Walter H. Riege

Cerebral metabolic relationships for selected brain regions in healthy adults

The local cerebral metabolic rate for glucose was determined in 26 regions of the brain in 31 healthy subjects who underwent resting fluorodeoxyglucose positron emission tomography. Intercorrelations among the 26 regional measures were accepted as reliable at p < 0.01 (r > 0.45), uncorrected for the number of measures. From the matrix two apparently separate functional metabolic systems were identified: (1) a superior system involving the superior and middle frontal gyri, the inferior parietal lobule, and the occipital cortex; and (2) an inferior system involving the inferior frontal, Brocas, and posterior temporal regions. Evidence is presented to suggest that the superior system is involved in visual processing, memory recognition, and decision making, while the inferior system seems to at least participate in language-related functions.

Cerebral Metabolic Relationships for Selected Brain Regions in Alzheimer's, Huntington's, and Parkinson's Diseases

Local CMRGlc values were determined for 13 regions in each hemisphere from tomographs of patients with Alzheimers, Huntingtons, and Parkinsons diseases who were studied using [18F]fluorodeoxyglucose with positron emission computed tomography. Intercorrelations among the 26 regional measures were calculated for each disease state and for normal controls, and were accepted as reliable at p < 0.01, uncorrected for the number of comparisons. The number of reliable correlations was found to be decreased in Parkinsons and Huntingtons diseases, two primarily subcortical disorders, and increased in Alzheimers disease, a primarily cortical disorder. The changes suggest that one role of the basal ganglia involves coordinating or pacing the ability of cortical brain regions to function as a unit.

Correlations of glucose metabolism and structural damage to language function in aphasia

Studies of aphasic patients using [18F]fluorodeoxyglucose positron computed tomographs have shown areas of metabolic depression in the left hemisphere larger than the area of infarction noted on CT. To evaluate these metabolic differences in relationship to language abnormalities, 11 patients had metabolic scans, CT, and were administered the Boston Diagnostic Aphasia Battery and the Porch Index of Communicative Ability. Correlation analyses were computed between metabolic, CT, and language data. CT demonstrated reliable correlations of speaking, oral reading, and repetition to Wernicke area, consistent with current anatomic language models, while metabolic data from areas posterior, inferior, and superior to the traditional Wernickes area and the head of the caudate nucleus also had reliable correlations with aphasic language function. The utilization of both structural and metabolic brain measures may improve our understanding of the anatomy of language as related to aphasia.

The course of chronic aphasia

Abstract Little is known about the long term recovery or stability of aphasia following brain injury. Thirty-five male stroke patients were studied repeatedly from 3 to 55 months post-onset with the Porch Index of Communicative Ability (PICA) in order to follow improvement in each of five previously extracted factors (speaking, writing, comprehension, gesturing, and copying) across the five-year span. Patients were grouped into one of four categories based on a previous analysis of 118 patients. PICA overall score increased over the first year, became asymptotic in the second year, and either remained level or declined in the third and fourth years post-onset. Language factors showed differential changes with the greatest improvement in speaking. Different categories of patients showed different patterns of change over time. Ten patients had greater than an 11% PICA overall decline beyond the second year. They were among those with the mildest aphasias. Reasons for decline included: change in health statu...

One-Trial Learning and Biphasic Time Course of Performance in the Goldfish

Goldfish (N = 408) spontaneously swam against flowing water into a calm-water well. After a single trial punished by brief electric shock, the fish avoided the well, as indexed by increased latencies of reentry. Avoidance declined during the first minute after shock, then rose to a peak 1 hour later. The biphasic time course is compatible with the two-store theory of memory formation.

Specificity of Memory Deficits in Alcoholism

Inferences of specific impairments in memory from prolonged abuse of alcohol have come from initial studies reporting that visuospatial memory and problem solving were impaired but verbal memory and learning were not. The apparent specificity, however, is demonstrated to be an artifact of the more difficult visual tests. With task complexity increased, impairments are shown also in both learning and recall of words, story, or designs. A common condition for deficits to be detected is the demand for effort in encoding and retrieving of to-be-remembered information. In general, deficits are mild and diffuse and do not seem to be clearly specific to material or modality. Furthermore, deficits are more pronounced in old alcoholics, although these tend to have longer drinking careers. Age and length of abstinence are more significant predictors of impairment than length or rate of alcohol drinking; however, concomitant disease and familial history of alcoholism are recognized to contribute to wide differences in effort-requiring memory processing.

