1. Ahmed B, Anderson JC, Martin KA and Nelson JC. (1997) Map of the synapses onto layer 4 basket cells of the primary visual cortex of the cat. J Comp Neurol 380:230-42.

NeuronCompartmentPropertyConnectivityNotes
Neocortex V1 interneuron basket PV GABA cellSomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Neocortex V1 interneuron basket PV GABA cellProximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Neocortex V1 interneuron basket PV GABA cellDistal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
SomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Proximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Distal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
Neocortex M1 interneuron basket PV GABA cellSomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Neocortex M1 interneuron basket PV GABA cellProximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Neocortex M1 interneuron basket PV GABA cellDistal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).
Neocortex U1 interneuron basket PV GABA cellSomaGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ).
Neocortex U1 interneuron basket PV GABA cellProximal equivalent dendriteGabafrom other GABAergic interneuronsGABA inactivation of large-basket cells of visual cortex resulted in weakened orientation and direction selectivity, via weakening of long-range lateral inhibition by the basket cells (Kisvárday ZF et al, 20002 ). Most layer 2/3 pyramidal neurons and interneurons received inhibitory input (presumably GABAergic) from neighboring interneurons in layer 2/3 (Dantzker JL and Callaway EM, 20003 ). Analysis of synaptic input to layer 4 basket cells show that 79% of symmetric synapses could have originated from other layer 4 basket cells. Soma and proximal dendrites received 76% of all the symmetric synapses (Ahmed B et al, 19971 ). GABAergic interneurons (basket cells, dendrite-targeting cells, and double-bouquet cells) form reciprocally interconnected intracortical networks in which basket cells play a prominent role, given the strength of innervation and the proximal placement of synapses by basket cells to their postsynaptic targets (Tamás G et al, 19984 ).
Neocortex U1 interneuron basket PV GABA cellDistal equivalent dendriteGlutamatefrom thalmic afferents, layer 6 pyramidal cells, and spiny stellate cellsLayer 2/3 fast-spiking interneurons (most of which are basket cells) received the strongest excitatory input (presumably glutamatergic) from layer 4 (Dantzker JL and Callaway EM, 20003 ). Layer 4 basket cells in cat visual cortex receive excitatory input from neighboring spiny neurons, resulting in large excitatory EPSPs. One third of spiny cell-smooth cell pair were connected reciprocally (postsynaptic targets include local spiny stellate, pyramidal cells, as well as smooth neurons), but the postsynaptic IPSPs evoked by basket cells are slower, GABAergic, probably of GABAA type (Tarczy-Hornoch K et al, 19985 ). Layer 4 basket cells in cat visual cortex receive asymmetric synapses from layer 6 pyramidal (~43%), the spiny stellate (44%) and thalamic afferents (13%) (Ahmed B et al, 19971 ). Dual recording from pyramidal cell-basket cell pairs reveal unitary EPSPs in basket cells mediated by one and two synaptic junctions. The unitary EPSPs have fast rising time and short time duration. Closely timed (10-50 ms) pairs of presynaptic action potentials resulted in statistically significant paired-pulse depression. The reliability of transmission is high, but the fast time course of the EPSPs constrains their temporal summation. Due to the relatively small amplitude of unitary EPSPs several convergent inputs will therefore be required to elicit suprathreshold responses. (Buhl EH et al, 19976 ).

Classical References: first publications on each compartmental property; search PubMed for complete list
1.  Ahmed B, Anderson JC, Martin KA and Nelson JC. (1997) Map of the synapses onto layer 4 basket cells of the primary visual cortex of the cat. J Comp Neurol 380:230-42.
2.  Kisvárday ZF, Crook JM, Buzás P and Eysel UT. (2000) Combined physiological-anatomical approaches to study lateral inhibition. J Neurosci Methods 103:91-106.
3.  Dantzker JL and Callaway EM. (2000) Laminar sources of synaptic input to cortical inhibitory interneurons and pyramidal neurons. Nat Neurosci 3:701-7 [Journal] .
4.  Tamás G, Somogyi P and Buhl EH. (1998) Differentially interconnected networks of GABAergic interneurons in the visual cortex of the cat. J Neurosci 18:4255-70.
5.  Tarczy-Hornoch K, Martin KA, Jack JJ and Stratford KJ. (1998) Synaptic interactions between smooth and spiny neurones in layer 4 of cat visual cortex in vitro. J Physiol 508 ( Pt 2):351-63.
6.  Buhl EH, Tamás G, Szilágyi T, Stricker C, Paulsen O and Somogyi P. (1997) Effect, number and location of synapses made by single pyramidal cells onto aspiny interneurones of cat visual cortex. J Physiol 500 ( Pt 3):689-713.