Recruitment Strength Research Articles

Spatiotemporal patterns of variability in the abundance and distribution of winter-spawned pelagic juvenile rockfish in the California Current.

Rockfish are an important component of West Coast fisheries and California Current food webs, and recruitment (cohort strength) for rockfish populations has long been characterized as highly variable for most studied populations. Research efforts and fisheries surveys have long sought to provide greater insights on both the environmental drivers, and the fisheries and ecosystem consequences, of this variability. Here, variability in the temporal and spatial abundance and distribution patterns of young-of-the-year (YOY) rockfishes are described based on midwater trawl surveys conducted throughout the coastal waters of California Current between 2001 and 2019. Results confirm that the abundance of winter-spawning rockfish taxa in particular is highly variable over space and time. Although there is considerable spatial coherence in these relative abundance patterns, there are many years in which abundance patterns are very heterogeneous over the scale of the California Current. Results also confirm that the high abundance levels of YOY rockfish observed during the 2014–2016 large marine heatwave were largely coastwide events. Species association patterns of pelagic YOY for over 20 rockfish taxa in space and time are also described. The overall results will help inform future fisheries-independent surveys, and will improve future indices of recruitment strength used to inform stock assessment models and marine ecosystem status reports.

Environmental drivers of golden tilefish (Lopholatilus chamaeleonticeps) commercial landings and catch‐per‐unit‐effort

AbstractWe explored a range of potential low and high‐frequency environmental drivers of fishery production (landings) and catch‐per‐unit‐effort (CPUE) for northern and southern stocks of golden tilefish (Lopholatilus chamaeleonticeps), a stenothermic species that prefers a narrow band of habitat along the continental shelf and upper slope of the eastern US. Random forest regression, a machine learning technique, was used to examine the impact of numerous and sometimes correlated environmental covariates. We used important random forest covariates to inform construction of a more parsimonious generalized additive mixed model for each data type and stock. We identified several potential environmental drivers of golden tilefish fishery and stock dynamics, including low‐frequency climate indices, oceanographic currents, and high‐frequency oceanographic conditions. Both Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation indices were associated with historical golden tilefish landings for the northern stock spanning 1915–2000 at lags of 7 and 3–4 years, respectively. CPUE for both stocks (north: 1995–2017, south: 1994–2018) was associated with the AMO and oceanographic currents. In addition, northern stock CPUE was negatively related to Labrador Current flow and positively related to northerly position of the Gulf Stream. Southern stock CPUE was associated with seasonal Florida Current transport, monthly sea surface temperatures, and latitude. Oceanographic currents and water temperature primarily influenced within‐year CPUE, indicating a potential effect on adult fish or fisher behavior. In contrast, low‐frequency climate indices were associated with CPUE and landings at lags of 3–7 years, indicating their primary impact was on recruitment strength.

Coupled Gluteus Maximus and Gluteus Medius Recruitment Patterns Modulate Hip Adduction Variability During Single-Limb Step-Downs: A Cross-Sectional Study.

Examining the coordinated coupling of muscle recruitment patterns may provide insight into movement variability in sport-related tasks. The purpose of this study was to examine the relationship between coupled gluteus maximus and medius recruitment patterns and hip-adduction variability during single-limb step-downs. Cross-sectional. Biomechanics laboratory. Forty healthy adults, including 26 women and 14 men, mean age 23.8 (1.6) years, mean body mass index 24.2 (3.1)kg/m2, participated. Lower-extremity kinematics were acquired during 20 single-limb step-downs from a 19-cm step height. Electromyography (EMG) signals were captured with surface electrodes. Isometric hip-extension strength was obtained. Hip-adduction variability, measured as the SD of peak hip adduction across 20 repetitions of the step-down task, was measured. The mean amplitudes of gluteus maximus and gluteus medius EMG recruitment were examined. Determinism and entropy of the coupled EMG signals were computed with cross-recurrence quantification analyses. Hip-adduction variability correlated inversely with determinism (r = -.453, P = .018) and positively with entropy (r = .409, P = .034) in coupled gluteus maximus/medius recruitment patterns but not with hip-extensor strength nor with magnitudes of mean gluteus maximus or medius recruitment (r = -.003, .081, and .035; P = .990, .688, and .864, respectively). Hip-adduction variability during single-limb step-downs correlated more strongly with measures of coupled gluteus maximus and medius recruitment patterns than with hip-extensor strength or magnitudes of muscle recruitment. Examining coupled recruitment patterns may provide an alternative understanding of the extent to which hip neuromuscular control modulates lower-extremity kinematics beyond examining muscle strength or EMG recruitment magnitudes.

