Discovery of Novel Steroid-Based Histamine H3 Receptor Antagonists/Inverse Agonists.

Steroid-based histamine H3 receptor antagonists (d-homoazasteroids) were designed by combining distinct structural elements of HTS hit molecules. They were characterized, and several of them displayed remarkably high affinity for H3 receptors with antagonist/inverse agonist features. Especially, the 17a-aza-d-homolactam chemotype demonstrated excellent H3R activity together with significant in vivo H3 antagonism. Optimization of the chemotype was initiated with special emphasis on the elimination of the hERG and muscarinic affinity. Additionally, ligand-based SAR considerations and molecular docking studies were performed to predict binding modes of the molecules. The most promising compounds (XXI, XXVIII, and XX) showed practically no muscarinic and hERG affinity. They showed antagonist/inverse agonist property in the in vitro functional tests that was apparent in the rat in vivo dipsogenia test. They were considerably stable in human and rat liver microsomes and provided significant in vivo potency in the place recognition and novel object recognition cognitive paradigms.

Optimization of Novel α7 Nicotinic Acetylcholine Receptor Positive Allosteric Modulators and the Discovery of a Preclinical Development Candidate Molecule (RGH-560).

During optimization of a previously identified lead compound, attempts were made to optimize the reactive indole structural element, the suboptimal metabolic stability, as well as the low kinetic solubility. It was concluded that the indole was important for in vitro activity. With the aim of further improvements, more thorough modifications were also carried out. As a result, a new chemotype (the azetidinespirochromone family) was identified, which proved to be 1 order of magnitude less lipophilic retaining the same high level of in vitro potency as the lead series itself, however, with improved metabolic stability and kinetic solubility. Compound 53 showed the most balanced physicochemical and pharmacological profile with significant in vivo efficacy in the scopolamine-induced amnesia test. Based on these promising results, cognitive enhancement through the positive modulation of α7 nAChRs appears to be a viable approach. Compound 53 was selected to be a preclinical development candidate (as RGH-560).

Response-related sensorimotor rhythms under scopolamine and MK-801 exposures in the touchscreen visual discrimination test in rats.

The human mu rhythm has been suggested to represent an important function in information processing. Rodent homologue rhythms have been assumed though no study has investigated them from the cognitive aspect yet. As voluntary goal-directed movements induce the desynchronization of mu rhythm, we aimed at exploring whether the response-related brain activity during the touchscreen visual discrimination (VD) task is suitable to detect sensorimotor rhythms and their change under cognitive impairment. Different doses of scopolamine or MK-801 were injected subcutaneously to rats, and epidural electroencephalogram (EEG) was recorded during task performance. Arciform ~ 10 Hz oscillations appeared during visual processing, then two characteristic alpha/beta desynchronization-resynchronization patterns emerged mainly above the sensorimotor areas, serving presumably different motor functions. Beyond causing cognitive impairment, both drugs supressed the touch-related upper alpha (10-15 Hz) reactivity for desynchronization. Reaction time predominantly correlated positively with movement-related alpha and beta power both in normal and impaired conditions. These results support the existence of a mu homologue rodent rhythm whose upper alpha component appeared to be modulated by cholinergic and glutamatergic mechanisms and its power change might indicate a potential EEG correlate of processing speed. The VD task can be utilized for the investigation of sensorimotor rhythms in rats.

Phenotypical Screening on Neuronal Plasticity in Hippocampal-Prefrontal Cortex Connectivity Reveals an Antipsychotic with a Novel Profile.

Dysfunction in the hippocampus-prefrontal cortex (H-PFC) circuit is a critical determinant of schizophrenia. Screening of pyridazinone-risperidone hybrids on this circuit revealed EGIS 11150 (S 36549). EGIS 11150 induced theta rhythm in hippocampal slice preparations in the stratum lacunosum molecular area of CA1, which was resistant to atropine and prazosin. EGIS 11150 enhanced H-PFC coherence, and increased the 8−9 Hz theta band of the EEG power spectrum (from 0.002 mg/kg i.p, at >30× lower doses than clozapine, and >100× for olanzapine, risperidone, or haloperidol). EGIS 11150 fully blocked the effects of phencyclidine (PCP) or ketamine on EEG. Inhibition of long-term potentiation (LTP) in H-PFC was blocked by platform stress, but was fully restored by EGIS 11150 (0.01 mg/kg i.p.), whereas clozapine (0.3 mg/kg ip) only partially restored LTP. EGIS 11150 has a unique electrophysiological profile, so phenotypical screening on H-PFC connectivity can reveal novel antipsychotics.

