC activity. Precisely how, and by how much, inhibitory tagging influences target selection by SC neurons, however, is unclear. The purpose of this study, therefore, was to characterize and quantify the influence of inhibitory tagging on target selection in the SC. Rhesus monkeys performed a visual search task involving time pressure and multiple saccades. Early in the fixation period between saccades in the context of this task, a subset of SC neurons reliably discriminated the stimulus selected as the next saccade goal, consistent with a role in target selection. Discrimination occurred earlier and was more robust, however, when unselected stimuli in the search array had been previously fixated on the same trial. This indicates that inhibitory tagging both speeds and strengthens saccade target selection in the SC during multisaccade search. The results provide constraints on models of target selection based on SC activity.NEW & NOTEWORTHY An important aspect of efficient behavior during difficult, time-limited visual search tasks is the efficient selection of sequential saccade targets. Inhibitory tagging, i.e., a reduction of neural activity associated with previously fixated objects, may help to facilitate such efficient selection by modulating the selection process in the superior colliculus (SC). In this study, we characterized and quantified this modulation and found that, indeed, inhibitory tagging both speeds and strengthens target selection in the SC.

Monocular eye patching modulates ipsilesional reactive saccades and smooth pursuit in patients with left hemispatial neglect

Patients with hemispatial neglect show multiple oculomotor deficits like delayed contralesional saccade latencies, hypometric saccade amplitudes, and impaired smooth pursuit. We aimed to investigate whether modulation of superior colliculus (SC) activity via monocular eye patching improves neglect patients’ eye movements to the contralesional side of space. Thirteen neglect patients with left-hemispheric (LH) stroke, 22 neglect patients with right-hemispheric (RH) stroke, and 24 healthy controls completed a video-oculographic examination of horizontal smooth pursuit and reactive saccades twice, while the left or right eye was covered with an eye patch. Independent of the eye patch position, LH and RH patients showed enlarged saccade latencies toward contralesional stimuli. In addition, both during smooth pursuit and reactive saccades, RH patients made significantly fewer rightward saccades when the right than when the left eye was patched. Moreover, during reactive saccades, RH patients made significantly fewer right than left saccades, but only when the right eye was patched. These findings suggest that the ipsilesional eye patch modulated ipsilesional ocular performance in the RH group, presumably resulting from differences in SC activity. Yet, ipsilesional eye patching did not improve eye movements to the contralesional side of space, possibly due to the incomplete contralateral retinocollicular projection in humans.

Activity of the Substantia Nigra pars Reticulata During Saccade Adaptation.

When movements become inaccurate, the resultant error induces motor adaptation to improve accuracy. This error-based motor learning is regarded as a cerebellar function. However, the influence of the other brain areas on adaptation is poorly understood. During saccade adaptation, a type of error-based motor learning, the superior colliculus (SC) sends a post-saccadic error signal to the cerebellum to drive adaptation. Since the SC is directly inhibited by the substantia nigra pars reticulata (SNr), we hypothesized that the SNr might influence saccade adaptation by affecting the SC error signal. In fact, previous studies indicated that the SNr encodes motivation and motivation influences saccade adaptation. In this study, we first established that the SNr projects to the rostral SC, where small error signals are generated, in non-human primates. Then, we examined SNr activity while the animal underwent adaptation. SNr neurons paused their activity in association with the error. This pause was shallower and delayed compared to those of no-error trial saccades. The pause at the end of the adaptation was shallower and delayed compared to that at the beginning of the adaptation. The change in the inter-trial interval, an indicator of motivation, and adaptation speed had a positive correlation with the changes in the error-related pause. These results suggest that 1: the SNr exhibits a unique activity pattern during the error interval, 2: SNr activity increases during adaptation, consistent with the decrease in SC activity, and 3: motivational decay during the adaptation session might increase SNr activity and influence the adaptation speed.Significance StatementMovements impaired due to stroke, injury, or aging recover gradually. To repair an inaccurate movement, the brain measures the error of the movement and changes the movement to minimize the error. This process is called motor adaptation. Although it has been established that the cerebellum plays an essential role in this adaptation, the influence of the other brain areas on the adaptation process is not well defined. The observation that motivation levels influence adaptation led us to suspect that the basal ganglia may influence adaptation. Here, we reveal the substantia nigra pars reticulata activity changes during saccade adaptation in monkeys and suggest how the basal ganglia influence the error signal.

