Data from a series of brain-behavior experiments utilizing techniques of ablation, ICS, and electrical recording emphasize the importance of the concept of levels of function in understanding behavior. Initiation, performance, and cessation of voluntary behaviors (e.g., walking, manipulating objects) are associated with activation of ascending pathways from the diencephalon to the hippocampus and neocortex. More automatic behaviors (e.g., chewing, emotional expression) are not directly dependent on these pathways, even when they occur as CRs. Electrical recordings indicate that hippocampal activity, in particular, is closely related to behavior. Wave morphology, amplitude, and frequency, are all related to different aspects of concurrent motor activity. Problems of the definition and mechanism of "voluntary" and "automatic" control of movement are discussed. (7 p. ref.)

Evidence is presented to suggest that the hippocampus receives 2 nonspecific inputs from the brainstem, each capable of producing rhythmical slow activity. The neocortex appears to receive 2 similar inputs, each capable of producing low voltage fast activity. One input to both hippocampus and neocortex is blocked by atropine and stimulated by eserine, and is essentially unrelated to concurrent motor activity. A second input to both hippocampus and neocortex is resistant to atropine, is depressed by phenothiazines, and is activated by d-amphetamine. Activity in this system is closely related to concurrent "voluntary" movement.

After surgical removal of the neocortex and hippocampal formation, rats retained most of the movement patterns of locomotion, climbing, grooming, feeding, and fighting. However, forepaw immobility during swimming was abolished. Feeding behavior was suppressed temporarily but recovered partially. The distinctive postures of sleep and waking and a circadian rhythm of motor activity were retained. However, behaviors were often not performed at the appropriate time and place. The normal sequence of grooming behavior was disrupted; food hoarding and social behavior were essentially abolished. Removal of the neocortex alone had much the same effect as removal of neocortex and hippocampus together. Removal of hippocampus alone produced only a mild disruption of behavior. It is suggested that ascending nonspecific projections to the cerebral cortex play an important role in the moment-tomoment control of behavior but are not essential for the sleep-waking cycle.Naturalistic studies of animal behavior have usually emphasized careful description of motor patterns as a first step in the analysis of behavior (e.g., Tinbergen, 1972). Paradoxically, this phase of research has been neglected in laboratory studies of brain and behavior even though the laboratory offers many advantages favoring accurate observation. The importance of close attention to the details of movement and posture has been emphasized by recent evidence that the electrical activity of the hippocampal formation, the neocortex, and the reticular formation exhibits surprisingly detailed relations to concurrent motor activity (

No abstract

FICUBE 4. The effect of an increased delay before shock on avoidance performance in thalamic lesion awtmnla-Both per cent avoidance and time scores are shown. After the 30th trial the delay was increased from 5 to 15 sec. for one group ("5-15"); for the other group ("5-5") it remained at 5 sec. Horizontal dashed lines indicate the points separating avoidance from escape as in Figure 2.