Intranasal Oxytocin Improves Social Behavior in Laboratory Beagle Dogs (Canis familiaris) Using a Custom-Made Social Test Battery.

For a long time, oxytocin has been thought to have a generally positive effect on social cognition and prosocial behavior; however, recent results suggested that oxytocin has beneficial effects only under certain conditions. The aim of the present study was to explore potential associations between social competence and the effect of intranasal oxytocin on the social behavior of laboratory beagle dogs. We expected oxytocin treatment to have a more pronounced positive effect on dogs with lower baseline performance in a social test battery. Thirty-six adult dogs of both sexes received 32 IU intranasal oxytocin and physiological saline (placebo) treatment in a double-blind, cross-over design, with 17-20 days between the two sessions. Forty minutes after the treatment, dogs participated in a social test battery consisting of eight situations. The situations were carried out within one session and took 20-30 min to complete. Principal component analysis on the coded behaviors identified four components (Willingness to interact, Preference for social contact, Non-aversive response to nonsocial threat, and Non-aversive response to social threat). The subjects' behavior during the placebo condition was used to assess their baseline performance. We found that oxytocin treatment had a differential effect on the behavior depending on the baseline performance of the individuals in all components, but only two treatment × baseline performance interactions remained significant in a less sensitive analysis. In accordance with our hypothesis, oxytocin administration increased dogs' contact seeking and affiliative behaviors toward humans but only for those with low baseline performance. Dogs with low baseline performance also showed significantly more positive (friendly) reactions to social threat after oxytocin administration than after placebo, while for dogs with high baseline performance, oxytocin administration led to a more negative (fearful) reaction. These results indicate that similar to those on humans, the effects of oxytocin on dogs' social behavior are not universally positive but are constrained by individual characteristics and the context. Nevertheless, oxytocin administration has the potential to improve the social behavior of laboratory beagle dogs that are socially less proficient when interacting with humans, which could have both applied and animal welfare implications.

Convergent cross-species pro-cognitive effects of RGH-235, a new potent and selective histamine H3 receptor antagonist/inverse agonist.

The histamine H3 receptor is a favourable target for the treatment of cognitive deficits. Here we report the in vitro and in vivo profile of RGH-235, a new potent, selective, and orally active H3 receptor antagonist/inverse agonist developed by Gedeon Richter Plc. Radioligand binding and functional assays were used for in vitro profiling. Procognitive efficacy was investigated in rodent cognitive tests, in models of attention deficit hyperactive disorder (ADHD) and in cognitive tests of high translational value (rat touch screen visual discrimination test, primate fixed-foreperiod visual reaction time task). Results were supported by pharmacokinetic studies, neurotransmitter release, sleep EEG and dipsogenia. RGH-235 displayed high affinity to H3 receptors (Ki = 3.0-9.2 nM, depending on species), without affinity to H1, H2 or H4 receptors and >100 other targets. RGH-235 was an inverse agonist ([35S] GTPγS binding) and antagonist (pERK1/2 ELISA), showing favourable kinetics, inhibition of the imetit-induced dipsogenia and moderate effects on sleep-wake EEG. RGH-235 stimulated neurotransmitter release both in vitro and in vivo. RGH-235 was active in spontaneously hypertensive rats (SHR), generally considered as a model of ADHD, and revealed a robust pro-cognitive profile both in rodent and primate tests (in 0.3-1 mg/kg) and in models of high translational value (e.g. in a rodent touch screen test and in non-human primates). The multiple and convergent procognitive effects of RGH-235 support the view that beneficial cognitive effects can be linked to antagonism/inverse agonism of H3 receptors.

Fragment-Based Optimization of Dihydropyrazino-Benzimidazolones as Metabotropic Glutamate Receptor-2 Positive Allosteric Modulators against Migraine.

Our previous scaffold-hopping attempts resulted in dihydropyrazino-benzimidazoles as metabotropic glutamate receptor-2 (mGluR2) positive allosteric modulators (PAMs) with suboptimal drug-like profiles. Here, we report an alternative fragment-based optimization strategy applied on the new dihydropyrazino-benzimidazolone scaffold. Analyzing published high-affinity mGluR2 PAMs, we used a pharmacophore-guided approach to identify suitable growing vectors and optimize the scaffold in these directions. This strategy resulted in a new fragment like lead (34) with improved druglike properties that were translated to sufficient pharmacokinetics and validated proof-of-concept studies in migraine. Gratifyingly, compound 34 showed reasonable activity in the partial infraorbital nerve ligation, a migraine disease model that might open this indication for mGluR2 PAMs.

