, 1997 and Crammond and Kalaska, 2000) and the posterior parietal

, 1997 and Crammond and Kalaska, 2000) and the posterior parietal cortex (Mountcastle et al., 1975, Snyder et al., 1997, Batista et al., 1999 and Gail and Andersen, 2006). The rule-selection hypothesis predicts that such areas only encode one goal at a time, according to the preliminarily selected Navitoclax rule, but not multiple rule-based potential goals simultaneously (Figure 1B, left). The goal-selection hypothesis predicts that they simultaneously encode all alternative potential movement goals prior to the decision (Figure 1B, right). Therefore, the two hypotheses are distinguishable only at predecision stages,

where the simultaneous existence of multiple, alternative, potential BIBW2992 order motor goals in a rule-selection task would favor the goal-selection hypothesis. Evidence for potential motor goal encoding in spatial rule selection tasks, i.e., in situations like in the example of the striker, is lacking. Several areas of the brain have been thought to

encode multiple potential motor goals in space, but only in experiments involving selection among multiple physical targets (Basso and Wurtz, 1998, Cisek and Kalaska, 2005 and Lau and Glimcher, 2008). However, in such tasks, multiple alternative spatial representations in the neural activity could be associated with multiple physical targets rather than motor goals. Therefore, target selection tasks are unsuitable for distinguishing between the rule- and

the goal-selection hypotheses. We measured the spatial selectivity of neurons in monkey parietal and premotor cortex during reach planning in a novel rule-selection task (Figure 2). We show that two spatial, rule-based potential motor goals can be simultaneously encoded, supporting the goal-selection hypothesis. Potential motor goals can encode all alternative choices as defined by the task (options), or biased representations of all choices based on before previous reward experience (preferences), depending on which stage of the decision process they represent. So far, empirical evidence for preference encoding has been lacking for skeletomotor tasks, even in target selection experiments. Many previous oculomotor studies showed modulation of neural target responses by choice probability or some form of value assignment (preference encoding) in different brain areas of monkey (Basso and Wurtz, 1998, Dorris and Munoz, 1998, Platt and Glimcher, 1999, Sugrue et al., 2004, Dorris and Glimcher, 2004, Yang and Shadlen, 2007, Lau and Glimcher, 2008, Kim and Basso, 2010 and Louie and Glimcher, 2010) and human (Hampton et al., 2006, Kable and Glimcher, 2007, Yanai et al., 2008 and Wunderlich et al., 2009). Target-selection experiments using skeletomotor behavior, like reaching, showed encoding of freely selected targets in the parietal reach region (PRR) (Scherberger and Andersen, 2007 and Pesaran et al.

This hypothesis was supported, in part, by the finding that MeCP2

This hypothesis was supported, in part, by the finding that MeCP2 and HDAC2 are colocalized in the NAc ( Figure 5A). The interactions of MeCP2 and HDAC2 were assessed using IP-Western blot analysis of vSTR proteins. We found that CUMS increased the formation of MeCP2-HDAC2 complexes in stressed BALB mice. This effect was reversed by continuous IMI treatment ( Figure 5B). Next, to investigate the effect of CUMS on the binding of MeCP2-HDAC2 complexes at the Gdnf promoter, we performed re-ChIP assays using an antibody for HDAC2 on the vSTR samples that were initially immunoprecipitated with an antibody for MeCP2. The re-ChIP assays indicated that the Gdnf promoter-containing DNA fragments of stressed BALB mice, see more but not B6 mice,

were significantly enriched compared with those of nonstressed mice, and this effect was reversed by continuous IMI treatment ( Figure 5C). These results suggest that the CUMS-induced binding of MeCP2-HDAC2 complexes to the Gdnf promoter silences this website its transcription. To investigate the role of DNA methylation in the CUMS-induced suppression of Gdnf expression and on depression-like behaviors, zebularine (ZEB), a DNA methyltransferase inhibitor, was continuously delivered into the NAc of BALB mice by an osmotic pump.

