Light Sensory Responses in Lower Plants: Photomovement Versus Photoadaptation

2003 ◽  
pp. 258-276
Author(s):  
Christoph Forreiter ◽  
Gottfried Wagner
Keyword(s):  
Sensory Responses ◽  
Lower Plants

Preserving without conserving: Memoryscopes and historically burdened heritage

2021 ◽  
pp. 105971232110008
Author(s):  
John Sutton
Keyword(s):  
The Past ◽  
Sensory Responses ◽  
Over Time

Rather than conserving or ignoring historically burdened heritage, RAAAF intervene. Their responses are striking, sometimes dramatic or destructive. Prompted by Rietveld’s discussion of the Luftschloss project, I compare some other places with difficult pasts which engage our embodied and sensory responses, without such active redirection or disruption. Ross Gibson’s concept of a ‘memoryscope’ helps us identify distinct but complementary ways of focussing the forces of the past. Emotions and imaginings are transmitted over time in many forms. The past is not easily washed, blasted or sliced away. By considering other settings and modes of encounter, we can recognise and applaud the novelty of RAAAF’s interventions while urging further attention to the variable dynamics and rhythms of remembering and of sociomaterial residues.

scholarly journals Comprehensive analysis of SSRs and database construction using all complete gene-coding sequences in major horticultural and representative plants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaoming Song ◽  
Qihang Yang ◽  
Yun Bai ◽  
Ke Gong ◽  
Tong Wu ◽  
...  
Keyword(s):  
Higher Plants ◽  
Extreme Environments ◽  
Gene Families ◽  
Comprehensive Analysis ◽  
Whole Genome ◽  
Flowering Genes ◽  
Database Construction ◽  
Myb Gene ◽  
Gene Coding ◽  
Lower Plants

AbstractSimple sequence repeats (SSRs) are one of the most important genetic markers and widely exist in most species. Here, we identified 249,822 SSRs from 3,951,919 genes in 112 plants. Then, we conducted a comprehensive analysis of these SSRs and constructed a plant SSR database (PSSRD). Interestingly, more SSRs were found in lower plants than in higher plants, showing that lower plants needed to adapt to early extreme environments. Four specific enriched functional terms in the lower plant Chlamydomonas reinhardtii were detected when it was compared with seven other higher plants. In addition, Guanylate_cyc existed in more genes of lower plants than of higher plants. In our PSSRD, we constructed an interactive plotting function in the chart interface, and users can easily view the detailed information of SSRs. All SSR information, including sequences, primers, and annotations, can be downloaded from our database. Moreover, we developed Web SSR Finder and Batch SSR Finder tools, which can be easily used for identifying SSRs. Our database was developed using PHP, HTML, JavaScript, and MySQL, which are freely available at http://www.pssrd.info/. We conducted an analysis of the Myb gene families and flowering genes as two applications of the PSSRD. Further analysis indicated that whole-genome duplication and whole-genome triplication played a major role in the expansion of the Myb gene families. These SSR markers in our database will greatly facilitate comparative genomics and functional genomics studies in the future.

scholarly journals Cortical layer 6 control of sensory responses in higher‐order thalamus

2020 ◽  
Vol 598 (18) ◽  
pp. 3973-4001 ◽  
Author(s):  
Josephine Ansorge ◽  
Desire Humanes‐Valera ◽  
François P. Pauzin ◽  
Martin K. Schwarz ◽  
Patrik Krieger
Keyword(s):  
Higher Order ◽  
Cortical Layer ◽  
Sensory Responses

scholarly journals Behavioral Effects of a Chemorepellent Receptor Knockout Mutation in Tetrahymena thermophila

mSphere ◽  
2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Dianxiong Zou ◽  
Todd M. Hennessey
Keyword(s):  
Receptor Gene ◽  
Classical Model ◽  
Model System ◽  
Model Systems ◽  
Unicellular Eukaryote ◽  
Wild Type ◽  
Inhibitory Neurotransmitter ◽  
In The Wild ◽  
Sensory Responses ◽  
Major Emphasis

