scholarly journals Triggering visually-guided behavior by holographic activation of pattern completion neurons in cortical ensembles

2018 ◽  
Author(s):  
Luis Carrillo-Reid ◽  
Shuting Han ◽  
Weijian Yang ◽  
Alejandro Akrouh ◽  
Rafael Yuste
Keyword(s):  
Task Performance ◽  
Behavioral Responses ◽  
Building Blocks ◽  
Causal Role ◽  
Behavioral Performance ◽  
Visually Guided ◽  
Pattern Completion ◽  
Neuronal Ensembles ◽  
Two Photon

AbstractNeuronal ensembles are building blocks of cortical activity yet it is unclear if they have any causal role in behavior. Here we tested if the precise activation of neuronal ensembles with two-photon holographic optogenetics in mouse primary visual cortex alters behavioral performance in a visual task. Disruption of behaviorally relevant cortical ensembles by activation of non-selective neurons decreased behavioral performance whereas optogenetic targeting of as few as two neurons with pattern completion capability from behaviorally relevant ensembles improved task performance by reliably recalling the whole ensemble. Moreover, in some cases, activation of two pattern completion neurons, in the absence of visual stimulus, triggered correct behavioral responses. Our results demonstrate a causal role of neuronal ensembles in a visually guided behavior and suggest that ensembles could represent perceptual states.

scholarly journals Seizures start as silent microseizures by neuronal ensembles

2018 ◽  
Author(s):  
Michael Wenzel ◽  
Jordan P. Hamm ◽  
Darcy S. Peterka ◽  
Rafael MD Yuste
Keyword(s):  
Calcium Imaging ◽  
Travelling Wave ◽  
Inhibitory Neurons ◽  
Neural Activation ◽  
Calcium Dynamics ◽  
Neuronal Ensembles ◽  
Two Photon ◽  
Step Model

AbstractUnderstanding seizure formation and spread remains a critical goal of epilepsy research. While many studies have documented seizure spread, it remains mysterious how they start. We used fast in-vivo two-photon calcium imaging to reconstruct, at cellular resolution, the dynamics of focal cortical seizures as they emerge in epileptic foci (intrafocal), and subsequently propagate (extrafocal). We find that seizures start as intrafocal coactivation of small numbers of neurons (ensembles), which are electrographically silent. These silent “microseizures” expand saltatorily until they break into neighboring cortex, where they progress smoothly and first become detectable by LFP. Surprisingly, we find spatially heterogeneous calcium dynamics of local PV interneuron sub-populations, which rules out a simple role of inhibitory neurons during seizures. We propose a two-step model for the circuit mechanisms of focal seizures, where neuronal ensembles first generate a silent microseizure, followed by widespread neural activation in a travelling wave, which is then detected electrophysiologically.

scholarly journals Sensory coding and the causal impact of mouse cortex in a visual decision

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Peter Zatka-Haas ◽  
Nicholas A Steinmetz ◽  
Matteo Carandini ◽  
Kenneth D Harris
Keyword(s):  
Task Performance ◽  
Causal Role ◽  
Behavioral Performance ◽  
Dorsal Cortex ◽  
Related Activity ◽  
Sensory Stimuli ◽  
Visual Contrast ◽  
Mouse Cortex ◽  
Causal Impact ◽  
Motor Actions

Correlates of sensory stimuli and motor actions are found in multiple cortical areas, but such correlates do not indicate whether these areas are causally relevant to task performance. We trained mice to discriminate visual contrast and report their decision by steering a wheel. Widefield calcium imaging and Neuropixels recordings in cortex revealed stimulus-related activity in visual (VIS) and frontal (MOs) areas, and widespread movement-related activity across the whole dorsal cortex. Optogenetic inactivation biased choices only when targeted at VIS and MOs,proportionally to each site's encoding of the visual stimulus, and at times corresponding to peak stimulus decoding. A neurometric model based on summing and subtracting activity in VIS and MOs successfully described behavioral performance and predicted the effect of optogenetic inactivation. Thus, sensory signals localized in visual and frontal cortex play a causal role in task performance, while widespread dorsal cortical signals correlating with movement reflect processes that do not play a causal role.

