The neuroscience of active learning and direct instruction

Dubinsky, J. M., Hamid, A. A.

Nature Magazine

Aug 1, 2024

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The neuroscience of active learning and direct instruction

Dubinsky, J. M., Hamid, A. A.

Nature Magazine

Aug 1, 2024

Abstract

Throughout the educational system, students experiencing active learning pedagogy perform better and fail less than those taught through direct instruction. Can this be ascribed to differences in learning from a neuroscientific perspective? This review examines mechanistic, neuroscientific evidence that might explain differences in cognitive engagement contributing to learning outcomes between these instructional approaches. In classrooms, direct instruction comprehensively describes academic content, while active learning provides structured opportunities for learners to explore, apply, and manipulate content. Synaptic plasticity and its modulation by arousal or novelty are central to all learning and both approaches. As a form of social learning, direct instruction relies upon working memory. The reinforcement learning circuit, associated agency, curiosity, and peer-to-peer social interactions combine to enhance motivation, improve retention, and build higher-order-thinking skills in active learning environments. When working memory becomes overwhelmed, additionally engaging the reinforcement learning circuit improves retention, providing an explanation for the benefits of active learning. This analysis provides a mechanistic examination of how emerging neuroscience principles might inform pedagogical choices at all educational levels

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Biological research and self-driving labs in deep space supported by artificial intelligence

Arif A. Hamid, Lauren M. Sanders, Ryan T. Scott

Nature Magazine

Mar 23, 2023

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Biological research and self-driving labs in deep space supported by artificial intelligence

Arif A. Hamid, Lauren M. Sanders, Ryan T. Scott

Nature Magazine

Mar 23, 2023

Abstract

Space biology research aims to understand fundamental spaceflight effects on organisms, develop foundational knowledge to support deep space exploration and, ultimately, bioengineer spacecraft and habitats to stabilize the ecosystem of plants, crops, microbes, animals and humans for sustained multi-planetary life. To advance these aims, the field leverages experiments, platforms, data and model organisms from both spaceborne and ground-analogue studies. As research is extended beyond low Earth orbit, experiments and platforms must be maximally automated, light, agile and intelligent to accelerate knowledge discovery. Here we present a summary of decadal recommendations from a workshop organized by the National Aeronautics and Space Administration on artificial intelligence, machine learning and modelling applications that offer solutions to these space biology challenges. The integration of artificial intelligence into the field of space biology will deepen the biological understanding of spaceflight effects, facilitate predictive modelling and analytics, support maximally automated and reproducible experiments, and efficiently manage spaceborne data and metadata, ultimately to enable life to thrive in deep space.

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Biomonitoring and precision health in deep space supported by artificial intelligence

Ryan T. Scott, Arif A. Hamid, Lauren M. Sanders

Nature Magazine

Mar 23, 2023

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Biomonitoring and precision health in deep space supported by artificial intelligence

Ryan T. Scott, Arif A. Hamid, Lauren M. Sanders

Nature Magazine

Mar 23, 2023

Abstract

Human exploration of deep space will involve missions of substantial distance and duration. To effectively mitigate health hazards, paradigm shifts in astronaut health systems are necessary to enable Earth-independent healthcare, rather than Earth-reliant. Here we present a summary of decadal recommendations from a workshop organized by NASA on artificial intelligence, machine learning and modelling applications that offer key solutions toward these space health challenges. The workshop recommended various biomonitoring approaches, biomarker science, spacecraft/habitat hardware, intelligent software and streamlined data management tools in need of development and integration to enable humanity to thrive in deep space. Participants recommended that these components culminate in a maximally automated, autonomous and intelligent Precision Space Health system, to monitor, aggregate and assess biomedical statuses.