ABSTRACT Although many single-cell eukaryotes have served as classical model systems for chemosensory studies for decades, the major emphasis has been on chemoattraction and no chemorepellent receptor gene has been identified in any unicellular eukaryote. This is the first description of a gene that codes for a chemorepellent receptor in any protozoan. Integration of both depolarizing chemorepellent pathways and hyperpolarizing chemoattractant pathways is as important to chemoresponses of motile unicells as excitatory and inhibitory neurotransmitter pathways are to neurons. Therefore, both chemoattractant and chemorepellent pathways should be represented in a useful unicellular model system. Tetrahymena cells provide such a model system because simple behavioral bioassays, gene knockouts, biochemical analysis, and other approaches can be used with these eukaryotic model cells. This work can contribute to the basic understanding of unicellular sensory responses and provide insights into the evolution of chemoreceptors and possible chemorepellent approaches for preventing infections by some pathogenic protozoa. A conditioned supernatant from Tetrahymena thermophila contains a powerful chemorepellent for wild-type cells, and a gene called G37 is required for this response. This is the first genomic identification of a chemorepellent receptor in any eukaryotic unicellular organism. This conditioned supernatant factor (CSF) is small (<1 kDa), and its repellent effect is resistant to boiling, protease treatment, and nuclease digestion. External BAPTA eliminated the CSF response, suggesting that Ca2+ entry is required for the classical avoiding reactions (AR) used for chemorepulsion. A macronuclear G37 gene knockout (G37-KO) mutant is both nonresponsive to the CSF and overresponsive to other repellents such as quinine, lysozyme, GTP, and high potassium concentrations. All of these mutant phenotypes were reversed by overexpression of the wild-type G37 gene in a G37 overexpression mutant. Overexpression of G37 in the wild type caused increased responsiveness to the CSF and underresponsiveness to high K+ concentrations. Behavioral adaptation (by prolonged exposure to the CSF) caused decreases in responsiveness to all of the stimuli used in the wild type and the overexpression mutant but not in the G37-KO mutant. We propose that the constant presence of the CSF causes a decreased basal excitability of the wild type due to chemosensory adaptation through G37 and that all of the G37-KO phenotypes are due to an inability to detect the CSF. Therefore, the G37 protein may be the CSF receptor. The physiological role of these G37-mediated responses may be to both moderate basal excitability and detect the CSF as an indicator of high cell density growth. IMPORTANCE Although many single-cell eukaryotes have served as classical model systems for chemosensory studies for decades, the major emphasis has been on chemoattraction and no chemorepellent receptor gene has been identified in any unicellular eukaryote. This is the first description of a gene that codes for a chemorepellent receptor in any protozoan. Integration of both depolarizing chemorepellent pathways and hyperpolarizing chemoattractant pathways is as important to chemoresponses of motile unicells as excitatory and inhibitory neurotransmitter pathways are to neurons. Therefore, both chemoattractant and chemorepellent pathways should be represented in a useful unicellular model system. Tetrahymena cells provide such a model system because simple behavioral bioassays, gene knockouts, biochemical analysis, and other approaches can be used with these eukaryotic model cells. This work can contribute to the basic understanding of unicellular sensory responses and provide insights into the evolution of chemoreceptors and possible chemorepellent approaches for preventing infections by some pathogenic protozoa.

Encoding of graded changes in spatial specificity of prior cues in human visual cortex

2014 ◽  
Vol 112 (11) ◽  
pp. 2834-2849 ◽  
Author(s):  
Yuko Hara ◽  
Justin L. Gardner
Keyword(s):  
Prior Information ◽  
Prior Probability ◽  
Blood Oxygenation ◽  
Response Magnitude ◽  
Behavioral Performance ◽  
Significant Difference ◽  
Cortical Responses ◽  
Sensory Responses ◽  
Contrast Discrimination ◽  
Spatial Specificity

