Shadmehr Lab
Shadmehr Lab
  • Видео 102
  • Просмотров 40 974
Devika Narain: Fast implicit learning of temporal context
One is seldom aware of the anticipatory and preemptive feats that the eyeblink systems achieves in daily life but it frequently protects the eye from projectiles gone awry and insects on apparent collision courses. This poor awareness is why predictive eyeblinks are considered a form of implicit learning. In motor neuroscience, implicit learning is considered to be slow and, eyeblink conditioning, in particular, is believed to be a rigid and inflexible cerebellar-dependent behavior. In cognitive neuroscience, however, implicit and automatic processes are thought to be rapidly acquired. Here we show that the eyeblink system is, in fact, capable of remarkable cognitive flexibility and can l...
Просмотров: 135

Видео

Jing-Ning Zhu: exercise and emotional stability
Просмотров 138Месяц назад
The non-motor functions of the cerebellum, especially its role in emotion regulation, have received more and more attention, but the underlying mechanisms remain unclear. Here, we explore a hypothalamo-cerebello-amygdalar circuit that may mediate motor-dependent alleviation of anxiety. This three-neuron loop, in which the cerebellar dentate nucleus (DN) takes center stage, bridges the motor sys...
A modelling approach to the role of olivary phase-locking oscillations in cerebellar adaptation
Просмотров 293Месяц назад
We will consider the dual functionality of the inferior olive (IO) in cerebellar motor control, reconciling hypotheses regarding its role as either a timing or an instructive signal. Specifically, we explore the role of subthreshold oscillations (STOs) within the IO, investigating their potential influence on the climbing fibres-to-Purkinje cell spike pattern responses and subsequent cerebellar...
Nirvik Sinha: cerebellar contributions to control of reaching
Просмотров 183Месяц назад
Cerebellar patients exhibit a broad range of impairments when performing voluntary movements. However, the sequence of events leading to these deficits and the distinction between primary and compensatory processes remain unclear. We addressed this question by reversibly blocking cerebellar outflow in monkeys performing a planar reaching task. We found that the reduced hand velocity observed un...
Brandon Stell: error signals in the cerebellum
Просмотров 1632 месяца назад
A core principle of cerebellar learning theory is that climbing fibers from the inferior olive convey error signals about movement execution to Purkinje cells in the cerebellar cortex. These inputs trigger synaptic changes which are purported to drive progressive adjustment of future movements. Individually, binary complex spike signals lack information about the sign and magnitude of errors wh...
Jorge Vera Buschmann: cerebellar inputs to dopamine
Просмотров 2452 месяца назад
Cerebellar dysfunction has been related to dystonia and linked to mental disorders like schizophrenia, autism, and addiction. A potential common theme among these disorders is the impairment of the dopamine system in the basal ganglia and prefrontal cortex, where dopamine signals are crucial to modulate both movement and reward-related processes. This link suggests that the cerebellum may play ...
Djaina Satoer and Ruben van der Giessen: Cognitive Deficits after Cerebellar Stroke
Просмотров 2322 месяца назад
About three decades ago the concept of “cerebellar neurocognition” known as the “Cerebellar Cognitive Affective Syndrome” (CCAS) was introduced (Schmahmann and Sherman (1998). Apart from neurocognitive deficits (e.g. attention, executive functions), the cerebellum's role in several linguistic functions has also been shown (Mariën et al. 2014). However, so far most clinical studies have been het...
Mireille Broucke: The internal model principle of control theory and the cerebellum
Просмотров 2342 месяца назад
The internal model principle was discovered in 1975 by Bruce Francis and Murray Wonham. Informally, the principle says that any good controller performing error regulation must contain an internal model of reference and disturbance signals impinging on the control loop. This talk discusses our modeling work based on this principle to elucidate the role of the floccular complex in the horizontal...
Sang Jeong Kim: Memory consolidation and the intrinsic synaptic plasticity of Purkinje cells
Просмотров 1492 месяца назад
Intrinsic plasticity of cerebellar Purkinje cells (PCs) has recently been demonstrated in cerebellar local circuits; however, its physiological impact on cerebellar learning and memory remains elusive. Here, we suggest that intrinsic plasticity of PCs is involved in motor memory consolidation based on findings from PC-specific STIM1 knockout male mice, which show severe memory consolidation def...
Robin Broersen: Synaptic mechanisms for associative learning in the cerebellar nuclei
Просмотров 2923 месяца назад
