Neuronal activity patterns in microcircuits of the cerebellar cortical C3 zone during reaching.

The cerebellum is the largest sensorimotor structure in the brain. A fundamental organizational feature of its cortex is its division into a series of rostrocaudally elongated zones. These are defined by their inputs from specific parts of the inferior olive and Purkinje cell output to specific cerebellar and vestibular nuclei. However, little is known about how patterns of neuronal activity in zones, and their microcircuit subdivisions, microzones, are related to behaviour in awake animals. In the present study, we investigated the organization of microzones within the C3 zone and their activity during a skilled forelimb reaching task in cats. Neurons in different microzones of the C3 zone, functionally determined by receptive field characteristics, differed in their patterns of activity during movement. Groups of Purkinje cells belonging to different receptive field classes, and therefore belonging to different microzones, were found to collectively encode different aspects of the reach controlled by the C3 zone. Our results support the hypothesis that the cerebellar C3 zone is organized and operates within a microzonal frame of reference, with a specific relationship between the sensory input to each microzone and its motor output. KEY POINTS: A defining feature of cerebellar organization is its division into a series of zones and smaller subunits termed microzones. Much of how zones and microzones are organized has been determined in anaesthetized preparations, and little is known about their function in awake animals. We recorded from neurons in the forelimb part of the C3 zone 'in action' by recording from single cerebellar cortical neurons located in different microzones defined by their peripheral receptive field properties during a forelimb reach-retrieval task in cats. Neurons from individual microzones had characteristic patterns of activity during movement, indicating that function is organized in relation to microcomplexes.

Redefining the cerebellar cortex as an assembly of non-uniform Purkinje cell microcircuits.

The adult mammalian cerebellar cortex is generally assumed to have a uniform cytoarchitecture. Differences in cerebellar function are thought to arise primarily through distinct patterns of input and output connectivity rather than as a result of variations in cortical microcircuitry. However, evidence from anatomical, physiological and genetic studies is increasingly challenging this orthodoxy, and there are now various lines of evidence indicating that the cerebellar cortex is not uniform. Here, we develop the hypothesis that regional differences in properties of cerebellar cortical microcircuits lead to important differences in information processing.

Sensorimotor, language, and working memory representation within the human cerebellum.

The cerebellum is involved in a wide range of behaviours. A key organisational principle from animal studies is that somatotopically corresponding sensory input and motor output reside in the same cerebellar cortical areas. However, compelling evidence for a similar arrangement in humans and whether it extends to cognitive functions is lacking. To address this, we applied cerebellar optimised whole-brain functional MRI in 20 healthy subjects. To assess spatial overlap within the sensorimotor and cognitive domains, we recorded activity to a sensory stimulus (vibrotactile) and a motor task; the Sternberg verbal working memory (VWM) task; and a verb generation paradigm. Consistent with animal data, sensory and motor activity overlapped with a somatotopic arrangement in ipsilateral areas of the anterior and posterior cerebellum. During the maintenance phase of the Sternberg task, a positive linear relationship between VWM load and activity was observed in right Lobule VI, extending into Crus I bilaterally. Articulatory movement gave rise to bilateral activity in medial Lobule VI. A conjunction of two independent language tasks localised activity during verb generation in right Lobule VI-Crus I, which overlapped with activity during VWM. These results demonstrate spatial compartmentalisation of sensorimotor and cognitive function in the human cerebellum, with each area involved in more than one aspect of a given behaviour, consistent with an integrative function. Sensorimotor localisation was uniform across individuals, but the representation of cognitive tasks was more variable, highlighting the importance of individual scans for mapping higher order functions within the cerebellum.

Cytokine therapy-mediated neuroprotection in a Friedreich's ataxia mouse model.

