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Neuroanatomy of basic cognitive function
Published in Mark J. Ashley, David A. Hovda, Traumatic Brain Injury, 2017
Mark J. Ashley, Jessica G. Ashley, Matthew J. Ashley
The thalamus is comprised of four groups of nuclei: the anterior, medial, ventral, and posterior.39 The anterior nucleus is a single nucleus that receives its major input from the mammillary nuclei of the hypothalamus and the presubiculum of the hippocampal formation. It is interconnected with the cingulate and frontal cortices and may be involved in memory. The medial nucleus is comprised of the mediodorsal nucleus, which has three subdivisions. Each of these projects to a particular region of the frontal cortex, and input is received from the basal ganglia, amygdala, and midbrain. The medial nucleus is also implicated in memory. The ventral nucleus is comprised of the ventral anterior and ventral lateral nuclei. These are involved in motor control. Input to these nuclei comes from the cerebellum and basal ganglia, and output is to the motor cortex. The ventral posterior nucleus, also part of the ventral nucleus, sends somatosensory information to the neocortex. Last, the posterior nucleus is made up of the medial geniculate, lateral geniculate, lateral posterior nuclei, and pulvinar. The medial geniculate nucleus receives tonotopic auditory stimulus and projects it to the superior temporal gyrus. The lateral geniculate receives information from the retina and projects it to the primary visual cortex.39
Phylogeny, Gene Structure, Expression, and Signaling
Published in Divya Vohora, The Third Histamine Receptor, 2008
Pertti Panula, CongYu Jin, Kaj Karlstedt, Remko A. Bakker
H3R radioligand [3H]Nα-methylhistamine binding is detected through all parts of the hippocampal formation and entorhinal cortex (Jin and Panula, unpublished; Figure 4.4G). The binding is most prominent in the dentate gyrus, high in the subicular complex and entorhinal cortex, and moderate to low in the hippocampal CA1–4 regions. In the hippocampus, H3R binding is prominent in CA1 and distributes in a decreasing order in CA3, CA4, and CA2. Similar to the other cortical areas, a layer preference is observed also in the subicular complex and entorhinal cortex. In the subicular complex, the binding density is high in the deep layer of subiculum and the superficial layers of presubiculum and parasubiculum. In the entorhinal cortex, the binding density is higher in the superficial and deep layers than the middle layers.
The relevance of hippocampal subfield integrity and clock drawing test performance for the diagnosis of Alzheimer’s disease and mild cognitive impairment
Published in The World Journal of Biological Psychiatry, 2019
Dusan Hirjak, Fabio Sambataro, Barbara Remmele, Katharina M. Kubera, Johannes Schröder, Ulrich Seidl, Anne K. Thomann, Klaus H. Maier-Hein, Robert C. Wolf, Philipp A. Thomann
In a further analytic step, hippocampal subfields and adjacent extrahippocampal structures were used for predicting CDT performance. We found that alterations of the whole hippocampus, the presubiculum, the hippocampal fissure, and the parahippocampal gyrus predict impaired CDT performance. The presubiculum is part of the “subicular complex” (Witter and Groenewegen 1990) and located between the subiculum and the parahippocampal gyrus (Lim et al. 2013). It receives input from subiculum and plays a crucial role in a forward projection from subiculum to entorhinal cortex. Although the specific role of presubiculum is not very clear yet, it may be involved in processing of episodic memory (Malkova and Mishkin 2003). In AD, the presubiculum contains high levels of amyloid plaques (Wisniewski et al. 1998). The parahippocampal gyrus is part of the medial temporal lobe and a scene-specific region in the ventral visual stream (Park and Chun 2009). It is involved in declarative memory processing and associated with episodic, spatial and contextual memory as well (Blaizot et al. 2004). The hippocampal fissure is located between the molecular layer of the CA1 and the dentate gyrus (Whelan et al. 2016). The perforant pathway comprising the connections between the neocortex and the hippocampus partially passes through the hippocampal fissure (Bastos-Leite et al. 2006). Because of its small size and complex cytoarchitecture, the segmentation oft he hippocampal fissure is a methodological challenge leading to difficulties when investigating its structure and function (Bastos-Leite et al. 2006). Enlargement of the hippocampal fissure is considered to be an indicator of medial temporal lobe atrophy in AD (Bastos-Leite et al. 2006). One might speculate that structural alterations of the above mentioned regions lead to aberrant hippocampal formation circuit and may be related to visual, spatial and contextual memory skills that are needed in order to draw a clock with digits and two hands (Seidl et al. 2012; Thomann et al. 2008).
Protective role of zinc against the neurotoxicity induced by exposure to cadmium during gestation and lactation periods on hippocampal volume of pups tested in early adulthood
Published in Drug and Chemical Toxicology, 2018
Safa Ben Mimouna, Marouane Chemek, Sana Boughammoura, Zohra Haouas, Imed Messaoudi
Different subregions of the hippocampus, the CA1, CA2, and CA3 fields, derive their names from an even older name for the structure, the cornu ammonis (horn of Amun, an ancient Greek god). Together with the dentate gyrus (DG) and parahippocampal regions, including the subiculum, presubiculum, parasubiculum, and the entorhinal cortex, the hippocampus is thought to play a key role in memory and navigation (Deshmukh et al.2012). In fact, the hippocampus is used for rapid, unstructured storage of information involving activity potentially arriving from many areas of the cortex, while the neocortex would gradually build and adjust on the basis of much accumulating information the semantic representation (McClelland et al. 1995). Within the hippocampus, recent studies have suggested important differences in the function of areas. Indeed, the CA3a,b subregion of the hippocampus plays an important role in the encoding of new spatial information, within short-term memory with a duration of seconds and minutes, novelty detection, and one-trial cued recall (all forms of episodic memory). Also, CA3a,b mediates encoding of information requiring multiple trials to construct relational representations. It should be noted that CA3a,b can also be involved in short-term memory retrieval as evidenced by support for a pattern completion process. Finally, the CA3c function is in part based on modulation of the DG in supporting pattern separation processes and may contribute to pattern separation of the geometry of the environment (Deshmukh and Knierim 2012, Kesner 2007, 2013). The CA1 recodes information from CA3 and sets up associatively learned back projections to neocortex to allow subsequent retrieval of information to neocortex. Behaviorally, the CA1 is implicated in processing temporal information as shown by investigations requiring temporal order pattern separation and associations across time and, computationally, this could involve associations in CA1 between object and timing information that have their origins in the lateral and medial entorhinal cortex respectively (Colgin et al. 2008, Kesner and Rolls 2015).