One-trial learning in goldfish: temperature dependence.

Abstract Goldfish (N = 2260) learned to suppress their spontaneous upstream swimming into a calm-water well, after a single trial punished by brief electric shock. Memory of this suppression was dependent upon water temperature (10°, 20°, or 30°), shock level (6, 9, 12, or 24 V), and test interval after shock (0.33-1024 min). During the first 16 min, retention increased with temperature and less so with shock. Retention declined to low levels 1024 min after the shock. A biphasic pattern of retention, with a dip at 1 min after shock, was observed at 10° with 24-V shock and at 20° with 6, 9, or 12-V shock but not under conditions of high temperature or shock. The biphasic dip is interpreted as reflecting the partial overlap of two phases of memory formation.

Factor-derived categories of chronic aphasia ☆

Abstract A large sample of patients with aphasia ( N = 118), unselected for etiology, were administered the Porch Index of Communicative Ability more than 6 months after the onset of aphasia. Factor analysis of PICA subtest scores identified five factors which accounted for 83.9% of the total variance. The factors were labeled speaking, writing, comprehension, gesturing, and copying. Cluster analyses of the factor scores yielded five patient categories which differed in the pattern of impairment on the language factors as well as in overall severity of aphasia. A subgroup of the parent sample consisting of 52 patients with localized left-hemisphere CVA had cluster analyses repeated after having first been studied as part of the larger sample. The factor-derived categories for the subgroup were similar to those of the entire group. Discriminant functions of the PICA raw scores of the 52-patient subsample correctly classified all of the patients. When discriminant functions were based upon the factor scores of the 118-patient parent sample, 80.7% of the 52 patients were correctly classified into the five categories.

Retroactive facilitation of memory in goldfish by flurothyl

The spontaneous upstream swimming of goldfish (N=1318) into a quiet well was suppressed in one trial by electric shock (2.0 V/cm). Independent groups of fish, at 25‡ C, retained this learned avoidance 1, 4, 16, and 64 h after training but not 256 h after training. When trained fish were treated, 3 min after training, with a 16-min exposure to convulsive solutions of flurothyl (Indoklon®), their retention of avoidance 16, 64, or 256 h later was facilitated. This retroactive facilitation (RF) of long-term memory in goldfish by flurothyl could not be attributed to proactive or aversive effects of the treatment. Goldfish treated in water saturated with carbon dioxide (80% CO2∶20% O2) showed retrograde amnesia (RA). Neither the RF from flurothyl nor the RA from CO2-treatment were diminished when training and treatment were given to goldfish at 20‡ or 15‡ C. The memory-enhancing effect of flurothyl convulsions, and its delayed onset, may relate to the dual stimulant-depressant action of the drug and differ from the RA effect reported for mice and chicks.

Retrograde enhancement of memory in goldfish by a time dependent temperature shift

Abstract Goldfish (N = 1528) at 25°C were trained to suppress their spontaneous upstream swimming into a quiet well in a single trial punished by brief electric shock. After graded delays of 4–1024 min the trained fish were cooled abruptly to 10°C, held at 10°C for graded durations of 0.07–960 min, then rewarmed abruptly to 25°C and held at 25°C. Brain temperature followed the abrupt water temperature shift within 60 sec. Retention of the learned suppression, tested 1, 2, or 4 days later, was enhanced compared to retention by trained controls held at 25°C throughout. The enhanced retention was an inverted-U function of the delay of cooling and of the duration at 10°C. Enhancement occurred only when the rewarming step fell within a sensitive period of 12–96 min after training, with a maximum at approximately 36 min, regardless of the delay to cooling or duration at 10°C. Cooling per se was not essential for enhancement of retention; the critical factor was the interval between training and rewarming. The time-dependent enhancement may result from one or more temperature-sensitive memory processes that were suppressed at 10°C, then stimulated above normal by return to 25°C.