The experimental design is shown in Figure S1E. Five days after surgery, mice were subjected to 4 weeks of CUMS, followed by behavioral and expression analyses. We found that the social interaction times and sucrose preferences of stressed mice receiving ZEB (100 μM) were significantly higher compared with those times and preferences of vehicle-treated mice ( Figures 6A and B). In the novelty-suppressed feeding test, the latency to feed was significantly decreased in stressed mice receiving ZEB compared with vehicle-treated controls ( Figure 6C). In the forced swim test, the immobility times were significantly shorter in stressed and nonstressed mice receiving ZEB compared with

the Phosphoprotein phosphatase times of vehicle-treated mice ( Figure 6D). Furthermore, the mRNA levels of Gdnf in ZEB-treated mice were greater than the levels in vehicle-treated mice ( Figure 6E) in stressed conditions. These findings confirm that there is less DNA methylation of CpG site 2 at the Gdnf promoter in stressed mice treated with ZEB compared with vehicle-treated mice ( Figure 6F). We also tested whether intra-NAc delivery of RG108, a potent, nonnucleoside inhibitor of DNA methylation, could reverse the increased depression-like behaviors in BALB mice. Similar to the effects of ZEB, continuous delivery of RG108 (100 μM) directly into the NAc increased the social interaction time ( Figure 6G) and sucrose preference ( Figure 6H) of mice in the stressed condition. Furthermore, we found that CUMS increased the mRNA expressions for DNA methyltransferase 1 (DNMT1) and DNMT3a, but not DNMT3b, in the vSTR of stressed mice. This effect was reversed by continuous intra-NAc delivery of ZEB and RG108 ( Figure 6I).

VAMP7 also localizes to endosomal and lysosomal membranes at the

VAMP7 also localizes to endosomal and lysosomal membranes at the cell body and dendrites, but it has been found to reside only on synaptic vesicles at boutons (Muzerelle et al., 2003, Salazar et al., 2006 and Scheuber et al., 2006), where we analyzed the data. We further confirm the localization of endogenous VAMP7 to membranes that behave like synaptic vesicles by both gradient fractionation and immunoisolation (Figure S4A–S4C). However, it remains possible that overexpression

may result in mislocalization of VAMP7 to endosomes or lysosomes at presynaptic sites, and hence an apparent reduction in recycling pool size. To address this possibility, we expressed VAMP7 and VAMP2 as control fused at their lumenal C-termini to horseradish peroxidase (HRP) (Leal-Ortiz et al., 2008). Localization of HRP within vesicles prevents diffusion of the HRP reaction product KU-57788 research buy and thus unambiguously labels the VAMP7+ or VAMP2+ population. Both VAMP7- and VAMP2-HRP indeed label only

a subset BMS-907351 in vitro of synaptic vesicles that intermingle with unlabeled vesicles (Figure 4A). In both cases, the HRP reaction product accumulates in small, round vesicles with the same diameter as unlabeled vesicles (Figures 4B and 4C), and not within any other compartment at or adjacent to the nerve terminal. Thus, VAMP7 localizes to membranes morphologically indistinguishable from synaptic vesicles. Resting pool vesicles do not apparently respond to field stimulation, but do they have the capacity for exocytosis under other circumstances? Previous work has suggested that evoked and spontaneous release may derive from distinct vesicle populations (Chung et al., 2010, Fredj and Burrone, 2009 and Sara et al., 2005) (but see also (Groemer and Klingauf, 2007, Hua et al., 2010 and Wilhelm et al., 2010). This predicts that as a protein enriched in the resting (and

hence unresponsive) pool of synaptic vesicles, VAMP7 may undergo more spontaneous release than VGLUT1. To test this possibility, we used an optical assay for spontaneous release. Like bafilomycin, the H+-ATPase inhibitor until folimycin prevents the reacidification of vesicles that have undergone exocytosis. However, folimycin is less cell permeant than bafilomycin, reducing its access to intracellular vesicles that have not undergone exocytosis (Atasoy et al., 2008). In the presence of folimycin and tetrodotoxin (TTX), the increase in fluorescence of VGLUT1- and VAMP7-pHluorin should thus reflect spontaneous release (Figure 5A). This increase in fluorescence is not due to leakage of folimycin into the neurons and alkalinization of vesicles that have not undergone exocytosis because it is greatly reduced by the high-affinity, cell-permeant calcium chelator BAPTA-AM (Figure S5A), consistent with the known calcium dependence of spontaneous release (Wasser and Kavalali, 2009).

