The adjacent nucleus ( Latin nucleus accumbens , abbreviated as NAcc, other names: the adjacent nucleus of the septum, reclining nucleus) - a group of neurons in the ventral part of the striatum , is an important part of the mesolimbic pathway involved in the reward system, the formation of pleasure, laughter, dependence, aggression , fear and placebo effect.
The adjacent nucleus receives information from dopamine neurons of the ventral zone and glutamine neurons of the prefrontal cortex , amygdala and hippocampus . Here, an analysis of sensory and emotional information and the formation of a behavioral response-response to motivating stimuli takes place.
The adjacent nucleus consists of two zones that differ in afferent and efferent bonds - the shell ( English shell ) and the core ( English core ). The basis of NAcc is GABA- containing medium needle neurons ( English medium spiny neurons ) (90-95%), the rest are cholinergic and GABAergic insertion neurons.
The different NAcc subregions (the core against the sheath) and the subpopulations of neurons in each region (middle spiny neurons like D1 and D2) are responsible for different cognitive functions. In general, core accumbens play an important role in cognitively processing motivation, disgust, reward (i.e. stimulus, pleasure, and positive reinforcement) and reinforcement learning (e.g. Pavlov instrumental). ); therefore, it plays a significant role in addiction. In addition, part of the core accumbens is centrally involved in the induction of slow sleep. The core of accumbens plays a smaller role in the treatment of fear (a form of disgust), impulsivity, and the placebo effect. He is also involved in coding new motor programs.
Structure
The adjacent nucleus is a collection of neurons that is described as having an outer shell and inner core.
Enter
The main glutamatergic entrances to the nucleus accumbens include the prefrontal cortex (especially the prelimbic cortex and the infraralimbic cortex ), the basolateral tonsil , the ventral hippocampus , the thalamus nuclei (especially the median thalamus nuclei and the intrallaminal thalamus nuclei) from the glutamatergic regions from the ventral region. [18] The nucleus accumbens receives dopaminergic inputs from the ventral region (VTA), which connect through the mesolimbic pathway. The nucleus accumbens is often described as part of the cortico-basal ganglia-thalamo-cortical loop.
Dopaminergic input from VTA modulates the activity of GABAergic neurons in the nucleus accumbens. These neurons are activated directly or indirectly with the help of euphoric drugs (e.g. amphetamine, opiates, etc.) and by participating in useful experiences (e.g. in sex, music, exercise, etc.). [20] [21]
Another important input source comes from CA1 and the ventral underlying tissue from the hippocampus in the dorsomedial region of the nucleus accumbens. Slight depolarization of cells in the nucleus accumbens correlates with the positivity of hippocampal neurons, making them more excitable. The correlated cells of these excited states of the middle spiny neurons in the nucleus accumbens are divided equally between the subiculum and CA1. It was found that subiculum neurons are hyperpolarized (increase negativity), while CA1 neurons “pulsate” (fire> 50 Hz) to perform this priming. [22]
The nucleus accumbens is one of the few regions that receive histaminergic projections from the tuberammammillary nucleus (the only source of histamine neurons in the brain).
Links
- Julia Smirnova. How the brain chooses music . “ Science and Life ” (April 15, 2013). Date of appeal September 17, 2013.
- Shabanov P.D., Lebedev A.A. Neurochemical mechanisms of the nucleus accumbens realizing the supporting effects of self-stimulation of the lateral hypothalamus // Medical Academic Journal. - 2012. - T. 12 , No. 2 . - S. 68-76 .