Activity in the human superior colliculus associated with reaching for tactile targets

The superior colliculus (SC) plays a major role in orienting movements of eyes and the head and in the allocation of attention. Functions of the SC have been mostly investigated in animal models, including non-human primates. Differences in the SC’s anatomy and function between different species question extrapolations of these studies to humans without further validation. Few electrophysiological and neuroimaging studies in animal models and humans have reported a role of the SC in visually guided reaching movements. Using BOLD fMRI imaging, we sought to decipher if the SC is also active during reaching movements guided by tactile stimulation. Participants executed reaching movements to visual and tactile target positions. When contrasted against visual and tactile stimulation without reaching, we found increased SC activity with reaching not only for visual but also for tactile targets. We conclude that the SC’s involvement in reaching does not rely on visual inputs. It is also independent from a specific sensory modality. Our results indicate a general involvement of the human SC in upper limb reaching movements.

Object-based saccadic enhancement of superior colliculus activity

Object-based saccadic enhancement of superior colliculus activity

Monocular eye patching modulates reorienting of covert attention in patients with unilateral middle cerebral artery stroke

Unilateral brain lesions can lead to impaired contralesional attention and reduced ipsilesional and enhanced contralesional superior colliculus (SC) activity. We aimed to investigate whether modulation of SC activation via monocular eye patching can improve contralesional attention. Twenty left-hemispheric (LH) and 20 right-hemispheric (RH) patients with an acute or subacute middle cerebral artery (MCA) stroke completed an endogenous version of the Posner cueing task twice, while the left or right eye was covered with an eye patch. The LH and RH patients showed significantly slower reactions to contralesional than to ipsilesional stimuli. In addition, the eye patch modulated responses to invalidly but not those to validly cued stimuli. Post hoc analyses could not discriminate whether this effect pertained to a particular target side or eye patch position. However, exploratory analyses indicated that the observed eye patch effect might affect the RH group more than the LH group. As predicted 36 years ago, monocular eye patching modulates visuospatial attention, presumably due to differences in SC activation between the two eye patch conditions. However, this modulation seems too weak and unspecific, and therefore possibly not strong enough to be a treatment option for patients with visuospatial attention impairments.

Monosynaptic trans-collicular pathways link mouse whisker circuits to integrate somatosensory and motor cortical signals.

The superior colliculus (SC), a conserved midbrain node with extensive long-range connectivity throughout the brain, is a key structure for innate behaviors. Descending cortical pathways are increasingly recognized as central control points for SC-mediated behaviors, but how cortico-collicular pathways coordinate SC activity at the cellular level is poorly understood. Moreover, despite the known role of the SC as a multisensory integrator, the involvement of the SC in the somatosensory system is largely unexplored in comparison to its involvement in the visual and auditory systems. Here, we mapped the connectivity of the whisker-sensitive region of the SC in mice with trans-synaptic and intersectional tracing tools and in vivo electrophysiology. The results reveal a novel trans-collicular connectivity motif in which neurons in motor- and somatosensory cortices impinge onto the brainstem-SC-brainstem sensory-motor arc and onto SC-midbrain output pathways via only one synapse in the SC. Intersectional approaches and optogenetically assisted connectivity quantifications in vivo reveal convergence of motor and somatosensory cortical input on individual SC neurons, providing a new framework for sensory-motor integration in the SC. More than a third of the cortical recipient neurons in the whisker SC are GABAergic neurons, which include a hitherto unknown population of GABAergic projection neurons targeting thalamic nuclei and the zona incerta. These results pinpoint a whisker region in the SC of mice as a node for the integration of somatosensory and motor cortical signals via parallel excitatory and inhibitory trans-collicular pathways, which link cortical and subcortical whisker circuits for somato-motor integration.

The Orienting Reflex Reveals Behavioral States Set by Demanding Contexts: Role of the Superior Colliculus.