There was a general consensus

that (if there was evidence

There was a general consensus

that (if there was evidence of effectiveness), the use of CM in principle might be a useful addition to the therapeutic armamentarium. This idea was most positively endorsed by those in the professional groups with greatest experience and training. AUY-922 clinical trial However, there was a range of views expressed: from unequivocal benefit, through to a more cautious acceptance of it. Concerns were raised that in a system with limited resources it may be seen as a cost saving alternative, replacing established and more valued interventions (e.g., time with a member of staff) and therefore best kept as a ‘last resort’. Much of the discussions of aspects of treatment delivery are common to other aspects of health care where incentives are used as part of treatment. They were framed within the concepts of health economics and medical ethics and included the following five themes: practicalities of implementation; the opportunity costs of the intervention; the possibility of CM acting as a perverse incentive; issues of equity; and the potential impact on the therapeutic relationship (see Fig. 2 and Table 2.1). The practicalities and potential problems of implementation was a major theme across all but one

focus group (service users) and included Selleckchem OTX015 aspects that would be anticipated from any discussion about change management. However, concerns were also expressed that were more specific to implementing a behavioural intervention, where it is well recognised that the precise details are integral to the effectiveness of the implementation, and the possibility of unintended consequences. Regarding

Calpain the implementation of CM within a publicly funded system, participants in four groups (3 professional groups and the ex-service user group) expressed concerns about the opportunity cost of such a change of focus. All nine groups expressed concerns about the feasibility of the level of urine testing (three times per week). However, whilst the professional teams viewed this as being resource heavy and had concerns about the potential opportunity costs of delivery (see Table 2.1), the service user groups felt strongly that such a regime acted as a disincentive that would outweigh any benefit from the financial incentive offered. Concerns about the notion of equity of access to interventions within the treatment system, and that CM might act to incentivise non-engagement (i.e., act as a perverse incentive) were discussed in 6/9 groups. Concerns about equity were primarily expressed in the professional groups. Service user groups felt it more appropriate for CM to be offered on an individual basis depending on the needs of the service user at a particular time, rather than being mandated to particular groups and certain points in their treatment journey.

The results of this analysis are summarized in Figure 4 Males an

The results of this analysis are summarized in Figure 4. Males and females showed strong and statistically indistinguishable positive relationships between the pace of left FPC CT change and that within widespread bilateral medial and see more lateral prefrontal, lateral temporal, angular and supramarginal, and superior parietal cortices (Figure 4A). Coupling with left FPC maturation was, however, significantly enhanced in females as compared to males in bilateral DLPFC and right VLPFC (Figure 4B). Enhanced coupling with left FPC maturation in males relative to females was restricted to small regions in the left orbitofrontal

cortex, marginal sulcus, and parieto-occipital fissure. These findings held when analyses were conducted using CT change maps in which CT had been expressed as a proportion

of starting CT (results not shown), suggesting that sex differences in maturational coupling are unlikely to be an artifact of differences in brain size between males and females. The findings generated by our study of correlated anatomical change within the developing human brain fall into three broad groups. First, we demonstrate that rates of anatomical change in different parts of the developing cortex show a highly nonrandom correlational structure, and that the magnitude of this maturational coupling varies systematically across the cortical sheet. Specifically, rates of CT change in frontal and temporal association Selleck Docetaxel cortices display the strongest and most spatially extensive correlation with CT changes in the rest of the cortex, whereas the opposite is seen in primary visual and sensorimotor cortices. These regional differences show several convergences with regional differences in cross-sectional CT correlation (Lerch et al., 2006), and we were able to rule out the possibility that these convergences solely arose as an artifact of hidden

relationship between CT and CT change Cell press in our data set. A reasonable inference therefore is that patterns of cross-sectional CT correlation arise as a result of correlated maturation over time. By extension, established characteristics of cross-sectional CT correlation including its heritability (Schmitt et al., 2009), network modularity (Chen et al., 2008), and relationship with cognitive ability (Lerch et al., 2006) are likely to apply to correlated CT change, and these hypotheses can be directly tested in future work. The factors that might contribute to the regional differences in degree of coupling with global cortical maturation remain unclear.

