Hippocampal storage and recall of neocortical “What”–“Where” representations

Hippocampus, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 2, 2024

Abstract A key question for understanding the function of hippocampus in memory is how information recalled from to neocortex. This was investigated a neuronal network model hippocampal system which “What” and “Where” firing rate vectors were applied separate neocortical modules, then activated entorhinal cortex dentate gyrus, CA3, CA1, cortex, backprojections showed that whole could be trained recall neocortex as retrieval cue neocortex, principle up towards theoretical capacity determined largely by number synapses onto any one neuron divided sparseness representation. The synaptic weights imported into an integrate‐and‐fire simulation same architecture, time presenting module approximately 100 ms. sufficiently fast backprojection still active neurons during storage episodic memory, this needed operate correctly These simulations also long loop neocortex–hippocampus–neocortex operates continuously may contribute complete neocortex; but positive feedback makes dynamical inherently liable pathological increase activity. Important factors contributed stability included increased inhibition CA3 CA1 keep rates low; temporal adaptation synapses, are proposed make important contribution stabilizing runaway excitation cortical circuits brain.

Language: Английский

---

A Theory and Model of Scene Representations With Hippocampal Spatial View Cells

Hippocampus, Journal Year: 2025, Volume and Issue: 35(3)

Published: April 28, 2025

ABSTRACT A theory and network model are presented of how scene representations built by forming spatial view cells in the ventromedial visual cortical pathway to hippocampus primates including humans. Layer 1, corresponding V1–V4, connects 2 retrosplenial area uses competitive learning form feature combination neurons for part being fixated, a fixation patch. In 3, parahippocampal hippocampus, patches stitched together whole representations. This is performed with continuous attractor made from overlapping Gaussian receptive fields as head rotates scene. addition, gain modulation gaze direction maps correct representation when saccades made. Each neuron 3 thus cell that responds location viewed based on features The novel conceptual advances this shows may be primates, humans, scenes anchor world (to allocentric, world‐based, space); contributes this. offers revolutionary approach understanding navigation episodic memory

Language: Английский

---

The memory systems of the human brain and generative artificial intelligence

Heliyon, Journal Year: 2024, Volume and Issue: 10(11), P. e31965 - e31965

Published: May 24, 2024

Generative Artificial Intelligence foundation models (for example Pre-trained Transformer - GPT models) can generate the next token given a sequence of tokens. How this 'generative AI' be compared with 'real' intelligence human brain, when for generates whole memory in response to an incomplete retrieval cue, and then further prospective thoughts? Here these two types generative intelligence, artificial machines real brain are compared, it is shown how memories generated by hippocampal recall what computes, computes it, very different from AI. Key differences use local associative learning rules system, non-local backpropagation error Indeed, argued that operation performed computationally differently implemented Moreover, emphasized primate including system includes computations about spatial view where objects people scenes, whereas rodents emphasis on place cells path integration movements between places. This comparison processing has interesting implications development AI neuroscience research.

Language: Английский

---

Slow semantic learning in the cerebral cortex, and its relation to the hippocampal episodic memory system

Cerebral Cortex, Journal Year: 2025, Volume and Issue: 35(5)

Published: May 1, 2025

Abstract A key question is how new semantic representations are formed in the human brain and this may benefit from hippocampal episodic memory system. Here, we describe major effective connectivity between system anterior temporal lobe (ATL) humans. Then, present model a theory of be ATL using slow associative learning attractor networks that receive inputs The hypothesis if one category being processed for several seconds, then short-term trace biologically plausible rule will enable all components during time to associated together network. This benefits binding provided by modeled four-layer network view-invariant visual object recognition, followed layer utilizes form categories based on occur close time, or world.

Language: Английский

---

Visual cortical networks for “What” and “Where” to the human hippocampus revealed with dynamical graphs

Cerebral Cortex, Journal Year: 2025, Volume and Issue: 35(5)

Published: May 1, 2025

Abstract Key questions for understanding hippocampal function in memory and navigation humans are the type source of visual information that reaches human hippocampus. We measured bidirectional pairwise effective connectivity with functional magnetic resonance imaging between 360 cortical regions while 956 Human Connectome Project participants viewed scenes, faces, tools, or body parts. developed a method using deterministic dynamical graphs to define whole networks flow both directions their over timesteps after signal is applied V1. revealed ventromedial “Where” network from V1 via retrosplenial medial parahippocampal scene areas hippocampus when scenes viewed. A ventrolateral “What” V2–V4, fusiform face cortex, lateral region TF faces/objects There major implications computations vs rodent navigation: primates fovea highly processing process about location objects, landmarks whereas rodents representations system mainly place where individual located self-motion places.

