THIS interesting monograph appears in Dr. J. W. Spengel's “Ergebnisse und Fortschritte der Zoologie.” It gives an excellent account of the structure and mechanism of the central nervous system founded on morphological and physiological facts, as these have been laboriously collected by the most modern methods by which the nervous elements have been examined. The author deals with the plan of reflex mechanisms, he describes the architecture and localisation of the central ganglia and nerve-roots, and his illustrations are drawn from morphological studies of the simpler types. One of the most important sections is No. vii., in which he discusses the functions of the great divisions of the nervous system. Nowhere have we seen a better discussion of the relations and functions of the cerebellum, or a more lucid account of the remarkable deep connections of the auditory nerves. The author has evidently received illumination from the researches and constructive criticism of Sherrington, while, as indicated by a good bibliography, he is acquainted with the literature of this vast subject. The work is a valuable contribution to human and comparative neurology. The Central Nervous System of Vertebrates. By J. B. Johnston. Pp. 170. (Jena: G. Fischer, 1909.)

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The Central Nervous System of Vertebrates

The neuropsychology of anxiety: an enquiry into the functions of the Septo-Hippocampal system, Gray J.A.. Oxford University Press, New York (1981), pp. 523.,£27.50

Neural Circuits of Interoception

Functions of the septo-hippocampal system

Abstract This paper integrates emerging evidence from two broad streams of scientific literature into one common framework: (a) hierarchical gradients of functional connectivity that reflect the brain’s large-scale structural architecture (e.g., a lamination gradient in the cerebral cortex); and (b) approaches to predictive processing and one of its specific instantiations called allostasis (i.e., the predictive regulation of energetic resources in the service of coordinating the body’s internal systems). This synthesis begins to sketch a coherent, neurobiologically inspired framework suggesting that predictive energy regulation is at the core of human brain function, and by extension, psychological and behavioral phenomena, providing a shared vocabulary for theory building and knowledge accumulation.

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Allostasis as a core feature of hierarchical gradients in the human brain

The primeval function of the mammalian hippocampus (HPC) remains uncertain. Implicated in learning and memory, spatial navigation, and neuropsychological disorders, evolutionary theory suggests that the HPC evolved from a primeval chemosensory epithelium. Deficits in sensing of internal body status ('interoception') in patients with HPC lesions argue that internal sensing may be conserved in higher vertebrates. We studied the expression patterns in mouse brain of 250 endocrine receptors that respond to blood-borne ligands. Key findings are (i) the proportions and levels of endocrine receptor expression in the HPC are significantly higher than in all other comparable brain regions. (ii) Surprisingly, the distribution of endocrine receptor expression within mouse HPC was found to be highly structured: receptors signaling 'challenge' are segregated in dentate gyrus (DG), whereas those signaling 'sufficiency' are principally found in cornu ammonis (CA) regions. Selective expression of endocrine receptors in the HPC argues that interoception remains a core feature of hippocampal function. Further, we report that ligands of DG receptors predominantly inhibit both synaptic potentiation and neurogenesis, whereas CA receptor ligands conversely promote both synaptic potentiation and neurogenesis. These findings suggest that the hippocampus acts as an integrator of body status, extending its role in context-dependent memory encoding from 'where' and 'when' to 'how I feel'. Implications for anxiety and depression are discussed.

/pdf/the-interoceptive-hippocampus-mouse-brain-endocrine-receptor-107ps2mmtt.pdf

The interoceptive hippocampus: Mouse brain endocrine receptor expression highlights a dentate gyrus (DG)-cornu ammonis (CA) challenge-sufficiency axis

The primeval function of the mammalian hippocampus (HPC) remains uncertain. Implicated in learning and memory, spatial navigation, and neuropsychological disorders, evolutionary theory suggests that the HPC evolved from a primeval chemosensory epithelium. Internal sensing deficits in patients with HPC lesions argue that internal sensing may be conserved in higher vertebrates. We studied the expression of 250 endocrine receptors in mouse brain. Key findings are (i) the proportions and levels of endocrine receptor expression in the HPC are significantly higher than in all other comparable brain regions. (ii) Surprisingly, the distribution of endocrine receptor expression within mouse HPC was found to be highly structured: receptors signaling ‘challenge’ are segregated in dentate gyrus (DG), whereas those signaling ‘sufficiency’ are principally found in cornu ammonis (CA) regions. Selective expression of endocrine receptors in the HPC argues that internal sensing remains a core feature of hippocampal function. Further, we report that ligands of DG receptors predominantly inhibit both synaptic potentiation and neurogenesis, whereas CA receptor ligands conversely promote both synaptic potentiation and neurogenesis. These findings suggest that the hippocampus acts as an integrator of body status, extending its role in context-dependent memory encoding from ‘where’ and ‘when’ to ‘how I feel’. Implications for anxiety and depression are discussed.

/pdf/the-interoceptive-hippocampus-mouse-brain-endocrine-receptor-3qrj4b63q9.pdf

The interoceptive hippocampus: mouse brain endocrine receptor expression highlights a dentate gyrus (DG)–cornu ammonis (CA) challenge– sufficiency axis

Sheena Singadia

Papers

The interoceptive hippocampus: Mouse brain endocrine receptor expression highlights a dentate gyrus (DG)-cornu ammonis (CA) challenge-sufficiency axis

The interoceptive hippocampus: mouse brain endocrine receptor expression highlights a dentate gyrus (DG)–cornu ammonis (CA) challenge– sufficiency axis