Biology subjects

Cazemier, J. L.

Publications and source records attributed to Cazemier, J. L..

4 recordsLinked to original sources

bioRxiv2023

Psycho-spatially distinct stressors prompt distinct behavioral strategies through a cell type-specific brain circuit

Adaptive behavioral responses to stressors are critical for survival. However, which brain areas orchestrate switching the appropriate stress responses to distinct contexts is an open question. This study aimed to identify the cell type-specific brain circuitry governing the selection of distinct behavioral strategies in response to stressors. Through novel mouse behavior paradigms, we observed distinct stressor-evoked behaviors in two psycho-spatially distinct contexts, characterized by stressors inside or outside the safe zone. The identification of brain regions activated in both conditions revealed the involvement of the dorsomedial hypothalamus (DMH). Further investigation using optogenetics, chemogenetics, and photometry uncovered that glutamatergic projections from the DMH to periaqueductal gray (PAG) mediated responses to inside-stressors, while GABAergic projections, particularly from tachykinin1-expressing neurons, played a crucial role in coping with outside-stressors. These findings elucidate the role of cell type-specific circuitry from the DMH to the PAG in shaping behavioral strategies in response to stressors. These findings have the potential to advance our understanding of fundamental neurobiological processes and inform the development of novel approaches for managing context-dependent and anxiety-associated pathological conditions such as agoraphobia and claustrophobia.

neuroscience↗

bioRxiv2022

Involvement of superior colliculus in complex figure detection of mice

Object detection is an essential function of the visual system. Although the visual cortex plays an important role in object detection, the superior colliculus can support detection when the visual cortex is ablated or silenced. Moreover, it has been shown that superficial layers of mouse SC (sSC) encode visual features of complex objects, and that this code is not inherited from the primary visual cortex. This suggests that mouse sSC may provide a significant contribution to complex object vision. Here, we use optogenetics to show that mouse sSC is causally involved in figure detection based on differences in figure contrast, orientation and phase. Additionally, our neural recordings show that in mouse sSC, image elements that belong to a figure elicit stronger activity than those same elements when they are part of the background. The discriminability of this neural code is higher for correct trials than incorrect trials. Our results provide new insight into the behavioral relevance of the visual processing that takes place in sSC.

neuroscience↗

bioRxiv2022

The direct and indirect pathways of the basal ganglia antagonistically influence cortical activity and perceptual decisions

The striatum, input nucleus of the basal ganglia, receives topographically organized input from the cortex and gives rise to the direct and indirect pathways with antagonistic effects on the output of the basal ganglia. We optogenetically stimulated the direct and indirect pathways in mice and measured their influence on perceptual decisions and neuronal activity in the cortex. In a task in which mice had to detect a visual stimulus, unilateral direct-pathway stimulation increased the probability of lick responses to the non-stimulated side and increased cortical activity globally. In contrast, indirect-pathway stimulation increased the probability of licks to the stimulated side and decreased activity in visual cortical areas. To probe the possible role of the two pathways in working memory, we trained the mice to report the location of a stimulus with licking one of two spouts, after a memory delay. Direct-pathway stimulation prior to and during the memory delay enhanced both the neural representation of a contralateral visual stimulus and the number of contraversive choices, whereas indirect-pathway stimulation had the opposite effects, in accordance with an antagonistic influence of the direct and indirect pathways on licking direction. Our results demonstrate how these two pathways influence perceptual decisions and working memories, and modify activity in the cerebral cortex. One sentence summaryVisuomotor transformations are influenced antagonistically by the direct and indirect pathways of the basal ganglia during visual detection and working memory tasks

neuroscience↗

bioRxiv2020

A parameter-free statistical test that improves the detection of neuronal responsiveness

Neurophysiological studies depend on a reliable quantification of whether and when a neuron responds to stimulation. Simple methods to determine responsiveness require arbitrary parameter choices, such as binning size, while more advanced model-based methods require fitting and hyperparameter tuning. These parameter choices can change the results, which invites bad statistical practice and reduces the replicability. New recording techniques that yield increasingly large numbers of cells would benefit from a test for cell-inclusion that requires no manual curation. Here, we present the parameter-free ZETA-test, which outperforms t-tests, ANOVAs, and renewal-process-based methods by including more cells at a similar false-positive rate. We show that our procedure works across brain regions and recording techniques, including calcium imaging and Neuropixels data. Furthermore, in illustration of the method, we show in mouse visual cortex that 1) visuomotor-mismatch and spatial location are encoded by different neuronal subpopulations; and 2) optogenetic stimulation of VIP cells leads to early inhibition and subsequent disinhibition.

neuroscience↗