Optimized iLID Membrane Anchors for Local Optogenetic Protein Recruitment.

Optogenetic protein dimerization systems are powerful tools to investigate the biochemical networks that cells use to make decisions and coordinate their activities. These tools, including the improved Light-Inducible Dimer (iLID) system, offer the ability to selectively recruit components to subcellular locations, such as micron-scale regions of the plasma membrane. In this way, the role of individual proteins within signaling networks can be examined with high spatiotemporal resolution. Currently, consistent recruitment is limited by heterogeneous optogenetic component expression, and spatial precision is diminished by protein diffusion, especially over long time scales. Here, we address these challenges within the iLID system with alternative membrane anchoring domains and fusion configurations. Using live cell imaging and mathematical modeling, we demonstrate that the anchoring strategy affects both component expression and diffusion, which in turn impact recruitment strength, kinetics, and spatial dynamics. Compared to the commonly used C-terminal iLID fusion, fusion proteins with large N-terminal anchors show stronger local recruitment, slower diffusion of recruited components, efficient recruitment over wider gene expression ranges, and improved spatial control over signaling outputs. We also define guidelines for component expression regimes for optimal recruitment for both cell-wide and subcellular recruitment strategies. Our findings highlight key sources of imprecision within light-inducible dimer systems and provide tools that allow greater control of subcellular protein localization across diverse cell biological applications.

Application of a multi-annual generalized depletion model to the Mediterranean sandeel fishery in Catalonia

A multi-annual generalized depletion (MAGD) model was applied to the data-limited Mediterranean sandeel boat seine fishery in Catalonia. The results show that catch and effort data at high temporal frequency (month), complemented with biological information on mean body weight and initial estimates of natural mortality and time of recruitment to the fishery, can be used to produce assessment results of interest to fisheries management. The estimates of fishing mortality obtained for the Mediterranean sandeel in this fishery are very low compared to natural mortality estimates (less than 10 %) and the important fluctuations in recruitment strength suggest that the dynamics of this fishery are mainly driven by density-dependent effects on the population dynamics of the species. Given the high rate of natural mortality estimated (∼ M = 2 y−1), its short life-span (1–2 y) and that exploitation is based on age 0 individuals, it is recommended to keep exploitation rates at current levels (<4%), which can be adapted on a short time basis, subject to the perceived availability of the stock. This low exploitation rate is compatible with a precautionary escapement biomass of 40 %. A parallel stock assessment was carried out with a surplus production model (SPiCT), which led to similar trends in biomass and fishing mortality as the MAGD model application. The parameter estimates obtained with both models have wide confidence intervals, particularly for the quantities related to population size, suggesting that these data-limited models are likely to suffer from low precision. Precision was lower for SPiCT than for MAGD, and the performance diagnostics for SPiCT were poor. The MAGD model can be used for small-scale fisheries that are unlikely to meet the requirements of standard stock assessments based on catch-at-age methods and can provide indicators (fishing mortality, vulnerable biomass) of interest to fisheries managers.

Age structure, recruitment variation, and sex ratio in blue cod (Parapercis colias) subpopulations in New Zealand

ABSTRACT Age compositions from eight blue cod (Parapercis colias) subpopulations off the South Island of New Zealand were compared to investigate recruitment patterns temporally and spatially. Findings indicate (1) recruitment is highly variable between years, (2) subpopulations closer to each other have similar age compositions, and (3) strong and weak recruitment events are linked and the key processes that drive recruitment strength are acting on a large spatial scale. Recruitment variability among years and similarities between areas are likely to be density-independent, due to environmental fluctuations. Age compositions exhibited modal progression of age classes providing validation of ageing based on counts of rings on otoliths. Sex ratio by age and length were compared in relation to their reproductive strategy of changing sex from female to male (protogynous hermaphrodites). Sex ratio pattern differed for each of the eight subpopulations but was most similar in those from the same area. Males dominate at younger ages and sex ratio swings in favour of females with increasing age. Patterns in sex ratio with size are virtually the opposite to those of age because the largest fish are invariably males. These results support the theory that the form of protogyny in blue cod is diandric.