Associative learning during delay eyeblink conditioning (EBC) depends on the cerebellum. However, the relative contribution of structural and physiological changes in the cerebellar nuclei to learning remains a subject of ongoing debate. In particular, little is known about the changes in synaptic inputs to cerebellar nuclei neurons that take place during EBC and how they shape the membrane pot...
Mark Wagner: temporal basis set for cerebellar learning
Просмотров 3823 месяца назад
In classical cerebellar learning, Purkinje cells associate climbing fiber error signals with predictive granule cells active just prior (~150ms). It has remained unclear how this elemental computation could contribute to longer-timescale behaviors. To investigate, we devised a strategy to record simultaneous granule cell-climbing fiber activity over days of forelimb operant conditioning for wat...
David Linden: cerebellar plasticity
Просмотров 5603 месяца назад
If you look carefully enough, most electrophysiological functions of neurons (and possibly, glial cells) are modulated by experience. The molecular details of synaptic and non-synaptic plasticity matter if one wishes to understand the transformation of neural signals by experience. David J. Linden is a Professor in the Solomon H. Snyder Department of Neuroscience at the Johns Hopkins University...
Nate Sawtell: connectivity underlying the generation of predictions in a cerebellum-like circuit
Просмотров 1,6 тыс.4 месяца назад
Many vertebrate brains contain both a cerebellum and one or more sensory processing structures with similarities to the cerebellum in terms of their development, gene expression, circuitry, and physiology. I will discuss our work on mechanisms for adaptive sensory processing in one such structure, the electrosensory lobe (ELL) of weakly electric mormyrid fish. Specifically, I will discuss recen...
Dick Jaarsma: caloric restriction and DNA repair
Просмотров 544 месяца назад
DNA damage arises from exposure to environmental factors, which in turn contribute to deficiencies in DNA repair capabilities that on many occasions produce nervous system abnormalities. Here, Dick Jaarma will present their work on nervous system pathology in nucleotide excision repair (NER)-deficient mice focusing on cerebellar cortex. NER is the primary DNA repair pathway for bulky transcript...
Nuo Li: Neural mechanisms of volitional movement
Просмотров 4794 месяца назад
Our goal is to understand how neural circuits in the brain give rise to volitional movement. A planning phase precedes all volitional movements in which the brain programs appropriate movement on the fly to achieve the goal at hand. This fundamental process dictates our behavior, ranging from speech to motor skills. Our work has isolated neural antecedents of volitional movements in the mouse b...
Neuropixels Ultra recording of a putative mossy fiber
Просмотров 1364 месяца назад
Neuropixels Ultra recording of a putative mossy fiber
Neuropixels Ultra recording of a Purkinje cell
Просмотров 2234 месяца назад
Neuropixels Ultra recording of a Purkinje cell
Jesse Goldberg: a collicular map for touch-guided tongue control
Просмотров 3845 месяцев назад
Jesse Goldberg: a collicular map for touch-guided tongue control
Martha Streng: Interrogating cerebellar network dynamics in health and epilepsy
Просмотров 1375 месяцев назад
Martha Streng: Interrogating cerebellar network dynamics in health and epilepsy
Jennifer Raymond: Cerebellar metaplasticity
Просмотров 4115 месяцев назад
Jennifer Raymond: Cerebellar metaplasticity
Ashok Litwin-Kumar: Generalizing theories of cerebellum-like learning
Просмотров 6415 месяцев назад
Ashok Litwin-Kumar: Generalizing theories of cerebellum-like learning
Mark Blumberg: Sleep-dependent development of the cerebellar system
Просмотров 6465 месяцев назад
Mark Blumberg: Sleep-dependent development of the cerebellar system
Timothy Balmer: transformation of neural signals by unipolar brush cell synapses and circuits
Просмотров 1426 месяцев назад
Timothy Balmer: transformation of neural signals by unipolar brush cell synapses and circuits
Rejuvenating silicon probes: Alden Shoup
Просмотров 1286 месяцев назад
Rejuvenating silicon probes: Alden Shoup
June Liu: Cerebellar circuit plasticity controls emotional memory formation
Просмотров 3306 месяцев назад
June Liu: Cerebellar circuit plasticity controls emotional memory formation
Jason Christie: Neural circuits for cerebellar learning
Просмотров 4586 месяцев назад
Jason Christie: Neural circuits for cerebellar learning
Michael Graupner: Cerebellar interneuron activity is triggered by reach endpoint
Просмотров 2537 месяцев назад
Michael Graupner: Cerebellar interneuron activity is triggered by reach endpoint
Aurélien Wyngaard: Detecting complex spikes in multielectrode recordings
Просмотров 1738 месяцев назад
Aurélien Wyngaard: Detecting complex spikes in multielectrode recordings
Abigail Person: A brief history of time (in the cerebellum)
Просмотров 1 тыс.8 месяцев назад
Abigail Person: A brief history of time (in the cerebellum)
Guy Bouvier: Impaired cerebellar plasticity hypersensitizes the VOR in SCN2A Autism
Просмотров 2799 месяцев назад
Guy Bouvier: Impaired cerebellar plasticity hypersensitizes the VOR in SCN2A Autism

