Janelle M.P. Pakan

Janelle M.P. Pakan
Otto-von-Guericke-Universität Magdeburg | OvGU · Institute for Cognitive Neurology and Dementia Research

PhD

About

72
Publications
17,658
Reads
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1,398
Citations
Additional affiliations
July 2017 - present
Otto-von-Guericke-Universität Magdeburg
Position
  • Group Leader
January 2014 - June 2017
The University of Edinburgh
Position
  • Fellow
August 2010 - December 2013
University College Cork
Position
  • IRCSET Post-Doctoral Fellow
Education
September 2004 - August 2009
University of Alberta
Field of study
  • Neuroscience

Publications

Publications (72)
Article
Full-text available
Nonsensory variables strongly influence neuronal activity in the adult mouse primary visual cortex. Neuronal responses to visual stimuli are modulated by behavioural state, such as arousal and motor activity, and are shaped by experience. This dynamic process leads to neural representations in the visual cortex that reflect stimulus familiarity, ex...
Article
Full-text available
Neural circuit assembly relies on the precise synchronization of developmental processes, such as cell migration and axon targeting, but the cell-autonomous mechanisms coordinating these events remain largely unknown. Here we found that different classes of interneurons use distinct routes of migration to reach the embryonic cerebral cortex. Somato...
Article
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Graphical Abstract Highlights d Most V1 L2/3 neurons show task-related activity after learning a rewarded task d A subset of neurons became responsive to an expected reward location d Without visual cues, behavioral and neuronal responses rely on self-motion signals d With visual cues, behavioral and neuronal responses rely on visual information In...
Article
Full-text available
The potential for neuronal representations of external stimuli to be modified by previous experience is critical for efficient sensory processing and improved behavioral outcomes. To investigate how repeated exposure to a visual stimulus affects its representation in mouse primary visual cortex (V1), we performed two-photon calcium imaging of layer...
Article
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The cerebral cortex and cerebellum both play important roles in sensorimotor processing, however, precise connections between these major brain structures remain elusive. Using anterograde mono-trans-synaptic tracing, we elucidate cerebrocerebellar pathways originating from primary motor, sensory, and association cortex. We confirm a highly organiz...
Preprint
Activated microglia play a significant role in synaptic elimination during neuroinflammation, however, the events prior to the uptake of synaptic material by these cells remain elusive. Here, we performed in vivo two-photon imaging of microglia-synapse interactions in the context of systemic inflammation and Alzheimer´s disease. Both treatments ind...
Article
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The olivocerebellar circuitry is important to convey both motor and non-motor information from the inferior olive (IO) to the cerebellar cortex. Several methods are currently established to observe the dynamics of the olivocerebellar circuitry, largely by recording the complex spike activity of cerebellar Purkinje cells; however, these techniques c...
Article
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The retrosplenial cortex (RSC) has diverse functional inputs and is engaged by various sensory, spatial, and associative learning tasks. We examine how multiple functional aspects are integrated on the single-cell level in the RSC and how the encoding of task-related parameters changes across learning. Using a visuospatial context discrimination pa...
Article
The primary visual cortex has the capacity to store stimulus-specific information locally. A new study reveals a direct role for the hippocampus in experience-dependent cortical plasticity when visual stimuli are presented in a predictable temporal order.
Article
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Executing learned motor behaviors often requires the transformation of sensory cues into patterns of motor commands that generate appropriately timed actions. The cerebellum and thalamus are two key areas involved in shaping cortical output and movement, but the contribution of a cerebellar-thalamocortical pathway to voluntary movement initiation r...
Article
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As we move through the environment we experience constantly changing sensory input that must be merged with our ongoing motor behaviors - creating dynamic interactions between our sensory and motor systems. Active behaviors such as locomotion generally increase the sensory-evoked neuronal activity in visual and somatosensory cortices, but evidence...
Preprint
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To initiate goal-directed behavior, animals must transform sensory cues into motor commands that generate appropriately timed actions. Sensorimotor transformations along the cerebellar-thalamocortical pathway are thought to shape motor cortical output and movement timing, but whether this pathway initiates goal-directed movement remains poorly unde...
