#] #] ********************* #] "$d_MindCode"'18_MindCode reference extracts.txt' www.BillHowell.ca 03Apr2021 initial # view in text editor, using constant-width font (eg courier), tabWidth = 3 17Nov2023 copied d_Qndfs: from d_MindCode (2020) to d_Mind2023 48************************************************48 24************************24 # Table of Contents : # $ grep "^#]" "$d_MindCode"'18_MindCode reference extracts.txt' | sed 's|^#\] | |' ********************* "$d_Qndfs"'Mind2023/18_MindCode reference extracts.txt' 03Apr2021 search "Non-spiking neuron" 03Apr2021 multi-spikes & bursting spikes 02Apr2020 I MUST have McCulloch & Pitts logic-type neurons with branching!!! 01Apr2021 cell membrane potential - cause or effect? 24************************24 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] ??Nov2023 08********08 #] 03Apr2021 search "Non-spiking neuron" https://en.wikipedia.org/wiki/Non-spiking_neuron Non-spiking neurons are neurons that are located in the central and peripheral nervous systems and function as intermediary relays for sensory-motor neurons. They do not exhibit the characteristic spiking behavior of action potential generating neurons. Qualities Spiking neurons Nonspiking neurons Location Peripheral and central Peripheral and central Behavior Action potential Fewer sodium channel proteins Non-spiking neural networks are integrated with spiking neural networks to have a synergistic effect in being able to stimulate some sensory or motor response while also being able to modulate the response. Definition A non-spiking neuron is a neuron that transmits a signal via graded potential. It will fire a signal regardless of any membrane potential threshold.[4] Non-spiking neurons are primitive in the sense that they have no on or off switch, and are more sensitive to signal noise than spiking neurons with membrane potentials. Studies show that these neurons may offer a contribution to learning and modulation of motor neuron networks. Spiking neurons and non-spiking neurons are usually integrated into the same neural network, but they possess specific characteristics. The major difference between these two neuron types is the manner in which encoded information is propagated along a length to the central nervous system or to some locus of interneurons, such as a neuromuscular junction. Non-spiking neurons propagate messages without eliciting an action potential. This is most likely due to the chemical composition of the membranes of the non-spiking neurons. They lack protein channels for sodium and are more sensitive to certain neurotransmitters. They function by propagating graded potentials and serve to modulate some neuromuscular junctions. Spiking neurons are noted as traditional action potential generating neurons.[4] 08********08 #] 03Apr2021 multi-spikes & bursting spikes http://www.scholarpedia.org/article/Bursting Eugene M. Izhikevich (2006), Scholarpedia, 1(3):1300. doi:10.4249/scholarpedia.1300 revision #150167 Eugene M. Izhikevich, Editor-in-Chief of Scholarpedia, the peer-reviewed open-access encyclopedia +-----+ Examples Almost every neuron can burst if stimulated or manipulated pharmacologically. Many burst autonomously due to the interplay of fast ionic currents responsible for spiking activity and slower currents that modulate the activity. Below is the list of the more "famous" bursting neurons. Neocortex IB: Intrinsically bursting neurons, if stimulated with a long pulse of dc current, fire an initial burst of spikes followed by shorter bursts, and then tonic spikes (Connors and Gutnick 1990). These are predominantly pyramidal neurons in layer 5. CH: Chattering neurons can fire high-frequency bursts of 3-5 spikes with a relatively short interburst period (Gray and McCormick 1996). Some call them fast rhythmic bursting (FRB) cells. These are pyramidal neurons in layer 2-4, mainly layer 3. Interneurons: Some cortical interneurons exhibit bursting activity in response to pulses of dc current (Markram et al. 2004). Hippocampus LTB: Low-threshold bursters fire high-frequency bursts in response to injected pulses of current. Some of these neurons burst spontaneously (Su et al. 2001). These are pyramidal neurons in CA1 region. HTB: High-threshold bursters fire bursters only in response to strong long pulses of current. Thalamus TC: Thalamocortical neurons can fire bursts if inhibited and then released from inhibition. This rebound burst is often called a low-threshold spike. Some fire bursts spontaneously in response to tonic inhibition. RTN: Reticular thalamic nucleus inhibitory neurons have bursting properties similar to those of TC cells. Cerebellum PC: Purkinje cells in cerebellar slices usually fire tonically but when synaptic input is blocked they can switch to a trimodal pattern which includes a bursting phase (Womack and Khodakhah 2002). Other structures pre-Bot: Respiratory neurons in pre-Bötzinger complex fire rhythmic bursts that control animal respiration cycle. MesV: Some Mesencephalic V neurons in brainstem may fire rhythmic bursts when slightly depolarized above the threshold. AB: Anterior bursting neuron in lobster stomatogastric ganglion fires rhythmic bursts autonomously. R15: Aplysia abdominal ganglion neuron R15 fires autonomous rhythmic bursts. β-cell: Pancreatic β-cells fire rhythmic bursts that control the secretion of insulin. Sometimes the term bursting is used in reference to the bursting pacemaker potential itself and not just the burst of spikes. So, in the literature, one might see references to bursts in the presence of TTX. There are also examples of one spike bursts such as in the CPGs for swimming in Clione and in Xenopus tadpoles. There are many hypotheses on the importance of bursting activity in neural computation. +-----+ Bursts as a Unit of Neuronal Information There are many hypotheses on the importance of bursting activity in neural computation. Bursts are more reliable than single spikes in evoking responses in postsynaptic cells. Indeed, excitatory post-synaptic potentials (EPSP) from each spike in a burst add up and may result in a superthreshold EPSP. Bursts overcome synaptic transmission failure. Indeed, postsynaptic responses to a single presynaptic spike may fail (release does not occur), however in response to a bombardment of spikes, i.e., a burst, synaptic release is more likely (Lisman 1997). Bursts facilitate transmitter release whereas single spikes do not (Lisman 1997). Indeed, a synapse with strong short-term facilitation would be insensitive to single spikes or even short bursts, but not to longer bursts. Each spike in the longer burst facilitates the synapse so the effect of the last few spikes may be quite strong. Bursts evoke long-term potentiation and hence affect synaptic plasticity much greater, or differently than single spikes (Lisman 1997). Bursts have higher signal-to-noise ratio than single spikes (Sherman 2001). Indeed, burst threshold is higher than spike threshold, i.e., generation of bursts requires stronger inputs. Bursts can be used for selective communication if the postsynaptic cells have subthreshold oscillations of membrane potential. Such cells are sensitive to the frequency content of the input. Some bursts resonate with oscillations and elicit a response, others do not, depending on the interburst frequency (Izhikevich et al. 2003). Bursts can resonate with short-term synaptic plasticity making a synapse a band-pass filter (Izhikevich et al. 2003). A synapse having short-term facilitation and depression is most sensitive to a burst having certain resonant interspike frequency. Such a burst evokes just enough facilitation, but not too much synaptic depression, so its effect on the postsynaptic target is maximal. Bursts encode different features of sensory input than single spikes (Gabbiani et al. 1996, Oswald et al. 2004). For example, neurons in the electrosensory lateral-line lobe (ELL) of weakly electric fish fire network induced-bursts in response to communication signals and single spikes in response to prey signals (Doiron et al. 2003). In the thalamus of the visual system bursts from pyramidal neurons encode stimuli that inhibit the neuron for a period of time and then rapidly excite the neuron (Lesica and Stanely, 2004). Natural scenes are often composed of such events. Bursts have more informational content than single spikes when analyzed as unitary events (Reinagel et al. 1999). This information may be encoded into the burst duration or in the fine temporal structure of interspike intervals within a burst. In summary, burst input is more likely to have a stronger impact on the postsynaptic cell than single spike input, so some believe that bursts are all-or-none events, whereas single spikes may be noise. 08********08 #] 02Apr2020 I MUST have McCulloch & Pitts logic-type neurons with branching!!! neural networks can NEVER work without them!!! conventional ANNs use this implicitly!!!! 08********08 #] 01Apr2021 cell membrane potential - cause or effect? Traditionally, ANNs assume that membrane cell potentials rise with inputs, and fire at a threshold potential. Analternate way to look at it, is that cell potenial rises as "correct" inputs are gradually recognized, and once complete, the threshold potential is a reflection and the neuron fires. # enddoc