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Etiopathogenic Models of Psychosis Spectrum Illnesses Must Resolve Four Key Features

Sophia Vinogradov, Arif A. Hamid, A. David Redish

Nature Magazine

Sep 15, 2022

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Etiopathogenic Models of Psychosis Spectrum Illnesses Must Resolve Four Key Features

Sophia Vinogradov, Arif A. Hamid, A. David Redish

Nature Magazine

Sep 15, 2022

Abstract

Etiopathogenic models for psychosis spectrum illnesses are converging on a number of key processes, such as the influence of specific genes on the synthesis of proteins important in synaptic functioning, alterations in how neurons respond to synaptic inputs and engage in synaptic pruning, and microcircuit dysfunction that leads to more global cortical information processing vulnerabilities. Disruptions in prefrontal operations then accumulate and propagate over time, interacting with environmental factors, developmental processes, and homeostatic mechanisms, eventually resulting in symptoms of psychosis and disability. However, there are 4 key features of psychosis spectrum illnesses that are of primary clinical relevance but have been difficult to assimilate into a single model and have thus far received little direct attention: 1) the bidirectionality of the causal influences for the emergence of psychosis, 2) the catastrophic clinical threshold seen in first episodes of psychosis and why it is irreversible in some individuals, 3) observed biotypes that are neurophysiologically distinct but clinically both convergent and divergent, and 4) a reconciliation of the role of striatal dopaminergic dysfunction with models of prefrontal cortical state instability. In this selective review, we briefly describe these 4 hallmark features and we argue that theoretically driven computational perspectives making use of both algorithmic and neurophysiologic models are needed to reduce this complexity and variability of psychosis spectrum illnesses in a principled manner.

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Dopaminergic specializations for flexible behavioral control: linking levels of analysis and functional architectures

Arif A Hamid

Nature Magazine

Oct 1, 2021

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Dopaminergic specializations for flexible behavioral control: linking levels of analysis and functional architectures

Arif A Hamid

Nature Magazine

Oct 1, 2021

Abstract

Dopamine potently regulates forebrain physiology that underlies reward learning and behavioral flexibility. A detailed accounting of how cellular and circuit interactions come to impact reinforcement learning continues to be refined at multiple levels of analysis. This review provides a brief summary of our current understanding of quantitative decision variables relayed by dopamine dynamics in striatal targets, circuit substrates that support specific dopaminergic computations, and how different behavioral task-demands leverage these specializations to afford adaptive behaviors. Moreover, we motivate the revision of a longstanding hypothesis for globally broadcast dopamine prediction error signals, and instead, make the case for regionally specialized forebrain dopamine dynamics tailored to local computational needs

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Wave-like dopamine dynamics as a mechanism for spatiotemporal credit assignment

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

May 13, 2021

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Wave-like dopamine dynamics as a mechanism for spatiotemporal credit assignment

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

May 13, 2021

Abstract

The dopamine projection from ventral tegmental area (VTA) to nucleus accumbens (NAc) is critical for motivation to work for rewards and reward-driven learning. How dopamine supports both functions is unclear. Dopamine cell spiking can encode prediction errors, which are vital learning signals in computational theories of adaptive behaviour. By contrast, dopamine release ramps up as animals approach rewards, mirroring reward expectation. This mismatch might reflect differences in behavioural tasks, slower changes in dopamine cell spiking or spike-independent modulation of dopamine release. Here we compare spiking of identified VTA dopamine cells with NAc dopamine release in the same decision-making task. Cues that indicate an upcoming reward increased both spiking and release. However, NAc core dopamine release also covaried with dynamically evolving reward expectations, without corresponding changes in VTA dopamine cell spiking. Our results suggest a fundamental difference in how dopamine release is regulated to achieve distinct functions: broadcast burst signals promote learning, whereas local control drives motivation.

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Dopamine waves as a mechanism for spatiotemporal credit assignment

Arif A. Hamid, Michael J. Frank, Christopher I. Moore

Nature Magazine

Jun 13, 2019

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Dopamine waves as a mechanism for spatiotemporal credit assignment

Arif A. Hamid, Michael J. Frank, Christopher I. Moore

Nature Magazine

Jun 13, 2019

Abstract

Significant evidence supports the view that dopamine shapes reward-learning by encoding prediction errors. However, it is unknown whether dopamine decision-signals are tailored to the functional specialization of target regions. Here, we report a novel set of wave-like spatiotemporal activity-patterns in dopamine axons across the dorsal striatum. These waves switch between different activational motifs and organize dopamine transients into localized clusters within functionally related striatal subregions. These specific motifs are associated with distinct task contexts: At reward delivery, dopamine signals rapidly resynchronize into propagating waves with opponent directions depending on instrumental task contingencies. Moreover, dopamine dynamics during reward pursuit signal the extent to which mice have instrumental control and interact with reward waves to predict future behavioral adjustments. Our results are consistent with a computational architecture in which striatal dopamine signals are sculpted by inference about instrumental controllability and provide evidence for a spatiotemporally “vectorized” role of dopamine in credit assignment.

