Long- and Short-Term Conductance Control of Artificial Polymer Wire Synapses

Networks in the human brain are extremely complex and sophisticated. The abstract model of the human brain has been used in software development, specifically in artificial intelligence. Despite the remarkable outcomes achieved using artificial intelligence, the approach consumes a huge amount of computational resources. A possible solution to this issue is the development of processing circuits that physically resemble an artificial brain, which can offer low-energy loss and high-speed processing. This study demonstrated the synaptic functions of conductive polymer wires linking arbitrary electrodes in solution. By controlling the conductance of the wires, synaptic functions such as long-term potentiation and short-term plasticity were achieved, which are similar to the manner in which a synapse changes the strength of its connections. This novel organic artificial synapse can be used to construct information-processing circuits by wiring from scratch and learning efficiently in response to external stimuli.

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Multiplexed neurochemical transmission emulated using a dual-excitatory synaptic transistor

npj 2D Materials and Applications ◽

10.1038/s41699-021-00205-4 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Mingxue Ma ◽

Yao Ni ◽

Zirong Chi ◽

Wanqing Meng ◽

Haiyang Yu ◽

...

Keyword(s):

Neural Network ◽

Central Nervous System ◽

Nervous System ◽

Long Term Potentiation ◽

Short Term ◽

Term Potentiation ◽

Binary Neural Network ◽

Neuromorphic Systems ◽

Human Brains

AbstractThe ability to emulate multiplexed neurochemical transmission is an important step toward mimicking complex brain activities. Glutamate and dopamine are neurotransmitters that regulate thinking and impulse signals independently or synergistically. However, emulation of such simultaneous neurotransmission is still challenging. Here we report design and fabrication of synaptic transistor that emulates multiplexed neurochemical transmission of glutamate and dopamine. The device can perform glutamate-induced long-term potentiation, dopamine-induced short-term potentiation, or co-release-induced depression under particular stimulus patterns. More importantly, a balanced ternary system that uses our ambipolar synaptic device backtrack input ‘true’, ‘false’ and ‘unknown’ logic signals; this process is more similar to the information processing in human brains than a traditional binary neural network. This work provides new insight for neuromorphic systems to establish new principles to reproduce the complexity of a mammalian central nervous system from simple basic units.

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Plasticity in the projection from the anterior thalamic nuclei to the anterior cingulate cortex in the rat in vivo: paired-pulse facilitation, long-term potentiation and short-term depression

Neuroscience ◽

10.1016/s0306-4522(01)00554-1 ◽

2002 ◽

Vol 109 (3) ◽

pp. 401-406 ◽

Cited By ~ 19

Author(s):

C. Gemmell ◽

S.M. O’Mara

Keyword(s):

Anterior Cingulate Cortex ◽

Long Term Potentiation ◽

Anterior Cingulate ◽

Thalamic Nuclei ◽

Short Term ◽

Paired Pulse ◽

Term Potentiation ◽

Anterior Thalamic Nuclei

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Altered Short-Term Synaptic Plasticity in Mice Lacking the Metabotropic Glutamate Receptor mGlu7

The Scientific World JOURNAL ◽

10.1100/tsw.2002.146 ◽

2002 ◽

Vol 2 ◽

pp. 730-737 ◽

Cited By ~ 35

Author(s):

Trevor J. Bushell ◽

Gilles Sansig ◽

Valerie J. Collett ◽

Herman van der Putten ◽

Graham L. Collingridge

Keyword(s):

Synaptic Plasticity ◽

Molecular Mechanisms ◽

Pyramidal Neurons ◽

Metabotropic Glutamate Receptor ◽

Long Term Potentiation ◽

Short Term ◽

Metabotropic Glutamate ◽

Term Potentiation ◽

Commissural Pathway ◽

Frequency Facilitation

Eight subtypes of metabotropic glutamate (mGlu) receptors have been identified of which two, mGlu5 and mGlu7, are highly expressed at synapses made between CA3 and CA1 pyramidal neurons in the hippocampus. This input, the Schaffer collateral-commissural pathway, displays robust long-term potentiation (LTP), a process believed to utilise molecular mechanisms that are key processes involved in the synaptic basis of learning and memory. To investigate the possible function in LTP of mGlu7 receptors, a subtype for which no specific antagonists exist, we generated a mouse lacking this receptor, by homologous recombination. We found that LTP could be induced in mGlu7-/- mice and that once the potentiation had reached a stable level there was no difference in the magnitude of LTP between mGlu7-/- mice and their littermate controls. However, the initial decremental phase of LTP, known as short-term potentiation (STP), was greatly attenuated in the mGlu7-/- mouse. In addition, there was less frequency facilitation during, and less post-tetanic potentiation following, a high frequency train in the mGlu7-/- mouse. These results show that the absence of mGlu7 receptors results in alterations in short-term synaptic plasticity in the hippocampus.