Chapter
Full-text available
Our ability to learn relies on the potential of neuronal circuits to change through experience. Recent advances in genetic tools and in vivo imaging have enabled novel investigations into the mechanisms of plasticity at the level of neuronal circuits. This chapter describes an experimental method for long-term activity monitoring of large neuronal...
Article
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Progress in neuroscience relies on new techniques for investigating the complex dynamics of neuronal networks. An ongoing challenge is to achieve minimally invasive and high-resolution observations of neuronal activity in vivo inside deep brain areas. Recently introduced methods for holographic control of light propagation in complex media enable t...
Preprint
Full-text available
Progress in neuroscience constantly relies on the development of new techniques to investigate the complex dynamics of neuronal networks. An ongoing challenge is to achieve minimally-invasive and high-resolution observations of neuronal activity in vivo inside deep brain areas. A perspective strategy is to utilise holographic control of light propa...
Article
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In vivo calcium imaging has become a method of choice to image neuronal population activity throughout the nervous system. These experiments generate large sequences of images. Their analysis is computationally intensive and typically involves motion correction, image segmentation into regions of interest (ROIs), and extraction of fluorescence trac...
Article
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Background Maternal immune activation (MIA) is a risk factor for neurodevelopmental disorders such as autism and schizophrenia, as well as seizure development. The amygdala is a brain region involved in the regulation of emotions, and amygdalar maldevelopment due to infection-induced MIA may lead to amygdala-related disorders. MIA priming of glial...
Article
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Significance statement: Neuronal activity leads to the generation of CO2, which has previously been shown to evoke cerebral blood flow (CBF) increases via the release of the vasodilator PgE2 We demonstrate that hypercapnia (increased CO2) evokes increases in astrocyte calcium signaling which in turn stimulates COX-1 activity and generates downstre...
Chapter
In this chapter we provide a description of the cerebellum in nonmammalian vertebrates. This includes comparative aspects of gross morphology, connectivity in the cerebellar cortex, and the organization of sagittal zones. We also examine variation in the degree of foliation of the cerebellum among species in relation to behavior and neural processi...
Article
Full-text available
Cortical responses to sensory stimuli are modulated by behavioral state. In the primary visual cortex (V1), visual responses of pyramidal neurons increase during locomotion. This response gain was suggested to be mediated through inhibitory neurons, resulting in the disinhibition of pyramidal neurons. Using in vivo two-photon calcium imaging in lay...
Article
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The cerebellum consists of sagittally oriented zones that are delineated by afferent input, Purkinje cell response properties, and the expression of molecular markers such as zebrin II (ZII). ZII is heterogeneously expressed in Purkinje cells such that there are parasagittal stripes of high expression (ZII+) interdigitated with stripes of little or...
Article
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Damage to the amygdala is often linked to Ammon's horn sclerosis (AHS) in surgical specimens of patients suffering from temporal lobe epilepsy (TLE). Moreover, amygdalar pathology is thought to contribute to the development of anxiety symptoms frequently found in TLE. The neuropeptide Y (NPY) Y1 receptor is critical in the regulation of anxiety-rel...
Article
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Cell-permeable phosphorescent probes enable the study of cell and tissue oxygenation, bioenergetics, metabolism, and pathological states such as stroke and hypoxia. A number of such probes have been described in recent years, the majority consisting of cationic small molecule and nanoparticle structures. While these probes continue to advance, adeq...
Article
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Monitoring of oxygenation is important for physiological experiments investigating the growth, differentiation and function of individual cells in 3D tissue models. Phosphorescence based O-2 sensing and imaging potentially allow this task; however, current probes do not provide the desired bio-distribution and analytical performance. We present sev...
Article
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The mammalian central nervous system (CNS) develops from multipotent progenitor cells, which proliferate and differentiate into the various cell types of the brain and spinal cord. Despite the wealth of knowledge from progenitor cell culture studies, there is a significant lack of understanding regarding dynamic progenitor cell behavior over the co...
Article