Sensory stimuli can trigger an orienting reflex (response) by which animals move the head to position their sensors (e.g., eyes, pinna, whiskers). Orienting responses may be important to evaluate stimuli that call for action (e.g., approach, escape, ignore), but little is known about the dynamics of orienting responses in the context of goal-directed actions. Using mice of either sex, we found that, during a signaled avoidance action, the orienting response evoked by the conditioned stimulus (CS) consisted of a fast head movement containing rotational and translational components that varied substantially as a function of the behavioral and underlying brain states of the animal set by different task contingencies. Larger CS-evoked orienting responses were associated with high-intensity auditory stimuli, failures to produce the appropriate signaled action, and behavioral states resulting from uncertain or demanding situations and the animal's ability to cope with them. As a prototypical orienting neural circuit, we confirmed that the superior colliculus controls and codes the direction of spontaneous exploratory orienting movements. In addition, superior colliculus activity correlated with CS-evoked orienting responses, and either its optogenetic inhibition or excitation potentiated CS-evoked orienting responses, which are likely generated downstream in the medulla. CS-evoked orienting responses may be a useful probe to assess behavioral and related brain states, and state-dependent modulation of orienting responses may involve the superior colliculus.SIGNIFICANCE STATEMENT Humans and other animals produce an orienting reflex (also known as orienting response) by which they rapidly orient their head and sensors to evaluate novel or salient stimuli. Spontaneous orienting movements also occur during exploration of the environment in the absence of explicit, salient stimuli. We monitored stimulus-evoked orienting responses in mice performing signaled avoidance behaviors and found that these responses reflect the behavioral state of the animal set by contextual demands and the animal's ability to cope with them. Various experiments involving the superior colliculus revealed a well-established role in spontaneous orienting but only an influencing effect over orienting responses. Stimulus-evoked orienting responses may be a useful probe of behavioral and related brain states.

Facilitated extinction but impaired extinction recall by eye movement manipulation in humans – Indications for action mechanisms and the applicability of eye movement desensitization

Eye movement desensitization and reprocessing (EMDR) therapy utilizes the manipulation of eye movements to reduce affective distress during fear-exposure. Animal research recently suggested a potential neural mechanism underlying these effects, by which increased activity of the superior colliculus (SC), mediating visual attention, increases the inhibition of the basolateral amygdala (BLA), mediating defensive plasticity.We tested such mechanism in forty healthy humans using a multiple-day single-cue fear conditioning and extinction paradigm. The activity of the SC during extinction was experimentally manipulated by eye movements, as half of the participants executed saccadic eye movements (n = 20; major SC involvement), while the other half executed smooth eye pursuits (n = 20; minor SC involvement). Amygdala-mediated fear-potentiated startle responses and fear bradycardia, as well as threat expectancy was analyzed.Saccadic eye movements facilitated the extinction of fear bradycardia and fear-potentiated startle responses. Higher saccadic accuracy and range correlated with reduced fear-potentiated startle. However, during extinction recall, fear-potentiated startle and fear bradycardia resurged and partly reached levels obtained after fear acquisition. Threat expectancy was not affected by different eye movements and was not elevated during extinction recall.Within limitations, results support an inhibitory SC-BLA pathway in humans by which eye movements may reduce low-level defensive responding, but not threat expectancy. Yet, manipulating eye movements during extinction learning seems to impair extinction recall for behavioral and physiological defensive response indices. Thus, increasing SC activity might enhance initial efficacy of exposure treatment, but additional strategies seem necessary for sustained fear attenuation.

Optogenetic activation of the superior colliculus attenuates spontaneous seizures in the pilocarpine model of temporal lobe epilepsy.

Decades of studies have indicated that activation of the deep and intermediate layers of the superior colliculus can suppress seizures in a wide range of experimental models of epilepsy. However, prior studies have not examined efficacy against spontaneous limbic seizures. The present study aimed to address this gap through chronic optogenetic activation of the superior colliculus in the pilocarpine model of temporal lobe epilepsy. Sprague Dawley rats underwent pilocarpine-induced status epilepticus and were maintained until the onset of spontaneous seizures. Virus coding for channelrhodopsin-2 was injected into the deep and intermediate layers of the superior colliculus, and animals were implanted with head-mounted light-emitting diodes at the same site. Rats were stimulated with either 5- or 100-Hz light delivery. Seizure number, seizure duration, 24-h seizure burden, and behavioral seizure severity were monitored. Both 5- and 100-Hz optogenetic stimulation of the deep and intermediate layers of the superior colliculus reduced daily seizure number and total seizure burden in all animals in the active vector group. Stimulation did not affect either seizure duration or behavioral seizure severity. Stimulation was without effect in opsin-negative control animals. Activation of the deep and intermediate layers of the superior colliculus reduces both the number of seizures and total daily seizure burden in the pilocarpine model of temporal lobe epilepsy. These novel data demonstrating an effect against chronic experimental seizures complement a long history of studies documenting the antiseizure efficacy of superior colliculus activation in a range of acute seizure models.

A deep neural network model of the primate superior colliculus for emotion recognition.

