Consciousness, EEG, Sleep and Emotions
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal in Principles of Physiology for the Anaesthetist, 2020
The functions of the limbic system can be summarised as follows: Hippocampus is concerned with memory acquisition and recall, formation of long-term memory and behaviour. Lesions of the hippocampus lead to anterograde amnesia, and it is thought that the hippocampus is involved in the transformation from short-term to long-term memory.Amygdaloid nuclei are linked with emotional content of stimuli, fear and rage behaviour anxiety.Septal nuclei are associated with pleasure and reward.Cingulate gyrus is involved in the evaluation of the affective aspects of events.
Neuroanatomy of basic cognitive function
Mark J. Ashley, David A. Hovda in Traumatic Brain Injury, 2017
Cholinergic neurons (Figure 6.15) project from the mesopontine tegmentum and the basal forebrain. The neurons of the pontine region provide a descending projectional pathway to the nuclei of the pontine and medullary reticular formation. They also project in a major ascending pathway to the thalamus. The ascending pathway to the thalamus exerts an arousal effect that is mediated indirectly by excitatory projections from the thalamus to the cortex.177 Projections arising in the basal forebrain provide indirect cholinergic input to the cortex. By contrast, cholinergic projections arising from the nucleus basalis neurons project entirely to nearly all the cerebral cortex. The hippocampal formation is fed by projections from the medial septal nuclei and the nucleus of the diagonal band of Broca. Cholinergic neurons of the descending pathway are thought to impact the sleep–wake cycle via these projections. Cholinergic blockade of central cholinergic transmission results in delirium, and blockade of the striatal neurons results in movement disorders.177 The primary function of acetylcholine is found in attention, memory, and learning.
Neurological Examination
Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner in The Integrated Nervous System, 2017
The areas of the brain associated with these emotional reactions are located for the most part in the temporal lobe. The relevant structures include the amygdala as well as other nuclei, and the cortex of the insula. Parts of the frontal lobe are also involved in emotional reactions, mostly the ventromedial aspects (in particular, the cingulate gyrus) and the orbital portion (sitting above the orbits; see Chapter 13). These brain structures are collectively called the limbic system and are considered in more depth in Chapter 13 (see Figure 13.5). Some limbic system components such as the septal nuclei and the nucleus accumbens (beneath the anterior corpus callosum and caudate head, respectively – see Chapter 13) are also involved in behaviour associated with rewards and punishment.
Neuropathological profile of the pentylenetetrazol (PTZ) kindling model
Published in International Journal of Neuroscience, 2018
E. Samokhina, Alexander Samokhin
The latter study that used classified seizures severity revealed more exhaustive involvement of the brain structures in PTZ kindling [22]. The earliest expression of c-Fos (at stages 1 and 2 of kindling according to Racine's acute seizure scale) was observed in piriform cortex, prefrontal cortex, and striatum. It is certain that striatum, like piriform cortex and prefrontal cortex, is characterized by a low excitation threshold to PTZ in kindling model. These brain structures are important for the propagation of epileptic activity due to their dense projections to other regions of the brain: amygdala, hippocampus, entorhinal cortex, perirhinal cortex, and substantia nigra [23]. At the third stage of kindling, central amygdala nuclei, entorhinal cortex, and lateral septal nuclei had enhanced concentrations of c-Fos. At the fourth stage of kindling, the increase in c-Fos expression was observed in the basolateral amygdala and CA1 region of the hippocampus. Finally, when tonic-clonic convulsions were fully developed, c-Fos labelling was found enhanced in the dentate gyrus.
Two Case Reports of Neuropsychological Functioning in Congenital Insensitivity to Pain with Anhidrosis (CIPA)
Published in Developmental Neuropsychology, 2020
Yanin Santoya-Montes, Karol Gutiérrez-Ruiz, Rodrigo Zequeira Cotes, Pedro Puentes Rozo
NGF-dependent neurons exist in various human brain regions including the basal forebrain (septal nuclei and substantia innominate), the striatum (body and tail of the caudate nucleus, nucleus accumbens, and putamen) and the hypothalamus (Indo, 2014, 2018). Studies have indicated that basal forebrain cholinergic neurons (BFCNs) and striatal cholinergic neurons are NGF-dependent (Cuello, Pentz, & Hall, 2019), and they provide the major cholinergic innervation to the hippocampus, amygdala, and neocortex (Indo, 2018; Mesulam, 2004). Cholinergic circuits are center stage for maintaining and focusing attention, and for normal executive and mnemonic functioning; hence, the loss of cholinergic signaling and cognitive decline are inextricably linked (Ballinger, Ananth, Talmage, & Role, 2016). It is therefore conceivable that cognitive impairments and characteristic behaviors observed in patients with CIPA may be related to defects of BFCNs and other NGF-dependent neurons in the brain (Indo, 2014, 2018).
Hypothalamic-pituitary-adrenal axis activity in post-traumatic stress disorder and cocaine use disorder
Published in Stress, 2020
Natalie A. Hadad, Marek Schwendt, Lori A. Knackstedt
CORT exerts its actions primarily via its two receptors: mineralocorticoid (MR, also known as Type I) and glucocorticoid (GR, also known as Type II). MR is found throughout the limbic system, especially in the hippocampus, whereas GR, although ubiquitous in the brain, is most abundant in hypothalamic CRH neurons and pituitary corticotroph cells (de Kloet et al., 1998; Reul & de Kloet, 1985). There is evidence of MR and GR co-expression in the hippocampus, amygdala, dentate gyrus, lateral septal nuclei, and some portions of the cortex (de Kloet et al., 2005). CORT has a 6- to 10-fold higher affinity to MR than GR (Reul & de Kloet, 1985). As such, approximately 90% of MR are occupied at basal levels of CORT (de Kloet et al., 1999; Reul & de Kloet, 1985). MR regulates basal CORT secretion across the circadiam rhythm and is implicated in the appraisal of, and the intitial response to, stress (de Kloet et al., 1998, 1999, 2005; Herman et al., 2012). In contrast to MR, GR are only occupied after exposure to stress, or at the diurnal peak (de Kloet et al., 1999; Reul & de Kloet, 1985). Stimulation of GR mobilizes energy resources, promotes the synthesis of newly learned information, and mediates the termination of the HPA axis via negative feedback (de Kloet et al., 1998, 1999, 2005; Herman et al., 2012). As such, the MR-GR balance is vital to homeostasis (de Kloet et al., 1998).
Related Knowledge Centers
- Amygdala
- Cingulate Cortex
- Midbrain
- Olfactory Bulb
- Septum Pellucidum
- Frontal Lobe
- Hippocampus
- Medial Septal Nucleus
- Hypothalamus
- Thalamus