HTS-based discovery and optimization of novel positive allosteric modulators of the α7 nicotinic acetylcholine receptor.

HTS campaign of the corporate compound collection resulted in a novel, oxalic acid diamide scaffold of α7 nACh receptor positive allosteric modulators. During the hit expansion, several derivatives, such as 4, 11, 17 demonstrated not only high in vitro potency, but also in vivo efficacy in the mouse place recognition test. The advanced hit molecule 11 was further optimized by the elimination of the putatively mutagenic aromatic-amine building block that resulted in a novel, aminomethylindole compound family. The most balanced physico-chemical and pharmacological profile was found in case of compound 55. Docking study revealed an intersubunit binding site to be the most probable for our compounds. 55 demonstrated favorable cognitive enhancing profile not only in scopolamine-induced amnesia (place recognition test in mice) but also in natural forgetting (novel object recognition test in rats). Compound 55 was, furthermore, active in a cognitive paradigm of high translational value, namely in the rat touch screen visual discrimination test. Therefore, 55 was selected as a lead compound for further optimization. Based on the obtained favorable results, the invented aminomethylindole cluster may provide a viable approach for cognitive enhancement through positive allosteric modulation of α7 nAChRs.

Discovery of novel positive allosteric modulators of the α7 nicotinic acetylcholine receptor: Scaffold hopping approach.

The paper focuses on the scaffold hopping-based discovery and characterization of novel nicotinic alpha 7 receptor positive modulator (α7 nAChR PAM) ligands around the reference molecule (A-867744). First, substantial efforts were carried out to assess the importance of the various pharmacophoric elements on the in vitro potency (SAR evaluation) by chemical modifications. Subsequently, several new derivatives with versatile, heteroaromatic central cores were synthesized and characterized. A promising, pyrazole-containing new chemotype with good physicochemical and in vitro parameters was identified. Retrospective analysis based on homology modeling was also carried out. Besides its favorable in vitro characteristics, the most advanced derivative 69 also showed in vivo efficacy in a rodent model of cognition (scopolamine-induced amnesia in the mouse place recognition test) and acceptable pharmacokinetic properties. Based on the in vivo data, the resulting molecule with advanced drug-like characteristics has the possibility to improve cognitive performance in a biologically relevant dose range, further strengthening the view of the supportive role of α7 nACh receptors in the cognitive processes.

Neuronal Dopamine D3 Receptors: Translational Implications for Preclinical Research and CNS Disorders.

Dopamine (DA), as one of the major neurotransmitters in the central nervous system (CNS) and periphery, exerts its actions through five types of receptors which belong to two major subfamilies such as D1-like (i.e., D1 and D5 receptors) and D2-like (i.e., D2, D3 and D4) receptors. Dopamine D3 receptor (D3R) was cloned 30 years ago, and its distribution in the CNS and in the periphery, molecular structure, cellular signaling mechanisms have been largely explored. Involvement of D3Rs has been recognized in several CNS functions such as movement control, cognition, learning, reward, emotional regulation and social behavior. D3Rs have become a promising target of drug research and great efforts have been made to obtain high affinity ligands (selective agonists, partial agonists and antagonists) in order to elucidate D3R functions. There has been a strong drive behind the efforts to find drug-like compounds with high affinity and selectivity and various functionality for D3Rs in the hope that they would have potential treatment options in CNS diseases such as schizophrenia, drug abuse, Parkinson's disease, depression, and restless leg syndrome. In this review, we provide an overview and update of the major aspects of research related to D3Rs: distribution in the CNS and periphery, signaling and molecular properties, the status of ligands available for D3R research (agonists, antagonists and partial agonists), behavioral functions of D3Rs, the role in neural networks, and we provide a summary on how the D3R-related drug research has been translated to human therapy.

Delay-dependent cholinergic modulation of visual short-term memory in rhesus macaques.