Linking flow attributes to recruitment to inform water management for an Australian freshwater fish with an equilibrium life-history strategy

Recognition that many species share key life-history strategies has enabled predictions of responses to habitat degradation or rehabilitation by these species groups. While such responses have been well documented for freshwater fish that exhibit ‘periodic’ and ‘opportunistic’ life-history strategies, this is rare for ‘equilibrium’ life-history, due largely to their longevity and by comparison, more regular and stable levels of recruitment. Unfortunately, this limits the confidence in using life-history strategies to refine water management interventions to rectify the negative impacts of river regulation for these species. We addressed this knowledge gap for Murray cod Maccullochella peelii, a high-profile, long-lived recreationally popular equilibrium species in south-eastern Australia. We used monitoring data collected across a gradient of hydrologically altered rivers over two decades, to test various hypotheses linking recruitment strength with key attributes of the flow regime.Although Murray cod recruited in most years, as expected for an equilibrium species, responses to flow varied among and within rivers among years. We found links between recruitment strength and the magnitude and variation in discharge during the spring spawning period, as well as flows experienced by juvenile fish during summer and winter - the hydrological components most affected by river regulation. However, the specific slopes and directions of some of these links varied idiosyncratically across rivers.Our results emphasise the importance of accounting for flows that influence each of the key life stages during the recruitment process and lend support for managing rivers in accordance with the natural flow regime. It also shows the need for waterway-specific studies and further refinement of existing flow metrics to allow more credible transferability of results. The approach used in this study can also be applied to other species sharing life-history strategies for which long-term monitoring data has been compiled and length-at-age relationships established.

Application of Generalized Depletion Model to Recruitment of American Eel Elvers and Empirical Support from Survey Data

AbstractRecruitment is one of the driving forces determining the population dynamics of a stock, and knowledge about recruitment is crucial in providing reliable results in modern stock assessment. The population of the American Eel Anguilla rostra is at risk, and the fisheries on the elvers are one threat for its persistence. We applied a generalized depletion model on the catch and effort data of the elver fishery of the East River, Chester, Nova Scotia, from 1996 to 2018. The elver fishery of the East River did not have high exploitation pressure on the elver waves passing through. The natural mortality rate varied substantially among years, with a mean generally in agreement with other studies. The estimates of the model parameters did not exhibit significant temporal trends. Moreover, the estimate of annual elver abundance matched well with the fishery‐independent abundance index, providing the first empirical support of the generalized depletion model. The generalized depletion model is an effective method to assess the exploitation status of elver fisheries, as well as providing an estimate of recruitment strength and natural mortality that can be used for stock assessment on the adult stocks when only fisheries‐dependent catch and effort data are available.

Rebuilding depleted fisheries towards BMSY under uncertainty: harvest control rules outperform combined management measures

AbstractRebuilding depleted fisheries towards sustainable levels, such as BMSY, is challenging under uncertainty. Although a substantial amount of research has highlighted the importance of accounting for uncertainty in fisheries management, tactical measures remain to be identified. We consider two approaches to achieve this goal: (i) the naive maximum sustainable yield (MSY) approach, combining management measures based on effort control, catch quotas, and spatial–temporal closures, and (ii) the harvest control rules (HCRs) approach, developing HCRs based on short-term or long-term targets. A suite of strategies is developed accordingly and tested with management strategy evaluation for their performance under four sources of uncertainty that may negatively impact management effects, including reduced recruitment strength, increased natural mortality, inadequate implementation error, and varying levels of temporal effort aggregation. Combining management measures using the naive MSY approach is found to perform poorly in tackling uncertainty. Complex HCRs that account for both short-term and long-term BMSY targets can mitigate the adverse effects of uncertainty. The rebuilding target can be only achieved by compromising yield, especially when uncertainties with natural mortality and recruitment are present. Strategies based on catch quotas are prone to all sources of uncertainty, indicating latent risks in many current management practices.

The Effect Of Team Winning Percentage On BCS Football Recruit Strength And Speed Characteristics