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Multiple sclerosis (MS) is characterized by the presence of inflammatory demyelinating foci throughout the brain and spinal cord, accompanied by axonal and neuronal damage. Although inflammatory processes are thought to underlie the pathological changes, the individual mediators of this damage are unclear. In order to study the role of pro-inflamma...
Article
Gonadotropin-releasing hormone (GnRH) expressing neurons in the preoptic area (POA) of the hypothalamus plays a key role in regulating reproductive function through the control of gonadotropin release. Several studies have illustrated the importance of the social environment in modulating the size of GnRH expressing neurons. In the African cichlid...
Article
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Radial glial cells serve diverse roles during the development of the central nervous system (CNS). In the embryonic brain, they are recognised as guidance conduits for migrating neuroblasts and as multipotent stem cells, generating both neurons and glia. While their stem cell capacities in the developing spinal cord are as yet not fully clarified,...
Article
Zebrin II (aldolase C) is expressed in a subset of Purkinje cells in the mammalian and avian cerebella such that there is a characteristic parasagittal organization of zebrin-immunopositive stripes alternating with zebrin-immunonegative stripes. Zebrin is expressed not only in the soma and dendrites of Purkinje cells but also in their axonal termin...
Article
The cerebellar cortex has a fundamental parasagittal organization that is reflected in the physiological responses of Purkinje cells, afferent and efferent connections, and the expression of several molecular markers. The most thoroughly studied of these molecular markers is zebrin II (ZII; a.k.a. aldolase C). ZII is differentially expressed in Pur...
Article
Full-text available
The cerebellar cortex has a fundamental parasagittal organization that is apparent in the physiological response properties of Purkinje cells (PCs) and the expression of several molecular markers such as zebrin II (ZII). ZII is heterogeneously expressed in PCs such that there are sagittal stripes of high expression [ZII immunopositive (ZII+)] inter...
Article
Full-text available
Recent studies have shown that the relative sizes of visual regions in the avian brain are correlated with behavioral differences among species. Despite the fact that the tectofugal pathway is the primary source of visual input to the avian brain, detailed interspecific comparisons of the relative size of nuclei within the pathway, the optic tectum...
Article
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Extensive research has revealed a fundamental organization of the cerebellum consisting of functional parasagittal zones. This compartmentalization has been well documented with respect to physiology, biochemical markers, and climbing fiber afferents. Less is known about the organization of mossy fiber afferents in general, and more specifically in...
Article
Full-text available
Over the past few decades there has been a massive amount of research on the geniculo-striate visual system in primates. However, studies of the avian visual system have provided a rich source of data contributing to our understanding of visual processing. In this paper we review the connectivity and function of the optic tectum (homolog of the sup...
Article
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In the avian brain, the optokinetic response is controlled by two retinal-recipient nuclei: the nucleus of the basal optic root (nBOR) of the accessory optic system and the pretectal nucleus lentiformis mesencephali (LM). Although considered sister nuclei because of their similar response properties and function, there are both similarities and dif...
Article
The parasagittal organization of the mammalian cerebellar cortex into zones has been well characterized by immunohistochemical, hodological and physiological studies in recent years. The pattern of these parasagittal bands across the cerebellum is highly conserved across mammals, but whether a similar conservation of immunohistochemically defined p...
Article
Full-text available
The cerebellum is organized into parasagittal zones with respect to the topography of climbing fiber (CF) afferents and the expression of molecular markers such as zebrin II. Zebrin is expressed by a subset of Purkinje cells that are distributed as a parasagittal array of immunopositive and immunonegative stripes. Several studies in rodents suggest...
Article
Full-text available
Calcium-binding protein expression has proven useful in delineating neural pathways. For example, in birds, calbindin is strongly expressed in the tectofugal pathway, whereas parvalbumin (PV) is strongly expressed in the thalamofugal pathway. Whether neurons within other visual regions also differentially express calcium-binding proteins, however,...
Article
Full-text available
The pigeon vestibulocerebellum is divided into two regions based on the responses of Purkinje cells to optic flow stimuli: the uvula-nodulus responds best to self-translation, and the flocculus responds best to self-rotation. We used retrograde tracing to determine whether the flocculus and uvula-nodulus receive differential mossy fiber input from...