axon initial segment

Chandelier cells shine a light on the emergence of GABAergic circuits in the cortex

GABAergic interneurons are chiefly responsible for controlling the activity of local circuits in the cortex. Chandelier cells (ChCs) are a type of GABAergic interneuron that control the output of hundreds of neighbouring pyramidal cells through axo-axonic synapses which target the axon initial segment (AIS). Despite their importance in modulating circuit activity, our knowledge of the development and function of axo-axonic synapses remains elusive. We have investigated the emergence and plasticity of axo-axonic synapses in layer 2/3 of the somatosensory cortex (S1) and found that ChCs follow what appear to be homeostatic rules when forming synapses with pyramidal neurons. We are currently implementing in vivo techniques to image the process of axo-axonic synapse formation during development and uncover the dynamics of synaptogenesis and pruning at the AIS. In addition, we are using an all-optical approach to both activate and measure the activity of chandelier cells and their postsynaptic partners in the primary visual cortex (V1) and somatosensory cortex (S1) in mice, also during development. We aim to provide a structural and functional description of the emergence and plasticity of a GABAergic synapse type in the cortex.

Brief Sensory Deprivation Triggers Cell Type-Specific Structural and Functional Plasticity in Olfactory Bulb Neurons

Can alterations in experience trigger different plastic modifications in neuronal structure and function, and if so, how do they integrate at the cellular level? To address this question, we interrogated circuitry in the mouse olfactory bulb responsible for the earliest steps in odor processing. We induced experience-dependent plasticity in mice of either sex by blocking one nostril for one day, a minimally invasive manipulation that leaves the sensory organ undamaged and is akin to the natural transient blockage suffered during common mild rhinal infections. We found that such brief sensory deprivation produced structural and functional plasticity in one highly specialized bulbar cell type: axon-bearing dopaminergic neurons in the glomerular layer. After 24 h naris occlusion, the axon initial segment (AIS) in bulbar dopaminergic neurons became significantly shorter, a structural modification that was also associated with a decrease in intrinsic excitability. These effects were specific to the AIS-positive dopaminergic subpopulation because no experience-dependent alterations in intrinsic excitability were observed in AIS-negative dopaminergic cells. Moreover, 24 h naris occlusion produced no structural changes at the AIS of bulbar excitatory neurons, mitral/tufted and external tufted cells, nor did it alter their intrinsic excitability. By targeting excitability in one specialized dopaminergic subpopulation, experience-dependent plasticity in early olfactory networks might act to fine-tune sensory processing in the face of continually fluctuating inputs. (https://www.jneurosci.org/content/41/10/2135)

AXON INITIAL SEGMENT PLASTICITY IN THE AUDITORY SYSTEM IN ADULT RATS FOLLOWING ACOUSTIC TRAUMA

FENS Forum 2026

VARIABILITY IN AXON INITIAL SEGMENT GEOMETRY OF HUMAN TEMPORAL LOBE NEURONS

FENS Forum 2026

AXONAL PROPAGATION FAILURE AND AXON INITIAL SEGMENT DISORGANIZATION IN THE PURKINJE CELLS OF A MOUSE MODEL OF ARSACS

FENS Forum 2026

AXON INITIAL SEGMENT REMODELLING IN CORTICOSPINAL TRACT NEURONS ACROSS ALS MOUSE MODELS

FENS Forum 2026

LAYER-SPECIFIC AXON INITIAL SEGMENT PLASTICITY UNDERLIES CORTICAL HYPEREXCITABILITY IN TRIGEMINAL PAIN

FENS Forum 2026

THE ROLE OF PRICKLE2 IN AXON INITIAL SEGMENT PLASTICITY AND ITS IMPLICATION IN NEURODEVELOPMENTAL PATHOLOGIES

FENS Forum 2026

CHARACTERIZING THE MOLECULAR COMPOSITION OF THE CISTERNAL ORGANELLE AT THE AXON INITIAL SEGMENT

FENS Forum 2026

Effects of anti-LGI1 human monoclonal antibodies on mouse behavior, ultrastructure, and ion channel distribution at synapses and axon initial segments

FENS Forum 2024

Colocalization of connexin and synaptopodin at the axon initial segment in adult mammalian projection neurons

Exploring the variability and functional implications of axon initial segment morphology in hippocampal neurons

FENS Forum 2024

Deep brain imaging of axon initial segment dynamics during associative fear learning

Endocytosis and polarity maintenance at the Axon Initial Segment

Formin-mediated actin filament regulation in the axon initial segment of hippocampal neurons

Temporal disparity of action potentials triggered in axon initial segments and distal axons in the neocortex

An ankyrin G binding motif mediates TRAAK localization to the axon initial segment

FENS Forum 2024

Dissecting the function of the cisternal organelle in the axon initial segment

FENS Forum 2024