Комментарии

  • @robertorodriguez-labrada6542
    @robertorodriguez-labrada6542 9 часов назад

    Very nice talk!. Very exciting topic! Undoubtedly it seems that the cerebellum will never cease to amaze us.

  • @samkrick2131
    @samkrick2131 24 дня назад

    hey thanks for uploading this! presenting this paper in lab in a couple weeks so this is super helpful!

  • @PapiyaDey-v8f
    @PapiyaDey-v8f Месяц назад

    Great presentation

  • @BibaswanNarayanDatta
    @BibaswanNarayanDatta Месяц назад

    Really great presentation. Thank you.

  • @birkdaleneurorehabilitatio9539
    @birkdaleneurorehabilitatio9539 2 месяца назад

    This is an amazing lecture as a neuro physiotherapist I understood the overshooting or undershooting saccade we see when we use a tobii eye gazing camera to record eye movements. thank you, and I agree with your mum so what. How can we improve eye-directed body movements and balance? it would be amazing if you could reply. Farshideh Bondarenko

    • @shadmehrlab1352
      @shadmehrlab1352 2 месяца назад

      Thank you for the comment. There are a few published reports of exercise-based techniques that have shown improvement in balance of people with cerebellar damage (for example, please see Keller and Bastian 2014).

    • @birkdaleneurorehabilitatio9539
      @birkdaleneurorehabilitatio9539 2 месяца назад

      Thank you , for your recommendation Will try and will report back.

  • @navidhakimi7122
    @navidhakimi7122 3 месяца назад

    fantastic talk and discussion!

  • @CHURINDOK
    @CHURINDOK 4 месяца назад

    Thank you.

  • @navidhakimi7122
    @navidhakimi7122 4 месяца назад

    Dear Reza, Thank you for organizing these talks! This one was amazing! Not sure if Prof. Li would be able to answer here; My question is about the right graph at minute 19:26. Prof. later mentions that the experiments confirm that the same attractors with the same dynamics are activated when we do reversals, from Task 1 to Task 2 back to Task 1. This is inline with some kind of change point detection and structure learning hypothesis that are abundant in fear conditioning experiments for example; However this particular graph shows that even after reversals, many thousands of trials are needed to get above chance success rate for the animal. With a robust structural learning model, this should only take a few trials. I was wondering what is the reason for this discrepancy.

    • @NuoLi-bcm
      @NuoLi-bcm 4 месяца назад

      Great question. In this paradigm, we did observe that mice were faster to re-learn task 1 after task 2, which is consistent with the widely reported saving effects in sensorimotor learning. We also could see neural correlates of this saving effect in ALM preparatory activity. Please stay tuned for the eventual paper. Nevertheless, it still takes mice thousands of trials to re-learn a previously learned sensorimotor contingency. Several factors could have contributed to this slow learning. 1) In this task, mice had to learn the sensorimotor contingency separated by a long temporal delay. We have found that the addition of a delay significantly slows learning. This is true even in mice previously trained in other delayed tasks. In fact, we found that in some conditions with very long delay, it could prevent learning altogether. It seems learning with a delay is generally hard for mice. 2) Sensorimotor adaptation appears to be slower than fear conditioning. It is interesting to speculate why that might be and possible constraints on their neural implementations. 3) Currently we do not have enough evidence to tell what strategy mice are adapting during learning. I suspect they are learning through trial-and-error rather than a model-based change detection. Investigating how mice learn and recall task-specific coding directions in preparatory activity is a very interesting direction. This requires longitudinal imaging during the learning process, which we are currently working on.