Due to the volatility of NCAA Division I BCS Football coaching and support staffs, it is difficult to collect reliable, longitudinal data using consistent physical performance tests on players entering the program. The data set in the current study represents a twenty-nine - year period collected by the same Head Strength and Conditioning Coach in the same football program. PURPOSE: The purpose of the study was to compare the physical testing of the players entering the program in the early years, (1987 -1998) of the Head Football Coach’s tenure, when the team studied winning percentage was (56.5%) to a later period (1999-2014) when the team’s winning percentage improved to (73.3%). METHODS: A cohort of 1094 NCAA Division I BCS level football players that played at the same institution under the same Head Football Coach and Head Strength and Conditioning Coach during the years of 1987-2104 were divided into two groups depending on the era in which they played. Group One (G1 n=581) played between 1987 and 1998 (12 year period). Group One’s win/loss record was 77-59, with a (56.5% winning percentage). Group 2 (G2 n=513) played between 1999 and 2014 (16 year period) the team win/loss record was 154-56 during this period representing a (73.3% winning percentage). Data were collected when each athlete joined the team in the following areas across the entire twenty-nine-year period. Measurements were collected in Height (HT), Body Mass (BM), One Repetition Maximum (1RM) in the Bench Press (BP), the Vertical Jump (VJ), and 40-yard dash (40YD). All data were collected by the same Head Strength and Conditioning Coach. All data were analyzed using paired t-tests for each parameter tested. RESULTS: G2 had significantly better initial test results in each of the following tests: BM (106.9 vs 101.7 kg.; P<0.01), BP (133.3 vs 124.9 kg.; P<0.01), VJ (30.1 vs 27.0 in.; P<0.01), and 40YD (4.8 vs 5.0 sec.; P<0.01). CONCLUSIONS: The results suggest that having a successful football program at the Division I BCS level may attract recruits that are bigger, stronger in the upper body, with greater lower body power and running speed. Although it may not be the only thing that affects the decision of 4 and 5-star athletes to sign with a Division I BCS football team, it appears to be a major factor.

How visual perspective influences the spatiotemporal dynamics of autobiographical memory retrieval

Visual perspective, recalling events from one's own eyes or one of several possible observer viewpoints, is a fundamental aspect of AM. Yet, exactly how visual perspective influences the functional mechanisms supporting retrieval is unclear. Here we used a multivariate analysis to characterize the spatiotemporal dynamics of networks supporting AM retrieval from multiple typical and atypical visual perspectives. Both own eyes and observer perspectives engaged an AM retrieval network (i.e., hippocampus, anterior and posterior midline, and lateral frontal and posterior cortices) that peaked during later retrieval periods, but was recruited less strongly for observer perspectives. Functional connectivity analyses with an anterior hippocampal seed revealed that visual perspective also affected the strength and timing of neural recruitment. There was stronger hippocampal connectivity with a posterior medial network during the initial retrieval of AMs from atypical observer perspectives and stronger within-MTL and ventromedial prefrontal cortex connectivity during later retrieval periods from own eyes perspectives, suggesting that visual perspective is an important factor in understanding how neocortical systems guide memory retrieval. Our findings demonstrate that adopting own eyes and observer perspectives during AM retrieval is correlated with distinct patterns of hippocampal–neocortical interactions associated with differential recruitment of the AM retrieval network during later retrieval periods, thereby supporting the central role of visual perspective in reconstructing the personal past.

Riverscape recruitment: a conceptual synthesis of drivers of fish recruitment in rivers

Most fish recruitment models consider only one or a few drivers in isolation, rarely include species’ traits, and have limited relevance to riverine environments. Despite their diversity, riverine fishes share sufficient characteristics that prediction of recruitment should be possible. Here we synthesize the essential components of fish recruitment hypotheses and the key features of rivers to develop a model that predicts relative recruitment strength, for all fishes, in rivers under all flow conditions. The model proposes that interactions between flow and physical complexity will create locations in rivers, at mesoscales, where energy and nutrients are enriched. The resultant production of small prey will be concentrated and prey and fish larvae located (through dispersal or retention) so that the larvae can feed, grow, and recruit. Our synthesis explains how flow and physical complexity affect fish recruitment and provides a conceptual basis to better conserve and manage riverine fishes globally.

General surface circulation controls the interannual fluctuations of anchovy stock biomass in the Central Mediterranean Sea

The sustainable exploitation of small pelagic fish populations, characterized by short life span and early age at first reproduction, is typically more influenced by the success of annual recruitment rather than by fishing mortality. Recruitment strength, in turn, is related to the high environmental variability characterizing the pelagic fish habitats, able to strongly affect the survival of early stages, from hatching to recruitment. Here, we consider the case study of anchovy (Engraulis encrasicolus) stock in the Strait of Sicily (Central Mediterranean). The interannual fluctuations exhibited over an 18-year long period by this fish population was found to be mainly linked to surface circulation patterns, as far as they are able to control retention/dispersal processes of larval stages. We firstly used Lagrangian simulations to reproduce the fate of anchovy early stages during their planktonic phase. Larval retention indices constructed from the output of the simulations were able alone to explain a large proportion of variance (up to 70%) in yearly biomass of the anchovy population, outclassing the other environmental factors considered in this study. Such results are relevant for fisheries management, for all fish stocks characterized by potentially high vulnerability of early life stages.