scholarly journals Co-allocation to overlapping dendritic branches in the retrosplenial cortex integrates contextual memories across time

2021 ◽  
Author(s):  
Megha Sehgal ◽  
Daniel Almeida-Filho ◽  
Sunaina Martin ◽  
Irene Davila Mejia ◽  
George Kastellakis ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Neuronal Excitability ◽  
Retrosplenial Cortex ◽  
Causal Role ◽  
Contextual Memory ◽  
Neuronal Ensembles ◽  
Two Photon ◽  
Dendritic Plasticity ◽  
Dendritic Branches

Events occurring close in time are often linked in memory, providing an episodic timeline and a framework for those memories. Recent studies suggest that memories acquired close in time are encoded by overlapping neuronal ensembles, and that this overlap is necessary for memory linking. Transient increases in neuronal excitability drive this ensemble overlap, but whether dendritic plasticity plays a role in linking memories is unknown. Here, we show that contextual memory linking is not only dependent on ensemble overlap in the retrosplenial cortex (RSC), but also on RSC branch-specific dendritic allocation mechanisms. Using longitudinal two-photon calcium imaging of RSC dendrites, we show that the same dendritic segments are preferentially activated by two linked (but not independent) contextual memories, and that spine clusters added after each of two linked (but not independent) contextual memories are allocated to the same dendritic segments. Importantly, with a novel optogenetic tool, selectively targeted to activated dendritic segments following learning, we show that reactivation of dendrites tagged during the first context exploration is sufficient to link two contextual memories. These results demonstrate a causal role for dendritic mechanisms in memory linking and reveal a novel set of rules that govern how linked, and independent memories are allocated to dendritic compartments.

scholarly journals First-order visual interneurons distribute distinct contrast and luminance information across ON and OFF pathways to achieve stable behavior

2021 ◽  
Author(s):  
Madhura D Ketkar ◽  
Burak Gür ◽  
Sebastian Molina-Obando ◽  
Maria Ioannidou ◽  
Carlotta Martelli ◽  
...  
Keyword(s):  
Behavioral Responses ◽  
Human Perception ◽  
Fruit Fly ◽  
Visual Environment ◽  
Behavioral Performance ◽  
Visually Guided ◽  
First Order ◽  
Visual Scenes ◽  
On And Off Pathways ◽  
Contrast Information

The accurate processing of contrast is the basis for all visually guided behaviors. Visual scenes with rapidly changing illumination challenge contrast computation, because adaptation is not fast enough to compensate for such changes. Yet, human perception of contrast is stable even when the visual environment is quickly changing. The fruit fly Drosophila also shows nearly luminance invariant behavior for both ON and OFF stimuli. To achieve this, first-order interneurons L1, L2 and L3 all encode contrast and luminance differently, and distribute information across both ON and OFF contrast-selective pathways. Behavioral responses to both ON and OFF stimuli rely on a luminance-based correction provided by L1 and L3, wherein L1 supports contrast computation linearly, and L3 non-linearly amplifies dim stimuli. Therefore, L1, L2 and L3 are not distinct inputs to ON and OFF pathways but the lamina serves as a separate processing layer that distributes distinct luminance and contrast information across ON and OFF pathways to support behavioral performance in varying conditions.

scholarly journals The causal role of three frontal cortical areas in grasping

2020 ◽  
Author(s):  
I Caprara ◽  
P Janssen
Keyword(s):  
Visual Information ◽  
Causal Role ◽  
Neuron Activity ◽  
Continuous Control ◽  
Visually Guided ◽  
Object Processing ◽  
Electrical Microstimulation ◽  
Prehension Movements ◽  
Shape Selective

