Faculty » Peter W. Hickmott

The organization of local circuitry throughout the brain plays a vital role in processing incoming information and controlling the behavioral responses to this information. This sort of organization has been closely studied in the cerebral cortex, particularly in primary sensory maps or representations. These maps are regions of the cortex that respond to specific sensory stimuli in a spatially organized across the map, in response to various manipulations that affect the activity of inputs to the cortex, and also to behavioral training and other natural stimuli. These sorts of cortical reorganizations are associated with important phenomena, such as recovery of function after stroke and improvements in performance due to sensory training. Furthermore, deficits in the control of cortical plasticity may be related to neuropathies from phantom pain and sensation after amputation to epilepsy to learning disabilities.

My research focuses on the basic cellular and synaptic properties that underlie the organization and plasticity of sensory maps, specifically the primary somatosensory cortex (S1). Ongoing experiments are examining the characteristics of local cortical circuitry with respect to the border between the representations of the forepaw and lower jaw in the normal map, and also in maps where the border regions is reorganized by a peripheral denervation or other change in the activity patterns to this region of cortex. In general, the local circuitry reflects the presence or absence of this border in the properties of excitation and inhibition onto neurons that lie close to the border, and also the morphology of these neurons.  We have recently begun to expand our analysis of circuit dynamics into the aging cortex and into possible effects of inflammation on circuits.  Techniques used in the laboratory include: in vivo and in vitro electrophysiology using extracellular and intracellular recording; analysis of neuronal morphology using standard and confocal microscopy; immunocytochemistry; and antero- and retrograde tracing of connections in the cortex.

Selected Publications

Hickmott, PW & Dinse, HR. (submitted) Effects of Aging on Properties of the Local Circuit in Rat Primary Somatosensory Cortex (S1) in Vitro.

Paullus, JR & Hickmott, PW.  (2011) Diverse excitatory and inhibitory synaptic plasticity outcomes in complex horizontal circuits near a functional border of adult neorcortex. Brain Res. 1416: 10-25.

Paullus JR, Pappademos MS, Nolen AM, Warmus BA, Hickmott PW (2011) Bidirectional axonal plasticity during reorganization of adult rat primary somatosensory cortex. Brain Res. 1387: 46-60.

Hickmott PW. (2010) Synapses of horizontal connections in adult rat somatosensory cortex have different properties depending on the source of their axons. Cereb Cortex. 20: 591-601

Marik SA & Hickmott PW. (2009) Plasticity of horizontal connections at a functional border in adult rat somatosensory cortex. Neural Plast. 2009: 294192. Epub 2010 Mar 3

Steen, PA, Mason, MT, Lefebfvre, Y, Pham, L & Hickmott, PW. (2007) Axonal bias at a representational border in adult rat somatosensory cortex (S1). J.Comp. Neurol. 500: 634-45.

Hickmott PW & Ethell IM. (2006) Dendritic plasticity in the adult neocortex. Neuroscientist. 12:16-28.

Hickmott, PW. (2005) Changes in the intrinsic properties of pyramidal neurons during reorganization of adult rat somatosensory cortex. J Neurophysiol. 94: 501-511.

Hickmott, PW & Steen, PA. (2005) Large-scale changes in dendritic structure during reorganization of adult somatosensory cortex. Nature Neurosci. 8:140-142.

Hickmott, PW & Merzenich, MM. (2002) Local circuit properties underlying plasticity of cortical maps. J Neurophysiol. 88:1288-1301.