scholarly journals Large Unresponsive Zones Appear in Cat Somatosensory Cortex Immediately After Ulnar Nerve Cut

1994 ◽  
Vol 21 (3) ◽  
pp. 233-247 ◽  
Author(s):  
Cheng-Xiang Li ◽  
Robert S. Waters ◽  
Akinniran Oladehin ◽  
Eldridge F. Johnson ◽  
Carl A. McCandlish ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Ulnar Nerve ◽  
Afferent Input ◽  
Primary Somatosensory Cortex ◽  
Nerve Transection ◽  
Ketamine Anesthesia ◽  
Stimulation Of ◽  
Immediate Response

Abstract:The organization of the primary somatosensory cortex innervated by the ulnar nerve was studied before and immediately after ulnar nerve transection in 11 cats electrophysiologically mapped under Nembutal or Ketamine anesthesia. The cortex was reexamined a second time beginning 42 hr after nerve transection in four cats anesthetized with Nembutal. One additional sham-operated control was also mapped. The region of cortex formerly served by the ulnar nerve remained largely unresponsive to somatic stimulation independent of the type of anesthetic used during recording. Nonetheless, animals anesthetized with Ketamine had more new responsive sites in deafferented cortex following nerve cut than cats anesthetized with Nembutal. New responses, when observed, were evoked by stimulation of a region of skin adjacent to the region served by the ulnar nerve. These findings suggest that the immediate response to deafferentation of somatosensory cortex is a limited acquisition of novel responses restricted to a region immediately adjacent to cortex containing normal afferent input.

scholarly journals Cutaneous stimulation of the digits and lips evokes responses with different adaptation patterns in primary somatosensory cortex

NeuroImage ◽  
2010 ◽  
Vol 52 (4) ◽  
pp. 1477-1486 ◽  
Author(s):  
Mihai Popescu ◽  
Steven Barlow ◽  
Elena-Anda Popescu ◽  
Meredith E. Estep ◽  
Lalit Venkatesan ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Cutaneous Stimulation ◽  
Stimulation Of

Emergence of Radial Nerve Dominance in Median Nerve Cortex After Median Nerve Transection in an Adult Squirrel Monkey

1997 ◽  
Vol 77 (1) ◽  
pp. 522-526 ◽  
Author(s):  
C. E. Schroeder ◽  
S. Seto ◽  
P. E. Garraghty
Keyword(s):  
Median Nerve ◽  
Squirrel Monkey ◽  
Ulnar Nerve ◽  
Action Potentials ◽  
Radial Nerve ◽  
Current Source ◽  
Short Latency ◽  
Nerve Transection ◽  
A Site ◽  
Stimulation Of

Schroeder, C. E., S. Seto, and P. E. Garraghty. Emergence of radial nerve dominance in median nerve cortex after median nerve transection in an adult squirrel monkey. J. Neurophysiol. 77: 522–526, 1997. Throughout the glabrous representation in Area 3b, electrical stimulation of the dominant (median or ulnar) input produces robust, short-latency excitation, evident as a net extracellular “sink” in the Lamina 4 current source density (CSD) accompanied by action potentials. Stimulation of the collocated nondominant (radial nerve) input produces a subtle short-latency response in the Lamina 4 CSD unaccompanied by action potentials and followed by a clear excitatory response 12–15 ms later. Laminar response profiles for both inputs have a “feedforward” pattern, with initial activation in Lamina 4, followed by extragranular laminae. Such corepresentation of nondominant radial nerve inputs with the dominant (median or ulnar nerve) inputs in the glabrous hand surface representation provides a likely mechanism for reorganization after median nerve section in adult primates. To investigate this, we conducted repeated recordings using an implanted linear multi-electrode array straddling the cortical laminae at a site in “median nerve cortex” (i.e., at a site with a cutaneous receptive field on the volar surface of D2 and thus with its dominant afferent input conveyed by the median nerve) in an adult squirrel monkey. We characterized the baseline responses to median, radial, and ulnar nerve stimulation. We then cut the median nerve and semi-chronically monitored radial nerve, ulnar nerve and median nerve (proximal stump) evoked responses. The radial nerve response in median nerve cortex changed progressively during the weeks after median nerve transection, ultimately assuming the characteristics of the dominant nerve profile. During this time, median, and ulnar nerve profiles displayed little or no change.

Intrinsic discharge patterns and somatosensory inputs for neurons in raccoon primary somatosensory cortex

1994 ◽  
Vol 72 (6) ◽  
pp. 2827-2839 ◽  
Author(s):  
P. J. Istvan ◽  
P. Zarzecki
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Primary Somatosensory Cortex ◽  
Membrane Properties ◽  
Postsynaptic Potentials ◽  
Synaptic Inputs ◽  
Ionic Conductances ◽  
Discharge Patterns ◽  
Intrinsic Membrane Properties ◽  
Stimulation Of

1. Discharge patterns of neurons are regulated by synaptic inputs and by intrinsic membrane properties such as their complement of ionic conductances. Discharge patterns evoked by synaptic inputs are often used to identify the source and modality of sensory input. However, the interpretation of these discharge patterns may be complicated if different neurons respond to the same synaptic input with a variety of discharge patterns due to differences in intrinsic membrane properties. The purposes of this study were 1) to investigate intrinsic discharge patterns of neurons in primary somatosensory cortex of raccoon in vivo and 2) to use somatosensory postsynaptic potentials evoked by stimulation of forepaw digits to determine thalamocortical connectivity for the same neurons. 2. Conventional intracellular recordings with sharp electrodes were made from 121 neurons in the cortical representation of glabrous skin of digit four (d4). Intracellular injection of identical current pulses (100-120 ms in duration) elicited various patterns of discharge in different neurons. Neurons were classified on the basis of these intrinsic patterns of discharge, rates of spike adaptation, and characteristics of spike waveforms. Three main groups were identified: regular spiking (RS) neurons, intrinsic bursting (IB) neurons, and fast spiking (FS) neurons. Subclasses were identified for the RS and IB groups. 3. Neurons were tested for somatosensory inputs by stimulating electrically d3, d4, and d5. Excitatory postsynaptic potentials (EPSPs) were elicited in 100% of the neurons by electrical stimulation of d4, the "on-focus" digit. EPSPs were usually followed by inhibitory postsynaptic potentials (IPSPs). Many neurons (41%) responded with EPSP-IPSP sequences after stimulation of d3 or d5, the "off-focus" digits. 4. Latencies of somatosensory EPSPs and IPSPs were used to determine the synaptic order in the cortical circuitry of RS, IB, and FS neurons. EPSPs with monosynaptic thalamocortical latencies were recorded in RS, IB, and FS neurons. 5. We conclude that precise patterns of neural discharge in primary somatosensory cortex cannot be reliable estimates of sensory inputs reaching these neurons because patterns of discharge are so strongly influenced by intrinsic membrane properties. Ionic conductances governing patterns of neuronal discharge seem almost identical in intact cortex of raccoon, rat, and cat, and in slices of rodent cortex, because similar patterns of discharge are found. The consistency of patterns of discharge across species and types of preparation suggests that these intrinsic membrane properties are a general property of cerebral cortical neurons and should be considered when evaluation sensory coding by these neurons.

Effect of tactile interference stimulation of the ear in human primary somatosensory cortex: a magnetoencephalographic study

2003 ◽  
Vol 114 (10) ◽  
pp. 1866-1878 ◽  
Author(s):  
T Nihashi ◽  
R Kakigi ◽  
M Hoshiyama ◽  
K Miki ◽  
Y Kajita ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Stimulation Of
Sign in / Sign up

Export Citation Format

Share Document