The amplitude and phase characteristics of an EOD can be manipulated in order to elucidate the receptive fields of the electrosensory neurons of the lateral line lobe. The experiment described above involving the Eigenmannia in a two-compartment chamber apparatus allows researchers to identify the approximate location of the neuron’s receptive field responding to amplitude modulations (Heiligenberg 1987). In order to identify the approximate location of the receptive fields for neurons that are responding to phase modulations, a different, more complicated, strategy must be employed (Heiligenberg 1987). By suspending the fish in a bigger tank and surrounding it with a variety of electrodes that will be used as the jamming signal, the neurons
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Therefore, it has been discovered that the ELL is specialized for processing amplitude and phase modulations from P and T units, respectively (Maler and Rogers 1981). The spherical cells of the ELL receive phase information directly from T units via electrical synapses (Maler and Rogers 1981). This cell though is constrained; it is subject to spatial summation (Maler and Rogers 1981). It will not fire upon input from only one T unit, it must receive synchronous input from various T units converging at the spherical cell at the same time (Maler and Rogers 1981). When this occurs, an action potential is generated. This was determined by a clever experiment in which, a fish was administer just enough anesthesia to disable its EOD (Maler and Rogers 1981). The researchers replaced its EOD with one that they produced and were able to modulate. They then recorded intracellularly at the spherical cell upon different modulations of their mimicked EOD (Maler and Rogers 1981). Low amplitudes of this EOD cause T units (synapsing on spherical cells) to fire sporadically. Therefore, as shown in Figure 4, when T units fire irregularly, no action potentials are generated, but when input arrives in unison, an action potential is produced (Maler and Rogers …show more content…
There are two types of pyramidal cells: basilar and nonbasilar (also referred to as E units and I units) (Maler and Rogers 1981). When amplitudes are high, P units are stimulated to fire action potentials more frequently. This in turn excites both basilar pyramidal cells as well as granule cells (Maler and Rogers 1981). Activation of granule cells in turn causes and inhibitory effect on nonbasilar cells. When amplitude is low, P unit firing rate is also low, and the opposite is observed (Maler and Rogers 1981). Basilar pyramidal cells and granule cells are not excited and therefore, nonbasilar pyramidal cells are released from their inhibition (Maler and Rogers 1981). Therefore, excitation of E units signals increases in stimulus amplitude, while excitation of nonbasilar cells signal decreases in stimulus amplitude (Maler and Rogers 1981). Furthermore, it was discovered that basilar and nonbasilar pyramidal cells have an on center off surround receptive field (Maler and Rogers 1981). That is, basilar pyramidal cells are excited by amplitude increases at the center of their receptive fields, and inhibited by increases in the periphery of their receptive fields (Maler and Rogers 1981). Opposite responses to the same stimulus are found in the center and surround of the receptive field of I
Therefore, it has been discovered that the ELL is specialized for processing amplitude and phase modulations from P and T units, respectively (Maler and Rogers 1981). The spherical cells of the ELL receive phase information directly from T units via electrical synapses (Maler and Rogers 1981). This cell though is constrained; it is subject to spatial summation (Maler and Rogers 1981). It will not fire upon input from only one T unit, it must receive synchronous input from various T units converging at the spherical cell at the same time (Maler and Rogers 1981). When this occurs, an action potential is generated. This was determined by a clever experiment in which, a fish was administer just enough anesthesia to disable its EOD (Maler and Rogers 1981). The researchers replaced its EOD with one that they produced and were able to modulate. They then recorded intracellularly at the spherical cell upon different modulations of their mimicked EOD (Maler and Rogers 1981). Low amplitudes of this EOD cause T units (synapsing on spherical cells) to fire sporadically. Therefore, as shown in Figure 4, when T units fire irregularly, no action potentials are generated, but when input arrives in unison, an action potential is produced (Maler and Rogers …show more content…
There are two types of pyramidal cells: basilar and nonbasilar (also referred to as E units and I units) (Maler and Rogers 1981). When amplitudes are high, P units are stimulated to fire action potentials more frequently. This in turn excites both basilar pyramidal cells as well as granule cells (Maler and Rogers 1981). Activation of granule cells in turn causes and inhibitory effect on nonbasilar cells. When amplitude is low, P unit firing rate is also low, and the opposite is observed (Maler and Rogers 1981). Basilar pyramidal cells and granule cells are not excited and therefore, nonbasilar pyramidal cells are released from their inhibition (Maler and Rogers 1981). Therefore, excitation of E units signals increases in stimulus amplitude, while excitation of nonbasilar cells signal decreases in stimulus amplitude (Maler and Rogers 1981). Furthermore, it was discovered that basilar and nonbasilar pyramidal cells have an on center off surround receptive field (Maler and Rogers 1981). That is, basilar pyramidal cells are excited by amplitude increases at the center of their receptive fields, and inhibited by increases in the periphery of their receptive fields (Maler and Rogers 1981). Opposite responses to the same stimulus are found in the center and surround of the receptive field of I