OBJECTIVES: Friedreich's ataxia is a devastating neurological disease currently lacking any proven treatment. We studied the neuroprotective effects of the cytokines, granulocyte-colony stimulating factor (G-CSF) and stem cell factor (SCF) in a humanized murine model of Friedreich's ataxia. METHODS: Mice received monthly subcutaneous infusions of cytokines while also being assessed at monthly time points using an extensive range of behavioral motor performance tests. After 6 months of treatment, neurophysiological evaluation of both sensory and motor nerve conduction was performed. Subsequently, mice were sacrificed for messenger RNA, protein, and histological analysis of the dorsal root ganglia, spinal cord, and cerebellum. RESULTS: Cytokine administration resulted in significant reversal of biochemical, neuropathological, neurophysiological, and behavioural deficits associated with Friedreich's ataxia. Both G-CSF and SCF had pronounced effects on frataxin levels (the primary molecular defect in the pathogenesis of the disease) and a regulators of frataxin expression. Sustained improvements in motor coordination and locomotor activity were observed, even after onset of neurological symptoms. Treatment also restored the duration of sensory nerve compound potentials. Improvements in peripheral nerve conduction positively correlated with cytokine-induced increases in frataxin expression, providing a link between increases in frataxin and neurophysiological function. Abrogation of disease-related pathology was also evident, with reductions in inflammation/gliosis and increased neural stem cell numbers in areas of tissue injury. INTERPRETATION: These experiments show that cytokines already clinically used in other conditions offer the prospect of a novel, rapidly translatable, disease-modifying, and neuroprotective treatment for Friedreich's ataxia. Ann Neurol 2017;81:212-226.

Neural Correlates of Fear in the Periaqueductal Gray.

The dorsal and ventral periaqueductal gray (dPAG and vPAG, respectively) are embedded in distinct survival networks that coordinate, respectively, innate and conditioned fear-evoked freezing. However, the information encoded by the PAG during these survival behaviors is poorly understood. Recordings in the dPAG and vPAG in rats revealed differences in neuronal activity associated with the two behaviors. During innate fear, neuronal responses were significantly greater in the dPAG compared with the vPAG. After associative fear conditioning and during early extinction (EE), when freezing was maximal, a field potential was evoked in the PAG by the auditory fear conditioned stimulus (CS). With repeated presentations of the unreinforced CS, animals displayed progressively less freezing accompanied by a reduction in event-related field potential amplitude. During EE, the majority of dPAG and vPAG units increased their firing frequency, but spike-triggered averaging showed that only ventral activity during the presentation of the CS was significantly coupled to EMG-related freezing behavior. This PAG-EMG coupling was only present for the onset of freezing activity during the CS in EE. During late extinction, a subpopulation of units in the dPAG and vPAG continued to show CS-evoked responses; that is, they were extinction resistant. Overall, these findings support roles for the dPAG in innate and conditioned fear and for the vPAG in initiating but not maintaining the drive to muscles to generate conditioned freezing. The existence of extinction-susceptible and extinction-resistant cells also suggests that the PAG plays a role in encoding fear memories. SIGNIFICANCE STATEMENT: The periaqueductal gray (PAG) orchestrates survival behaviors, with the dorsal (dPAG) and ventral (vPAG) PAG concerned respectively with innate and learnt fear responses. We recorded neural activity from dPAG and vPAG in rats during the expression of innate fear and extinction of learned freezing. Cells in dPAG responded more robustly during innate fear, but dPAG and vPAG both encoded the time of the conditioned stimulus during early extinction and displayed extinction sensitive and resistant characteristics. Only vPAG discharge was correlated with muscle activity, but this was limited to the onset of conditioned freezing. The data suggest that the roles of dPAG and vPAG in fear behavior are more complex than previously thought, including a potential role in fear memory.

Heterogeneity of Purkinje cell simple spike-complex spike interactions: zebrin- and non-zebrin-related variations.

KEY POINTS: Cerebellar Purkinje cells (PCs) generate two types of action potentials, simple and complex spikes. Although they are generated by distinct mechanisms, interactions between the two spike types exist. Zebrin staining produces alternating positive and negative stripes of PCs across most of the cerebellar cortex. Thus, here we compared simple spike-complex spike interactions both within and across zebrin populations. Simple spike activity undergoes a complex modulation preceding and following a complex spike. The amplitudes of the pre- and post-complex spike modulation phases were correlated across PCs. On average, the modulation was larger for PCs in zebrin positive regions. Correlations between aspects of the complex spike waveform and simple spike activity were found, some of which varied between zebrin positive and negative PCs. The implications of the results are discussed with regard to hypotheses that complex spikes are triggered by rises in simple spike activity for either motor learning or homeostatic functions. ABSTRACT: Purkinje cells (PCs) generate two types of action potentials, called simple and complex spikes (SSs and CSs). We first investigated the CS-associated modulation of SS activity and its relationship to the zebrin status of the PC. The modulation pattern consisted of a pre-CS rise in SS activity, and then, following the CS, a pause, a rebound, and finally a late inhibition of SS activity for both zebrin positive (Z+) and negative (Z-) cells, though the amplitudes of the phases were larger in Z+ cells. Moreover, the amplitudes of the pre-CS rise with the late inhibitory phase of the modulation were correlated across PCs. In contrast, correlations between modulation phases across CSs of individual PCs were generally weak. Next, the relationship between CS spikelets and SS activity was investigated. The number of spikelets/CS correlated with the average SS firing rate only for Z+ cells. In contrast, correlations across CSs between spikelet numbers and the amplitudes of the SS modulation phases were generally weak. Division of spikelets into likely axonally propagated and non-propagated groups (based on their interspikelet interval) showed that the correlation of spikelet number with SS firing rate primarily reflected a relationship with non-propagated spikelets. In sum, the results show both zebrin-related and non-zebrin-related physiological heterogeneity in SS-CS interactions among PCs, which suggests that the cerebellar cortex is more functionally diverse than is assumed by standard theories of cerebellar function.