Effect of retention processes on the recruitment of tropical arrow squid (Doryteuthis pleii): An individual-based modeling case study in southeastern Brazil

Squid recruitment depends on paralarvae survival, as the parental stock dies following reproduction. Therefore, the biotic and abiotic environmental conditions experienced by paralarvae control recruitment strength. To benefit from the favorable environments (i.e. nursery grounds) in the dynamic pelagic domain, paralarvae rely on passive retention by currents to remain in suitable nursery habitat. To evaluate the retention conditions for tropical arrow squid (Doryteuthis pleii) paralarvae off the South Brazil Bight (SBB, 22–29 °S), we ran a series of particle-tracking Individual-Based Models (IBM) coupled to a 3D Princeton Ocean Model (POM). We forced the hydrodynamic model with observed satellite data obtained from January 2000 to December 2010. The IBM-POM models considered two transport scenarios: (1) passive Lagrangian transport and (2) Diel Vertical Migration (DVM). The results show a high retention on actual and putative nursery grounds that could retain paralarvae in a suitable environment for survival, growth, and ultimately to recruit to the adult population. Moreover, model outputs showed high correlation between autumn-winter retention indexes and spring-summer commercial and artisanal landings in the following year. Considering the nine-month post-hatching lifespan of the species, autumn-winter retention indexes potentially provide forthcoming adult biomass predictions.

Receptor Heterodimerization Modulates Endocytosis through Collaborative and Competitive Mechanisms

Recruitment of receptors into clathrin-coated structures is essential to signal transduction and nutrient uptake. Among the many receptors involved in these processes, a significant fraction forms dimers. Dimerization of identical partners has generally been thought to promote receptor recruitment for uptake because of increased affinity of the dimer for the endocytic machinery. But what happens when receptors with substantially different affinities for the endocytic machinery come together to form a heterodimer? Evidence from diverse receptor classes, including G-protein-coupled receptors and receptor tyrosine kinases, suggests that heterodimerization with a strongly recruited receptor can drive significant recruitment of a receptor that lacks direct interactions with the endocytic machinery. However, a systematic biophysical understanding of this effect has yet to be established. Motivated by the potential of such events to influence cell signaling, here, we investigate the impact of receptor heterodimerization on endocytic recruitment using a family of engineered model receptors. As expected, we find that dimerization of a weakly recruited receptor with a strongly recruited receptor promotes incorporation of the weakly recruited receptor to endocytic structures. However, the effectiveness of this collaborative mechanism depends heavily on the relative strengths of endocytic recruitment of the two receptors that make up the dimer. Specifically, as the strength of endocytic recruitment of the weakly recruited receptor approaches that of the strongly recruited receptor, monomers of each receptor compete with heterodimers for space within endocytic structures. In this regime, the presence of the strongly recruited receptor drives a reduction in incorporation of the weakly recruited receptor into clathrin-coated structures. Similarly, as the strength of the dimer bond between the two receptors is progressively weakened, competition begins to dominate over collaboration. Collectively, these results demonstrate that the impact of receptor heterodimerization on endocytic recruitment is controlled by a delicate balance between collaborative and competitive mechanisms.

Population responses of common carp Cyprinus carpio to floods and droughts in the Pampean wetlands of South America

Common carp (Cyprinuscarpio) is a global invader that exhibits a wide distribution in Argentina, particularly in shallow lakes and wetlands of the Pampean region. The hydrological conditions of these environments are driven by variations in annual precipitation that determine inter annual changes in water levels leading to flood-drought cycles. The present study focused on understanding the C.carpio population responses to annual rainfall regime and long-term flood and drought events in the Ajó wetlands located in the east of the Pampean region. The results of a two-year biological sampling program showed that C.carpio feeding rate, reproduction, condition, and recruitment were associated with the hydrological cycle. Otolith derived age structure of the population and back-calculated recruitment strength revealed that extraordinary flooding events generated strong cohorts while dry years resulted in low recruitment. Its long-life span (maximum 14 years in Ajó) coupled with a high fecundity, and broad diet allows C.carpio to persist in refugia during dry years and capitalize on wet years when inundation of the floodplain enhances recruitment and facilitates spread. Management and control strategies for this invader should therefore incorporate hydrological variability by promoting intensive removal campaigns during dry years when populations are dominated by large fish confined in remnant water-bodies and, during wet years, carp harvest fisheries should be promoted to reduce population density when increased connectivity is likely to facilitate spread.