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Dissociable dopamine dynamics for learning and motivation

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

Jun 6, 2019

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Dissociable dopamine dynamics for learning and motivation

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

Jun 6, 2019

Abstract

The dopamine projection from ventral tegmental area (VTA) to nucleus accumbens (NAc) is critical for motivation to work for rewards and reward-driven learning. How dopamine supports both functions is unclear. Dopamine cell spiking can encode prediction errors, which are vital learning signals in computational theories of adaptive behaviour. By contrast, dopamine release ramps up as animals approach rewards, mirroring reward expectation. This mismatch might reflect differences in behavioural tasks, slower changes in dopamine cell spiking or spike-independent modulation of dopamine release. Here we compare spiking of identified VTA dopamine cells with NAc dopamine release in the same decision-making task. Cues that
indicate an upcoming reward increased both spiking and release. However, NAc core dopamine release also covaried with dynamically evolving reward expectations, without corresponding changes in VTA dopamine cell spiking. Our results suggest a fundamental difference in how dopamine release is regulated to achieve distinct functions: broadcast burst signals promote learning, whereas local control drives motivation.

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Publisher Correction: Dissociable dopamine dynamics for learning and motivation(Nature, (2019), 570, 7759, (65-70), 10.1038/s41586-019-1235-y)

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

Jun 4, 2019

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Publisher Correction: Dissociable dopamine dynamics for learning and motivation(Nature, (2019), 570, 7759, (65-70), 10.1038/s41586-019-1235-y)

Arif A. Hamid, Ali Mohebi, Jeffrey R. Pettibone

Nature Magazine

Jun 4, 2019

Abstract

Change history: In this Article, an extraneous label appeared in Fig. 4b, and has been removed in the online version.

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Forebrain dopamine value signals arise independently from midbrain dopamine cell firing.

Arif Hamid, Ali Mohebi, Jeffrey Pettibone

Nature Magazine

May 30, 2018

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Forebrain dopamine value signals arise independently from midbrain dopamine cell firing.

Arif Hamid, Ali Mohebi, Jeffrey Pettibone

Nature Magazine

May 30, 2018

Abstract

The mesolimbic dopamine projection from the ventral tegmental area (VTA) to nucleus accumbens (NAc) is a key pathway for reward-driven learning, and for the motivation to work for more rewards. VTA dopamine cell firing can encode reward prediction errors (RPEs1,2), vital learning signals in computational theories of adaptive behavior. However, NAc dopamine release more closely resembles reward expectation (value), a motivational signal that invigorates approach behaviors3-7. This discrepancy might be due to distinct behavioral contexts: VTA dopamine cells have been recorded under head-fixed conditions, while NAc dopamine release has been measured in actively-moving subjects. Alternatively the mismatch may reflect changes in the tonic firing of dopamine cells8, or a fundamental dissociation between firing and release. Here we directly compare dopamine cell firing and release in the same adaptive decision-making task. We show that dopamine release covaries with reward expectation in two specific forebrain hotspots, NAc core and ventral prelimbic cortex. Yet the firing rates of optogenetically-identified VTA dopamine cells did not correlate with reward expectation, but instead showed transient, error-like responses to unexpected cues. We conclude that critical motivation-related dopamine dynamics do not arise from VTA dopamine cell firing, and may instead reflect local influences over forebrain dopamine varicosities.

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Mesolimbic dopamine signals the value of work

Arif A Hamid, Jeffrey R Pettibone, Omar S Mabrouk

Nov 23, 2015

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Mesolimbic dopamine signals the value of work

Arif A Hamid, Jeffrey R Pettibone, Omar S Mabrouk

Nov 23, 2015

Abstract

Dopamine cell firing can encode errors in reward prediction, providing a learning signal to guide future behavior. Yet dopamine is also a key modulator of motivation, invigorating current behavior. Existing theories propose that fast (phasic) dopamine fluctuations support learning, whereas much slower (tonic) dopamine changes are involved in motivation. We examined dopamine release in the nucleus accumbens across multiple time scales, using complementary microdialysis and voltammetric methods during adaptive decision-making. We found that minute-by-minute dopamine levels covaried with reward rate and motivational vigor. Second-by-second dopamine release encoded an estimate of temporally discounted future reward (a value function). Changing dopamine immediately altered willingness to work and reinforced preceding action choices by encoding temporal-difference reward prediction errors. Our results indicate that dopamine conveys a single, rapidly evolving decision variable, the available reward for investment of effort, which is employed for both learning and motivational functions.

