Cortical-limbic mechanisms and response control: A theoretical review

Abstract

The literature dealing with the behavioral effects produced by lesions of the septum, frontal cortical areas, and the hippocampus is reviewed. It is concluded that the dorsomedial septum, the dorsolateral frontal cortex (and homologous structures), and the dorsal hippocampus form a nodal point within a larger neuronal system that is involved in response regulation. A model describing the response regulatory processes mediated by this frontal cortical-limbic system is proposed. Motor programs are written in frontal cortex and temporarily stored in hippocampus. Feedback stimuli derived from response initiation and maintenance are compared against the stored hippocampal motor program. If the feedback information matches with the expected outcomes dictated by the motor program, the response sequence is terminated. If comparator deviations arise, the frontal cortical areas are signaled of error and a new motor program is written. Hippocampal theta activity is postulated to be a correlate of comparator activation and feedback analysis.

Specific Spatial Defect in a Child with Septo‐optic Dysplasia

“…The question therefore arises whether the spatial defects of our patient with septooptic dysplasia are analogous t o those found in lower-order species with experimentally-induced lesions of the septum. Numan's model, derived from animal data, proposes that the septum functions as part of a re-afferent feedback loop or comparator circuit, by means of which kinaesthetic sensory information from the musculature is compared with movement intentions (Numan 1978). Motor programmes, the model states, are formulated in the pre-frontal cortex and simultaneously transmitted to the peripheral musculature and t o the hippocampus.…”

A match-mismatch theory of limbic system function

“…likely to disturb a number of functions in the reinforcer and habituative systems by virtue of the intermediary role of the septum. One must agree with Numan (1978) that, in the future, researchers must make distinctions between lesions of the lateral and medial septum in order to obtain theoretically useful results. The present theory makes it clear that these two regions are performing very different functions, which achieve unity only in the sense that they are both involved in the exchange of information between two important stimulus-analyzing systems.…”

Hippocampus, space, and memory

“…For example, take the evidence cited by Olton et al that primate hippocampal function differs from that of rats, and evidence cited by Horel (1978) and others (e.g., Iversen 1977; Oscar-Berman, Sahakian and Wikmark 1976;Oscar-Berman and Zola-Morgan 1979a, b;Weiskrantz 1978) about lack of correspondence between nonhuman animal results and those obtained from human bitemporal-iobe patients. (Additional evidence and issues are reviewed by Kinsboume and Wood 1975;Lhermette and Signoret 1976;Isaacson and Pribram 1975;Iversen 1977;Numan 1978;O'Keefe and Nadel 1978;Oscar-Berman and Zola-Morgan 1979a, b;Rozin 1976;and Weiskrantz 1978. ) However, parsimony is appealing, and just as I was intrigued by Kinsboume and Wood's (1975) notion that human amnesics suffer from a reduced ability to use episodic memory in contrast to their intact semantic memory (Tulving 1972), my intrigue was sustained with the analogous dissociation of impaired working memory and normal reference (Oscar-Berman, Goodglass, and Cherlow 1973); they have restricted selective attention (Oscar-Berman and Samuels 1977;Talland 1965), retarded associative learning ability (Oscar-Berman and Zola-Morgan 1979a, b), and decreased sensitivity to changing reinforcement rates (Heyman, Oscar-Berman, Bonner, and Ryder 1979).…”