Cholinergic neuromodulation is known to play a key role in visual working memory (VWM) - keeping relevant stimulus representations available for cognitive processes for short time periods (up to a few minutes). Despite the growing body of evidence on how the neural and cognitive mechanisms of VWM dynamically change over retention time, there is mixed evidence available on cholinergic effects as a function of VWM delay period in non-human primates. Using the delayed matching to sample VWM task in rhesus macaques (N = 6), we aimed to characterize VWM maintenance in terms of performance changes as a function of delay duration (across a wide range of delays from 1 to 76 s). Then, we studied how cholinergic neuromodulation influences VWM maintenance using the muscarinic receptor antagonist scopolamine administered alone as transient amnestic treatment, and in combination with two doses of the acetylcholinesterase inhibitor donepezil, a widely used Alzheimer's medication probing for the reversal of scopolamine-induced impairments. Results indicate that scopolamine-induced impairments of VWM maintenance are delay-dependent and specifically affect the 15-33 s time range, suggesting that scopolamine worsens the normal decay of VWM with the passage of time. Donepezil partially rescued the observed scopolamine-induced impairments of VWM performance. These results provide strong behavioral evidence for the role of increased cholinergic tone and muscarinic neuromodulation in the maintenance of VWM beyond a few seconds, in line with our current knowledge on the role of muscarinic acetylcholine receptors in sustained neural activity during VWM delay periods.

Acute blockade of NR2C/D subunit-containing N-methyl-D-aspartate receptors modifies sleep and neural oscillations in mice.

N-methyl-d-aspartate receptors (NMDARs) play an important role in excitatory neurotransmission and have been associated with psychiatric conditions including schizophrenia and major depressive disorder. NMDARs are composed of two NR1 and two NR2 subunits. The type of NR2 subunit determines electrophysiological and pharmacological properties of the receptor. As the precise role of NR2C/D subunit-containing NMDARs is poorly understood in vivo, we have performed behavioural, quantitative electroencephalographic (qEEG) and polysomnographic analysis following acute pharmacological blockade of these receptor subtypes in adult male CD1 mice. We found that NR2C/D blockade impaired motor coordination and decreased the amount of gross movement. Moreover, EEG power in multiple frequency bands including theta and sigma were found to decrease significantly together with a decrease of theta oscillation frequency. Changes of these qEEG measures were accompanied by a decrease in time spent in slow-wave and rapid eye movement sleep, but an increase of time spent in quiet wakefulness. Furthermore, there was a significant decrease of sleep spindle oscillation density. These findings highlight the importance of NR2C/D-containing NMDARs and take a step towards establishing a link between electrophysiological correlates of psychiatric disorders and underlying synaptic dysfunctions.

Converging Evidence on D-Amino Acid Oxidase-Dependent Enhancement of Hippocampal Firing Activity and Passive Avoidance Learning in Rats.

BACKGROUND: N-methyl-D-aspartate (NMDA) receptor activation requires the binding of a co-agonist on the glycine-binding site. D-serine is the main endogenous co-agonist of NMDA receptors, and its availability significantly depends on the activity of the metabolic enzyme D-amino acid oxidase (DAAO). Inhibition of DAAO increases the brain levels of D-serine and modulates a variety of physiological functions, including cognitive behavior. METHODS: Here, we examined the effects of a novel 4-hydroxypyridazin-3(2H)-one derivative DAAO inhibitor, Compound 30 (CPD30), on passive avoidance learning and on neuronal firing activity in rats. RESULTS: D-serine administration was applied as reference, which increased cognitive performance and enhanced hippocampal firing activity and responsiveness to NMDA after both local and systemic application. Similarly to D-serine, CPD30 (0.1 mg/kg) effectively reversed MK-801-induced memory impairment in the passive avoidance test. Furthermore, local iontophoretic application of CPD30 in the vicinity of hippocampal pyramidal neurons significantly increased firing rate and enhanced their responses to locally applied NMDA. CPD30 also enhanced hippocampal firing activity after systemic administration. In 0.1- to 1.0-mg/kg doses, CPD30 increased spontaneous and NMDA-evoked firing activity of the neurons. Effects of CPD30 on NMDA responsiveness emerged faster (at 10 minutes post-injection) when a 1.0-mg/kg dose was applied compared with the onset of the effects of 0.1 mg/kg CPD30 (at 30 minutes post-injection). CONCLUSIONS: The present results confirm that the inhibition of DAAO enzyme is an effective strategy for cognitive enhancement. Our findings further facilitate the understanding of the cellular mechanisms underlying the behavioral effects of DAAO inhibition in the mammalian brain.