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Differential modulation of short-term synaptic dynamics by long-term potentiation at mouse hippocampal mossy fibre synapses

The Journal of Physiology ◽

10.1113/jphysiol.2007.143925 ◽

2007 ◽

Vol 585 (3) ◽

pp. 853-865 ◽

Cited By ~ 16

Author(s):

Anja Gundlfinger ◽

Christian Leibold ◽

Katja Gebert ◽

Marion Moisel ◽

Dietmar Schmitz ◽

...

Keyword(s):

Long Term Potentiation ◽

Mossy Fibre ◽

Differential Modulation ◽

Short Term ◽

Term Potentiation ◽

Synaptic Dynamics

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Cognitive functions and underlying parameters of human brain physiology are associated with chronotype

Nature Communications ◽

10.1038/s41467-021-24885-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Mohammad Ali Salehinejad ◽

Miles Wischnewski ◽

Elham Ghanavati ◽

Mohsen Mosayebi-Samani ◽

Min-Fang Kuo ◽

...

Keyword(s):

Motor Learning ◽

Human Brain ◽

Cognitive Functions ◽

Cortical Excitability ◽

Long Term Potentiation ◽

Cortical Inhibition ◽

Memory And Attention ◽

Brain Physiology ◽

Brain Functions ◽

Term Potentiation

AbstractCircadian rhythms have natural relative variations among humans known as chronotype. Chronotype or being a morning or evening person, has a specific physiological, behavioural, and also genetic manifestation. Whether and how chronotype modulates human brain physiology and cognition is, however, not well understood. Here we examine how cortical excitability, neuroplasticity, and cognition are associated with chronotype in early and late chronotype individuals. We monitor motor cortical excitability, brain stimulation-induced neuroplasticity, and examine motor learning and cognitive functions at circadian-preferred and non-preferred times of day in 32 individuals. Motor learning and cognitive performance (working memory, and attention) along with their electrophysiological components are significantly enhanced at the circadian-preferred, compared to the non-preferred time. This outperformance is associated with enhanced cortical excitability (prominent cortical facilitation, diminished cortical inhibition), and long-term potentiation/depression-like plasticity. Our data show convergent findings of how chronotype can modulate human brain functions from basic physiological mechanisms to behaviour and higher-order cognition.

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Overexpression of wild-type human amyloid precursor protein alters GABAergic transmission

Scientific Reports ◽

10.1038/s41598-021-97144-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anna Kreis ◽

Jana Desloovere ◽

Nuria Suelves ◽

Nathalie Pierrot ◽

Xavier Yerna ◽

...

Keyword(s):

Amyloid Precursor Protein ◽

Neuronal Loss ◽

Gaba Release ◽

Long Term Potentiation ◽

Precursor Protein ◽

Wild Type ◽

Inhibitory Neurotransmission ◽

Gaba Production ◽

Synaptic Functions ◽

Term Potentiation

AbstractThe function of the amyloid precursor protein (APP) is not fully understood, but its cleavage product amyloid beta (Aβ) together with neurofibrillary tangles constitute the hallmarks of Alzheimer’s disease (AD). Yet, imbalance of excitatory and inhibitory neurotransmission accompanied by loss of synaptic functions, has been reported much earlier and independent of any detectable pathological markers. Recently, soluble APP fragments have been shown to bind to presynaptic GABAB receptors (GABABRs), subsequently decreasing the probability of neurotransmitter release. In this body of work, we were able to show that overexpression of wild-type human APP in mice (hAPPwt) causes early cognitive impairment, neuronal loss, and electrophysiological abnormalities in the absence of amyloid plaques and at very low levels of Aβ. hAPPwt mice exhibited neuronal overexcitation that was evident in EEG and increased long-term potentiation (LTP). Overexpression of hAPPwt did not alter GABAergic/glutamatergic receptor components or GABA production ability. Nonetheless, we detected a decrease of GABA but not glutamate that could be linked to soluble APP fragments, acting on presynaptic GABABRs and subsequently reducing GABA release. By using a specific presynaptic GABABR antagonist, we were able to rescue hyperexcitation in hAPPwt animals. Our results provide evidence that APP plays a crucial role in regulating inhibitory neurotransmission.

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Stimulus configuration, long-term potentiation, and the hippocampus

Behavioral and Brain Sciences ◽

10.1017/s0140525x97411597 ◽

1997 ◽

Vol 20 (4) ◽

pp. 629-631 ◽

Cited By ~ 3

Author(s):

Nestor A. Schmajuk

Keyword(s):

Neural Network ◽

Computer Simulations ◽

Neural Network Model ◽

Long Term Potentiation ◽

Stimulus Configuration ◽

Association Cortex ◽

Hippocampal Function ◽

Term Potentiation ◽

External Stimuli

Shors & Matzel propose that hippocampal LTP increases the effective salience of discrete external stimuli and thereby facilitates the induction of memories at distant places. In line with this suggestion, a neural network model of associative learning and hippocampal function assumes that LTP increases hippocampal error signals to the cortex, thereby facilitating stimulus configuration in association cortex. Computer simulations show that under these assumptions the model correctly describes the effect of LTP induction and blockade in classical discriminations and place learning.

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