Attention and memory trials during neuronal recording from the primate pulvinar and posterior parietal cortex (area PG).

Cynomolgus monkeys were trained on a delayed match-to-sample (DMS) task. Several controls were performed for the separation of memory effects from other factors such as attention, stimulus attributes and eye movements. One of the controls employed a standardised sequence of events ('window trial') during which a window in a black screen was opened and a face, an object or a picture was presented. Unit cell activity was recorded from 209 sites in the posterior parietal cortex (area PG) and 186 sites in the pulvinar. Some units responded during the presentation of the DMS stimuli, mostly those in that part of area PG located in the superior temporal sulcus. They often appeared to be related to the task-related state of attention. There was no indication of pure memory-related changes in activity such as sustained responses during the inter-stimulus interval or specific responses to the second stimulus that would indicate a dependence on the kind of the preceding stimulus. In the window trial, some parietal units, mostly in that part of area PG located in the intraparietal sulcus (a region termed area LIP), responded in a relatively specific manner during and sometimes even after, the presentation of a human face. The responses often seemed to be related to the animal's state of attention. Almost no pulvinar unit responded in this paradigm. It is concluded that area PG and, to a lesser extent, the pulvinar are involved in the modulation of attention in relation to behaviourally relevant changes in the environment. If these structures have a role in memory function, it must be secondary to a role in controlling or regulating attention.

Multicentric double-blind study comparing efficacy and safety of minaprine and imipramine in dysthymic disorders.

This multicentre study compares the therapeutic efficacy and safety of minaprine (200 mg) to that of imipramine (50, 75, 100 mg) in the treatment of patients over 40 years suffering from dysthymic disorders as diagnosed according to DSM III. After 4-7 days on placebo, 67 patients were randomly assigned to receive either drug for a period of 6 weeks in a double-blind manner. As rated by the Hamilton Depression Rating Scale and evaluated by exploratory statistics, minaprine showed similar efficacy to imipramine in these patients. Minaprine was better tolerated than imipramine according to the physicians' tolerance rating (p < 0.05) and produced significantly fewer symptoms of the autonomic nervous system as compared to imipramine (p < 0.01).

[Tetrazepam in the treatment of acute cervical syndrome. Randomized double-blind pilot study comparing tetrazepam and placebo]. / Tetrazepam in der Behandlung akuter Zervikalsyndrome. Randomisierte doppelblinde Pilotstudie zum Vergleich von Tetrazepam und Plazebo.

METHODS: In a double-blind study, 20 ambulatory patients with acute painful restriction of mobility of the cervical spine and overall marked impairment were treated for seven days with tetrazepam (150 mg or a lower dose from the third day onward) or placebo. Paracetamol was permitted in addition if required. Test criteria: The main criterion of efficacy was a summed score of three parameters: pain, restriction of mobility, and general impairment. RESULTS: The difference between the groups was statistically highly significant (p = 0.005). Tolerability was adjudged to be "very good" for the placebo group, and, on average, "good" for the tetrazepam group.

Functional comparison of neuronal properties in the primate posterior hippocampus and parahippocampus (area TF/TH) during different behavioural paradigms involving memory and selective attention.

Monkeys were trained on a delayed match-to-sample (DMS) task. In addition a standardized behavioural trial was performed which involved an experimenter approaching the animal in certain sequence and presenting edible or other objects ('raisin trial'). Neuronal activity of 617 units was recorded in the posterior parahippocampus (PH) and in the posterior hippocampus (H). In many cases, we compared the activity of the same neuron in different tasks. 32.7% of the 455 PH neurons and 28.5% of the 130 H cells responded during the presentation of the visual stimuli in the DMS task. These responses were only mildly influenced by the physical dimensions of the visual stimulus, but often depended on the context in which the stimuli were presented. There was no differential response to the second stimulus that clearly depended on the nature of the first stimulus. 6.2% of the PH units, but none in H, responded in relation to the reward. 4.4% of the PH neurons, but none in H, showed a mild response during the interstimulus interval. 38.1% of 215 PH neurons and 37.8% of 45 H cells responded during one or more phases of the raisin trial. These responses were not related to the physical dimensions of the sensory stimuli. 210 PH and 41 H units were investigated during the DMS task as well as during the raisin trial. 18.1% (PH) and 12.2% (H) of the units responded during the DMS task, but not during the raisin trial; 17.1% (PH) and 36.6% (H) responded vice versa. A response in both trials was found in 17.1% of the PH neurons, but in none of the H cells. There were also other PH unit types showing responses during different aspects of the DMS task and even in other control paradigms, while no such overlap was encountered in H. Our results suggest a function of H and PH in the evaluation of the behavioural significance of sensory information. It may be this aspect which leads to anterograde memory disturbances after lesion of these areas. Since representation of neuronal information was found to be more specific in H, a possible function as an 'evaluation index' is discussed.

[Importance of the hippocampus and parahippocampus with reference to normal and disordered memory function]. / Zur Bedeutung von Hippocampus und Parahippocampus hinsichtlich normaler und gestörter Gedächtnisfunktionen.

For decades there have been differing, partly controversial ideas concerning the function of the hippocampus. They were newly stimulated by the discovery of the widespread neocortical connexions of the adjacent parahippocampus, which itself is closely interconnected via its anterior part with the hippocampus. All theories have in common that they conceive these areas to be sites for the integration of complex information. However, some of the observations regarding their role in various memory functions are very contradictory. The present article gives a survey of the current state of knowledge concerning anatomy, physiology and pathophysiology of these cerebral areas. It appears that hippocampus and parahippocampus play a significant part in the regulation of selective attention and expectation. Thus they might also influence the process of comparison and valuation which modulates the access to neocortical associative information stores.

Unit activity in the hippocampus and the parahippocampal temporobasal association cortex related to memory and complex behaviour in the awake monkey.

Monkeys (Macaca fascicularis) were trained on a delayed match-to-sample (DMS) task using delays of upto 20 s. Unit activity was recorded from the hippocampus and the temporo-basal association cortex in the lateral parahippocampal region (partly corresponding to TF and TH) during the DMS task, as well as during a visual object discrimination task and some behavioural situations involving the experimenter. Units were encountered that gave visual responses which were sometimes context-dependent. Changes in discharge rate during the delay period of the DMS task were very rare and when present, very weak. On the other hand, many neurones, including some of those which were unresponsive during the DMS task fired vigorously (or were inhibited) during situations which involved attention, expectation or food consumption. For example, the neurones' firing rate was altered when the cage door was opened or closed, the experimenter entered or left the room or showed the monkey a piece of food before giving it to him. A variety of such responses in complex behavioural situations were seen, sometimes even in neurones which did not respond in the DMS task. Activity changes in neurons of the temporo-basal cortex thus appear to be related to the internal state associated with a stimulus and even some of the responses obtained in the DMS task can be interpreted as being related to changes in the behavioural state rather than to the mnemonic elements of the task.