Sensory stimulation enhances phantom limb perception and movement decoding.

OBJECTIVE: A major challenge for controlling a prosthetic arm is communication between the device and the user's phantom limb. We show the ability to enhance phantom limb perception and improve movement decoding through targeted transcutaneous electrical nerve stimulation in individuals with an arm amputation. APPROACH: Transcutaneous nerve stimulation experiments were performed with four participants with arm amputation to map phantom limb perception. We measured myoelectric signals during phantom hand movements before and after participants received sensory stimulation. Using electroencephalogram (EEG) monitoring, we measured the neural activity in sensorimotor regions during phantom movements and stimulation. In one participant, we also tracked sensory mapping over 2 years and movement decoding performance over 1 year. MAIN RESULTS: Results show improvements in the participants' ability to perceive and move the phantom hand as a result of sensory stimulation, which leads to improved movement decoding. In the extended study with one participant, we found that sensory mapping remains stable over 2 years. Sensory stimulation improves within-day movement decoding while performance remains stable over 1 year. From the EEG, we observed cortical correlates of sensorimotor integration and increased motor-related neural activity as a result of enhanced phantom limb perception. SIGNIFICANCE: This work demonstrates that phantom limb perception influences prosthesis control and can benefit from targeted nerve stimulation. These findings have implications for improving prosthesis usability and function due to a heightened sense of the phantom hand.

Measuring sociability of mice using a novel three-chamber apparatus and algorithm of the LABORAS™ system.

BACKGROUND: The social approach and social novelty tests utilizing the three-chamber apparatus are widely accepted to measure social behavior of rodents. The LABORAS™ system offers a possibility to assess sociability of mice in a reliable and objective manner. NEW METHOD: We assessed the capability of the LABORAS™ sociability cage and algorithm (2.6.6) to detect social behaviors in mice. Furthermore, we investigated whether the system is able to detect various levels of sociability due to genetic background or after pharmacological treatments. RESULTS: By comparing manual scoring with various detection zone settings of the automated registration, the most fitting algorithm with a detection zone radius of 90 mm was identified. When different strains were investigated, C57Bl/6 J and NMRI mice proved to be social, while CD1 mice were found asocial. The system was able to detect the sociability increasing effect of R-baclofen (0.5 mg/kg i.p.) and oxytocin (12 ng i.c.v.) in asocial CD1 mice. The negative control PCP impaired social behavior of C57Bl/6 J mice (1 mg/kg i.p.) and increased social avoidance in CD1 mice (0.3 mg/kg i.p.). COMPARISON WITH EXISTING METHOD(S): This setup, in contrast to video frame analysis softwares, determines signal changes caused by movements of rodents allowing accurate detection and analysis of trajectories. Parallel automated measurements also allow replacing time and labor intensive, highly subjective human observational work. CONCLUSIONS: The set-up provides a fast and reliable method to examine social behavior of mice in the three-chamber apparatus. The system is capable of detecting pro or antisocial activity of pharmacological agents.

Stable Responsive EMG Sequence Prediction and Adaptive Reinforcement With Temporal Convolutional Networks.

Prediction of movement intentions from electromyographic (EMG) signals is typically performed with a pattern recognition approach, wherein a short dataframe of raw EMG is compressed into an instantaneous feature-encoding that is meaningful for classification. However, EMG signals are time-varying, implying that a frame-wise approach may not sufficiently incorporate temporal context into predictions, leading to erratic and unstable prediction behavior. OBJECTIVE: We demonstrate that sequential prediction models and, specifically, temporal convolutional networks are able to leverage useful temporal information from EMG to achieve superior predictive performance. METHODS: We compare this approach to other sequential and frame-wise models predicting 3 simultaneous hand and wrist degrees-of-freedom from 2 amputee and 13 non-amputee human subjects in a minimally constrained experiment. We also compare these models on the publicly available Ninapro and CapgMyo amputee and non-amputee datasets. RESULTS: Temporal convolutional networks yield predictions that are more accurate and stable than frame-wise models, especially during inter-class transitions, with an average response delay of 4.6 ms and simpler feature-encoding. Their performance can be further improved with adaptive reinforcement training. SIGNIFICANCE: Sequential models that incorporate temporal information from EMG achieve superior movement prediction performance and these models allow for novel types of interactive training. CONCLUSIONS: Addressing EMG decoding as a sequential modeling problem will lead to enhancements in the reliability, responsiveness, and movement complexity available from prosthesis control systems.

