scholarly journals Hippocampal connectivity with sensorimotor cortex during volitional finger movements I. Laterality and relationship to motor learning

2018 ◽  
Author(s):  
Douglas D. Burman

AbstractHippocampal interactions with the motor system are often assumed to reflect the role of memory in motor learning. Here, we examine hippocampal connectivity with sensorimotor cortex during two tasks requiring paced movements, one with a mnemonic component (sequence learning) and one without (repetitive tapping). Functional magnetic resonance imaging activity was recorded from thirteen right-handed subjects; connectivity was identified from sensorimotor cortex (SMC) correlations with psychophysiological interactions in hippocampal activity between motor and passive visual tasks. Finger movements in both motor tasks anticipated the timing of the metronome, reflecting cognitive control, yet evidence of motor learning was limited to the sequence learning task; nonetheless, hippocampal connectivity was observed during both tasks. Connectivity from corresponding regions in the left and right hippocampus overlapped extensively, with improved sensitivity resulting from their conjunctive (global) analysis. The cortical laterality of SMC connectivity depended both on the hippocampal source and the task.Functionally-defined seeds produced bilateral connectivity within the hand representation, regardless of whether finger movements were uni- or bimanual; these seeds were located midlateral within the hippocampus, whereas structural seeds were located in the posterior hippocampus and produced unilateral connectivity. Results implicate the hippocampus in volitional finger movements even in the absence of motor learning or recall.

2006 ◽  
Vol 95 (3) ◽  
pp. 1639-1644 ◽  
Author(s):  
Anna Floyer-Lea ◽  
Marzena Wylezinska ◽  
Tamas Kincses ◽  
Paul M. Matthews

Movement representations within the human primary motor and somatosensory cortices can be altered by motor learning. Decreases in local GABA concentration and its release may facilitate this plasticity. Here we use in vivo magnetic resonance spectroscopy (MRS) to noninvasively measure serial changes in GABA concentration in humans in a brain region including the primary sensorimotor cortex contralateral to the hand used for an isometric motor sequence learning task. Thirty minutes of motor sequence learning reduced the mean GABA concentration within a 2 × 2 × 2-cm3 voxel by almost 20%. This reduction was specific to motor learning: 30 min of similar, movements with an unlearnable, nonrepetitive sequence were not associated with changes in GABA concentration. No significant changes in GABA concentration were found in the primary sensorimotor cortex ipsilateral to the hand used for learning. These changes suggest remarkably rapid, regionally specific short-term presynaptic modulation of GABAergic input that should facilitate motor learning. Although apparently confined to the contralateral hemisphere, the magnitude of changes seen within a large spectroscopic voxel suggests that these changes occur over a wide local neocortical field.


2014 ◽  
Vol 111 (3) ◽  
pp. 628-640 ◽  
Author(s):  
Fatemeh Noohi ◽  
Nate B. Boyden ◽  
Youngbin Kwak ◽  
Jennifer Humfleet ◽  
David T. Burke ◽  
...  

Individuals learn new skills at different rates. Given the involvement of corticostriatal pathways in some types of learning, variations in dopaminergic transmission may contribute to these individual differences. Genetic polymorphisms of the catechol- O-methyltransferase (COMT) enzyme and dopamine receptor D2 (DRD2) genes partially determine cortical and striatal dopamine availability, respectively. Individuals who are homozygous for the COMT methionine ( met) allele show reduced cortical COMT enzymatic activity, resulting in increased dopamine levels in the prefrontal cortex as opposed to individuals who are carriers of the valine ( val) allele. DRD2 G-allele homozygotes benefit from a higher striatal dopamine level compared with T-allele carriers. We hypothesized that individuals who are homozygous for COMT met and DRD2 G alleles would show higher rates of motor learning. Seventy-two young healthy females (20 ± 1.9 yr) performed a sensorimotor adaptation task and a motor sequence learning task. A nonparametric mixed model ANOVA revealed that the COMT val-val group demonstrated poorer performance in the sequence learning task compared with the met-met group and showed a learning deficit in the visuomotor adaptation task compared with both met-met and val-met groups. The DRD2 TT group showed poorer performance in the sequence learning task compared with the GT group, but there was no difference between DRD2 genotype groups in adaptation rate. Although these results did not entirely come out as one might predict based on the known contribution of corticostriatal pathways to motor sequence learning, they support the role of genetic polymorphisms of COMT val158met (rs4680) and DRD2 G>T (rs 1076560) in explaining individual differences in motor performance and motor learning, dependent on task type.


2019 ◽  
Author(s):  
Nicolas Ludolph ◽  
Thomas M. Ernst ◽  
Oliver M. Mueller ◽  
Sophia L. Goericke ◽  
Martin A. Giese ◽  
...  

ABSTRACTThe role of the cerebellum in error-based motor adaptation is well examined. In contrast, the involvement of the cerebellum in reward-based motor learning is less clear. In this study, we examined cerebellar involvement in a reward-based motor learning task, namely learning to control a virtual cart-pole system, over five consecutive days. Subjects with focal cerebellar lesions were compared to age-matched controls in terms of learning performance and underlying control mechanisms.Based on the overall balancing performance we have identified two subgroups of patients: (1) patients with learning performance comparable to healthy controls and (2) patients with decelerated learning, unsaturated learning progress after five days and decreased inter-manual transfer. Furthermore, we found that online learning is impaired while offline learning is partly preserved in cerebellar subjects. Regarding control mechanisms, decreased control performance was associated with impairments in predictive action timing.Voxel-wise lesion symptom mapping based on the two subgroups revealed strong associations between impairments in controlling the virtual cart-pole system and lesions in intermediate and lateral parts of lobules V and VI. These results together with previous reports suggest that the ability to predict the dynamics of the cart-pole system is an important factor for the reward-based skill acquisition process.