Language: Английский

---

Selective activations and functional connectivities to the sight of faces, scenes, body parts and tools in visual and non-visual cortical regions leading to the human hippocampus

Brain Structure and Function, Journal Year: 2024, Volume and Issue: 229(6), P. 1471 - 1493

Published: June 5, 2024

Connectivity maps are now available for the 360 cortical regions in Human Connectome Project Multimodal Parcellation atlas. Here we add function to these by measuring selective fMRI activations and functional connectivity increases stationary visual stimuli of faces, scenes, body parts tools from 956 HCP participants. Faces activate ventrolateral stream (FFC), superior temporal sulcus (STS) face head motion; inferior parietal (PGi) somatosensory (PF) regions. Scenes ventromedial VMV PHA parahippocampal scene area; medial (7m) lateral (PGp) regions; reward-related orbitofrontal cortex. Body cortex object (TE1p, TE2p); but also motion (MT, MST, FST); (PGi, PGs) unpleasant-related Tools an intermediate ventral area (VMV3, VVC, PHA3); (FST); (1, 2); auditory (A4, A5) The findings maps; show how other related their associations, including motion, somatosensory, auditory, semantic, value-related,

Language: Английский

---

A ventromedial visual cortical ‘Where’ stream to the human hippocampus for spatial scenes revealed with magnetoencephalography

Communications Biology, Journal Year: 2024, Volume and Issue: 7(1)

Published: Aug. 25, 2024

Abstract The primate including the human hippocampus implicated in episodic memory and navigation represents a spatial view, very different from place representations rodents. To understand this system humans, computations performed, pathway for view information to reach was analysed humans. Whole-brain effective connectivity measured with magnetoencephalography between 30 visual cortical regions 150 other using HCP-MMP1 atlas 21 participants while performing 0-back scene task. In ventromedial stream, V1–V4 connect ProStriate region where retrosplenial area is located. has VMV1–3 VVC. These medial parahippocampal PHA1–3, which, VMV regions, include area. have entorhinal cortex, perirhinal hippocampus. contrast, when viewing faces, more through ventrolateral stream via fusiform face cortex inferior temporal TE2p TE2a. A ‘Where’ scenes supported by diffusion topography 171 HCP at 7 T.

Language: Английский

---

Selective Brain Activations and Connectivities Related to the Storage and Recall of Human Object‐Location, Reward‐Location, and Word‐Pair Episodic Memories

Human Brain Mapping, Journal Year: 2024, Volume and Issue: 45(15)

Published: Oct. 15, 2024

ABSTRACT Different cortical systems to the hippocampus were activated using fMRI during different types of episodic memory task. For object with scene location memory, activations high in involved spatial processing, including ventromedial visual and medial parahippocampal system. These for system higher right hemisphere. The face processing ventrolateral stream regions FFC, PIT, V8 TE2p object‐location task than reward‐location task, also hippocampus, but selectively storage key reward (ventromedial prefrontal 10r, 10v, 10d; pregenual anterior cingulate d32, p24, p32, s32; orbitofrontal cortex reward‐related pOFC, 11l, OFC). word‐pair lower stream, language‐related Broca's area (44, 45, 47l), left hemisphere these many highly connected inferior frontal gyrus Further, effective connectivity analyses tasks showed that direction was from early V2–V4 VMV1–3 VVC processing; hippocampal system; FFC/V8/PIT temporal cortex, which has lateral TF, turn forward hippocampus.

Language: Английский

---

Hippocampal Discoveries: Spatial View Cells, Connectivity, and Computations for Memory and Navigation, in Primates Including Humans

Hippocampus, Journal Year: 2024, Volume and Issue: 35(1)

Published: Dec. 17, 2024

Two key series of discoveries about the hippocampus are described. One is discovery hippocampal spatial view cells in primates. This opens way to a much better understanding human episodic memory, for memory prototypically involves where people or objects rewards have been seen locations "out there" which could never be implemented by place that encode location rat mouse. Further, valuable navigation using vision and viewed landmarks, provide richer, vision-based, than self-motion update performed rats mice who live dark underground tunnels. Spatial thus offer revolution our functions humans other primates with well-developed foveate vision. The second describes computational theory hippocampal-neocortical system includes only quantitative how information recalled from neocortex. It shown foundations this research were reward neurons food reward, non-reward, primate orbitofrontal cortex, representations value including monetary cortex; face identity expression inferior temporal visual cortex they represent transform-invariant information. illustrates order understand brain computation, whole integrated interdisciplinary needed build operation each neural system.

Language: Английский

---

Oligomer sensitive in-situ detection and characterization of gold colloid aggregate formations observed within the hippocampus of the Alzheimer’s disease rat

Neuroscience Letters, Journal Year: 2025, Volume and Issue: unknown, P. 138218 - 138218

Published: March 1, 2025

Language: Английский

---