The dynamic relationship between cerebellar Purkinje cell simple spikes and the spikelet number of complex spikes.

KEY POINTS: Purkinje cells are the sole output of the cerebellar cortex and fire two distinct types of action potential: simple spikes and complex spikes. Previous studies have mainly considered complex spikes as unitary events, even though the waveform is composed of varying numbers of spikelets. The extent to which differences in spikelet number affect simple spike activity (and vice versa) remains unclear. We found that complex spikes with greater numbers of spikelets are preceded by higher simple spike firing rates but, following the complex spike, simple spikes are reduced in a manner that is graded with spikelet number. This dynamic interaction has important implications for cerebellar information processing, and suggests that complex spike spikelet number may maintain Purkinje cells within their operational range. ABSTRACT: Purkinje cells are central to cerebellar function because they form the sole output of the cerebellar cortex. They exhibit two distinct types of action potential: simple spikes and complex spikes. It is widely accepted that interaction between these two types of impulse is central to cerebellar cortical information processing. Previous investigations of the interactions between simple spikes and complex spikes have mainly considered complex spikes as unitary events. However, complex spikes are composed of an initial large spike followed by a number of secondary components, termed spikelets. The number of spikelets within individual complex spikes is highly variable and the extent to which differences in complex spike spikelet number affects simple spike activity (and vice versa) remains poorly understood. In anaesthetized adult rats, we have found that Purkinje cells recorded from the posterior lobe vermis and hemisphere have high simple spike firing frequencies that precede complex spikes with greater numbers of spikelets. This finding was also evident in a small sample of Purkinje cells recorded from the posterior lobe hemisphere in awake cats. In addition, complex spikes with a greater number of spikelets were associated with a subsequent reduction in simple spike firing rate. We therefore suggest that one important function of spikelets is the modulation of Purkinje cell simple spike firing frequency, which has implications for controlling cerebellar cortical output and motor learning.

The Roles of the Olivocerebellar Pathway in Motor Learning and Motor Control. A Consensus Paper.

For many decades, the predominant view in the cerebellar field has been that the olivocerebellar system's primary function is to induce plasticity in the cerebellar cortex, specifically, at the parallel fiber-Purkinje cell synapse. However, it has also long been proposed that the olivocerebellar system participates directly in motor control by helping to shape ongoing motor commands being issued by the cerebellum. Evidence consistent with both hypotheses exists; however, they are often investigated as mutually exclusive alternatives. In contrast, here, we take the perspective that the olivocerebellar system can contribute to both the motor learning and motor control functions of the cerebellum and might also play a role in development. We then consider the potential problems and benefits of it having multiple functions. Moreover, we discuss how its distinctive characteristics (e.g., low firing rates, synchronization, and variable complex spike waveforms) make it more or less suitable for one or the other of these functions, and why having multiple functions makes sense from an evolutionary perspective. We did not attempt to reach a consensus on the specific role(s) the olivocerebellar system plays in different types of movements, as that will ultimately be determined experimentally; however, collectively, the various contributions highlight the flexibility of the olivocerebellar system, and thereby suggest that it has the potential to act in both the motor learning and motor control functions of the cerebellum.

Proceedings of the workshop on Cerebellum, Basal Ganglia and Cortical Connections Unmasked in Health and Disorder held in Brno, Czech Republic, October 17th, 2013.