2020 ◽  
Author(s):  
N Dolfen ◽  
B R King ◽  
L Schwabe ◽  
M A Gann ◽  
M P Veldman ◽  
...  

Abstract The functional interaction between hippocampo- and striato-cortical regions during motor sequence learning is essential to trigger optimal memory consolidation. Based on previous evidence from other memory domains that stress alters the balance between these systems, we investigated whether exposure to stress prior to motor learning modulates motor memory processes. Seventy-two healthy young individuals were exposed to a stressful or nonstressful control intervention prior to training on a motor sequence learning task in a magnetic resonance imaging (MRI) scanner. Consolidation was assessed with an MRI retest after a sleep episode. Behavioral results indicate that stress prior to learning did not influence motor performance. At the neural level, stress induced both a larger recruitment of sensorimotor regions and a greater disengagement of hippocampo-cortical networks during training. Brain-behavior regression analyses showed that while this stress-induced shift from (hippocampo-)fronto-parietal to motor networks was beneficial for initial performance, it was detrimental for consolidation. Our results provide the first experimental evidence that stress modulates the neural networks recruited during motor memory processing and therefore effectively unify concepts and mechanisms from diverse memory fields. Critically, our findings suggest that intersubject variability in brain responses to stress determines the impact of stress on motor learning and subsequent consolidation.


1998 ◽  
Vol 51 (2) ◽  
pp. 251-281 ◽  
Author(s):  
Axel Buchner Melanie C. Steffens Rainer Rothkegel

1998 ◽  
Vol 51 (2) ◽  
pp. 251-281 ◽  
Author(s):  
Axel Buchner ◽  
Melanie C. Steffens ◽  
Rainer Rothkegel

There has been considerable debate about whether or not we need to distinguish between the acquisition of implicit—and, independently thereof, the acquisition of explicit—knowledge in sequence learning tasks. Proponents of the view that a unitary knowledge base is formed assume (a) that the knowledge acquired is explicitly available, and (b) that information about sequence fragments forms the core of this explicit knowledge. Both of these issues are addressed empirically in the present article. In two experiments, an adapted process dissociation procedure and a suitable measurement model were used to separate recollective (explicit) and fluency-based (implicit) memory processes in a sequence learning task. Experiment 1 demonstrated that fluency-based processes came into play much later than recollective processes. Such recollective processes have been conceptualized as being based on simple knowledge about sequence fragments or chunks. Indeed, Experiment 2 showed that recollective processes are more likely to contribute to sequence judgements if chunks are readily available at test than if they are not. Together, these results are in line with the view that the learning of an event systematicity can be conceived of as the memorization of chunks of events that support both the speeding up of reaction times to systematic events and explicit, recollective memory processes even after relatively little training.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nina Dolfen ◽  
Menno P. Veldman ◽  
Mareike A. Gann ◽  
Andreas von Leupoldt ◽  
Nicolaas A. J. Puts ◽  
...  

AbstractPrevious research has demonstrated that stress modulates the competitive interaction between the hippocampus and striatum, two structures known to be critically involved in motor sequence learning. These earlier investigations, however, have largely focused on blood oxygen-level dependent (BOLD) responses. No study to date has examined the link between stress, motor learning and levels of striatal and hippocampal gamma-aminobutyric acid (GABA). This knowledge gap is surprising given the known role of GABA in neuroplasticity subserving learning and memory. The current study thus examined: a) the effects of motor learning and stress on striatal and hippocampal GABA levels; and b) how learning- and stress-induced changes in GABA relate to the neural correlates of learning. To do so, fifty-three healthy young adults were exposed to a stressful or non-stressful control intervention before motor sequence learning. Striatal and hippocampal GABA levels were assessed at baseline and post-intervention/learning using magnetic resonance spectroscopy. Regression analyses indicated that stress modulated the link between striatal GABA levels and functional plasticity in both the hippocampus and striatum during learning as measured with fMRI. This study provides evidence for a role of GABA in the stress-induced modulation of striatal and hippocampal systems.


2020 ◽  
Author(s):  
Christine Schubert ◽  
Alhuda Dabbagh ◽  
Joseph Classen ◽  
Ulrike M. Krämer ◽  
Elinor Tzvi

AbstractAlpha oscillations (8-13 Hz) have been shown to play an important role in dynamic neural processes underlying learning and memory. The goal of this study was to scrutinize the role of α oscillations in communication within a network implicated in motor sequence learning. To this end, we conducted two experiments using the serial reaction time task. In the first experiment, we explored changes in α power and cross-channel α coherence. We found a gradual decrease in learning-related α power over left premotor cortex (PMC), somatosensory cortex (S1) and tempo-parietal junction (TPJ). Alpha coherence between left PMC/S1 and right cerebellar crus I was reduced for sequence learning, possibly reflecting a functional decoupling in a motor-cerebellar loop during the motor learning process. In the second experiment in a different cohort, we applied 10Hz transcranial alternating current stimulation (tACS), a method shown to entrain local oscillatory activity, to left M1 (lM1) and right cerebellum (rCB) during sequence learning. We observed learning deficits during rCB tACS compared to sham, but not during lM1 tACS. In addition, learning-related α power following rCB tACS was increased in left PMC, possibly reflecting a decrease in neural activity. Importantly, learning-specific coherence between left PMC and right cerebellar lobule VIIb was enhanced following rCB tACS. These findings suggest that interactions within a premotor-cerebellar loop, which are underlying motor sequence learning, are mediated by α oscillations. We show that they can be modulated through external entrainment of cerebellar oscillations, which then modulates motor cortical α and interferes with sequence learning.


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