Space

The representation of space in the brain 2017 a review of place cells, direction cells, grid cells, and their collectively formation of the neural basis of a cognitive map.

• Hippocampus is found, from the study of H.M.(Hery Molaison), to be closely related to physical map, and spatial tasks.
• Place cells - a population uniquely represent entire environment. partially indicated by external cues.
• Head direction cells - fires when heading towards preferred fire direction.
• Grid cells - fire in multiple discrete and regularly spaced locations.
  • involved in path integration.
  • formed by speed cells and band cells.
• Interneurons control their neighbors via short-range inhibitory connections (using GABA). Important to modulate local field potential oscillatory signal.
• Boundary cells - fire when encounters an environmental boundary in that direction.
• Object cells - more active near or around specific objects.
• Goal cells - fire based on distance to the current goal.
• Conjunctive cells - cells associated with integrative processes.
• Movement-or action-sensitive cells - self-motion information.

Memory

Molecular Biology of Memory: A Dialogue Between Genes and Synapses, lecture pdf.

• Problem of memory storage :
  1. (this lecture) the storage component of memory, the molecular mechanism whereby information is stored.
  2. (for further research) the systems component of memory, the mechanisms whereby the storage sites at each point in the explicit or implicit neural system that mediates memory interact to encode, store, and recall memory.
• Molecular Mechanism: used in Aplysia, can be applied for both implicit and explicit memory.
  • synaptic changes:
    • The short-term synaptic changes involve covalent modification of pre-existing proteins, leading to modification of pre-existing synaptic connections.
    • the long-term synaptic changes involve activation of gene expression, new protein synthesis, and the formation of new connections.
  • memory storage:
    • short-term memory storage uses different signaling kinases for implicit and explicit memory.
    • long-term storage of both implicit and explicit memory uses as a core signaling sequence PKA, MAPK, and CREB-1.
  • all are regulated by a number of inhibitory constraints.
• Modulatory transmitters:
  1. they activate secondmessenger kinases that are transported to the nucleus where they initiate processes required for neuronal growth and long-term memory.
  2. they mark the specific synapses for capture of the long-term process and regulate local protein synthesis for stabilization.
  3. they appear to mediate attentional processes required for memory formation and recall.
• The extensive dialog between the synapse and the nucleus and the nucleus and the synapse. In the long-term process the response of a synapse is not simply determined by its own history of activity. It is also significantly determined by the history of transcriptional activation in the nucleus.