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μ-Opioid receptors within subregions of the striatum mediate pair bond formation through parallel yet distinct reward mechanisms

Arif A. Hamid, Ahanna L. Resendez, MacKenzie Dome

May 22, 2013

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μ-Opioid receptors within subregions of the striatum mediate pair bond formation through parallel yet distinct reward mechanisms

Arif A. Hamid, Ahanna L. Resendez, MacKenzie Dome

May 22, 2013

Abstract

The prairie vole is a socially monogamous rodent that is an excellent animal model for studies of the neurobiology of social attachment. Such studies have demonstrated that activation of reward circuitry during social interactions facilitates pair bond formation. Within this circuitry, μ-opioid receptors (MORs) modulate naturally rewarding behavior in an anatomically segregated manner; MORs located throughout the striatum (dorsal striatum, NAc core, and the entire NAc shell) are implicated in general motivational processes, whereas those located specifically within the dorsomedial NAc shell mediate positive hedonics (and are referred to as a "hedonic hotspot"). The purpose of the present study was to determine whether MORs within these distinct subregions differentially mediate pair bond formation. We first used receptor autoradiography to compare MOR binding densities between these regions. MOR binding was significantly higher in the NAc core and dorsomedial NAc shell compared with the ventral NAc shell. We next used partner preference testing to determine whether MORs within these subregions differentially mediate pair bonding. Blockade of MORs using 1 or 3 μg of H-d-Phe-Cys-Tyr-d-Trp-Arg-Thr-Pen-Thr-NH2 within the dorsal striatum decreased mating during the cohabitation period and inhibited partner preference formation. In contrast, blockade of MORs within dorsomedial NAc shell inhibited partner preference formation without effecting mating behavior, whereas other regions were not involved. Thus, MORs within the dorsal striatum mediate partner preference formation via impairment of mating, whereas those in the dorsomedial NAc shell appear to mediate pair bond formation through the positive hedonics associated with mating.

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Oxygen modulation of neurovascular coupling in the retina

A. Hamid, A. Mishra, E. A. Newman

Nature Magazine

Oct 25, 2011

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Oxygen modulation of neurovascular coupling in the retina

A. Hamid, A. Mishra, E. A. Newman

Nature Magazine

Oct 25, 2011

Abstract

Neurovascular coupling is a process throughwhich neuronal activity leads to local increases in blood flow in the central nervous system. In brain slices, 100% O 2 has been shown to alter neurovascular coupling, suppressing activity-dependent vasodilation. However, in vivo, hyperoxia reportedly has no effect on blood flow. Resolving these conflicting findings is important, given that hyperoxia is often used in the clinic in the treatment of both adults and neonates, and a reduction in neurovascular coupling could deprive active neurons of adequate nutrients. Here we address this issue by examining neurovascular coupling in both ex vivo and in vivo rat retina preparations. In the ex vivo retina, 100% O 2 reduced light-evoked arteriole vasodilations by 3.9-fold and increased vasoconstrictions by 2.6-fold. In vivo, however, hyperoxia had no effect on light-evoked arteriole dilations or blood velocity. Oxygen electrode measurements showed that 100% O 2 raised pO 2 in the ex vivo retina from 34 to 548 mm Hg, whereas hyperoxia has been reported to increase retinal pO 2 in vivo to only ∼53 mm Hg [Yu DY, Cringle SJ, Alder VA, Su EN (1994) Am J Physiol 267:H2498-H2507]. Replicating the hyperoxic in vivo pO 2 of 53 mm Hg in the ex vivo retina did not alter vasomotor responses, indicating that although O 2 can modulate neurovascular coupling when raised sufficiently high, the hyperoxia-induced rise in retinal pO 2 in vivo is not sufficient to produce a modulatory effect. Our findings demonstrate that hyperoxia does not alter neurovascular coupling in vivo, ensuring that active neurons receive an adequate supply of nutrients.

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