Structural organization of the dendritic reticulum linked by gap junctions in layer 4 of the visual cortex

نویسنده

  • Takaichi Fukuda
چکیده

Neuronal gap junctions are ubiquitous in the brain, but their precise positions in actual neuronal circuits have been uncertain, and their functional roles remain unclear. In this study, I visualized connexin36-immunoreactive gap junctions and examined the structural features of the interconnected dendrites arising from parvalbumin (PV)-positive interneurons in layer 4 of the feline visual cortex. I observed evidence for net-like dense linkages of dendrites among virtually all PV neurons (56/58 cells, 96.6%) in the tissue. This dendritic reticulum established connections among clustered cells and further among remote cells. The latter connectivity exhibited a preference for vertical direction, including translaminar linkages, but was also characterized by lateral continuity. Measurement of the distances from each dendritic gap junction back to the two connected somata revealed that at least one of two somata was within 50μm from the junction in 77.5% of the cases and within 75μm in 91.2% of the cases. Thus, distal gap junctions mediated morphologically asymmetrical connection where one soma was close to, but the other soma was far from the connecting junction. This connectivity was typically observed between neurons located apart in the same columnar space, where a long vertical dendrite bridged two neurons through an asymmetrically positioned gap junction. In contrast, gap junctions formed between nearby cells were close to both somata. Thalamocortical afferents established synapses densely on somata of layer 4 PV neurons, indicating the possible involvement of proximal gap junctions in visual stimulus-driven feedforward regulation. These findings provide a new structural basis for cortical investigations.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Structural organization of the gap junction network in the cerebral cortex.

Neurons in mammalian brains are heavily interconnected by specialized junctions called chemical synapses. At chemical synapses, signals are transmitted rather indirectly between connected neurons with some delay. Recent studies have revealed additional channels for neuronal communication, that is, gap junctions. As electrical signals are directly transmitted through gap junctions without delay,...

متن کامل

Primed-burst potentiation in adult rat visual cortex in vitro

  The effectiveness of θ pattern primed-bursts (PBs) on development of primed-burst (PB) potentiation was investigated in layer II/III of the adult rat visual cortex in vitro. Experiments were carried out in the visual cortical slices. Population excitatory post-synaptic potentials (pEPSPs) were evoked in layer II/III by stimulation of either white mater or layer IV. To induce long-term potenti...

متن کامل

Action of brain-derived neurotrophic factor on function and morphology of visual cortical neurons

Brain-derived neurotrophic factor (BDNF) is known to play a role in experience-dependent plasticity of the developing visual cortex. For example, BDNF acutely enhances long-term potentiation and blocks long-term depression in the visual cortex of young rats. Such acute actions of BDNF suggested to be mediated mainly through presynaptic mechanisms. A chronic application of BDNF to the visual cor...

متن کامل

Action of brain-derived neurotrophic factor on function and morphology of visual cortical neurons

Brain-derived neurotrophic factor (BDNF) is known to play a role in experience-dependent plasticity of the developing visual cortex. For example, BDNF acutely enhances long-term potentiation and blocks long-term depression in the visual cortex of young rats. Such acute actions of BDNF suggested to be mediated mainly through presynaptic mechanisms. A chronic application of BDNF to the visual cor...

متن کامل

Effects of visual deprivation on epileptic activity in mature rat visual cortex

  Effects of visual deprivation on the induction of epileptiform activity were studied in layer II/III of mature rat primary visual cortex. Field potentials were evoked by stimulation of layer IV in slices from control and dark-reared (OR) rats. Picrotoxin (PTX)-induced epileptic activity was characterized by spontaneous and evoked epileptic field potentials (EFPs). The results showed that OR s...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Neuroscience

دوره 340  شماره 

صفحات  -

تاریخ انتشار 2017