    • @navidhakimi7122
      @navidhakimi7122 4 месяца назад

      @@NuoLi-bcm Thank you for the detailed response. Very fascinating subject. Looking forward to the paper! The points you mentioned about working hypothesis about the reason why the reversal takes so long are very interesting.

  • @Vyshada
    @Vyshada 4 месяца назад

    Looks like aim labs.

  • @bullzeegh6610
    @bullzeegh6610 5 месяцев назад

    If I want to look at something at my left I have to move my shoulders first then my head would follow because only to move my eyes to the left is a times impossible with holding my head straight. As well there is no such thing as straight my head is tilted as my null point of view. I was diagnosed with cervical dystonia, spasmodic torticollis. And not to mention that as a child I had strabismus.

  • @briseboy
    @briseboy 5 месяцев назад

    1. Reafference would appear to occur in the high cerebellar activity of entrainment of motor response to novel activity so useful in prediction. Prediction might be regarded as the final or evolutionarily sole value of a brain, opposed to mere neural entrainment occurring in cnidarians, as contrast, in motile organisms. For others outside mammalian brain-mapping, i note that highly socially, behaviorally, conscious sauropsids, and through to perhaps all Vertebrata, develop dense brain structure most likely endowing/including the plasticity useful for continual learning and modifiable sensorimotor response. In your brain, by the way, one half of the approximate totality of neurons, are contained in the cerebellum, which, despite its relatively smaller dimensions, indicates preserved utility. Speech, such as youtube comment, is relatively insignificant, being useful for symbolic informational utility, and subject, somewhat of an epiphenomenon, to the extreme deceptiveness to which many members of our species largely use it. Epiphenomena are very likely very transiently extant occurrences, immediately subject to selection. To digress, as youtube is so popular as to include much of human cognitive variations, were it not for our dense sympatric exuberance, we might have some time ago, speciated, separated through our sensorimotor distaste between those seeking to understand reality and those seeking permanent immersion in delusion, infantilizing oneself. Only we adolescents who remain rather critical of contrafactual ideation as social dogma, may be poised at a developmental stage useful for avoidance of reversion to medieval eroneous formation of heuristics, a term for distillation of novel stimuli and previously consolidated distillations, resimulating our individually highly limited past. Such differently-valenced and always contingent simplified distillation may confer great utility to some exafferent signal usage in the human brain. This is only generalized fodder for any as pissed off as i concerning what occurs in the anthropocentric fantasia outside laboratories.

  • @briseboy
    @briseboy 5 месяцев назад

    1. RE: "twitch". Muscle itself as a word, arose from the perception of movement under skin that appeared similar to " musculus", mouse, in Latin. 2. Evolution is implicitly or explicitly defined as any proliferative change occurring in a population. Adaptation to niches in circadian cycle, that is, conditions favorable to survival/reproductive success during specific periods of light, dark, heat variance, even the obvious but unexplored lunar light variance affecting differential intentional utilities, too correlated to every physiological, hormonal, and circadian variability to be regarded as "error" when so obviously entrained. Coevolution, including predator-prey, sociocognitive, sociobehavioral optimalities, hormonal correlations, introduces some complexity to assessing both developmental and lifespan- related plasticity in wake-sleep states. What is not adaptive, is induced cyclic behavioral rigidity, beyond that essential for development of plasticity in response itself. So the question of optimality in neural, hormonal, and even glial monitoring of neurodevelopment, the latter also not well explored in development and functionality, may have to be approached across time, model organisms, and periodicity for clearer factor observation, hypotheses, experiments, conclusions. 3. The present difficulties in measurement of such plasticity in successful mature ( or any developmental stage) correctively self-entraining behavioral, and neuroconnective optimality does preclude observation of well-adapted cerebellar development of unconstrained individuals. Since cerebellum is involved in novel sensorimotor experience as well as sleep consolidation thereof, INCLUDING physical and incorrectly separated cognitive event consolidation, some noninvasive monitoring of Purkinje and cascading occurrences, including hippocampal, memory-encoding, and salience-encoding relational casades. Cerebellar activity, if reduced in intensity, continues to occur in familiar complex activity. These are only preliminary notes, formed within the first few minutes of the lecture.

  • @laulaja-7186
    @laulaja-7186 5 месяцев назад

    Is this a new channel? Good content, love to see more! Definitely gonna get more subs!