In addition, all subjects received transdermal nicotine replaceme

In addition, all subjects received transdermal nicotine replacement for 8 weeks following their quit date and brief smoking cessation counseling throughout the entire treatment

period. We hypothesized that participants who received naltrexone would report higher rates of abstinence from cigarette smoking and lower post-quit weight gain compared to participants who received placebo. One hundred seventy-two cigarette smokers were enrolled. Recruitment was via advertisements placed in local media outlets, mailings (to past participants, potential participants, and health care professionals), fliers, fax referrals from healthcare providers, press see more releases, and websites. To be eligible, all smokers needed Saracatinib to be classified as weight-concerned smokers based on 2 criteria. Concern about gaining weight after quitting was assessed using the questions Perkins et al. (2001) used to define weight

concern in their clinical trial of CBT. These included “How concerned are you about gaining weight after quitting?” and “How concerned would you be if quitting smoking caused you to permanently gain 10 lbs?” Consistent with their criteria, a rating of 50 or higher on a 100 mm scale on either question qualified the subject on this criterion. Smoking to manage weight was assessed with the weight

control subscale of the Smoking Consequences Questionnaire [SCQ] (Copeland et al., 1995) on which participants rate their expectations about the consequences of smoking a cigarette on a scale of 0-9 with 1 being “completely unlikely” and 9 being “completely likely”. Five items make up this subscale (alpha = 0.96) and include “smoking keeps my weight down”, “cigarettes keep Parvulin me from eating more than I should”, “smoking helps me control my weight’, “cigarettes keep me from overeating”, and “smoking controls my appetite”. A mean rating of 6 or above (“somewhat likely”) qualified participants on this criterion. Other inclusion and exclusion criteria were age 18 and older, willingness and ability to give written consent, smoking greater than 10 cigarettes per day for at least 1 year, at least 1 prior attempt to stop smoking, baseline expired carbon monoxide (CO) level of at least 10 ppm, weight of at least 100 lbs, English speaking, and only 1 participant per household.

For all figures p-values are as follows ∗p < 0 05, ∗∗p < 0 01, ∗∗

For all figures p-values are as follows ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. All statistics were performed in Graphpad Prism. We thank Rylan Larsen and Matt Judson for critical readings of the manuscript, Paul Manis for experimental advice, Yong-hui Jiang for his generous donation of C57BL/6J Ube3a-deficient mutant mice and Kristen Phend for histological support. Imaging was supported by the Confocal and Multiphoton Imaging Core

of NINDS Center Grant P30 NS045892 and NICHD Center Grant P30 HD03110. M.L.W was supported by a Neurobiology Research Training Grant from NINDS (5T32NS007431) and a National Research Service Award from NINDS (1F31NS077847). R.J.W. was supported by NINDS Ruxolitinib cell line (5R01NS035527). B.D.P was supported by the Angelman Syndrome Foundation, the Simons Foundation, the National Eye Institute (R01EY018323), and the National Institute of Mental Health (1R01MH093372). “
“Estrogens influence hippocampal function through multiple mechanisms with time

courses ranging from minutes to days. Recent recognition that a key estrogen, GW786034 supplier 17β-estradiol (E2), is produced as a neurosteroid in the brains of both males and females has fueled a resurgence of interest in acute nongenomic estrogen signaling (Woolley, 2007). Many hippocampal neurons express the E2-synthesizing enzyme P450 aromatase (Hojo et al., 2004), which could provide a source of locally generated E2 to acutely modulate synaptic function in vivo. E2 applied to hippocampal slices rapidly potentiates synaptically evoked field excitatory postsynaptic potentials (EPSPs) in the CA1 region (Teyler et al., 1980), as well as intracellularly recorded EPSPs (Wong and Moss, 1992) and excitatory postsynaptic currents (EPSCs) (Smejkalova and Woolley, 2010) in CA1 pyramidal cells. On the one hand, E2 appears to act on excitatory synapses through the β form of the classical estrogen receptor (ERβ). ERβ agonists rapidly increase AMPA receptor (AMPAR)-mediated field EPSPs (Kramár et al., 2009) and unless EPSCs (Smejkalova and Woolley, 2010), whereas ERα agonists do not affect AMPAR-mediated responses. On the other hand, E2-induced potentiation of field EPSPs is reduced in ERα knockout

compared to wild-type mice (Fugger et al., 2001), suggesting a more complex action of E2. One possibility is that E2 acutely potentiates excitatory synapses via ERβ and simultaneously suppresses inhibitory synapses via ERα. To investigate acute modulation of inhibitory synapses, we recorded GABAA receptor-mediated inhibitory postsynaptic currents (IPSCs) in CA1 pyramidal cells with application of E2 to hippocampal slices from adult female rats. We found that, in a subset of cells, E2 rapidly suppresses IPSCs. Subsequent studies indicated that E2-induced IPSC suppression depends on ERα- and mGluR1-dependent mobilization of endocannabinoids to decrease the probability of GABA release from CB1R-containing inhibitory synaptic inputs. Additionally, E2-induced suppression of IPSCs occurred in females but not in males.