Although sensory processing is pivotal to nearly every theory of emotion, the evaluation of the visual input as ‘emotional’ (e.g. a smile as signalling happiness) has been traditionally assumed to take place in supramodal ‘limbic’ brain regions. Accordingly, subcortical structures of ancient evolutionary origin that receive direct input from the retina, such as the superior colliculus (SC), are traditionally conceptualized as passive relay centres. However, mounting evidence suggests that the SC is endowed with the necessary infrastructure and computational capabilities for the innate recognition and initial categorization of emotionally salient features from retinal information. Here, we built a neurobiologically inspired convolutional deep neural network (DNN) model that approximates physiological, anatomical and connectional properties of the retino-collicular circuit. This enabled us to characterize and isolate the initial computations and discriminations that the DNN model of the SC can perform on facial expressions, based uniquely on the information it directly receives from the virtual retina. Trained to discriminate facial expressions of basic emotions, our model matches human error patterns and above chance, yet suboptimal, classification accuracy analogous to that reported in patients with V1 damage, who rely on retino-collicular pathways for non-conscious vision of emotional attributes. When presented with gratings of different spatial frequencies and orientations never ‘seen’ before, the SC model exhibits spontaneous tuning to low spatial frequencies and reduced orientation discrimination, as can be expected from the prevalence of the magnocellular (M) over parvocellular (P) projections. Likewise, face manipulation that biases processing towards the M or P pathway affects expression recognition in the SC model accordingly, an effect that dovetails with variations of activity in the human SC purposely measured with ultra-high field functional magnetic resonance imaging. Lastly, the DNN generates saliency maps and extracts visual features, demonstrating that certain face parts, like the mouth or the eyes, provide higher discriminative information than other parts as a function of emotional expressions like happiness and sadness. The present findings support the contention that the SC possesses the necessary infrastructure to analyse the visual features that define facial emotional stimuli also without additional processing stages in the visual cortex or in ‘limbic’ areas.This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

A spiking neural network model of the Superior Colliculus that is robust to changes in the spatial\u2013temporal input

Previous studies have indicated that the location of a large neural population in the Superior Colliculus (SC) motor map specifies the amplitude and direction of the saccadic eye-movement vector, while the saccade trajectory and velocity profile are encoded by the population firing rates. We recently proposed a simple spiking neural network model of the SC motor map, based on linear summation of individual spike effects of each recruited neuron, which accounts for many of the observed properties of SC cells in relation to the ensuing eye movement. However, in the model, the cortical input was kept invariant across different saccades. Electrical microstimulation and reversible lesion studies have demonstrated that the saccade properties are quite robust against large changes in supra-threshold SC activation, but that saccade amplitude and peak eye-velocity systematically decrease at low input strengths. These features were not accounted for by the linear spike-vector summation model. Here we show that the model’s input projection strengths and intra-collicular lateral connections can be tuned to generate saccades and neural spiking patterns that closely follow the experimental results.

440 Modulating decreases in Superior Colliculus activity through optogenetic activation attenuates seizures in the WAG/Rij genetic model of Absence Epilepsy

OBJECTIVES/GOALS: While anti-seizure medications are effective, nearly one third of patients have seizures that go untreated. Prior studies using evoked seizure models have shown that activation of the Superior Colliculus (SC) display anti-seizure effects. Here we monitored and modulated the DLSC to suppress spontaneous seizures in a genetic model of epilepsy. METHODS/STUDY POPULATION: WAG/Rij rats (4 months old) were employed as study subjects. Animals were surgically prepared for virus injection (ChR2 excitatory opsin, or control vector), fiber optic implantation and cortical EEG for optogenetic studies. For In vivo electrophysiology, animals were implanted with a 16 wire multi-electrode array into the DLSC. In optogenetic experiments, we compared the efficacy of continuous neuromodulation to that of on-demand neuromodulation (real time detection of seizures) paradigms on a within-subject basis. We compared three stimulation frequencies on a within-subject basis (5, 20, 100 Hz). We quantified the number and duration of each spike wave discharge (SWD) during each two-hour-long trial. Electrode array single units were sorted and analyzed for activity before, during and after seizures. RESULTS/ANTICIPATED RESULTS: In vivo electrophysiology found there to be a significant decrease in single unit activity leading up to the start of SWDs. Interestingly, on-demand neuromodulation was effective in both females and males – where the greatest reduction in seizure duration was under 100 Hz light delivery. As expected, male and female animals injected with a control vector did not show a reduction in seizures in response to light delivery. In the open-loop (continuous) stimulation paradigm, optogenetic activation of the DLSC was without effect on the number or duration of SWDs at any of the frequencies examined. DISCUSSION/SIGNIFICANCE: SC activity is significantly decreased prior to the start of seizures. Furthermore, activation of the SC displays anti-seizure effects in a model of spontaneous seizures. A striking difference between open and closed-loop neuromodulation approaches underscores the importance of stimulation paradigm in determining therapeutic effect.