Discovery of dihydropyrazino-benzimidazole derivatives as metabotropic glutamate receptor-2 (mGluR2) positive allosteric modulators (PAMs).

A scaffold hopping strategy converted the known 1-[(1-methyl-1H-imidazol-2-yl)methyl]-4-phenylpiperidine core (1 and 2) by cyclization to a fused [6 + 5+6] membered heterocyclic mGluR2 PAM scaffold. Pharmacophore guided structure-activity relationship (SAR) studies resulted in a series of potent and metabolically stable mGluR2 PAMs. A representative optimized compound (95) having the most balanced profile, demonstrated efficacy in the PCP-induced hyper-locomotion model in mice that revealed the new chemotype being a promising PAM lead targeting mGluR2 receptors and providing support for further translational studies.

Discovery of novel steroidal histamine H3 receptor antagonists/inverse agonists. Part 2. Versatile steroidal carboxamide derivatives.

To further proceed with our previous work, novel steroid-based histamine H3 receptor antagonists were identified and characterized. Using an 'amine-to-amide' modification strategy at position 17, in vitro and in vivo potent monoamino steroid derivatives were found during the lead optimization. Usage of the non-basic amide moiety resulted in beneficial effects both in activity and selectivity. The 15α-carboxamido derivative 10 was not only highly active at human and rat H3 receptors, but also showed negligible activity at rat muscarinic receptors. Furthermore, it proved to be considerably stable in human and rat microsomes and showed significant in vivo potency in the pharmacodynamic rat dipsogenia test and in the water-labyrinth cognitive model. Based on all of these considerations, compound 10 was appointed to be a preclinical candidate.

Proprioceptive Sonomyographic Control: A novel method for intuitive and proportional control of multiple degrees-of-freedom for individuals with upper extremity limb loss.

Technological advances in multi-articulated prosthetic hands have outpaced the development of methods to intuitively control these devices. In fact, prosthetic users often cite "difficulty of use" as a key contributing factor for abandoning their prostheses. To overcome the limitations of the currently pervasive myoelectric control strategies, namely unintuitive proportional control of multiple degrees-of-freedom, we propose a novel approach: proprioceptive sonomyographic control. Unlike myoelectric control strategies which measure electrical activation of muscles and use the extracted signals to determine the velocity of an end-effector; our sonomyography-based strategy measures mechanical muscle deformation directly with ultrasound and uses the extracted signals to proportionally control the position of an end-effector. Therefore, our sonomyography-based control is congruent with a prosthetic user's innate proprioception of muscle deformation in the residual limb. In this work, we evaluated proprioceptive sonomyographic control with 5 prosthetic users and 5 able-bodied participants in a virtual target achievement and holding task for 5 different hand motions. We observed that with limited training, the performance of prosthetic users was comparable to that of able-bodied participants and thus conclude that proprioceptive sonomyographic control is a robust and intuitive prosthetic control strategy.

Purkinje cell number-correlated cerebrocerebellar circuit anomaly in the valproate model of autism.

While cerebellar alterations may play a crucial role in the development of core autism spectrum disorder (ASD) symptoms, their pathophysiology on the function of cerebrocerebellar circuit loops is largely unknown. We combined multimodal MRI (9.4 T) brain assessment of the prenatal rat valproate (VPA) model and correlated immunohistological analysis of the cerebellar Purkinje cell number to address this question. We hypothesized that a suitable functional MRI (fMRI) paradigm might show some altered activity related to disrupted cerebrocerebellar information processing. Two doses of maternal VPA (400 and 600 mg/kg, s.c.) were used. The higher VPA dose induced 3% smaller whole brain volume, the lower dose induced 2% smaller whole brain volume and additionally a focal gray matter density decrease in the cerebellum and brainstem. Increased cortical BOLD responses to whisker stimulation were detected in both VPA groups, but it was more pronounced and extended to cerebellar regions in the 400 mg/kg VPA group. Immunohistological analysis revealed a decreased number of Purkinje cells in both VPA groups. In a detailed analysis, we revealed that the Purkinje cell number interacts with the cerebral BOLD response distinctively in the two VPA groups that highlights atypical function of the cerebrocerebellar circuit loops with potential translational value as an ASD biomarker.