The proceedings of the workshop synthesize the experimental, preclinical, and clinical data suggesting that the cerebellum, basal ganglia (BG), and their connections play an important role in pathophysiology of various movement disorders (like Parkinson's disease and atypical parkinsonian syndromes) or neurodevelopmental disorders (like autism). The contributions from individual distinguished speakers cover the neuroanatomical research of complex networks, neuroimaging data showing that the cerebellum and BG are connected to a wide range of other central nervous system structures involved in movement control. Especially, the cerebellum plays a more complex role in how the brain functions than previously thought.

Structural basis of cerebellar microcircuits in the rat.

The topography of the cerebellar cortex is described by at least three different maps, with the basic units of each map termed "microzones," "patches," and "bands." These are defined, respectively, by different patterns of climbing fiber input, mossy fiber input, and Purkinje cell (PC) phenotype. Based on embryological development, the "one-map" hypothesis proposes that the basic units of each map align in the adult animal and the aim of the present study was to test this possibility. In barbiturate anesthetized adult rats, nanoinjections of bidirectional tracer (Retrobeads and biotinylated dextran amine) were made into somatotopically identified regions within the hindlimb C1 zone in copula pyramidis. Injection sites were mapped relative to PC bands defined by the molecular marker zebrin II and were correlated with the pattern of retrograde cell labeling within the inferior olive and in the basilar pontine nuclei to determine connectivity of microzones and patches, respectively, and also with the distributions of biotinylated dextran amine-labeled PC terminals in the cerebellar nuclei. Zebrin bands were found to be related to both climbing fiber and mossy fiber inputs and also to cortical representation of different parts of the ipsilateral hindpaw, indicating a precise spatial organization within cerebellar microcircuitry. This precise connectivity extends to PC terminal fields in the cerebellar nuclei and olivonuclear projections. These findings strongly support the one-map hypothesis and suggest that, at the microcircuit level of resolution, the cerebellar cortex has a common plan of spatial organization for major inputs, outputs, and PC phenotype.

Consensus paper: current views on the role of cerebellar interpositus nucleus in movement control and emotion.

In the present paper, we examine the role of the cerebellar interpositus nucleus (IN) in motor and non-motor domains. Recent findings are considered, and we share the following conclusions: IN as part of the olivo-cortico-nuclear microcircuit is involved in providing powerful timing signals important in coordinating limb movements; IN could participate in the timing and performance of ongoing conditioned responses rather than the generation and/or initiation of such responses; IN is involved in the control of reflexive and voluntary movements in a task- and effector system-dependent fashion, including hand movements and associated upper limb adjustments, for quick effective actions; IN develops internal models for dynamic interactions of the motor system with the external environment for anticipatory control of movement; and IN plays a significant role in the modulation of autonomic and emotional functions.

Cerebellar contributions across behavioural timescales: a review from the perspective of cerebro-cerebellar interactions.

Performing successful adaptive behaviour relies on our ability to process a wide range of temporal intervals with certain precision. Studies on the role of the cerebellum in temporal information processing have adopted the dogma that the cerebellum is involved in sub-second processing. However, emerging evidence shows that the cerebellum might be involved in suprasecond temporal processing as well. Here we review the reciprocal loops between cerebellum and cerebral cortex and provide a theoretical account of cerebro-cerebellar interactions with a focus on how cerebellar output can modulate cerebral processing during learning of complex sequences. Finally, we propose that while the ability of the cerebellum to support millisecond timescales might be intrinsic to cerebellar circuitry, the ability to support supra-second timescales might result from cerebellar interactions with other brain regions, such as the prefrontal cortex.

Slower rates of prism adaptation but intact aftereffects in patients with early to mid-stage Parkinson's disease.

There is currently mixed evidence on the effect of Parkinson's disease on motor adaptation. Some studies report that patients display adaptation comparable to age-matched controls, while others report a complete inability to adapt to novel sensory perturbations. Here, early to mid-stage Parkinson's patients were recruited to perform a prism adaptation task. When compared to controls, patients showed slower rates of initial adaptation but intact aftereffects. These results support the suggestion that patients with early to mid-stage Parkinson's disease display intact adaptation driven by sensory prediction errors, as shown by the intact aftereffect. But impaired facilitation of performance through cognitive strategies informed by task error, as shown by the impaired initial adaptation. These results support recent studies that suggest that patients with Parkinson's disease retain the ability to perform visuomotor adaptation, but display altered use of cognitive strategies to aid performance and generalises these previous findings to the classical prism adaptation task.

Spatial localization and projection densities of brainstem mossy fibre afferents to the forelimb C1 zone of the rat cerebellum.