Prior information about the relevance of spatial locations can vary in specificity; a single location, a subset of locations, or all locations may be of potential importance. Using a contrast-discrimination task with four possible targets, we asked whether performance benefits are graded with the spatial specificity of a prior cue and whether we could quantitatively account for behavioral performance with cortical activity changes measured by blood oxygenation level-dependent (BOLD) imaging. Thus we changed the prior probability that each location contained the target from 100 to 50 to 25% by cueing in advance 1, 2, or 4 of the possible locations. We found that behavioral performance (discrimination thresholds) improved in a graded fashion with spatial specificity. However, concurrently measured cortical responses from retinotopically defined visual areas were not strictly graded; response magnitude decreased when all 4 locations were cued (25% prior probability) relative to the 100 and 50% prior probability conditions, but no significant difference in response magnitude was found between the 100 and 50% prior probability conditions for either cued or uncued locations. Also, although cueing locations increased responses relative to noncueing, this cue sensitivity was not graded with prior probability. Furthermore, contrast sensitivity of cortical responses, which could improve contrast discrimination performance, was not graded. Instead, an efficient-selection model showed that even if sensory responses do not strictly scale with prior probability, selection of sensory responses by weighting larger responses more can result in graded behavioral performance benefits with increasing spatial specificity of prior information.

Longitudinal imaging of VIP interneurons reveals sup-population specific effects of stroke that can be rescued with chemogenetic therapy

2021 ◽  
Author(s):  
Mohamad Motaharinia ◽  
Kimberly Gerrow ◽  
Roobina Boghozian ◽  
Emily White ◽  
Sun-Eui Choi ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Cortical Excitability ◽  
Sensory Response ◽  
Inhibitory Interneurons ◽  
Partial Recovery ◽  
Highly Active ◽  
Specific Effects ◽  
Somatosensory Responses ◽  
Sensory Responses ◽  
Longitudinal Imaging

Abstract Stroke profoundly disrupts cortical excitability which impedes recovery, but how it affects the function of specific inhibitory interneurons, or subpopulations therein, is poorly understood. Interneurons expressing vasoactive intestinal peptide (VIP) represent an intriguing stroke target because they can regulate cortical excitability through disinhibition. Here we chemogenetically augmented VIP interneuron excitability after stroke to show that it enhances somatosensory responses and improves recovery of paw function. Using longitudinal calcium imaging, we discovered that stroke primarily disrupts the fidelity (fraction of responsive trials) and predictability of sensory responses within a subset of highly active VIP neurons. Partial recovery of responses occurred largely within these active neurons and was not accompanied by the recruitment of minimally active neurons. Importantly, chemogenetic stimulation preserved sensory response fidelity and predictability in highly active neurons. These findings provide a new depth of understanding into how stroke and prospective therapies (chemogenetics), can influence subpopulations of inhibitory interneurons.

Graded Potentials and Spiking in Single Units of the Oval Organ, a Mechanoreceptor in the Lobster Ventilatory System: II. Individuality of the Three Afferent Fibres

1983 ◽  
Vol 107 (1) ◽  
pp. 451-464
Author(s):  
B.M.H. BUSH ◽  
V.M. PASZTOR
Keyword(s):  
Connective Tissue ◽  
Firing Rate ◽  
Fibre Type ◽  
Firing Frequency ◽  
Tissue Array ◽  
Burst Frequency ◽  
Impulse Generation ◽  
Dynamic Phase ◽  
Branching Patterns ◽  
Sensory Responses

1. The peripheral dendritic arborizations of sensory units X, Y and Z of the oval organ have similar branching patterns. All three permeate the whole array of connective tissue strands without apparent regionalization or specialization. 2. The analogue components of sensory responses elicited in fibres X, Y and Z when the connective tissue array is stretched show considerable diversity: fibre Z has a higher threshold than X and Y; the dynamic peak values of X and Y saturate at pulls mid-range for Z; X, Y and Z form a spectrum of increasing adaptation. 3. Application of TTX abolishes impulse generation in fibre X earlier than in fibre Y, indicating diversity in spike initiating mechanisms from one fibre type to another. 4. Fibre X only spikes between certain limits of membrane depolarization. Usually the response includes one to five spikes which occur during the dynamic phase of a trapezoidal stretch stimulus. 5. Fibre Y fires throughout the stimulus duration for pulls of moderate amplitude and velocity. Spiking inactivation and a low maximum firing frequency (approximately 80 s−1) limit the range of length sensitivity in fibre Y. 6. Fibre Z attains higher firing frequencies than either X or Y (approximately 110 s−1). The initial burst frequency (velocity dependent) may equal the firing rate of the dynamic peak.

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