A question of scale: Weak evidence for broad regional synchrony in fish year-class strength within or among species in inland lakes

Spatially-correlated abiotic and biotic conditions can potentially induce synchrony in the dynamics of disparate populations or species. However, such potential synchrony among species or populations may be tempered by dynamics operating at finer temporal and spatial scales, as well as species-specific responses to environmental conditions. We examined within- and among-species synchrony in year-class strength across 130 lakes in northern Indiana over 30 years to evaluate the relative scale of potential synchrony and its possible ecological mechanisms in five recreationally important fish species: black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), redear sunfish (L. microlophus), and yellow perch (Perca flavescens). Bluegill and black crappie recruitment was significantly positively correlated when the species coexisted, and relative year-class strength of both species was positively related to mean annual wind speed. However, there were few other instances of recruitment synchrony between or within species, regardless of whether synchrony was assessed within or among lake systems. In addition, habitat similarity and regional weather patterns also played a limited and inconsistent role in shaping recruitment strength or synchrony in these small inland systems. These results suggest that fish recruitment dynamics in small, inland systems are most often a function of system-specific biotic interactions that mask limited input from broader climatological influences, and that understanding recruitment in small lakes will require examinations on appropriately fine spatial and temporal scales.

Physical-biological interactions in the ocean: case studies from the northern Canary Current Upwelling Ecosystem

Physical-biological interactions in the ocean: case studies from the northern Canary Current Upwelling Ecosystem

Implications of a climate-induced recruitment shift in the stock assessment of Patagonian grenadier (Macruronus magellanicus) in Chile

Patagonian grenadier (Macruronus magellanicus) is the most abundant demersal fisheries resource off Chilean Patagonia, and also is a key fisheries species off the south of Argentina and off the Falkland Islands. A Stock Synthesis assessment shows that this stock has declined in abundance off Chile, which has been attributed to a major change in recruitment strength, and subsequent production, after 1999. An assessment is conducted in which the change in recruitment is modelled as a shift in the stock-recruitment relationship. Management Strategy Evaluation is then used to examine the consequences of a mis-match between the assumptions related to recruitment in the assessment used to set the annual total allowable catch (TAC), and those in the operating model that represents the actual situation being managed. A management strategy that does not consider a shift in recruitment resulted in average TAC values of approximately 125,000 t, substantially larger than the sustainable yield of 45,000 t when there is a recruitment shift. A management strategy based on ignoring the shift in recruitment would thus lead to unsustainable catches, with major impacts on the ecosystem as well as the industry and coastal communities reliant on the fishery, if there was an actual shift in recruitment. Management of the fishery has not accounted for a recruitment shift, and annual landings have been consistently lower than the estimated annual TACs. The 2014 landings are similar to the long term TAC estimated by the assessment models under the Shift operating model. The history of the Patagonian grenadier fishery demonstrates the benefits of taking a precautionary approach that accounts for changes in fish productivity (whether climate-driven or otherwise). However, there can be considerable delays before a shift is observed in recruitment estimates or assessment model mis-specification is detected. The need for alternative approaches for providing more timely recruitment information is discussed.

Perineuronal nets control visual input via thalamic recruitment of cortical PV interneurons.

In the neocortex, critical periods (CPs) of plasticity are closed following the accumulation of perineuronal nets (PNNs) around parvalbumin (PV)-positive inhibitory interneurons. However, how PNNs tune cortical function and plasticity is unknown. We found that PNNs modulated the gain of visual responses and γ-oscillations in the adult mouse visual cortex in vivo, consistent with increased interneuron function. Removal of PNNs in adult V1 did not affect GABAergic neurotransmission from PV cells, nor neuronal excitability in layer 4. Importantly, PNN degradation coupled to sensory input potentiated glutamatergic thalamic synapses selectively onto PV cells. In the absence of PNNs, increased thalamic PV-cell recruitment modulated feed-forward inhibition differently on PV cells and pyramidal neurons. These effects depended on visual input, as they were strongly attenuated by monocular deprivation in PNN-depleted adult mice. Thus, PNNs control visual processing and plasticity by selectively setting the strength of thalamic recruitment of PV cells.