It is challenging to measure brain activity in awake toddlers bec

It is challenging to measure brain activity in awake toddlers because of their inability to remain still. Several studies, however, have successfully measured brain activity in typically developing toddlers under anesthesia (Kiviniemi et al., 2000), under mild sedation (Fransson et al., CHIR99021 2007), or during natural sleep (Gao et al., 2009 and Liu et al., 2008). Here, we report fMRI data acquired from 72 naturally sleeping toddlers (1–3.5 years old) who were either typically developing, language delayed, or autistic. Compared to both other groups, toddlers with autism exhibited significantly

weaker interhemispheric correlations in inferior frontal gyrus (IFG) and superior temporal gyrus (STG), two areas commonly associated with language production and comprehension. Interhemispheric synchronization strength was positively correlated with verbal ability and negatively correlated with autism severity, and it enabled accurate identification of autistic toddlers with high sensitivity (72%) and specificity (84%). These results

suggest that poor neural synchronization is a notable neurophysiological characteristic that is evident at the earliest stages of autism development and is related to the severity of behavioral symptoms. Finally, the ability to measure this characteristic NLG919 mouse during sleep, when task compliance and subject cooperation are not required, suggests its utility as a possible diagnostic measure to aid growing efforts of identifying autism during infancy Ketanserin (Pierce et al., 2009 and Zwaigenbaum et al., 2009). The data presented in this study were gathered from several studies performed at the Autism Center of Excellence (ACE) in San Diego, CA. In all scans, toddlers were presented with blocks of soft auditory stimuli that were interleaved with silence.

To ensure that the differences in synchronization between the groups were not due to differences in possible auditory-evoked responses, we first “regressed out” the experiment structure from the data of each subject (see Experimental Procedures). This ensured that there was zero correlation between each voxel’s time course and the experiment structure, effectively removing stimulus-evoked responses while leaving spontaneous fMRI fluctuations in the data (see analyses below). Spontaneous fMRI activity during natural sleep exhibited robust and spatially selective correlations between homologous locations across the two hemispheres. To demonstrate this, we sampled activity in six left hemisphere “seed” regions of interest (ROIs) and computed the correlation between each “seed” time course and the time course of every voxel in the cortex.

In summary, we report that excitatory synaptic input from columna

In summary, we report that excitatory synaptic input from columnar and long-range intracortical circuits targeted to segregated sites within the electrically distributed dendritic tree of L5B pyramidal neurons can be integrated by the nonlinear interaction between axosomatic, apical dendritic trunk, and tuft integration compartments. Dendritic voltage-gated KV channels control this interaction. We suggest, therefore, that apical dendritic trunk and tuft KV channels operate as a tuneable gain control for interactive integration. As KV channels are regulated by neuromodulatory systems (Hoffman and Johnston, 1998, Hoffman and Johnston, 1999 and Nicoll

et al., 1990), apical dendritic KV channels may represent an important target for refining interactive integration in pyramidal neurons to guide behaviorally relevant Navitoclax research buy neuronal computations. Coronal brain slices containing the somatosensory Bortezomib price cortices were prepared from 4- to 7-week-old male Wistar rats following university and institutional guidelines using methods previously described (Williams, 2004 and Williams, 2005). Slices were submerged in artificial cerebrospinal fluid (aCSF) containing (in mM): 125 NaCl, 25 NaHCO3, 1.25 NaH2PO4, 3 KCl, 2 or 1.3 CaCl2, 1.0 MgCl2,