Striatal indirect pathway mediates exploration via collicular competition.

The ability to suppress actions that lead to a negative outcome and explore alternative actions is necessary for optimal decision making. Although the basal ganglia have been implicated in these processes1-5, the circuit mechanisms underlying action selection and exploration remain unclear. Here, using a simple lateralized licking task, we show that indirect striatal projection neurons (iSPN) in the basal ganglia contribute to these processes through modulation of the superior colliculus (SC). Optogenetic activation of iSPNs suppresses contraversive licking and promotes ipsiversive licking. Activity in lateral superior colliculus (lSC), a region downstream of the basal ganglia, is necessary for task performance and predicts lick direction. Furthermore, iSPN activation suppresses ipsilateral lSC, but surprisingly excites contralateral lSC, explaining the emergence of ipsiversive licking. Optogenetic inactivation reveals inter-collicular competition whereby each hemisphere of the superior colliculus inhibits the other, thus allowing the indirect pathway to disinhibit the contralateral lSC and trigger licking. Finally, inactivating iSPNs impairs suppression of devalued but previously rewarded licking and reduces exploratory licking. Our results reveal that iSPNs engage the competitive interaction between lSC hemispheres to trigger a motor action and suggest a general circuit mechanism for exploration during action selection.

Functional coupling between target selection and acquisition in the superior colliculus.

Survival in unpredictable environments requires that animals continuously evaluate their surroundings for behavioral targets, direct their movements toward those targets, and terminate movements once a target is reached. The ability to select, move toward, and acquire spatial targets depends on a network of brain regions, but it remains unknown how these goal-directed processes are linked by neural circuits. Within this network, common circuits in the midbrain superior colliculus (SC) mediate the selection and initiation of movements to spatial targets. However, SC activity often persists throughout movement, suggesting that the same SC circuits underlying target selection and movement initiation may also contribute to "target acquisition": stopping the movement at the selected target. Here, we examine the hypothesis that SC functional circuitry couples target selection and acquisition using a "default motor plan" generated by selection-related neuronal activity. Recordings from intermediate and deep layer SC neurons in mice performing a spatial choice task demonstrate that choice-predictive neurons, including optogenetically identified GABAergic neurons whose activity mediates target selection, exhibit increased activity during movement to the target. By recording from rostral and caudal SC in separate groups of mice, we also revealed higher activity in rostral than caudal neurons during target acquisition. Finally, we used an attractor model to examine how-invoking only SC circuitry-caudal SC activity related to selecting an eccentric target could generate higher rostral than caudal acquisition-related activity. Overall, our results suggest a functional coupling between SC circuits for target selection and acquisition, elucidating a key mechanism for goal-directed behavior.NEW & NOTEWORTHY How do neural circuits ensure that selected targets are successfully acquired? Here, we examine whether choice-related activity in the superior colliculus (SC) promotes a motor plan for target acquisition. By demonstrating that choice-predictive SC neurons-including GABAergic neurons-remain active throughout movement, while the activity of rostral SC neurons increases during acquisition, and by recapitulating these dynamics with an attractor model, our results support a role for SC circuits in coupling target selection and acquisition.

Alcohol use severity and the neural correlates of the effects of sleep disturbance on sustained visual attention

Alcohol misuse is associated with sleep disturbance and cognitive dysfunction. However, the neural processes inter-relating the severity of alcohol use, sleep disturbance and cognitive performance remain under-investigated. We addressed this issue with a dataset of 964 subjects (504 women) curated from the Human Connectome Project. Participants were assessed with the Pittsburgh Sleep Quality Index (PSQI) and fMRI while identifying relational dimension pictures and matching dimension pictures (as a control) in alternating blocks. Imaging data were analyzed with published routines and the results were evaluated at a corrected threshold. Subjects showed lower accuracy rate and longer reaction time (RT) in relational than control blocks. The difference in RT between the two blocks (RTRel-Con) was driven primarily by the RT and correlated positively with performance accuracy of relational trials, suggesting that a more cautious response (i.e., longer RTRel-Con) improved accuracy. The severity of alcohol use, identified from principal component analysis of drinking metrics, was positively correlated with sleep disturbance. Further, whole-brain regression identified activity of the superior colliculus (SC) during relational vs. control blocks in positive and negative correlation with RTRel-Con and PSQI score, respectively. Mediation and path analyses demonstrated a significant model: more severe alcohol use → greater sleep disturbance → diminished SC activity → impaired performance. These findings support the influences of alcohol misuse on sleep and suggest neural correlates that mediate the relationship between sleep disturbance and altered sustained attention in young adults.