Author(s): Grossberg, S. |
Citation: Mathematical Biosciences, 15, 253-285
Abstract: Quantitative neural networks are derived from psychological postulates about punishment and avoidance. The classical notion that drive reduction is reinforcing is replaced by a precise physiological altetAative akin to Miller s ""Go"" mechanism and Estes s ""amplifier"" elements. Cell clusters d} and dj are introduced which supply negative and positive incentive motivation, respectively, for classical conditioning of sensory-motor acts. The dj cells are persistently turned on by shock (on-cells). The dj cells a,re transiently turned on by shock termination (off-cells). The rebound from d} cell activation to d1 cell activation replaces drive reduction in the case of shock. Classicalc onditioning from sensoryc ells .,9?to the pattern of activity playing on arousal cells d I = (dj, dj) can occur. Sufficiently positive net feedback from d I to.,9? can releases ampling, and subsequenlte arning, by prescribe.dc ells in .,9?o f motor output controls. Once sampled, thesec ontrols can be reactivated by .,9?o n recall trials. This concept avoids some difficulties of two-factor theories of punishment and avoidance. Recent psychophysiologicadl ata and concepts are analyzed in terms of network analogs, and some predictions are made. The rebound from dj c~ll activation to dj cell activation at shock termination is interpreted to be a consequenceo f different rates of transmitter accumulation -depletion in the parallel neural channels associated with dj and dj. This interpretation culminates in an analogy with adrenergic and cholinergic interactions at lateral and ventromedial hypothalamic sites, dependent on phasic sensory input and tonic reticular formation input. Mechanisms are suggested for such phenomena as: the i~$5 er rewarding effect of reducing J units of shock to J/2 units than of reducing J/2 units to 0 units; a relationship between the rewarding effect of reducing J units of shock to J/2 units and the possibility of releasing a conditioned avoidance r esponsein the presenceo f fearful cues; two kinds of depressede motional affect, one due to overarousal, that can also be associated with massive associational confusions and poor paying attention, and one due to underarousal, that can also be associated with overreactive fear and relief responses; persistent nonspecific fear that biases interpretation of specific cues, and can ""resist"" new learning or ""repress"" old learning; differente ffectso f graduala nd abrupt shock on responses uppression;r esponse generalizationf rom one shock levelt o another; reductiono f pain in the presenceo f loud noise (analgesia); influences of drugs, such as carbachol, atropine, and scopolamine on conditioned emotional and avoidancer esponsesa, nd on self-stimulation via implanted hypothalamic electrodes; sensory-drive heterarchy that allows changes in situational cuest o releaser esponsesc ompatible with any of severaln onprepotentd rives; feedback inhibition of adrenergic transmitter production; potentiation of adrenergic production by prlesynaptic spiking, and by postsynaptic spiking via a feedback loop that controls higher-order instrumental conditioning; learning at cholinergic synapses.