AbstractEfficient object grasping requires the continuous control of arm and hand movements based on visual information. Previous studies have identified a network of parietal and frontal areas that is crucial for the visual control of prehension movements. Electrical microstimulation of 3D shape-selective clusters in AIP during fMRI activates areas F5a and 45B, suggesting that these frontal areas may represent important downstream areas for object processing during grasping, but the role of area F5a and 45B in grasping is unknown. To assess their causal role in the frontal grasping network, we reversibly inactivated 45B, F5a and F5p during visually-guided grasping in macaque monkeys. First, we recorded single neuron activity in 45B, F5a and F5p to identify sites with object responses during grasping. Then, we injected muscimol or saline to measure the grasping deficit induced by the temporary disruption of each of these three nodes in the grasping network. The inactivation of all three areas resulted in a significant increase in the grasping time in both animals, with the strongest effect observed in area F5p. These results not only confirm a clear involvement of F5p, but also indicate causal contributions of area F5a and 45B in visually-guided object grasping.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

Do Writing Directions Influence How People Map Space onto Time?

2018 ◽  
Vol 77 (4) ◽  
pp. 173-184
Author(s):  
Wenxing Yang ◽  
Ying Sun
Keyword(s):  
Mental Representations ◽  
Space Time ◽  
Horizontal Axis ◽  
Causal Role ◽  
Writing Systems ◽  
Temporal Cognition ◽  
Japanese Speakers ◽  
Psychological Experiments ◽  
Vertical Up

Abstract. The causal role of a unidirectional orthography in shaping speakers’ mental representations of time seems to be well established by many psychological experiments. However, the question of whether bidirectional writing systems in some languages can also produce such an impact on temporal cognition remains unresolved. To address this issue, the present study focused on Japanese and Taiwanese, both of which have a similar mix of texts written horizontally from left to right (HLR) and vertically from top to bottom (VTB). Two experiments were performed which recruited Japanese and Taiwanese speakers as participants. Experiment 1 used an explicit temporal arrangement design, and Experiment 2 measured implicit space-time associations in participants along the horizontal (left/right) and the vertical (up/down) axis. Converging evidence gathered from the two experiments demonstrate that neither Japanese speakers nor Taiwanese speakers aligned their vertical representations of time with the VTB writing orientation. Along the horizontal axis, only Japanese speakers encoded elapsing time into a left-to-right linear layout, which was commensurate with the HLR writing direction. Therefore, two distinct writing orientations of a language could not bring about two coexisting mental time lines. Possible theoretical implications underlying the findings are discussed.

Response Interference as a Mechanism Underlying Implicit Measures

2008 ◽  
Vol 24 (4) ◽  
pp. 218-225 ◽  
Author(s):  
Bertram Gawronski ◽  
Roland Deutsch ◽  
Etienne P. LeBel ◽  
Kurt R. Peters
Keyword(s):  
Task Performance ◽  
Psychological Research ◽  
Implicit Measures ◽  
Mediation Model ◽  
Response Interference ◽  
Relevant Evidence ◽  
Moderated Mediation Model ◽  
Stimulus Features ◽  
Underlying Mechanisms

Over the last decade, implicit measures of mental associations (e.g., Implicit Association Test, sequential priming) have become increasingly popular in many areas of psychological research. Even though successful applications provide preliminary support for the validity of these measures, their underlying mechanisms are still controversial. The present article addresses the role of a particular mechanism that is hypothesized to mediate the influence of activated associations on task performance in many implicit measures: response interference (RI). Based on a review of relevant evidence, we argue that RI effects in implicit measures depend on participants’ attention to association-relevant stimulus features, which in turn can influence the reliability and the construct validity of these measures. Drawing on a moderated-mediation model (MMM) of task performance in RI paradigms, we provide several suggestions on how to address these problems in research using implicit measures.

Sign in / Sign up

Export Citation Format

Share Document