An oblique dendrite is a

dendrite A dendrite (from Ancient Greek language, Greek δένδρον ''déndron'', "tree") or dendron is a branched cytoplasmic process that extends from a nerve cell that propagates the neurotransmission, electrochemical stimulation received from oth ...

that branches from an

apical dendrite An apical dendrite is a dendrite that emerges from the apex of a pyramidal cell. Apical dendrites are one of two primary categories of dendrites, and they distinguish the pyramidal cells from spiny stellate cells in the cortices. Pyramidal cells ar ...

that emerges from the apex of a

pyramidal cell Pyramidal cells, or pyramidal neurons, are a type of multipolar neuron found in areas of the brain including the cerebral cortex, the hippocampus, and the amygdala. Pyramidal cells are the primary excitation units of the mammalian prefrontal cort ...

. Oblique dendrites typically branch one to two times before terminating. Dendrites are extensions of the

cell body In cellular neuroscience, the soma (: somata or somas; ), neurocyton, or cell body is the bulbous, non-process portion of a neuron or other brain cell type, containing the cell nucleus. Although it is often used to refer to neurons, it can also ...

of a

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

Growth and development

The growth and development of oblique dendrites in rats has been linked to the type of environment, or condition, they are placed in. This is also known as

environmental enrichment Environmental enrichment is the stimulation of the brain by its physical and social surroundings. Brains in richer, more stimulating environments have higher rates of synaptogenesis and more complex dendrite arbors, leading to increased brain a ...

. The three types of conditions used in studies are an enriched conditioned, standard condition, and impoverished condition. The enriched condition contains mazes, an exercise wheel, other rats, and toys. The standard condition generally has a wheel for voluntary exercise and other rats. The impoverished condition only contains fellow rats. Animals placed in an enriched environment had heavier, thicker cortexes and an increase in the number of dendritic branches (including oblique dendrites) in the

hippocampus The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the ...

than the standard or impoverished condition. This phenomenon is known as

neuroplasticity Neuroplasticity, also known as neural plasticity or just plasticity, is the ability of neural networks in the brain to change through neurogenesis, growth and reorganization. Neuroplasticity refers to the brain's ability to reorganize and rewir ...

. Furthermore, the enriched condition may show in increase in

monoamine neurotransmitter Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, norepinephrine and serotonin. All monoamines ...

release such as

serotonin Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...

and

noradrenaline Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" (from ...

which have been linked to

synaptic plasticity In neuroscience, synaptic plasticity is the ability of synapses to Chemical synapse#Synaptic strength, strengthen or weaken over time, in response to increases or decreases in their activity. Since memory, memories are postulated to be represent ...

and

learning Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, Attitude (psychology), attitudes, and preferences. The ability to learn is possessed by humans, non-human animals, and ...

. This is important because an increase in oblique dendrites and dendritic branching allows for increased neurotransmitter uptake. Environmental enrichment is crucial in early brain development due to increase formation of synapses, or

synaptogenesis Synaptogenesis is the formation of synapses between neurons in the nervous system. Although it occurs throughout a healthy person's lifespan, an explosion of synapse formation occurs during early brain development, known as exuberant synaptogene ...

. This results in an increase in oblique dendrites and dendritic branching.

Effects on oblique dendrites from Alzheimer’s disease

The

beta amyloid Amyloid beta (Aβ, Abeta or beta-amyloid) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid-beta precursor pro ...

peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...

, which may lead to the formation of

amyloid plaques Amyloid plaques (also known as neuritic plaques, amyloid beta plaques or senile plaques) are extracellular deposits of amyloid beta (Aβ) protein that present mainly in the grey matter of the brain. Degeneration (medical), Degenerative neuronal ...

, has been linked to

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

. The peptide has been shown to block A-type

voltage-gated potassium channel Voltage-gated potassium channels (VGKCs) are potassium channel, transmembrane channels specific for potassium and Voltage-gated ion channel, sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a ...

dendrites; the thin branches of the oblique dendrites are especially susceptible to disruption from the beta amyloid blockage of the A-type potassium channels which may lead to decline in cognitive function in the early stages of Alzheimer's disease.Morse, Thomas M., Nicholas T. Carnevale, Pradeep G. Mutalik, Michele Migliore, and Gordon M. Shepherd. "Abnormal excitability of oblique dendrites implicated in early Alzheimer's: a computational study." National Center for Biotechnology Information. U.S. National Library of Medicine, 31 May 2010.

References

Dailey ME and Smith SJ, ''The Dynamics of Dendritic Structure in Developing Hippocampal Slices''. J Neurosci 16(9), 1996 pp. 2983-2994.Watson, Neil V., and S. Marc. Breedlove, "The Mind's Machine: Foundations of Brain and Behavior". Sunderland, MA: Sinauer Associates, 2012. N. pag. Print.van Praag, Henriette, Gerd Kempermann, and Fred H. Gage. "Neural consequences of environmental enrichment." Nature Reviews Neuroscience 1.3 (2000): 191-198.Morse, Thomas M., Nicholas T. Carnevale, Pradeep G. Mutalik, Michele Migliore, and Gordon M. Shepherd. "Abnormal excitability of oblique dendrites implicated in early Alzheimer's: a computational study." National Center for Biotechnology Information. U.S. National Library of Medicine, 31 May 2010.
Neurohistology

Growth and development

Effects on oblique dendrites from Alzheimer’s disease

See also

References