  • @peixotomxg
    @peixotomxg 5 месяцев назад

    uhm uhm uhm uhn uhm uhm uhm uhn uh uhm uhn uhm uhn

  • @navidhakimi7122
    @navidhakimi7122 5 месяцев назад

    amazing talk!

  • @CharlesVanNoland
    @CharlesVanNoland 6 месяцев назад

    Pure gold!

  • @navidhakimi7122
    @navidhakimi7122 10 месяцев назад

    amazing talk Reza! Really enjoyed it. can the integration be done non locally, with the help of other circuits, maybe out of the CB, in a recurrent fashion, By which I mean that the integration result goes out of the CB, and then comes back again as a new input? The integration seems possible with addition of a memory unit, which can be represented in the hidden state of an RNN

    • @shadmehrlab1352
      @shadmehrlab1352 10 месяцев назад

      Thank you for the comment. We don't know if integration takes place in the cerebellar neurons, and there is some hints in our data that we get something that looks like integration in the mossy fiber input. That input could be coming from the prepositus nucleus, which is an integrator for gaze holding. But I suspect that if we want something as sophisticated as a forward model, you need a learning system as powerful as the cerebellum to perform the integration to give the output coordinates that you need for comparison to the goal state.

    • @navidhakimi7122
      @navidhakimi7122 10 месяцев назад

      Thank you for the reply! I think your slide at minute 35 is very instructive. It seems that integration is a central function of the cerebellum function: it is an integral calculator in this way that it receives the motor command u0, it receives an initial state x0, and it also receives a target/final state xd. There probably is a transformation to make the coordinate system such that x0=0. xd needs to be updated iteratively with xd_1 = xd_0 - u0*delta_t. xd_1 is the momentary output of the CB, it goes outside and then comes back as the new input. this continues until xd~0. My point is that xd might go outside of the CB and come back as the new input for the continuation of the integration. Do I understand this correctly? @shadmehrlab1352

    • @shadmehrlab1352
      @shadmehrlab1352 10 месяцев назад

      It turns out that a small part of the mossy fiber input looks to be the integral of the motor commands. However, it is important to note that the coordinate system of xd (goal) is sensory, whereas the coordinate system of u is motor. In principle, you need to transform via a forward model to be able to estimate your current state with respect to the goal state. It would be very cool to find evidence for or against this idea in the cerebellum.

  • @user-cw5ob3nd4v
    @user-cw5ob3nd4v Год назад

    Крутое видео получилось

  • @Brainisnotacomputer
    @Brainisnotacomputer Год назад

    This was fun. Thank you for uploading!

  • @themidstream
    @themidstream Год назад

    Fascinating.

  • @tech_science_tutos4155
    @tech_science_tutos4155 2 года назад

    at 53:46 is it a variance or covarianve C*cov(x)*CT

  • @tech_science_tutos4155
    @tech_science_tutos4155 2 года назад

    at 41:14 wd times xd not wn times xn

  • @rafeedrahman5420
    @rafeedrahman5420 2 года назад

    This is just different formulations of normal PCA. I did not find robust PCA in any part of this lecture. Totally misleading video title

  • @marcogelsomini7655
    @marcogelsomini7655 2 года назад

    beautiful lesson!

  • @BillHaug
    @BillHaug 2 года назад

    59:05..... WOOOOOOOO-HOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  • @anilcelik16
    @anilcelik16 2 года назад

    Thanks. Then is there any reason to use regular PCA at all?

  • @jesseg1mit
    @jesseg1mit 3 года назад

    Money talk, Paul! And sooo great to see the Shadmehr lab diving into this new direction. Tongues are amazing!

  • @georgehage1
    @georgehage1 3 года назад

    Great work Paulie. Proud!!

  • @linlinzhao9085
    @linlinzhao9085 4 года назад

    This is a crystal clear lecture on classical PCA. But why is it named robust PCA? I was expecting explanations on this: arxiv.org/pdf/0912.3599.pdf

  • @19916718514
    @19916718514 4 года назад

    What a great insight! Did not see Kalman from this way before

  • @haoyang7981
    @haoyang7981 4 года назад

    very knowledgeable professor, I really love this teaching style. Thanks for sharing.

  • @ProfessionalTycoons
    @ProfessionalTycoons 5 лет назад

    very good lecture