25 glucose, and 3 Na-pyruvate at 36°C –37°C. Dual and triple whole-cell recordings were made from thick-tufted L5B pyramidal neurons with BVC-700A (Dagan) amplifiers in “bridge” mode, and the electrode capacitance was carefully compensated. Somatic pipettes had open tip resistance of 3–6 MΩ and dendritic pipettes 10–12 MΩ, when filled with (in mM): 135 K-gluconate; 7 NaCl; 10 HEPES; 10 phosphocreatine; 2 Na2-ATP; 0.3 Na-GTP; 2 MgCl2 and 0.01 Alexa Fluor 568 or 594 (Molecular Probes) (pH 7.3–7.4; KOH). Neuronal

morphology was recorded by fluorescence microscopy (QImaging). Data were excluded if the nexus recording electrode was >50 μm from this site. The length of the apical dendritic Mephenoxalone trunk measured from structural images (soma intersection to nexus) was 749 ± 26 μm and diameter 2.8 ± 0.1 μm at 20 μm from the nexus (n = 13). The path length of tuft dendrites was 413 ± 14 μm and diameter between 0.8 and 2.3 μm (n = 40). Tuft recordings were discarded if series resistance was >60 MΩ. Simulated EPSCs were generated as ideal current sources (τrise and τdecay of 0.5 and 5 ms, respectively). Temporally uncorrelated barrages of simulated EPSCs were generated as trains of pseudorandomly occurring inputs (peak amplitude 0.1 nA) and injected at somatic and dendritic sites as previously described (Williams, 2005). Simulated EPSCs were therefore generated at somatic and dendritic sites as point current sources and not distributed conductances. Current and voltage signals were low pass filtered (DC to 10 kHz) and acquired at 30–50 kHz. Data were acquired and analyzed using AxographX software (AxographX). All drugs were dissolved in the recording aCSF and applied by bath perfusion.

, 2010 and Haider et al , 2013), which is partly attributed

, 2010 and Haider et al., 2013), which is partly attributed SAHA HDAC in vitro to increased inhibition in the cortical network (Haider et al., 2010, Adesnik et al., 2012, Nienborg et al., 2013 and Vaiceliunaite et al., 2013). However, when averaged over the entire stimulation period, we found that costimulation of the surround with either natural or phase-scrambled movies slightly depolarized the median absolute Vm in immature and mature mice (Figures 3B and 3H; p = 0.017 and p <

0.0001, respectively; Friedman’s test). Because it is unclear how such small average differences in Vm could contribute to changes in the spiking response selectivity, we focused our analysis on how Vm temporal dynamics are altered by surround stimulation. We quantified moment-to-moment differences in Vm between RF and full-field stimulation for each neuron (ΔVm = VmRF+surround − VmRF; see Experimental Procedures). Both natural and phase-randomized surround

stimuli induced hyperpolarizing (negative ΔVm) and depolarizing (positive ΔVm) Vm changes relative to RF stimulation alone (Figures 3C and 3G). Plotting the median ΔVm of each cell against its average change in firing rate revealed Alisertib cell line that ΔVm was strongly correlated with the firing rate suppression during full-field stimulation in mature, but not in immature mice (Figures 3D and 3I; see figure legend for details). Moreover, the distribution of ΔVm was shifted to more negative values during natural than phase-randomized surround stimulation in mature V1 (Figure 3D, p = 0.027, Wilcoxon rank sum test), but not in immature V1 (Figure 3I, p = 0.6, Wilcoxon rank sum test). How could relatively small differences in ΔVm between natural and phase-randomized surround stimulation lead to pronounced differences in firing rate suppression check incurred by these surround stimuli in mature V1? To address this question, we determined the dependency of ΔVm on the particular membrane potential value (relative to spike threshold) elicited by the RF stimulus at each time point during movie presentation (VmRF). Strikingly, in both age groups, ΔVm exhibited a negative linear dependency on membrane depolarization during RF stimulation:

neurons were relatively most hyperpolarized during RF + surround stimulation (negative ΔVm) specifically at times when VmRF was closest to spiking threshold (Figures 3E and 3J). Which mechanisms underlie the pronounced surround-induced relative hyperpolarization when the Vm is most depolarized during RF stimulation? Surround stimulation has been shown to increase synaptic inhibition (Haider et al., 2010, Haider et al., 2013 and Adesnik et al., 2012). We therefore tested the influence of chloride (Cl−)-mediated conductances on the inverse relationship between ΔVm and VmRF. We performed whole-cell recordings using an elevated Cl− concentration in the intracellular solution ([Cl−]i, see Experimental Procedures) to modify the reversal potential of GABAA-mediated conductances (Figure 4A).