The present study uses a double retrograde tracer technique in rats to examine the spatial localization and pattern of axonal branching in mossy fibres arising from three major sources in the medulla-the external cuneate nucleus, the sensory trigeminal nucleus and the reticular formation, to two electrophysiologically-identified parts of the cerebellar cortex that are linked by common climbing fibre input - the forelimb-receiving parts of the C1 zone in lobulus simplex and the paramedian lobule. In each experiment a small injection of rhodamine-tagged beads was injected into one cortical region and an injection of fluorescein-tagged beads was injected into the other region. The main findings were: (i) the proportion of double-labelled cells in each of the three precerebeller sources of mossy fibres was positively correlated with those in the inferior olive; and (ii) the C1 zone in lobulus simplex was found to receive a greater density of projections from all three sources of mossy fibres than the C1 zone in the paramedian lobule. These data suggest that two rostrocaudally separated but somatotopically corresponding parts of the C1 zone receive common mossy fibre and climbing fibre inputs. However, the differences in projection densities also suggest that the two parts of the zone differ in the extent to which they receive mossy fibre signals arising from the same precerebellar nuclei. This implies differences in function between somatotopically corresponding parts of the same cortical zone, and could enable a higher degree of parallel processing and integration of information within them.

Cerebello-Thalamo-Cortical Network Dynamics in the Harmaline Rodent Model of Essential Tremor.

Essential Tremor (ET) is a common movement disorder, characterised by a posture or movement-related tremor of the upper limbs. Abnormalities within cerebellar circuits are thought to underlie the pathogenesis of ET, resulting in aberrant synchronous oscillatory activity within the thalamo-cortical network leading to tremors. Harmaline produces pathological oscillations within the cerebellum, and a tremor that phenotypically resembles ET. However, the neural network dynamics in cerebellar-thalamo-cortical circuits in harmaline-induced tremor remains unclear, including the way circuit interactions may be influenced by behavioural state. Here, we examined the effect of harmaline on cerebello-thalamo-cortical oscillations during rest and movement. EEG recordings from the sensorimotor cortex and local field potentials (LFP) from thalamic and medial cerebellar nuclei were simultaneously recorded in awake behaving rats, alongside measures of tremor using EMG and accelerometery. Analyses compared neural oscillations before and after systemic administration of harmaline (10 mg/kg, I.P), and coherence across periods when rats were resting vs. moving. During movement, harmaline increased the 9-15 Hz behavioural tremor amplitude and increased thalamic LFP coherence with tremor. Medial cerebellar nuclei and cerebellar vermis LFP coherence with tremor however remained unchanged from rest. These findings suggest harmaline-induced cerebellar oscillations are independent of behavioural state and associated changes in tremor amplitude. By contrast, thalamic oscillations are dependent on behavioural state and related changes in tremor amplitude. This study provides new insights into the role of cerebello-thalamo-cortical network interactions in tremor, whereby neural oscillations in thalamocortical, but not cerebellar circuits can be influenced by movement and/or behavioural tremor amplitude in the harmaline model.

Sensory and motor electrophysiological mapping of the cerebellum in humans.

Cerebellar damage during posterior fossa surgery in children can lead to ataxia and risk of cerebellar mutism syndrome. Compartmentalisation of sensorimotor and cognitive functions within the cerebellum have been demonstrated in animal electrophysiology and human imaging studies. Electrophysiological monitoring was carried out under general anaesthesia to assess the limb sensorimotor representation within the human cerebellum for assessment of neurophysiological integrity to reduce the incidence of surgical morbidities. Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. Sensory evoked field potentials were recorded in response to mapping (n = 8) to electrical stimulation of limb nerves or muscles. For motor mapping (n = 5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles. Sensory evoked potentials were found in two patients (25%). Responses were located on the surface of the right inferior posterior cerebellum to stimulation of the right leg in one patient, and on the left inferior posterior lobe in another patient to stimulation of left forearm. No evoked EMG responses were found for the motor mapping. The present study identifies challenges with using neurophysiological methods to map functional organization within the human cerebellum and considers ways to improve success.

Behavioural significance of cerebellar modules.

