Neural Activity and the Development of Brain Circuits

Abstract

The development of highly interconnected circuits in the brain relies on patterns of neural activity. These patterns produce a cascade of events that refine initially imprecise connectivity into precise circuits. The presence of neural activity is particularly important during well‚Äźdefined critical periods in early life.

Keywords: visual system; synapse; retinal axons; LTP; critical period

Figure 1.

The primary visual pathway and examples of the activity‐dependent development of brain circuits. (a) Retinal ganglion cells mediating perception of a visual hemifield project their axons to the contralateral lateral geniculate nucleus (LGN). Relay cells of the LGN innervate layer 4 of the visual cortex. (b) Early in development axons from the ipsilateral and contralateral eyes are intermingled in the LGN. Later, axons from the two eyes segregate to form eye‐specific laminae and, shortly thereafter, sublaminae that receive inputs from either ON‐ or OFF‐centre retinal ganglion cells. (c) Similarly, axons from both LGN laminae initially overlap at their target, layer 4 of the visual cortex, and are subsequently refined such that they occupy distinct ocular dominance columns. (d) Maps of the orientation preference of neurons (depicted as shades of blue) in visual cortex show relatively little clustering of neurons with like orientation preferences in early development. As the circuitry matures, maps reveal extensive clustering of similar orientation preferences in a pinwheel‐like organization. (e) Developing pyramidal neurons in the superficial layers of visual cortex extend their axons horizontally in a relatively crude manner, showing little preference for any particular area within their reach. As development proceeds, the axonal arborization is elaborated in areas of similar orientation preferences, and branches are removed from dissimilar areas.

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Further Reading

Constantine‐Paton M and Cline HT (1998) LTP and activity‐dependent synaptogenesis: the more alike they are, the more different they become. Current Opinion in Neurobiology 8: 139–148.

Cramer K and Sur M (1995) Activity‐dependent remodeling of connections in the mammalian visual system. Current Opinion in Neurobiology 5: 106–111.

Goodman CS and Shatz CJ (1993) Developmental mechanisms that generate precise patterns of neuronal connectivity. Cell 72: 77–98.

Hohnke CD and Sur M (1999) Development of the visual pathways: effects of neural activity. Mental Retardation and Developmental Disabilities Research Reviews 5: 51–59.

Hubel DH, Wiesel TN and Levay S (1977) Plasticity of ocular dominance columns in the monkey striate cortex. Philosophical Transactions of the Royal Society of London 278: 377–409.

Kandel ER, Schwartz JH and Jessell TM (1991) Principles of Neural Science, pp. 945–958. Norwalk, Connecticut: Appleton and Lange.

Katz LC and Shatz CJ (1996) Synaptic activity and the construction of cortical circuits. Science 274: 1133–1138.

Sur M, Pallas SL and Roe AW (1990) Cross‐modal plasticity in cortical development: differentiation and specification of sensory neocortex. Trends in Neurosciences 13(6): 227–233.

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How to Cite close
Hohnke, Carsten D, and Sur, Mriganka(Aug 2001) Neural Activity and the Development of Brain Circuits. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0000800]