scholarly journals Scaling principles of distributed circuits

2018 ◽  
Author(s):  
Shyam Srinivasan ◽  
Charles F Stevens
Keyword(s):  
Visual Acuity ◽  
Piriform Cortex ◽  
Quantitative Relationship ◽  
Functional Abilities ◽  
Invariant Property ◽  
Information Encoding ◽  
Scalable Systems ◽  
Distributed Circuits ◽  
Olfactory Ability ◽  
Circuit Components

AbstractDistributed circuits like the olfactory cortex, hippocampus, and cerebellum contain sub-circuits whose inputs distribute their axons over the entire circuit creating a puzzle of how information is encoded. One method for approaching the puzzle is to view them as scalable systems. In scalable systems the quantitative relationship between circuit components is conserved across brain sizes, and by mapping circuit size to functional abilities - e.g. visual acuity in the visual circuit - scientists have explained information encoding. This approach has not been applied to anti-map circuits as their scalability is unknown. To address this gap in knowledge, we obtained quantitative descriptions of the olfactory bulb and piriform cortex in six mammals using stereology techniques and light microscopy. We found that the olfactory circuit is scalable as it satisfies three requirements of scalable systems. First, quantitative relationships between circuit components are conserved: the number piriform neurons n scales with bulb glomeruli g as n ∼ g3/2. Second, the olfactory circuit has an invariant property: the average number of synapses between a bulb glomerulus and piriform neuron is one. Third, the olfactory circuit is symmorphic, i.e. olfactory ability improves with circuit size. Other distributed circuits with similar properties might also be scalable.

Trajectories of Depressive Symptoms in Advanced Old Age

GeroPsych ◽  
2013 ◽  
Vol 26 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Oliver K. Schilling ◽  
Hans-Werner Wahl ◽  
Ortrun Reidick
Keyword(s):  
Visual Acuity ◽  
Depressive Symptoms ◽  
Old Age ◽  
Functional Ability ◽  
Handgrip Strength ◽  
Functional Abilities ◽  
Intraindividual Change ◽  
Growth Mixture ◽  
Depression Level ◽  
Baseline Levels

This study applied a growth mixture approach to intraindividual trajectories of depressive symptoms in advanced old age. Data from 124 elders born 1912–1922, repeatedly assessed on five occasions between 2009–2012, revealed three prototypical patterns: (1) stably low depressive symptoms (expected frequency 28%), (2) stability at major depression level (29%), (3) increase from low to high depressive symptoms (43%). The links of each pattern with functional ability, handgrip strength, and visual acuity were analyzed. High baseline levels of functional abilities and visual acuity, and concurrent stability of functional abilities increased the probability of the “stably low” pattern, but none predicted the increase pattern. We conclude that focus on diverse intraindividual change patterns adds to the understanding of depression in advanced old age.

scholarly journals Orchestration of Hippocampal Information Encoding by the Piriform Cortex

2019 ◽  
Vol 30 (1) ◽  
pp. 135-147 ◽  
Author(s):  
Christina Strauch ◽  
Denise Manahan-Vaughan
Keyword(s):  
Information Processing ◽  
Piriform Cortex ◽  
Long Term Potentiation ◽  
Early Gene ◽  
Perforant Path ◽  
Dependent Manner ◽  
Information Encoding ◽  
Term Potentiation ◽  
Processing And Storage ◽  
Stimulation Of

Abstract The hippocampus utilizes olfactospatial information to encode sensory experience by means of synaptic plasticity. Odor exposure is also a potent impetus for hippocampus-dependent memory retrieval. Here, we explored to what extent the piriform cortex directly impacts upon hippocampal information processing and storage. In behaving rats, test-pulse stimulation of the anterior piriform cortex (aPC) evoked field potentials in the dentate gyrus (DG). Patterned stimulation of the aPC triggered both long-term potentiation (LTP > 24 h) and short-term depression (STD), in a frequency-dependent manner. Dual stimulation of the aPC and perforant path demonstrated subordination of the aPC response, which was nonetheless completely distinct in profile to perforant path-induced DG plasticity. Correspondingly, patterned aPC stimulation resulted in somatic immediate early gene expression in the DG that did not overlap with responses elicited by perforant path stimulation. Our results support that the piriform cortex engages in specific control of hippocampal information processing and encoding. This process may underlie the unique role of olfactory cues in information encoding and retrieval of hippocampus-dependent associative memories.

Scanning Electron Microscopy in Hybrid Microelectronics

1976 ◽  
Vol 34 ◽  
pp. 456-457
Author(s):  
S. Khadpe ◽  
R. Faryniak
Keyword(s):  
Integrated Circuits ◽  
Thick Film ◽  
Integrated Circuit ◽  
Failure Modes ◽  
Three Dimensional ◽  
Circuit Components ◽  
Hybrid Microcircuit ◽  
Electrical Connections ◽  
Scanning Electron

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

Self-Reported Sense of Smell Predicts Disgust Sensitivity and Disgust Reactivity

2018 ◽  
Vol 39 (4) ◽  
pp. 191-195
Author(s):  
Nicholas J. Kelley ◽  
Adrienne L. Crowell
Keyword(s):  
Individual Differences ◽  
Individual Difference ◽  
Olfactory Stimulus ◽  
Disgust Sensitivity ◽  
Sense Of Smell ◽  
Olfactory Ability ◽  
Good Proxy ◽  
Insight Into

Abstract. Two studies tested the hypothesis that self-reported sense of smell (i.e., metacognitive insight into one’s olfactory ability) predicts disgust sensitivity and disgust reactivity. Consistent with our predictions two studies demonstrated that disgust correlates with self-reported sense of smell. Studies 1 and 2 demonstrated, from an individual difference perspective, that trait-like differences in disgust relate to self-reported sense of smell. Physical forms of disgust (i.e., sexual and pathogen disgust) drove this association. However, the association between self-reported sense of smell and disgust sensitivity is small, suggesting that it is likely not a good proxy for disgust sensitivity. The results of Study 2 extended this finding by demonstrating that individual differences in self-reported sense of smell influence how individuals react to a disgusting olfactory stimulus. Those who reported having a better sense of smell (or better insight into their olfactory ability) found a disgusting smell significantly more noxious as compared to participants reporting having a poor sense of smell (or poor insight into their olfactory ability). The current findings suggest that a one-item measure of self-reported sense of smell may be an effective tool in disgust research.

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