A key organisational feature of the cerebellum is its division into a series of cerebellar modules. Each module is defined by its climbing input originating from a well-defined region of the inferior olive, which targets one or more longitudinal zones of Purkinje cells within the cerebellar cortex. In turn, Purkinje cells within each zone project to specific regions of the cerebellar and vestibular nuclei. While much is known about the neuronal wiring of individual cerebellar modules, their behavioural significance remains poorly understood. Here, we briefly review some recent data on the functional role of three different cerebellar modules: the vermal A module, the paravermal C2 module and the lateral D2 module. The available evidence suggests that these modules have some differences in function: the A module is concerned with balance and the postural base for voluntary movements, the C2 module is concerned more with limb control and the D2 module is involved in predicting target motion in visually guided movements. However, these are not likely to be the only functions of these modules and the A and C2 modules are also both concerned with eye and head movements, suggesting that individual cerebellar modules do not necessarily have distinct functions in motor control.

Mechanisms of synchronous activity in cerebellar Purkinje cells.

Complex spike synchrony is thought to be a key feature of how inferior olive climbing fibre afferents make their vital contribution to cerebellar function. However, little is known about whether the other major cerebellar input, the mossy fibres (which generate simple spikes within Purkinje cells, PCs), exhibit a similar synchrony in impulse timing. We have used a multi-microelectrode system to record simultaneously from two or more PCs in the posterior lobe of the ketamine/xylazine-anaesthetized rat to examine the relationship between complex spike and simple spike synchrony in PC pairs located mainly in the A2 and C1 zones in crus II and the paramedian lobule. PC pairs displaying correlations in the occurrence of their complex spikes (coupled PCs) were usually located in the same zone and were also more likely to exhibit correlations in the timing of their spontaneous simple spikes and associated pauses in activity. In coupled PCs, synchrony in both complex spike and simple spike activity was enhanced and the relative timing in the occurrence of complex spikes could be altered by peripheral stimulation. We conclude that the functional coupling between PC pairs in their complex spike and simple spike activity can be significantly modified by sensory inputs, and that mechanisms besides electrotonic coupling are involved in generating PC synchrony. Synchronous activity in multiple PCs converging onto the same cerebellar nuclear cells is likely to have a significant impact on cerebellar output that could form important timing signals to orchestrate coordinated movements.

Electrophysiological characterization of the cerebellum in the arterially perfused hindbrain and upper body of the rat.

In the present study, a non-pulsatile arterially perfused hindbrain and upper body rat preparation is described which is an extension of the brainstem preparation reported by Potts et al., (Brain Res Bull 53(1):59-67), 1. The modified in situ preparation allows study of cerebellar function whilst preserving the integrity of many of its interconnections with the brainstem, upper spinal cord and the peripheral nervous system of the head and forelimbs. Evoked mossy fibre, climbing fibre and parallel fibre field potentials and EMG activity elicited in forelimb biceps muscle by interpositus stimulation provided evidence that both cerebellar inputs and outputs remain operational in this preparation. Similarly, the spontaneous and evoked single unit activity of Purkinje cells, putative Golgi cells, molecular interneurones and cerebellar nuclear neurones was similar to activity patterns reported in vivo. The advantages of the preparation include the ability to record, without the complications of anaesthesia, stabile single unit activity for extended periods (3 h or more), from regions of the rat cerebellum that are difficult to access in vivo. The preparation should therefore be a useful adjunct to in vitro and in vivo studies of neural circuits underlying cerebellar contributions to movement control and motor learning.

Pre-movement changes in sensorimotor beta oscillations predict motor adaptation drive.

Beta frequency oscillations in scalp electroencephalography (EEG) recordings over the primary motor cortex have been associated with the preparation and execution of voluntary movements. Here, we test whether changes in beta frequency are related to the preparation of adapted movements in human, and whether such effects generalise to other species (cat). Eleven healthy adult humans performed a joystick visuomotor adaptation task. Beta (15-25 Hz) scalp EEG signals recorded over the motor cortex during a pre-movement preparatory phase were, on average, significantly reduced in amplitude during early adaptation trials compared to baseline, late adaptation, or aftereffect trials. The changes in beta were not related to measurements of reaction time or reach duration. We also recorded local field potential (LFP) activity within the primary motor cortex of three cats during a prism visuomotor adaptation task. Analysis of these signals revealed similar reductions in motor cortical LFP beta frequencies during early adaptation. This effect was present when controlling for any influence of the reaction time and reach duration. Overall, the results are consistent with a reduction in pre-movement beta oscillations predicting an increase in adaptive drive in upcoming task performance when motor errors are largest in magnitude and the rate of adaptation is greatest.